Wow. I wasn't expecting that. The final point about exporting 6-9pm instead of 4-7pm is a great one. If you want to feel better about the numbers, work out the annual EV mileage and compare that to equivalent ICE vehicle CO2 emissions.
@@TimAndKatsGreenWalk Living in rural Cumbria, dispensing with the ICE completely would limit my travel range so severely that I would need to add hours to any significant journey. I just looked into replacing my diesel with a hybrid petrol model of the same model, then discovered that even the oldest models of the hybrid are subject to the government's "luxury tax" for another 2 years, effectively adding another cost on top of the depreciation in value. I'm kicking the can on that idea down the road for those 2 years. In the mean time, what about extending the range of an EV with an extra battery pack in a trailer, with those batteries participating in energy arbitrage when at home!?
As always Tim, an interesting video. I would like to add one point, you include the electricity you use to charge the car, that is used external to your house and is a replacement for petrol / diesel. Therefore I would say you should include the CO2 you offset from using those kWh to run the car.
@ yup, that was my first thought too. Then I could account for the offsetting of not using an ICE car for the miles we drive in the EV as a separate calculation.
Very good analysis. It's the Carbon Intensity of our energy usage that is of prime importance for a survivable world . . . . while our society is utterly fixated on money values.
Indeed. There are ways of aligning those two goals (by paying a good export rate at times of high grid carbon intensity, for example) but it's not quite there yet, as I suggested near the end of the video with the Flux tariff paying the most for export before the peak in carbon intensity.
Whilst true, we are fortunate that renewables are cheaper than fossil fuel sources of energy. If this weren't the case, I expect we would likely be doomed as a species. As you'd never be able to convince the money men to sacrifice short term profits in order to do the right thing long term.
This is all very in depth! Loving the spreadsheet. Those carbon intensity figures must have taken a bit of tracking down. Shame about the results, but you are certainly doing better on this than most of us. 🙂 Interesting note about the tariffs too
Thank you. There are several different sources for this sort of data but I ended up using the one that was easiest to download in one big chunk. It actually goes right back to 2009, so there's the possibility of some interesting historical analysis too. It also comes with the generation mix for each half hour so you can really go down some rabbit holes if you were so inclined. I'm glad this data is available though, it's an interesting thing to investigate. And you're right, we're actually doing pretty well, all in all, I'm pretty pleased about that.
That carbon intensity API is absolutely a pain for regional. If I would try to do the same thing, I would need the regional data, because South Wales often seems to be significantly dirtier than everywhere else, sadly.
Yeah, it was a total pain getting anything other than national data, which is why I did it that way! There must be another good source of regional data that's easier to obtain.
The South Wales intensity is really interesting. On the one hand it's unfair - it gets penalised in regional data because Pembroke power station is one of the biggest and most efficient gas fired stations in the country and in a really strategic position so it runs a lot. It's not south Wales' fault that Manchester and Liverpool consume lots of power and National Grid can't get their act together in bringing more power out of Scotland (though it would then get soaked up by Birmingham in the regional methodology) On the flip side, Wales hasn't exploited its renewable resources anywhere near as much as Scotland has, doesn't want pilons running north/ south and environmental purists could argue the new electric arc furnaces should go to where the green power is, despite Port Talbot desperately needing the jobs. It's a really difficult social / environmental challenge.
@@TimAndKatsGreenWalk Only took an hour or so to sort all the data. Import 341kgCO2, export 305kgCO2 on electricity from similar solar/battery to yourselves. Unfortunately another bit of maths on our gas usage (heating, water and hob) gives me an extra 2,400kg of CO2!
Amazing analysis as per usual. One point on the comparison with a gas boiler - a combi boiler consumes about 200 watts (it varies though) so that would widen the CO2 intensity gap between the two technologies.
We had an extension built. A few years back and specced it with double insulation, been slowly working through the house upgrading including this year the roof. The UFH i had installed on the ground floor goes off around March April and start up again October/ November Since having the roof done the upstairs radiators are off most of the time and it wil be interesting to see how much less i use on heating next year. I put this because even if you have a gas boiler UFH on the ground floor and double insulation especially from under the floors is a game changer
Very interesting Tim. I'm not sure why you are looking at the grid’s carbon intensity at the time your export is made rather than the intensity of where it came from (overnight import or the roof). Your export to the grid at that high intensity period came from low intensity sources. There just aren't enough of us doing this time shifting (yet) for it to register at the national level of intensity. I appreciate I may have completely missed the point or misunderstood your logic or both!! Keep it up.
By exporting at times of high grid carbon intensity I'm offsetting some of that generation by replacing it with low carbon energy (from my roof, for example), so I'm affectively preventing that same amount of carbon from entering the grid. So I measure what I take from the grid at the relevant time and then offset that with what I send back at a different time. It doesn't matter that it's a tiny amount. It's a bit hard to explain, but I hope that makes sense.
Really interesting, thank you. My heat pump was due to be installed next week but has been postponed until March due to, amongst other factors, the fact that it's being funded by a tax free lump sum from my pension and the chancellor created a stampede for pension withdrawals by bringing pensions within scope of inheritance tax and I'm stuck in the resulting queue. Still, I will be switching an 18 kW from radiator gas central heating boiler to 4 kW underfloor heat pump heating and my goal is to become carbon negative in my retirement. From your analysis it seems that investing in Ripple's next wind farm might be necessary to achieve this, otherwise low carbon imports in winter are not possible. I also do energy arbitrage on Octopus Flux and my net electricity bill last week (excluding the standing charge) was 10p, which is remarkable for January, but I am sure that my CO2 footprint will have been horrendous as there has been very little wind. I think a really good way to lower our carbon footprint would be to reduce or eliminate our overnight import during spring and summer, but still export to grid during the evening peak. That way we know that our carbon import is being minimised and our exports are building carbon credit.
Ah, dang, I hope you make it to the front of the queue soon. Very exciting though, that'll be great once you've got your heat pump installed. I'm interested to see how the summer goes, if I stay on Go it'll still make more sense to import overnight, but I'll probably shift to exporting a bit later since the export rate for Go is flat through the day.
What if you charge your EV on the 'Greener Days' when it is windy? Is that accounted for here? We only need to charge ours once a week most weeks. Another factor is that the grid will get greener each year, so it is only going to get better.
Yes, that would help a bit, for sure. It's not always practical and the effect would be relatively small since we don't do many miles, but it would help if we could manage it.
Home assistant tracks this continuously for me. Despite having a smaller array, and battery, I imported just over 70% “Low carbon”, and generated another 20% myself. So 10% of my usage was fossil fuelled (and of course Drax is a bit more again). Not sure how valid it is to rate your solar export as “grid average” - that’s purely carbon neutral, and exports from your battery have already had their carbon content calculated on import, so I think you’re double counting there as well. Oh, and since 30% of my usage was EV… that’s offsetting diesel as well.
I think that's the only reasonably way to do it. Or at least the regional grid average (although as mentioned that data was a pain to get hold of, so I used national instead).
Your winter, blue line, export looks to be in line with the carbon intensity peak. Summer's peak was later. So for max carbon offsetting, perhaps your export window should slide left and right with the time of year, in pace with the solar day? Interesting content as usual.
Yes, exactly, that would be the ideal, and if I stick with Octopus Go this summer I'll do just that. But Flux/IOF has a peak export rate from 4-7pm, so you wouldn't get the best export rate by shifting your export later in the summer. I think Octopus should have a carbon minimisation tariff with the peak export rate following the peak of the carbon intensity, but I doubt they'll do that as it won't align with the peak of the grid price. But you never know!
I have another roof that is NW facing that i am thinking of adding some panels it will only fit 6 panels on but that will help. Looking at trying to get low voltage startup so that it does its best. This will help yearly average but not this time of year. I am on IOG and randomly was exporting later - mainly because the SOC% in my battery stats is so unreliable. So that was handy. Now if I could just persuade my wife to let me put some vertical panels on the wall that faces SW ! That would then pick up the low sun at this time of year (and work when the others are covered in flipping snow/ice). Jan has been a hopeless generation month gloomy so much of the time - today again. Looking forward to seeing what you come up with. You did mention Ripple awhile ago which seems and easy win. I would also like more battery as with no solar in the day we do run out sometimes. But a hit of extra £7k is impossible to square financially. Maybe V2G will be mainstream soon. Got a lovely 70kWh battery sat on the drive !
Haha! I'm sure your wife can be persuaded. I did wonder about adding panels to the walls but I don't think we'll need that as we've got a fair bit more roof we can use. As it happens we do have a small amount of Ripple investment in the new solar farm but that's not generating just yet, so it'll be interesting to see how that affects things when it starts up later this year. V2G really will be a game changer if it ever gets off the ground in a meaningful way. Let's hope so.
Interesting analysis thanks Tim and particularly the sumer vs winter curves. Makes sense when you explain them, but not what you’d immediately think of. Flux is looking increasingly disappointing as a tariff, 13.6p day-rate export, notably less than the 15p fixed export rate. I ran the numbers and whilst the 27.4p peak export is of course better, overall I don’t think I’ll save much given the import rates are comparatively high. And as you say the fixed export rate gives opportunity to export in a more carbon positive way. I generate about 2-3,000kWh more than I consume so probably for me the figures would show I’m more carbon neutral. I have recently just swapped to Agile Outgoing for the winter as the only times I export are in DFS sessions and this gives a higher export income. I’ll swap back when the heating is required less and I can start exporting excess solar again, but its an interesting experiment to try
I got rid of Flux back in the summer for the reasons you state and just went to Economy 7. My array is mainly East facing so it's hard to get much export in the peak period. Was only on it a couple of months (managed to have an argument with Octopus overcharging me because my meter thought the cheap hours were 01:00 -> 08:00 instead of 00:00 -> 07:00) and then got an EV so moved to the tariff for that. Have now changed electricity import and solar export to E-On Next because it's cheaper through the day, longer night hours and better export rate of 16.5p.
I'm probably also going to forego Flux this summer and stick with Go, probably. I think my rule of thumb will show it's pretty close in either case and sticking with Go will save me having to switch, which despite being relatively easy usually comes with a bit of hassle, for one reason or another.
@@TimAndKatsGreenWalk I have pretty much made the same decision to stay with Agile (and 15p export) this summer as well as I did last year. From the analysis I did there was very little in it, and the higher Flux import rates put me off. I did try enrolling with IOF as your rule of thumb suggested it would be the most beneficial to me given our generation to consumption ratio, but Octopus can’t cope with having two inverters on one account, the IOF enrolment process fails.
Another thought... I'm guessing you charge your storage batteries from the grid at times, probably more so in the winter. GivEnergy quote a round trip energy (RTE) efficiency of 93% for their batteries. I don't know whether this includes losses at the inverter or not, I haven't checked. That means energy is 'wasted'/consumed in charging from the grid then using or exporting that energy at a later point in time. Have you factored this in to your estimates in any way? Would it be worthwhile doing so if the data is available? Thanks for the video btw, it's proving to be better brain exercise than most on YT!
That's another good point, yes, although the data I'm using is the meter data from Octopus, so it's everything that goes in and out of our home. So in that sense the carbon neutrality of it (or otherwise) is well defined as the net between the two. The consumption value is the one that would be affected by those losses you mentioned, I agree, so effectively we're consuming slightly more than is strictly necessary compared to if we instead used all our energy directly from the grid. So I expect our consumption would really be a bit lower than the 7,800 kWh I showed in the video, as that includes the charging and discharging losses. You can get a rough approximation of those losses by seeing the difference between the total you charge the battery and the total you discharge the battery over a given window (see my latest stats video as an example where I show that at about 12:32: ruclips.net/video/sWMZaNi-lRI/видео.html ). Although I suppose if the consumption value is lower then so would the import value. It's all very confusing.
@@TimAndKatsGreenWalk It is indeed very confusing! I think it's safe to assume all energy put in to the batteries is subject to a 7% loss if the RTE is 93%. This is regardless of whether it comes from the grid or from self generation. So if you know, or can approximate, how much energy is put in to the batteries you can work out the equivalent carbon intensity of that 'lost' energy (I think). If you exported all excess solar to the grid, there wouldn't be a 7% loss. If you import energy from the grid to charge the batteries then there is a 7% loss. Obviously this doesn't take account of cleverly importing energy when the carbon intensity of the grid is low and exporting when it's high, which you did suggest was something you might try and would result in a lowered carbon footprint. All other things being equal that is. On a more general note, I know there are many reasons for having battery storage, but they can and probably do represent a positive contribution to increased carbon intensity in many use cases. Many people with batteries think of maximising the financial benefit by importing when energy is cheap and exporting when more expensive. If batteries are used in that way, then their use may well contribute towards moving us away from carbon neutrality rather than towards it. Now I wish I hadn't have thought that thought!
@CazBag I think as long as batteries are charged overnight it's hard for them to end up adding carbon to the grid overall, unless they're deliberately discharged at other times when the grid is very low carbon too. But it would need some careful analysis, as you say! I think I'll park that one for the time being.
Hi, I added generation to my house by buying Ripple Energy shares. As I charge my battery for 7p overnight and ripple pays 6.3p per unit generated by the wind farm, I effectively pay 0.7p per unit. This also reduces my carbon intensity but I haven’t gone into this level of detail to know exactly how much I use.
I've also got a bit of Ripple investment (the solar farm) but it's not online yet, so that'll help a bit when it starts generating (hopefully this year some time).
It is worth also noting that you are carbon neutral because of REGO. As octopus adds your load to the 100% carbon neutral side of the generation. The dirty side of the grid comes from people not using 100% renewable energy suppliers. Also you need to treat your car separately as the diesel offset makes a difference.
I'm not sure I agree with the argument that just because I'm on a 100% green tariff that I can claim to be carbon neutral. The grid doesn't send me only renewable power, it'll be whatever the current mix is. I personally think claiming certain tariffs are 100% green is a bit misleading, really, we all get the same power mix at the end of the day. The point about the car is a good one, though, a couple of others have mentioned that and I think I need to do a follow-up video on that subject at some point.
While what you say is true REGO creates demand for more renewables on the grid. This directs corporate investment in the desired direction. Without it our desire for renewables couldn’t be communicated to investors.
@@pmac6584 oh yes, I agree about that part completely. I'm not saying it's not a great idea, it is. Encouraging investment by showing a demand for renewable power is very valuable. But I'm not going to claim I consume only renewable power from the grid for the purposes of this particular study.
Any idea why carbon intensity and cost don't line up? I thought the theory was that when there is peak demand then gas was used (because its expensive and easy to turn on/off) which is high intensity.
It's a good question and I'm not really sure. I will have to delve a bit deeper into the generation mix data to see what I can find out. My hunch is that the solar generation in the mid afternoon is keeping the carbon intensity lower than it otherwise would be even with higher demand, and that as the solar dies away the gas proportion increases even as the overall demand falls a bit into the later evening, causing the carbon intensity to rise. That's my suspicion anyway.
Great video again! A lot of battery and hydro will be exported to cover demand during the peak, which may reduce the carbon at peak time. While you may reduce your own carbon offset, you wouldn't reduce the overall grid carbon, because now a bit more gas now needs to be burned at peak, to cover you exporting later. Continuing to export after 7pm would be the only way I think you would have an effect, rather than just shifting your export, because you may prevent more gas being burned and then recharge with excess night wind.
Honestly I’d have approached this as two separate calculations and graphs - one GMT and one BST to account for seasonal drift. I get you combined these but it does, for me at least, make untangling the impact and where positive changes could be made more difficult. The annual figures do, as you say, largely cancel out but I’d have liked to have had seasonal summaries. Not sure I’m explaining myself clearly as to where my aim diverges from what you said.
I accounted for the clock change in the analysis, so all the numbers are correctly aligned with the time as it was on any given day. And I did show a seasonal split, that was the explanation for why my assumption was wrong. By all means process the data how you see fit! I provide the link to it in the description.
@ yes, I was mostly thinking of avoiding an annual overall calculation and just doing a season - you compared both together to get your annual which is different.
Is there not a distinct probability that the peak carbon generation is after peak demand *because* tariffs encourage selling back to the grid during peak demand? Selling it later could well flatten out the carbon curve but quite possibly wouldn’t reduce overall carbon use across the system.
That's a good question. At the moment I'm not sure there's enough domestic exporting to really have a significant effect on the carbon peak, but I'd be interested to see if there have been any studies into this. Regardless, the more domestic solar/battery export there is the lower the grid carbon intensity will be overall, so it's all good.
Batteries are exporting in the peak to assist the ramping in of gas as the sun goes down and demand goes up. It's possible grid scale batteries are therefore helping reduce the carbon intensity in this period too, not just domestic.
For comparison you should add the theoretical carbon intensity of the house consumption, assuming you had purchased electricity straight from the grid and not had solar and battery. That should give you a baseline to compare your carbon savings against - I suspect that number will be considerably higher than 399.9 kgCO2
when comparing the winter carbon intensity peak to the summer one, have you taken into account the time changes with BST? the winter peak is still 1730-1800....
@@TimAndKatsGreenWalk Thanks, interesting how it's so much later in summer. If I add battery and stick on IOG, I will force discharge depending on carbon intensity, not just the 1600-1900 slot I was going to assume....thanks Tim!
@@justinjoanknecht3475 yes, indeed it's quite a surprising result. I think it's due to the higher solar generation in summer suppressing the grid carbon intensity in the early evening, and so effectively pushing that peak back later. If I stick with Go this summer I'll do exactly that too.
It's high time Hinkley Point C was online. Many things are out of the consumers control sadly. Governments and suppliers have been too slow over the last decade to decarbonise. The rest of us are doing what we can, but facts are facts.
To be fair, 10 or so years ago coal made up over 40% of our grid mix and is now 0% so a fair achievement. In contrast, wind has gone from 3.9% to over 26%. This has meant the the carbon intensity has more than halved from 467g/kWh to 180g (MygridGB). Agree Hinkley is taking too long and more could be done (homes were meant to have been net zero back in 2016 under the old "Code for Sustainable Homes") but progress is being made so there are positives out there!
@@steve_787 absolutely, every year the grid becomes noticeably greener, so in a few more years I won't have to work so hard to get to net zero, even without extra generation!
Tim Isn't the export carbon intensity reduced by you and people like you exporting to the grid. You need to use the higher figure to calculate the saved export figure. I'm not sure if this data is available in order to do the calculation?
Ah, interesting thought. I have no idea how to go about assessing this effect but my suspicion is that it's pretty small right now. It'd be nice to know the total amount of domestic export though, I'll keep my eye out for any good sources of data on that.
Great thoughtful video. i think making your own household carbon neutral on those terms may not be particularly good for the UK? Its Energy market is trying to persuade you to do things with price signals, so perhaps we could assume their most efficient take on carbon neutrality needs you to accept a personal carbon budget that 'appears' to be a bit more carbon intensive than you'd like? We all operate within a bigger system etc... indeed there are times when it probably makes sense for UK to export greenish energy to somewhere in Europe where horribly carbon intensive energy would otherwise be being used. Wouldn't be great for UK carbon intensity.. but would be great for the planet? So this is good news for you financially as everyone's best interest is served by you looking after yourselves financially..
It's certainly true that in general green energy tends to be cheap and dirty energy tends to be expensive, so price signals do help, for sure. But not always perfectly, as I demonstrated in the last part of the video where the high export rates don't necessarily coincide with the highest carbon intensive grid power.
Very interesting, i cant get solor because we are on the shaded side if a mountain, but having an ev, ive been thinking about time shifting my energy via carging up battries overnight at thd 7p tarrif rate and using it in the day time. My house uses an average of 8kw a day, rearly it oeaks at just umder 10kw. So i was thining of a 15kw battery. My usage is not taking into acount of the car. And id not jave the car touch the battery. I dont see the point, only downsides doen that route. Only over xmas did i stsrt thinking about this, so its going to be my project for 2025. All the ore packed options are far to expensive. You can do it for far cheaper with a little know how and alot of research. Also this way tou knek haoe to service your own equipment. Which for me is always the best way to go.
Batteries get cheaper every year, and they only save you money if you can use most of the capacity as often as possible, so don't buy more than you need right now. I'd go for a 10kWh battery and ensure you can add more easily if you need it later.
@TimAndKatsGreenWalk I agree, this is why I'll be using a hybrid inverter, that will have the opportunity to grow in the future, with either PV or wind. Then I'd then be looking at increasing battery capacity and selling it back at the optimal times just like your doing yourself. But at the moment I'm just looking at tying to put a system together for the cheap price. If you can make this really affordable, and then get a government grant behind this for OAPs, this could quarter the cost of their electricity bill, with a single one off winter fuel payment. Saving them more money than they ever have before. And it could help if all these household battery packs could help balance the grid when needed, instead of the grid having to pay millions to peko factories to turn on for two hours at at time. I started thinking about this for my own bills. And I've gone down a rabbit hole where there could be a business in this, where all parties win. there isn't a company that offers an out of a box system at a cost that makes it make sense to the majority of people. The gateway is blocked by cost. I've been looking at the cost of batteries, the. The cost of producing the batteries yourself, that's a 4x savings, investors in the UK are priced wildly. But direct from China (Who produces the ones sold in the UK), 2-3x savings. I'm yet to look into BMS system, but that's the basic outline of what you need. (Mostly). I think it can be done. We could bring a package together, and the pest part, when youre communicating and collaborating with Chinese companies, they will keep you in the loop, bring to every decision, good or bad, to make and sign off on. These guys, get a bad name in the world, but they work hard, work well and value the customer and will produce.
@@robinbennett5994 10kw would scrape it, but just like your phone and your car, for longevity you don't want to fill it and drain it every day. I'd have my 15kw battery utilise about 80% of it. This should increase its lifespan a lot.
@@StephenButlerOne I was thinking that if you usually use 8kWh, then 80% of a 10kWh battery would be about right. You'd probably need a spreadsheet to calculate the relative effect of needing to buy a little full-price power for a few days per year, vs the cost of the extra battery.
A few thoughts - 1) 400 odd kg of CO2 for all heat, power and transport is amazing - I'm not sure what the national average is these days, but I suspect it's at least 10x that. 2) is your solar export during the day before the evening peak skewing down your average export "carbon credit" value? 3) I question the methodology - your importing and exporting is impacting marginal generators, not average intensity. This is almost always CCGTs with a near-flat carbon intensity. I'd argue you can only claim better if you're relieving a grid constraint (unlikely where you live I'd suspect - solar isn't constrained at midnight or 4pm). On the export side, you can only improve on CCGT levels of imported carbon if you are pushing diesel gensets and OCGT down, so in very high demand (usually winter) hours - this is certainly not every evening. Basically, I'm a contrarian and think batteries domestically are a bad idea today: embedded carbon is huge; they're not providing frequency response and other grid services in the way utility scale batteries do and they aren't saving any carbon by increasing CCGT generation at one hour and reducing CCGT on another - indeed they're net consumers, adding to total demand. This will change over time and domestic batteries will have environmental purpose when we reach California levels of duck curves, but that's not the case today. If carbon is your motivation, it could be interesting to control the battery on Agile with variable export pricing, not Go. I suspect you'd force export a lot less and battery ROI would take a major hit. You'll also be tempted to shiver your way through the dunkleflaute!
1) yes, that is pretty good, I'm definitely pleased with that, but I thought I was doing better! 2) yes, it all contributes to the effect I measured with a lower than expected export intensity 3) I disagree. I've heard that argument before and although I see the logic I don't think it's the fair way to do it. It would suggest load shifting has no effect on grid carbon intensity but that is definitely not true, since if you increase demand when it's windy, for example, you can prevent curtailment of wind farms and thus help reduce the grid carbon intensity overall. So if load shifting works then by definition you can't claim that it makes no difference when you import or export. Another way to think about it: it can't possibly be true that every household in the country is using marginal power (with high carbon intensity) at any given time, that's ridiculous, so therefore the only fair way to assess an individual's contribution is by taking the overall average. And if you make that argument for consumption then you necessarily have to make the same argument for export, i.e. taking the overall average is the only fair way to do it. I hope I've explained that well enough. I can definitely see the argument you make, but every time I think about it (which is more often that you'd imagine!) I come down on the side of using the overall average rather than marginal levels.
I can see the argument, but how would you ever reach the threshold at which batteries can have enough aggregate effect to stop gas or diesel generation if you don't start installing them from a low base? And as Tim says, we already curtail wind energy all the time that could be soaked up by more battery demand. I don't think Octopus would be building their business model around these incentives if they hadn't modeled and projected this stuff forward into the future.
@ I think both rebuttals bring forward fair points. Despite what I said, I will be getting a hybrid inverter and batteries with my solar install this year, for instance, but primarily because it saves multiple install visits and will give me more MPPT's for my complicated roof structure, which would otherwise require more string inverter spend which will be obsolete when the batteries start adding environmental value. However, based on marginal dispatch, I don't expect the battery to be of any real carbon benefit until 2027-ish. I think my point is that you can't operate your batteries for maximum ROI and then expect it to produce carbon optimal outcomes, and regarding the point about Octopus - I don't think what they've done is wrong; creating business models for people to incentivise early adoption and bring capacity online that will have long term benefits. I just think that selling based on environmental benefits today is a bit disingenuous. Overall, I think Tim's methodology is consistent - it helps in some ways, it hinders in others (e.g. not taking full carbon credit for solar displacing CCGT).
Hi Octopus only use Renewables generated electricity which must mean your starting point is wrong re co2 imported and export ? This is a statement on octopus web page The carbon footprint for a typical British home using a year's worth of electricity at the national average was 574kg of CO2 per year in 2022 -23. The same electricity for Octopus Energy customers had a carbon footprint of 0.
That's not really how it works though is it, they buy enough green kwh on the market to cover what they sell. But in reality, the energy we fill our batteries with overnight on a calm day is not coming from solar or wind.
So I guess in summary those of us with batteries etc, are buying cheap dirty electricity at night and selling expensive green electricity during the day?
It's a fiction that any given consumer can receive entirely renewable energy. The grid doesn't send you specific generation. So I don't think it's valid for me to claim I receive zero carbon electricity from Octopus.
@@TimAndKatsGreenWalk I agree , but it’s no different to charging a battery at night and offsetting it with exporting the battery in the day or exporting solar after charging the battery
@@markreynolds8050 yes, but we also consume the power from that charged battery, so that results in emissions if that power was not totally renewable. Hence needing more generation to cover it.
The carbon intensity figures you're using appear to be per kWh of generation, whereas your usage figures are presumably meter reads, ie consumption. I believe average line losses (transmission+distribution) in the UK are around 8%. If 8% is roughly correct for your area, that means that for each kWh of imported energy you consume your carbon intensity figure needs to be multiplied by 1/0.92, as more energy is generated than you will read at your meter. There is also a line loss related to export, though this should be lower than 8%. You may have already factored this in, apologies if I've missed where you've done that. If you haven't then your calculations are somewhat mixing apples and pears and unfortunately put you further away from carbon neutrality than you have estimated.
Ah ha! I found the definition of the CARBON_INTESITY column for the dataset I used. "The carbon intensity of electricity is a measure of how much Carbon dioxide emissions are produced per kilowatt hour of electricity consumed." As taken from this page: www.neso.energy/data-portal/historic-generation-mix/historic_gb_generation_mix So I think what I did was ok.
@@TimAndKatsGreenWalk Ah yes, so the carbon intensity data must be adjusted for losses in some way. Agreed, what you did was okay for imported energy, not sure about exported though as that will be a generation figure I guess? I've no idea how it could be quantified either!
@@CazBag well, anything I export will be used by my neighbours, effectively reducing their consumption by the same amount. So I think that's all good too.
@@TimAndKatsGreenWalk What you export will reduce the load on the local transformer supplying you and your neighbours, which then has a ripple effect all the way back up and through the network. In that sense, the energy you export doesn't really get used by your neighbours, but it does contribute towards lowering total generation. It's difficult to put any numbers on it to quantify the contribution and therefore the effect on overall carbon intensity. The kWh you export are generation and not consumption though. Does that make a material difference? Still no idea! Sometimes things are best kept simple, that I do know!
Hold on Tim. You are with Octopus aren't you? They give you green electricity. I know that the grid where you are connected to comes from arguably anywhere so you've looked at average grid figures for percentage of carbon etc but it looks like you are not accounting for Octopus offsetting sources so they can claim to give you green electricity. So arguably you are carbon neutral when combined with Octopus's efforts.
I don't really agree with the argument that "100% renewable tariffs" really mean you're using exclusively renewable energy. All that means is it's a signal to investors that there's a demand for green power and so more investment is made for the future resulting in a gradually greener grid. Another way to think about it: If I buy renewable power someone else effectively receives dirtier power because there's less green available for them. So I don't believe it's right to claim I'm green by doing that as it's not really changed anything for the grid mix as of that day.
@@TimAndKatsGreenWalkOctopus buys electricity from green sources like wind, solar, and hydro and they also buy green REGO certificates and energy directly from UK green generators. Effectively they offset their balance by trading origin certificates. It's not made up it's traceable in their FMD (fuel mix disclosure report).That's how they can claim when you buy electricity off them you are paying for green electricity. Of course they don't send only green electrons down the wires to you because of the grid but as all the electricity you are buying is 100% green and your money ends up paying green sources then you too are 100% green if you follow the money. That is in fact the only sensible calculation you can make. You can't apply average grid source balance figures to your local situation as you have done, although I can see what you are trying to do, because you are not evenly connected across the entire grid. You are locally connected and unless you are the district network operator you won't have a clue where your actual electrons come from. It all depends on the active generators in your area and the local loading. If you live next door to a nuclear power station then all your grid electricity is likely to come from there (shortest path of least resistance) but you might have an active local solar, wind or battery farm and it might come from there but then again you don't know the local loading situation which might have all the green electrons gobbled up by the local arc smelting works and in fact your local area has power dumped into it from hundreds of miles away possibly France. You just don't know so your actual source balance could be entirely different to the average grid balance figures you've used rendering your personal calculations meaningless because you are not evenly connected to the whole grid - you have a unique local situation. You'd need load and distribution figures off your DNO coupled with district feed figures from National Grid and that would be far too difficult to do. Using the grid averages is a flawed approach for that reason and can't even be said to be approximate as you are not an average grid consumer either. Everyone is different and uniquely connected. The only sensible and thankfully easy way is to follow the money and accept that Octopus sell you green electricity. It's a certificated and traceable system. Congrat's you are carbon neutral 😃👍
Take this to the extreme and imagine every consumer in the UK signs up to a 100% renewable tariff. By your logic that means the whole UK grid is magically 100% renewable and so everyone can claim to be carbon neutral. That is clearly nonsense, the grid still has non-renewable generation in the mix. Claiming that buying credits is equivalent to actually generating green power is something I consider to be Greenwashing, and so I'll never use the argument that just because Octopus is selling me ostensibly 100% renewable energy I can claim to be carbon neutral. I did mention that I used the national average because it was a pain to get regional data. Although as it happens our region is often quite similar to the national average anyway so I consider that to be a reasonable compromise. And in any case it didn't really matter for the purposes of the message I was trying to convey with this video - that you can change your carbon impact by changing the times you import and export to/from the grid.
@@TimAndKatsGreenWalkThat's not really a logical argument because 100% of customers can't be Octopus customers and Octopus claim 100% green sourcing at the same time. That wouldn't be possible under the audited REGO scheme administered by Ofgem which provides guarantees of origin. There's only so much green to go round You've nabbed your bit well done. If the scheme didn't work you could make a complaint to the advertising standards authority and ultimately sue Octopus for misselling. Good luck with that! In any case following the money through the scheme is better than your unknown local sourcing and loading situation and trying to apply an incompatible national average as I have explained. Your general push to be greener of cause I applaud and the discussing of it stimulates thought and innovation.
I may be missing something but your solar generated kWh is zero carbon. The biggest fact is the reduction of what you have used from the grid. Again the strategy used by us to get paid for more export actually causes us to use more and increase our CO2 levels. If you stopped importing to the battery and exporting it, your CO2 would be lower.
Anything I import to the batteries leaves more solar to export, so that doesn't really matter, as long as you're charging the batteries at times of low carbon (i.e. overnight) then you'll be reducing the grid carbon intensity overall. If I don't import to the batteries overnight then I'd have to use my solar myself instead, and therefore wouldn't be helping reduce the grid carbon intensity by exporting at times of high carbon. So I don't believe that importing and exporting to/from the batteries increases the carbon intensity.
@@TimAndKatsGreenWalk I totally agree as I am doing the same, but my big point is the more that we import the higher our CO2 will be. For me the the zero carbon solar would reduce the amount of kWh imported. We are just in this strange but good moment that we have a way of buying at 7p and selling at 15p. Best for the pocket but not the CO2!
I still disagree with that in some situations though, if you import overnight at 50gCO2/kWh and then export that same power back out when the grid is at 200gCO2/kWh then you prevent 150gCO2/kWh net being needed (ignoring conversion losses etc.). Your import may be higher but so is your export, and the result is that the net difference in CO2 is beneficial, not detrimental. As I showed at the end of the video if you can target your export at the peak of the carbon intensity curve in the summer (between 6pm and 9pm, say) then you're definitely helping to reduce the carbon intensity of the grid by utilising your batteries. Although I agree that if all you're doing is exporting back at a time when the grid carbon intensity is similar to when you imported it then that doesn't help at all.
![Felix "Unfair" | [Stray Kids : SKZ-PLAYER]](http://i.ytimg.com/vi/Oswujxm2Ag0/mqdefault.jpg)
Wow. I wasn't expecting that. The final point about exporting 6-9pm instead of 4-7pm is a great one.
If you want to feel better about the numbers, work out the annual EV mileage and compare that to equivalent ICE vehicle CO2 emissions.
Yup, that is a great point and I think calls for a follow-up video at some point. A good excuse for another spreadsheet!
@@TimAndKatsGreenWalk Living in rural Cumbria, dispensing with the ICE completely would limit my travel range so severely that I would need to add hours to any significant journey. I just looked into replacing my diesel with a hybrid petrol model of the same model, then discovered that even the oldest models of the hybrid are subject to the government's "luxury tax" for another 2 years, effectively adding another cost on top of the depreciation in value. I'm kicking the can on that idea down the road for those 2 years. In the mean time, what about extending the range of an EV with an extra battery pack in a trailer, with those batteries participating in energy arbitrage when at home!?
Nerd spreadsheet, that's all I needed to hear...i'm in! 🤓
Glad to hear it!
As always Tim, an interesting video. I would like to add one point, you include the electricity you use to charge the car, that is used external to your house and is a replacement for petrol / diesel. Therefore I would say you should include the CO2 you offset from using those kWh to run the car.
That's a good point actually, I'll have to have a think about how to do that. Shouldn't be too hard to do.
Could also exclude the car charging electricty from the calculation - which is probably easier to do?
@ yup, that was my first thought too. Then I could account for the offsetting of not using an ICE car for the miles we drive in the EV as a separate calculation.
Very good analysis. It's the Carbon Intensity of our energy usage that is of prime importance for a survivable world . . . . while our society is utterly fixated on money values.
Indeed. There are ways of aligning those two goals (by paying a good export rate at times of high grid carbon intensity, for example) but it's not quite there yet, as I suggested near the end of the video with the Flux tariff paying the most for export before the peak in carbon intensity.
Whilst true, we are fortunate that renewables are cheaper than fossil fuel sources of energy. If this weren't the case, I expect we would likely be doomed as a species. As you'd never be able to convince the money men to sacrifice short term profits in order to do the right thing long term.
This is all very in depth! Loving the spreadsheet. Those carbon intensity figures must have taken a bit of tracking down. Shame about the results, but you are certainly doing better on this than most of us. 🙂 Interesting note about the tariffs too
Thank you. There are several different sources for this sort of data but I ended up using the one that was easiest to download in one big chunk. It actually goes right back to 2009, so there's the possibility of some interesting historical analysis too. It also comes with the generation mix for each half hour so you can really go down some rabbit holes if you were so inclined. I'm glad this data is available though, it's an interesting thing to investigate. And you're right, we're actually doing pretty well, all in all, I'm pretty pleased about that.
Great explanation, Tim.
Great video, thanks. Would be interesting to see an annual update on this as the grid becomes more renewables based.
Yup, it's changing quite quickly at the moment so I suspect it'll be very different next year.
That carbon intensity API is absolutely a pain for regional. If I would try to do the same thing, I would need the regional data, because South Wales often seems to be significantly dirtier than everywhere else, sadly.
Yeah, it was a total pain getting anything other than national data, which is why I did it that way! There must be another good source of regional data that's easier to obtain.
The South Wales intensity is really interesting. On the one hand it's unfair - it gets penalised in regional data because Pembroke power station is one of the biggest and most efficient gas fired stations in the country and in a really strategic position so it runs a lot. It's not south Wales' fault that Manchester and Liverpool consume lots of power and National Grid can't get their act together in bringing more power out of Scotland (though it would then get soaked up by Birmingham in the regional methodology)
On the flip side, Wales hasn't exploited its renewable resources anywhere near as much as Scotland has, doesn't want pilons running north/ south and environmental purists could argue the new electric arc furnaces should go to where the green power is, despite Port Talbot desperately needing the jobs.
It's a really difficult social / environmental challenge.
I look forward to your plans for increasing your generation.
I hope it works out.
Dammit. Now you've suggested it I have to do this 😆
Haha! It's quite a fun little project, mind, I'm sure you'll enjoy it.
@TimAndKatsGreenWalk Just one more energy usage spreadsheet... this will be the last one... honest!
@@MethodicalMark haha!
@@TimAndKatsGreenWalk Only took an hour or so to sort all the data. Import 341kgCO2, export 305kgCO2 on electricity from similar solar/battery to yourselves.
Unfortunately another bit of maths on our gas usage (heating, water and hob) gives me an extra 2,400kg of CO2!
Amazing analysis as per usual. One point on the comparison with a gas boiler - a combi boiler consumes about 200 watts (it varies though) so that would widen the CO2 intensity gap between the two technologies.
Thank you. That's a good point about boilers, I'll have to factor that in next time I do something like this.
We had an extension built. A few years back and specced it with double insulation, been slowly working through the house upgrading including this year the roof.
The UFH i had installed on the ground floor goes off around March April and start up again October/ November
Since having the roof done the upstairs radiators are off most of the time and it wil be interesting to see how much less i use on heating next year.
I put this because even if you have a gas boiler UFH on the ground floor and double insulation especially from under the floors is a game changer
I would love underfloor heating on the ground floor, that would be great. One day we might do something like that, but it's probably many years off.
Very interesting Tim. I'm not sure why you are looking at the grid’s carbon intensity at the time your export is made rather than the intensity of where it came from (overnight import or the roof). Your export to the grid at that high intensity period came from low intensity sources. There just aren't enough of us doing this time shifting (yet) for it to register at the national level of intensity.
I appreciate I may have completely missed the point or misunderstood your logic or both!!
Keep it up.
By exporting at times of high grid carbon intensity I'm offsetting some of that generation by replacing it with low carbon energy (from my roof, for example), so I'm affectively preventing that same amount of carbon from entering the grid. So I measure what I take from the grid at the relevant time and then offset that with what I send back at a different time. It doesn't matter that it's a tiny amount. It's a bit hard to explain, but I hope that makes sense.
If you save your solar for the grid increasing your exports and imports it would lower the average g/kWh figure.
Really interesting, thank you. My heat pump was due to be installed next week but has been postponed until March due to, amongst other factors, the fact that it's being funded by a tax free lump sum from my pension and the chancellor created a stampede for pension withdrawals by bringing pensions within scope of inheritance tax and I'm stuck in the resulting queue. Still, I will be switching an 18 kW from radiator gas central heating boiler to 4 kW underfloor heat pump heating and my goal is to become carbon negative in my retirement. From your analysis it seems that investing in Ripple's next wind farm might be necessary to achieve this, otherwise low carbon imports in winter are not possible. I also do energy arbitrage on Octopus Flux and my net electricity bill last week (excluding the standing charge) was 10p, which is remarkable for January, but I am sure that my CO2 footprint will have been horrendous as there has been very little wind. I think a really good way to lower our carbon footprint would be to reduce or eliminate our overnight import during spring and summer, but still export to grid during the evening peak. That way we know that our carbon import is being minimised and our exports are building carbon credit.
Ah, dang, I hope you make it to the front of the queue soon. Very exciting though, that'll be great once you've got your heat pump installed. I'm interested to see how the summer goes, if I stay on Go it'll still make more sense to import overnight, but I'll probably shift to exporting a bit later since the export rate for Go is flat through the day.
What if you charge your EV on the 'Greener Days' when it is windy? Is that accounted for here? We only need to charge ours once a week most weeks. Another factor is that the grid will get greener each year, so it is only going to get better.
Yes, that would help a bit, for sure. It's not always practical and the effect would be relatively small since we don't do many miles, but it would help if we could manage it.
Home assistant tracks this continuously for me.
Despite having a smaller array, and battery, I imported just over 70% “Low carbon”, and generated another 20% myself.
So 10% of my usage was fossil fuelled (and of course Drax is a bit more again).
Not sure how valid it is to rate your solar export as “grid average” - that’s purely carbon neutral, and exports from your battery have already had their carbon content calculated on import, so I think you’re double counting there as well.
Oh, and since 30% of my usage was EV… that’s offsetting diesel as well.
I think that's the only reasonably way to do it. Or at least the regional grid average (although as mentioned that data was a pain to get hold of, so I used national instead).
Your winter, blue line, export looks to be in line with the carbon intensity peak. Summer's peak was later. So for max carbon offsetting, perhaps your export window should slide left and right with the time of year, in pace with the solar day?
Interesting content as usual.
Yes, exactly, that would be the ideal, and if I stick with Octopus Go this summer I'll do just that. But Flux/IOF has a peak export rate from 4-7pm, so you wouldn't get the best export rate by shifting your export later in the summer. I think Octopus should have a carbon minimisation tariff with the peak export rate following the peak of the carbon intensity, but I doubt they'll do that as it won't align with the peak of the grid price. But you never know!
I have another roof that is NW facing that i am thinking of adding some panels it will only fit 6 panels on but that will help. Looking at trying to get low voltage startup so that it does its best. This will help yearly average but not this time of year.
I am on IOG and randomly was exporting later - mainly because the SOC% in my battery stats is so unreliable. So that was handy.
Now if I could just persuade my wife to let me put some vertical panels on the wall that faces SW ! That would then pick up the low sun at this time of year (and work when the others are covered in flipping snow/ice). Jan has been a hopeless generation month gloomy so much of the time - today again.
Looking forward to seeing what you come up with. You did mention Ripple awhile ago which seems and easy win.
I would also like more battery as with no solar in the day we do run out sometimes. But a hit of extra £7k is impossible to square financially. Maybe V2G will be mainstream soon. Got a lovely 70kWh battery sat on the drive !
Haha! I'm sure your wife can be persuaded. I did wonder about adding panels to the walls but I don't think we'll need that as we've got a fair bit more roof we can use. As it happens we do have a small amount of Ripple investment in the new solar farm but that's not generating just yet, so it'll be interesting to see how that affects things when it starts up later this year. V2G really will be a game changer if it ever gets off the ground in a meaningful way. Let's hope so.
Interesting analysis thanks Tim and particularly the sumer vs winter curves. Makes sense when you explain them, but not what you’d immediately think of.
Flux is looking increasingly disappointing as a tariff, 13.6p day-rate export, notably less than the 15p fixed export rate. I ran the numbers and whilst the 27.4p peak export is of course better, overall I don’t think I’ll save much given the import rates are comparatively high. And as you say the fixed export rate gives opportunity to export in a more carbon positive way.
I generate about 2-3,000kWh more than I consume so probably for me the figures would show I’m more carbon neutral. I have recently just swapped to Agile Outgoing for the winter as the only times I export are in DFS sessions and this gives a higher export income. I’ll swap back when the heating is required less and I can start exporting excess solar again, but its an interesting experiment to try
I got rid of Flux back in the summer for the reasons you state and just went to Economy 7. My array is mainly East facing so it's hard to get much export in the peak period. Was only on it a couple of months (managed to have an argument with Octopus overcharging me because my meter thought the cheap hours were 01:00 -> 08:00 instead of 00:00 -> 07:00) and then got an EV so moved to the tariff for that. Have now changed electricity import and solar export to E-On Next because it's cheaper through the day, longer night hours and better export rate of 16.5p.
I'm probably also going to forego Flux this summer and stick with Go, probably. I think my rule of thumb will show it's pretty close in either case and sticking with Go will save me having to switch, which despite being relatively easy usually comes with a bit of hassle, for one reason or another.
@@TimAndKatsGreenWalk I have pretty much made the same decision to stay with Agile (and 15p export) this summer as well as I did last year. From the analysis I did there was very little in it, and the higher Flux import rates put me off. I did try enrolling with IOF as your rule of thumb suggested it would be the most beneficial to me given our generation to consumption ratio, but Octopus can’t cope with having two inverters on one account, the IOF enrolment process fails.
Another thought... I'm guessing you charge your storage batteries from the grid at times, probably more so in the winter. GivEnergy quote a round trip energy (RTE) efficiency of 93% for their batteries. I don't know whether this includes losses at the inverter or not, I haven't checked. That means energy is 'wasted'/consumed in charging from the grid then using or exporting that energy at a later point in time. Have you factored this in to your estimates in any way? Would it be worthwhile doing so if the data is available?
Thanks for the video btw, it's proving to be better brain exercise than most on YT!
That's another good point, yes, although the data I'm using is the meter data from Octopus, so it's everything that goes in and out of our home. So in that sense the carbon neutrality of it (or otherwise) is well defined as the net between the two. The consumption value is the one that would be affected by those losses you mentioned, I agree, so effectively we're consuming slightly more than is strictly necessary compared to if we instead used all our energy directly from the grid. So I expect our consumption would really be a bit lower than the 7,800 kWh I showed in the video, as that includes the charging and discharging losses. You can get a rough approximation of those losses by seeing the difference between the total you charge the battery and the total you discharge the battery over a given window (see my latest stats video as an example where I show that at about 12:32: ruclips.net/video/sWMZaNi-lRI/видео.html ). Although I suppose if the consumption value is lower then so would the import value. It's all very confusing.
@@TimAndKatsGreenWalk It is indeed very confusing! I think it's safe to assume all energy put in to the batteries is subject to a 7% loss if the RTE is 93%. This is regardless of whether it comes from the grid or from self generation. So if you know, or can approximate, how much energy is put in to the batteries you can work out the equivalent carbon intensity of that 'lost' energy (I think). If you exported all excess solar to the grid, there wouldn't be a 7% loss. If you import energy from the grid to charge the batteries then there is a 7% loss. Obviously this doesn't take account of cleverly importing energy when the carbon intensity of the grid is low and exporting when it's high, which you did suggest was something you might try and would result in a lowered carbon footprint. All other things being equal that is.
On a more general note, I know there are many reasons for having battery storage, but they can and probably do represent a positive contribution to increased carbon intensity in many use cases. Many people with batteries think of maximising the financial benefit by importing when energy is cheap and exporting when more expensive. If batteries are used in that way, then their use may well contribute towards moving us away from carbon neutrality rather than towards it. Now I wish I hadn't have thought that thought!
@CazBag I think as long as batteries are charged overnight it's hard for them to end up adding carbon to the grid overall, unless they're deliberately discharged at other times when the grid is very low carbon too. But it would need some careful analysis, as you say! I think I'll park that one for the time being.
Hi, I added generation to my house by buying Ripple Energy shares. As I charge my battery for 7p overnight and ripple pays 6.3p per unit generated by the wind farm, I effectively pay 0.7p per unit. This also reduces my carbon intensity but I haven’t gone into this level of detail to know exactly how much I use.
I've also got a bit of Ripple investment (the solar farm) but it's not online yet, so that'll help a bit when it starts generating (hopefully this year some time).
It is worth also noting that you are carbon neutral because of REGO. As octopus adds your load to the 100% carbon neutral side of the generation. The dirty side of the grid comes from people not using 100% renewable energy suppliers. Also you need to treat your car separately as the diesel offset makes a difference.
I'm not sure I agree with the argument that just because I'm on a 100% green tariff that I can claim to be carbon neutral. The grid doesn't send me only renewable power, it'll be whatever the current mix is. I personally think claiming certain tariffs are 100% green is a bit misleading, really, we all get the same power mix at the end of the day. The point about the car is a good one, though, a couple of others have mentioned that and I think I need to do a follow-up video on that subject at some point.
While what you say is true REGO creates demand for more renewables on the grid. This directs corporate investment in the desired direction. Without it our desire for renewables couldn’t be communicated to investors.
@@pmac6584 oh yes, I agree about that part completely. I'm not saying it's not a great idea, it is. Encouraging investment by showing a demand for renewable power is very valuable. But I'm not going to claim I consume only renewable power from the grid for the purposes of this particular study.
Any idea why carbon intensity and cost don't line up? I thought the theory was that when there is peak demand then gas was used (because its expensive and easy to turn on/off) which is high intensity.
It's a good question and I'm not really sure. I will have to delve a bit deeper into the generation mix data to see what I can find out. My hunch is that the solar generation in the mid afternoon is keeping the carbon intensity lower than it otherwise would be even with higher demand, and that as the solar dies away the gas proportion increases even as the overall demand falls a bit into the later evening, causing the carbon intensity to rise. That's my suspicion anyway.
Great video again! A lot of battery and hydro will be exported to cover demand during the peak, which may reduce the carbon at peak time. While you may reduce your own carbon offset, you wouldn't reduce the overall grid carbon, because now a bit more gas now needs to be burned at peak, to cover you exporting later. Continuing to export after 7pm would be the only way I think you would have an effect, rather than just shifting your export, because you may prevent more gas being burned and then recharge with excess night wind.
Honestly I’d have approached this as two separate calculations and graphs - one GMT and one BST to account for seasonal drift. I get you combined these but it does, for me at least, make untangling the impact and where positive changes could be made more difficult. The annual figures do, as you say, largely cancel out but I’d have liked to have had seasonal summaries. Not sure I’m explaining myself clearly as to where my aim diverges from what you said.
I accounted for the clock change in the analysis, so all the numbers are correctly aligned with the time as it was on any given day. And I did show a seasonal split, that was the explanation for why my assumption was wrong. By all means process the data how you see fit! I provide the link to it in the description.
@ yes, I was mostly thinking of avoiding an annual overall calculation and just doing a season - you compared both together to get your annual which is different.
@@AmsNl2BcnEs gotcha. Yeah, I'm building up a fair old list of possible follow-up videos with this! It's sparked quite the discussion in the comments.
Is there not a distinct probability that the peak carbon generation is after peak demand *because* tariffs encourage selling back to the grid during peak demand? Selling it later could well flatten out the carbon curve but quite possibly wouldn’t reduce overall carbon use across the system.
That's a good question. At the moment I'm not sure there's enough domestic exporting to really have a significant effect on the carbon peak, but I'd be interested to see if there have been any studies into this. Regardless, the more domestic solar/battery export there is the lower the grid carbon intensity will be overall, so it's all good.
Batteries are exporting in the peak to assist the ramping in of gas as the sun goes down and demand goes up. It's possible grid scale batteries are therefore helping reduce the carbon intensity in this period too, not just domestic.
For comparison you should add the theoretical carbon intensity of the house consumption, assuming you had purchased electricity straight from the grid and not had solar and battery. That should give you a baseline to compare your carbon savings against - I suspect that number will be considerably higher than 399.9 kgCO2
Yes, you're right I could do that too, that'll be interesting. I could do a whole series of videos on this it seems!
when comparing the winter carbon intensity peak to the summer one, have you taken into account the time changes with BST? the winter peak is still 1730-1800....
Yes, I'm pretty confident I've dealt with the time change correctly.
@@TimAndKatsGreenWalk Thanks, interesting how it's so much later in summer. If I add battery and stick on IOG, I will force discharge depending on carbon intensity, not just the 1600-1900 slot I was going to assume....thanks Tim!
@@justinjoanknecht3475 yes, indeed it's quite a surprising result. I think it's due to the higher solar generation in summer suppressing the grid carbon intensity in the early evening, and so effectively pushing that peak back later. If I stick with Go this summer I'll do exactly that too.
It's high time Hinkley Point C was online. Many things are out of the consumers control sadly. Governments and suppliers have been too slow over the last decade to decarbonise. The rest of us are doing what we can, but facts are facts.
It's crazy how long that's been going on.
To be fair, 10 or so years ago coal made up over 40% of our grid mix and is now 0% so a fair achievement. In contrast, wind has gone from 3.9% to over 26%. This has meant the the carbon intensity has more than halved from 467g/kWh to 180g (MygridGB). Agree Hinkley is taking too long and more could be done (homes were meant to have been net zero back in 2016 under the old "Code for Sustainable Homes") but progress is being made so there are positives out there!
@@steve_787 absolutely, every year the grid becomes noticeably greener, so in a few more years I won't have to work so hard to get to net zero, even without extra generation!
Tim
Isn't the export carbon intensity reduced by you and people like you exporting to the grid. You need to use the higher figure to calculate the saved export figure. I'm not sure if this data is available in order to do the calculation?
Ah, interesting thought. I have no idea how to go about assessing this effect but my suspicion is that it's pretty small right now. It'd be nice to know the total amount of domestic export though, I'll keep my eye out for any good sources of data on that.
just live man!
You say that like I'm not. How about you let people do what they want without judgement, eh?
Great thoughtful video. i think making your own household carbon neutral on those terms may not be particularly good for the UK? Its Energy market is trying to persuade you to do things with price signals, so perhaps we could assume their most efficient take on carbon neutrality needs you to accept a personal carbon budget that 'appears' to be a bit more carbon intensive than you'd like?
We all operate within a bigger system etc... indeed there are times when it probably makes sense for UK to export greenish energy to somewhere in Europe where horribly carbon intensive energy would otherwise be being used. Wouldn't be great for UK carbon intensity.. but would be great for the planet?
So this is good news for you financially as everyone's best interest is served by you looking after yourselves financially..
It's certainly true that in general green energy tends to be cheap and dirty energy tends to be expensive, so price signals do help, for sure. But not always perfectly, as I demonstrated in the last part of the video where the high export rates don't necessarily coincide with the highest carbon intensive grid power.
Very interesting, i cant get solor because we are on the shaded side if a mountain, but having an ev, ive been thinking about time shifting my energy via carging up battries overnight at thd 7p tarrif rate and using it in the day time.
My house uses an average of 8kw a day, rearly it oeaks at just umder 10kw. So i was thining of a 15kw battery.
My usage is not taking into acount of the car. And id not jave the car touch the battery. I dont see the point, only downsides doen that route.
Only over xmas did i stsrt thinking about this, so its going to be my project for 2025. All the ore packed options are far to expensive. You can do it for far cheaper with a little know how and alot of research. Also this way tou knek haoe to service your own equipment. Which for me is always the best way to go.
Solar is getting cheaper all the time so it might well become viable even in shady spots. It might surprise you
Batteries get cheaper every year, and they only save you money if you can use most of the capacity as often as possible, so don't buy more than you need right now. I'd go for a 10kWh battery and ensure you can add more easily if you need it later.
@TimAndKatsGreenWalk I agree, this is why I'll be using a hybrid inverter, that will have the opportunity to grow in the future, with either PV or wind.
Then I'd then be looking at increasing battery capacity and selling it back at the optimal times just like your doing yourself.
But at the moment I'm just looking at tying to put a system together for the cheap price. If you can make this really affordable, and then get a government grant behind this for OAPs, this could quarter the cost of their electricity bill, with a single one off winter fuel payment. Saving them more money than they ever have before. And it could help if all these household battery packs could help balance the grid when needed, instead of the grid having to pay millions to peko factories to turn on for two hours at at time.
I started thinking about this for my own bills. And I've gone down a rabbit hole where there could be a business in this, where all parties win.
there isn't a company that offers an out of a box system at a cost that makes it make sense to the majority of people. The gateway is blocked by cost.
I've been looking at the cost of batteries, the. The cost of producing the batteries yourself, that's a 4x savings, investors in the UK are priced wildly. But direct from China (Who produces the ones sold in the UK), 2-3x savings.
I'm yet to look into BMS system, but that's the basic outline of what you need. (Mostly).
I think it can be done. We could bring a package together, and the pest part, when youre communicating and collaborating with Chinese companies, they will keep you in the loop, bring to every decision, good or bad, to make and sign off on. These guys, get a bad name in the world, but they work hard, work well and value the customer and will produce.
@@robinbennett5994 10kw would scrape it, but just like your phone and your car, for longevity you don't want to fill it and drain it every day. I'd have my 15kw battery utilise about 80% of it. This should increase its lifespan a lot.
@@StephenButlerOne I was thinking that if you usually use 8kWh, then 80% of a 10kWh battery would be about right.
You'd probably need a spreadsheet to calculate the relative effect of needing to buy a little full-price power for a few days per year, vs the cost of the extra battery.
A few thoughts -
1) 400 odd kg of CO2 for all heat, power and transport is amazing - I'm not sure what the national average is these days, but I suspect it's at least 10x that.
2) is your solar export during the day before the evening peak skewing down your average export "carbon credit" value?
3) I question the methodology - your importing and exporting is impacting marginal generators, not average intensity. This is almost always CCGTs with a near-flat carbon intensity. I'd argue you can only claim better if you're relieving a grid constraint (unlikely where you live I'd suspect - solar isn't constrained at midnight or 4pm).
On the export side, you can only improve on CCGT levels of imported carbon if you are pushing diesel gensets and OCGT down, so in very high demand (usually winter) hours - this is certainly not every evening.
Basically, I'm a contrarian and think batteries domestically are a bad idea today: embedded carbon is huge; they're not providing frequency response and other grid services in the way utility scale batteries do and they aren't saving any carbon by increasing CCGT generation at one hour and reducing CCGT on another - indeed they're net consumers, adding to total demand.
This will change over time and domestic batteries will have environmental purpose when we reach California levels of duck curves, but that's not the case today. If carbon is your motivation, it could be interesting to control the battery on Agile with variable export pricing, not Go. I suspect you'd force export a lot less and battery ROI would take a major hit. You'll also be tempted to shiver your way through the dunkleflaute!
1) yes, that is pretty good, I'm definitely pleased with that, but I thought I was doing better!
2) yes, it all contributes to the effect I measured with a lower than expected export intensity
3) I disagree. I've heard that argument before and although I see the logic I don't think it's the fair way to do it. It would suggest load shifting has no effect on grid carbon intensity but that is definitely not true, since if you increase demand when it's windy, for example, you can prevent curtailment of wind farms and thus help reduce the grid carbon intensity overall. So if load shifting works then by definition you can't claim that it makes no difference when you import or export. Another way to think about it: it can't possibly be true that every household in the country is using marginal power (with high carbon intensity) at any given time, that's ridiculous, so therefore the only fair way to assess an individual's contribution is by taking the overall average. And if you make that argument for consumption then you necessarily have to make the same argument for export, i.e. taking the overall average is the only fair way to do it. I hope I've explained that well enough. I can definitely see the argument you make, but every time I think about it (which is more often that you'd imagine!) I come down on the side of using the overall average rather than marginal levels.
I can see the argument, but how would you ever reach the threshold at which batteries can have enough aggregate effect to stop gas or diesel generation if you don't start installing them from a low base? And as Tim says, we already curtail wind energy all the time that could be soaked up by more battery demand. I don't think Octopus would be building their business model around these incentives if they hadn't modeled and projected this stuff forward into the future.
@ I think both rebuttals bring forward fair points. Despite what I said, I will be getting a hybrid inverter and batteries with my solar install this year, for instance, but primarily because it saves multiple install visits and will give me more MPPT's for my complicated roof structure, which would otherwise require more string inverter spend which will be obsolete when the batteries start adding environmental value. However, based on marginal dispatch, I don't expect the battery to be of any real carbon benefit until 2027-ish.
I think my point is that you can't operate your batteries for maximum ROI and then expect it to produce carbon optimal outcomes, and regarding the point about Octopus - I don't think what they've done is wrong; creating business models for people to incentivise early adoption and bring capacity online that will have long term benefits. I just think that selling based on environmental benefits today is a bit disingenuous.
Overall, I think Tim's methodology is consistent - it helps in some ways, it hinders in others (e.g. not taking full carbon credit for solar displacing CCGT).
Hi
Octopus only use Renewables generated electricity which must mean your starting point is wrong re co2 imported and export ?
This is a statement on octopus web page
The carbon footprint for a typical British home using a year's worth of electricity at the national average was 574kg of CO2 per year in 2022 -23.
The same electricity for Octopus Energy customers had a carbon footprint of 0.
That's not really how it works though is it, they buy enough green kwh on the market to cover what they sell. But in reality, the energy we fill our batteries with overnight on a calm day is not coming from solar or wind.
So I guess in summary those of us with batteries etc, are buying cheap dirty electricity at night and selling expensive green electricity during the day?
It's a fiction that any given consumer can receive entirely renewable energy. The grid doesn't send you specific generation. So I don't think it's valid for me to claim I receive zero carbon electricity from Octopus.
@@TimAndKatsGreenWalk I agree , but it’s no different to charging a battery at night and offsetting it with exporting the battery in the day or exporting solar after charging the battery
@@markreynolds8050 yes, but we also consume the power from that charged battery, so that results in emissions if that power was not totally renewable. Hence needing more generation to cover it.
The carbon intensity figures you're using appear to be per kWh of generation, whereas your usage figures are presumably meter reads, ie consumption. I believe average line losses (transmission+distribution) in the UK are around 8%. If 8% is roughly correct for your area, that means that for each kWh of imported energy you consume your carbon intensity figure needs to be multiplied by 1/0.92, as more energy is generated than you will read at your meter. There is also a line loss related to export, though this should be lower than 8%. You may have already factored this in, apologies if I've missed where you've done that. If you haven't then your calculations are somewhat mixing apples and pears and unfortunately put you further away from carbon neutrality than you have estimated.
Hmm, that's a good point, I'll have to check what the data actually means, whether it's carbon intensity as generated, or consumed.
Ah ha! I found the definition of the CARBON_INTESITY column for the dataset I used. "The carbon intensity of electricity is a measure of how much Carbon dioxide emissions are produced per kilowatt hour of electricity consumed." As taken from this page: www.neso.energy/data-portal/historic-generation-mix/historic_gb_generation_mix
So I think what I did was ok.
@@TimAndKatsGreenWalk Ah yes, so the carbon intensity data must be adjusted for losses in some way. Agreed, what you did was okay for imported energy, not sure about exported though as that will be a generation figure I guess? I've no idea how it could be quantified either!
@@CazBag well, anything I export will be used by my neighbours, effectively reducing their consumption by the same amount. So I think that's all good too.
@@TimAndKatsGreenWalk What you export will reduce the load on the local transformer supplying you and your neighbours, which then has a ripple effect all the way back up and through the network. In that sense, the energy you export doesn't really get used by your neighbours, but it does contribute towards lowering total generation. It's difficult to put any numbers on it to quantify the contribution and therefore the effect on overall carbon intensity. The kWh you export are generation and not consumption though. Does that make a material difference? Still no idea! Sometimes things are best kept simple, that I do know!
Hold on Tim. You are with Octopus aren't you? They give you green electricity. I know that the grid where you are connected to comes from arguably anywhere so you've looked at average grid figures for percentage of carbon etc but it looks like you are not accounting for Octopus offsetting sources so they can claim to give you green electricity. So arguably you are carbon neutral when combined with Octopus's efforts.
I don't really agree with the argument that "100% renewable tariffs" really mean you're using exclusively renewable energy. All that means is it's a signal to investors that there's a demand for green power and so more investment is made for the future resulting in a gradually greener grid. Another way to think about it: If I buy renewable power someone else effectively receives dirtier power because there's less green available for them. So I don't believe it's right to claim I'm green by doing that as it's not really changed anything for the grid mix as of that day.
@@TimAndKatsGreenWalkOctopus buys electricity from green sources like wind, solar, and hydro and they also buy green REGO certificates and energy directly from UK green generators. Effectively they offset their balance by trading origin certificates. It's not made up it's traceable in their FMD (fuel mix disclosure report).That's how they can claim when you buy electricity off them you are paying for green electricity. Of course they don't send only green electrons down the wires to you because of the grid but as all the electricity you are buying is 100% green and your money ends up paying green sources then you too are 100% green if you follow the money.
That is in fact the only sensible calculation you can make. You can't apply average grid source balance figures to your local situation as you have done, although I can see what you are trying to do, because you are not evenly connected across the entire grid. You are locally connected and unless you are the district network operator you won't have a clue where your actual electrons come from. It all depends on the active generators in your area and the local loading. If you live next door to a nuclear power station then all your grid electricity is likely to come from there (shortest path of least resistance) but you might have an active local solar, wind or battery farm and it might come from there but then again you don't know the local loading situation which might have all the green electrons gobbled up by the local arc smelting works and in fact your local area has power dumped into it from hundreds of miles away possibly France. You just don't know so your actual source balance could be entirely different to the average grid balance figures you've used rendering your personal calculations meaningless because you are not evenly connected to the whole grid - you have a unique local situation. You'd need load and distribution figures off your DNO coupled with district feed figures from National Grid and that would be far too difficult to do. Using the grid averages is a flawed approach for that reason and can't even be said to be approximate as you are not an average grid consumer either. Everyone is different and uniquely connected.
The only sensible and thankfully easy way is to follow the money and accept that Octopus sell you green electricity. It's a certificated and traceable system. Congrat's you are carbon neutral 😃👍
Take this to the extreme and imagine every consumer in the UK signs up to a 100% renewable tariff. By your logic that means the whole UK grid is magically 100% renewable and so everyone can claim to be carbon neutral. That is clearly nonsense, the grid still has non-renewable generation in the mix. Claiming that buying credits is equivalent to actually generating green power is something I consider to be Greenwashing, and so I'll never use the argument that just because Octopus is selling me ostensibly 100% renewable energy I can claim to be carbon neutral. I did mention that I used the national average because it was a pain to get regional data. Although as it happens our region is often quite similar to the national average anyway so I consider that to be a reasonable compromise. And in any case it didn't really matter for the purposes of the message I was trying to convey with this video - that you can change your carbon impact by changing the times you import and export to/from the grid.
@@TimAndKatsGreenWalkThat's not really a logical argument because 100% of customers can't be Octopus customers and Octopus claim 100% green sourcing at the same time. That wouldn't be possible under the audited REGO scheme administered by Ofgem which provides guarantees of origin. There's only so much green to go round You've nabbed your bit well done. If the scheme didn't work you could make a complaint to the advertising standards authority and ultimately sue Octopus for misselling. Good luck with that!
In any case following the money through the scheme is better than your unknown local sourcing and loading situation and trying to apply an incompatible national average as I have explained. Your general push to be greener of cause I applaud and the discussing of it stimulates thought and innovation.
@johnh9449 I still claim greenwashing on that one I'm afraid. But regardless, I stand by my methodology and conclusion.
I may be missing something but your solar generated kWh is zero carbon. The biggest fact is the reduction of what you have used from the grid. Again the strategy used by us to get paid for more export actually causes us to use more and increase our CO2 levels. If you stopped importing to the battery and exporting it, your CO2 would be lower.
Anything I import to the batteries leaves more solar to export, so that doesn't really matter, as long as you're charging the batteries at times of low carbon (i.e. overnight) then you'll be reducing the grid carbon intensity overall. If I don't import to the batteries overnight then I'd have to use my solar myself instead, and therefore wouldn't be helping reduce the grid carbon intensity by exporting at times of high carbon. So I don't believe that importing and exporting to/from the batteries increases the carbon intensity.
@@TimAndKatsGreenWalk I totally agree as I am doing the same, but my big point is the more that we import the higher our CO2 will be. For me the the zero carbon solar would reduce the amount of kWh imported. We are just in this strange but good moment that we have a way of buying at 7p and selling at 15p. Best for the pocket but not the CO2!
I still disagree with that in some situations though, if you import overnight at 50gCO2/kWh and then export that same power back out when the grid is at 200gCO2/kWh then you prevent 150gCO2/kWh net being needed (ignoring conversion losses etc.). Your import may be higher but so is your export, and the result is that the net difference in CO2 is beneficial, not detrimental. As I showed at the end of the video if you can target your export at the peak of the carbon intensity curve in the summer (between 6pm and 9pm, say) then you're definitely helping to reduce the carbon intensity of the grid by utilising your batteries. Although I agree that if all you're doing is exporting back at a time when the grid carbon intensity is similar to when you imported it then that doesn't help at all.
@@TimAndKatsGreenWalk Good point!! Slightly different viewpoint helps to understand. Thanks
What the hell does it matter 🤣🤣🤣🤣
Why the hell are you commenting?