which is that representative politics is the problem. We’re all arguing about the mechanism by which we give a small number of people the power to decide things for us rather than questioning whether they should have that power at all or how we hold them to account if they misuse it.

What alternative to that is there, besides the public having a referendum on every single decision a government would usually make? The answer is citizens assemblies, whereby a random pool of 200 or so people can send decisions back to the commons for a blind vote (so MPs can vote against their party without fear).

Rory Stewart (again) keeps banging on about that idea and I think it would be great.

all powered with hydro power

I’m not taking the bait

Not tried it myself, but I saw a video suggesting that by lightly squeezing a syringe of brake fluid in at the caliper as you close the nut, you will reduce the freestroke. Like pressurising the system.

There’s actually a fairly significant amount of time now when wind farms are paid not to generate so the marginal electricity is renewable. This expected to become more of an issue for next decade or so. So if you charge an EV overnight and at lowest cost times if you have a suitable tariff it will most likely be renewable electricity. More tariffs will appear for this. Apps showing live grid generation mix are available too so easy enough to see what is happening.

That’s interesting. Just read that it is caused by the infrastructure not being good enough to get the energy to where it is needed (out of the north sea and into southern England). So excess renewables in Scotland, but they still have to fire up a gas station in England to meet demand.

I’m (purposefully) undermining the widespread but incorrect belief that if I have an EV and am on a green electricity tariff, then each mile I drive is practically carbon neutral, and so there is no benefit in reducing mileage.

There is probably a really interesting stat available somewhere. How often is it the case that, if it weren’t for EVs being charged, there would be excess renewables. During those periods, I would absolutely agree that the marginal power demand of charging EVs, taken collectively, is partly renewable electricity.

For example, let’s say it’s 30th December 2022 and the grid is 100% renewable with 1KW to spare. My neighbour switches on his dishwasher and uses that last 1KW. The grid is now 100% renewable, 0% gas. I switch mine on 2 minutes later, therefore the gas turbines get spun up to meet the demand.

Using my preferred methodology, the grid and therefore both dishwashers are now 99.999999% renewable, 0.000001% gas.

But that’s an edge case which only occurs for a very rare instant. In that situiation I would agree that smudging together you and your neighbours usage to consider collectively would be sensible. 99.9% of the time, the marginal generation is very clear-cut, either by gas or renewables.

An enormous game changer of EVs is that they are very flexible about when they consume power, so they can wait for times when the marginal power is renewable, and gobble up all the excess. In 2024 this is still extremely rare, but it will become much more common in the future, especially on windy nights.

What we are objecting to is using this to claim that EVs are 100% fossil fuel powered.

Any time the grid is needing to be topped up by gas, the marginal power use of each EV charge, just like the marginal power use of any electrical device being turned on, is 100% fossil fuel.

So just like turning on any electrical device, each time I plug in an EV to charge, the additional power required to charge it, compared to a parallel universe where is not plugged in to charge, will need to be generated 100% by burning more gas.

That remains true whether the grid is powered by 20% renewable or 80% renewable. Because renewables cannot be turned up to meet additional demand. It only stops being true when we have excess renewables.

I’m talking about marginal demand and generation. The additional difference resulting from turning something on compared to a parallel universe where it was not turned on. The additional power having to be generated almost always comes 100% from an increase in gas power production.

You are talking about overall demand and overall generation. That’s all of the energy generated across the entire grid, and everything consuming it. That might be 50% renewable and 50% gas, or more, or less, depending on the weather and time of day.

I’m sorry I can’t think of any better way to explain.

No, but my car can wait to charge until the most renewable power is available. It doesn’t start charging as soon as I plug it in. You know this, right?

It makes no difference whether the overall grid is 20% or 60% renewable, if it is having to be topped up by gas, then any additional marginal generation will be 100% gas.

Why is it my EV and not your dishwasher?

Every time I turn on my dishwasher, the additional power required, compared to a parallel universe where I had not turned it on, is generated 100% by gas.

only equivalent until you start pointing fingers at EVs being 100% fossil powered.

I’m not pointing fingers at EVs. As repeatedly said, it applies to (almost) all electricity consumption.

Kelvin – I don’t think anyone is disputing that.

So every electrical appliance is 100% fueled by gas?

No, the power required to fuel marginal use is 100% by gas.

Do you understand the difference between a marginal tax rate and an average tax rate?

And when Moly gets a piece of the renewable pie, everyone else has less renewable pie, and so has to have a little bit more gas pie. And so the gas pie has to be made a little bit bigger, because the renewable pie is a fixed size, until we build more renewables.

The gas pie had to be made bigger by the exact amount that Moly needed to charge his/her EV.

Now tell us why the same argument doesn’t apply to every single electrical appliance in the country.

It does apply to every electrical appliance! Every unit of electricity we don’t use is a unit less than has to be generated by gas. Until we stop having to use gas. Gas is the difference between renewable supply and overall demand (a bit simplistic but basically true).

I have been talking about the marginal generation of additional power, not allocating our existing production or consumption.

I completely agree that we will produce more renewable power in the future, and if we produce enough to not need to top it up with gas, then this problem will go away.

You agree that a percentage of electricity is produced from renewables, right? So who is using that “green” electricity?

We all are. We have used the whole lot of it, and we cant squeeze out any more. Trying to allocate who used which unit of electricity is arbitrary and pointless.

Can we agree that while the charging of all the EVs currently in existence today might be partly powered by renewables, each new EV added to the cohort will be powered by gas? Or, equivalently, owing to the addition of this new EV, the proportion of EV charging done by using renewables will decrease?

@Molgrips I think we have to agree to disagree. I’ve run out of analogies or ways to explain it. For every additional EV plugged into the grid to get 1kwh of charge, one additional kwh has to be generated by burning gas. The same is true for every additional pair of hair straighteners, or every additional lightbuld. We already use more electricty than we generate via renewables, so the additional has to come from gas. This will be true until our renewable generation is large enough to not need topping up with gas.

It isn’t creative accounting and I am not trying to disparage EVs. It is just an often overlooked fact.

The French scheme with the Renault Five is interesting… not just using the car battery to shift energy demand in the home, but across the local grid as a whole. Those cars on that scheme will help doubly when it comes to shifting energy use to renewables… they’ll end up meaning that less fossil fuels as a whole will be burnt than if they didn’t exist… they won’t just mean less compared to using an ICE car… but less than if no car was at those households. That’s mind boggling and totally unintuitive.

[ simple version … V2G (vehicle to grid) uses all those car batteries as a distributed storage system for the grid, not just for each home, allowing peak to off peak demand shifting both for the grid and for energy generation ]

This is the awesome bit about EVs, and I dont understand why is it not widespread already. A fully charged EV could power a household for a few days. Or many households for a few hours. Pimping out your EV’s battery to the national grid will be a vital way to redistribute energy between periods of high and low renewable generation. As others have pointed out, EV batteries are enormous compared to powerwalls and other household batteries.

To put it another way, suppose that tomorrow we all used 1% less electricity. Do you think our solar and wind generation would fall by 1%?

Molgrips. I don’t pay 20% tax overall on average, I pay 10%. But on every single day of last year, if I had not worked that day, I would not have paid 20% tax on that day. Every single day has a marginal tax rate of 20%, until I cut out so many days that I fall below the personal allowance. 

Say we generate 500kwh of electricity via renewables. That is fixed because that’s how sunny and windy it is today. Gas is used to make up the shortfall, say that happens to be 100kwh. If we had required 1kwh less, we would have chosen to only generate 99 kWh from gas. It wouldn’t matter which of the 600kwh of electricity we had not needed, and so the marginal generation for all of those 600kwh was gas, unless we cut out 100kwh or more, in which case the marginal power is from renewables.

https://www.instituteforgovernment.org.uk/article/explainer/electricity-market

The marginal producer of electricity in the UK is most often gas because it is one of the most expensive sources, so is chosen last in the ‘merit order’ on the spot market. But it serves a vital role because gas-fired power stations can be easily switched on and off at short notice to make sure that supply balances to meet demand. Renewable energy sources, on the other hand, are unpredictable due to changes in weather, while nuclear energy provides a fairly constant source of power that is difficult to turn on and off.

Any additional unit demanded, (or unit not used) is allocated to gas because that is the marginal generation. It doesnt matter whether it is an EV being charged or someones hair straighteners.

Just like how if I had not worked on any given day last year, I would have avoided paying 20% tax on that day, even though my average tax rate was 10%.

My point was actually something different. If you are saying that every user should be counted as contributing 100% to has burning, then my question is who is using all that green energy? Not EV owners (in your argument). Not cooks. Not factories. So who? You end up with a contradiction.

I am not saying anything at all about how we should count individuals contributions. A bunch of green eneregy gets generated, which is usually less than the total amount people want. So we burn gas to make up the shortfall. If anyone used less electricity, it doesnt matter who, we would burn less gas.

Everyone’s marginal generation comes from gas. There is no contradiction.

Its like tax. Say I have a personal allowance, then pay 20% over and above that. My overall average tax rate is 10%, but my marginal rate is 20%. I could arbitrarily assign which hours of which days I assigned to which tax rate, but it wouldnt matter, cutting out any given hour would always mean a 20% marginal tax rate. This will continue to be true until I fall back below the personal allowance threshold. There is no contradiction.

At any given moment, our renewable and nuclear genaration is the grid’s personal allowance, and if we are to generate more than that, it has to come from gas. There is no point allocating which person is using which unit of electricity.

But can’t you apply that argument to any user? I decided not to cook my dinner last night – so the gas power station wasn’t turned on.  So cooking can’t be said to benefit from renewable energy. The local factory cancelled a shift. Ditto. Etc etc etc. So who does benefit?

Yes, you can apply it to any user. Most of the time, every kwh that you dont use is one kwh less gas generation. This will continue to be the case until we generate enough renewable power such that we dont need to top up with gas.

I wish this was appreciated more widely!

I’m not trying to imply that EVs will never be beneficial. They obviously will be an incredible asset in the future to providing low carbon travel, and smooth grid demand so that we can get the most out of renewables and reduce the requirement for fossil fuels. In the meantime, while the marginal method of power generation in the UK is almost always gas, the case is less strong. Perhaps still very convincing if you need to do a lot of miles.

I bought solar panels rather than an EV. I also dont drive that much so the EV would have been a waste of money anway.

You are suggesting that if a car were not charged then a gas power station would be turned down – but I don’t think this is the case, because things running overnight – factories, hospitals etc – need constant power and therefore cannot rely solely on renewables; but EV charging does not need constant power.

Like I said it is incredibly rare that renewables generate all the electricity we need, they are pretty much always topped up by gas.

Suppose I had used a bit less power last night (or didn’t need to charge my hypothetical EV). Would the UK have generated any less wind energy? No. Any less solar? No. It would have burned less gas. Even if I had been selective in when I used (or didnt use) electricity.

You forgot to convert the manufacturer’s g/km figures in to g/mile.

Ahh yeah fair point I’ll take that back.

You ignored the energy required to extract the oil, ship it to a refinery and turn it into petrol and diesel.

I acknowledged that, I also ignored the energy in extracting and transporting gas, losses during trasmitting across the grid and battery charging. And probably a load of other stuff too.

will increase further as more renewables come online

Completely agree with that, it will be a no-brainer one day.

that is still a strong argument for making your new car an electric car

Fair, I can’t argue that emissions per mile are indeed lower and even 25% is not to be sniffed at. Especially applicable for high annual mileage.

If one accepts 25% as a current day situation (I don’t, it’s poppycock)

Still keen to hear a rebuttal about the gas thing rather than just being told “it isn’t that simple”. Like I said, happy to read an article.

a very disingenuous comparison,

My whole point is that at present it is entirely correct and reasonable to assume that the energy will be produced by burning gas.

FWIW I took the numbers for the most efficient type of gas power station listed, so that is in favour of the EV.

Ford focus was just the first car that came to mind, not cherry picked.

the carbon emissions running your car is far lower than using an straight ICE engine, or the most efficient lightweight hybrid.

I did some very rough maths on the last page which I am happy to have holes picked in. It’s only about 25% lower.

I plug it in and say ‘I want it at 80% by 7am’ and it chooses when to charge.  So whenever the wind picks up, I get charge.

But as I understand it, it is incredibly rare for there to be so much wind that it is not necessary to top it up by gas. Like a handful of times per year. Definitely not every night, even for a few seconds.

Mert – I’m very familiar with that. The point is that just because the electricity currently being generated is 50% renewable, it absolutely does not mean that if we needed to generate an additional 10kw, it would also be 50% renewable.

Solar and wind generate whatever they generate based on how sunny and windy it is, nuclear runs fairly constantly, the rest is gas and biomass.

So if we need an extra 10kw, it will be gas and biomass. It’s a simplification but is broadly true.

Molgrips – do you know of data showing how often renewables plus nuclear is providing over, say, 90% of UK power generation? I get that gas and biomass can’t just be turned off.

I get that it will happen more in the future, but I understand is very rare now, and therefore the vast majority of EV charging happens at a time when the marginal power generations is from gas.

If it isn’t that simple, please could you give a hint as to what I am missing? Happy to read an article or something.

Molgrips – I completely see how in the future, regular excess renewables, flexible charging and vehicle to grid discharging will make EVs an environmental no-brainer. But it isn’t there yet and I have not seen any thoughtful projection of when it might be.

TJ – I’m not so het up about weeks of still weather in winter when renewable generation is rubbish. I get that this happens, and when it does we will have to burn gas. An EV powered by renewables for 10 or 11 months of the year would still be a big win. The point I’m making is that there is still far to go before we get anywhere near that.

AFAIU this is a spurious argument

Which bit of the argument is spurious?

as even if we accept the premise that EVs are 100% charged via gas the efficiency of the gas to wheel is higher than petrol/diesel to wheel in terms of CO2 output.

The difference is small, see above.

Beyond that a high proportion of EV charging is done overnight and this will be significantly provided by wind turbines even now.

Even if a significant proportion of overnight power is provided via wind, once the wind is maxed out then any additional demand from chagring EVs must be served by burning gas.

the carbon emissions are still *far* lower than burning diesel or petrol in an ICE

I had a look at this.

A gas power station emits 0.354 kg of CO2e per kwh.

https://questions-statements.parliament.uk/written-questions/detail/2015-11-26/17799

A very efficient EV consumes 0.25 kwh per mile.

https://ev-database.org/uk/cheatsheet/energy-consumption-electric-car

So an EV charged by a gas power plant emits 0.0885 kg CO2e per mile.

A sensible ford focus mild hybrid emits 0.118 – 0.126 kg CO2e per mile. A bonkers ST non-hybrid is 0.182

https://www.ford.co.uk/content/dam/guxeu/uk/documents/price-list/cars/PL-New_Focus.pdf

So the EV is about 75% of the CO2e emissions per mile of a petrol hybrid.

There is no end of nuance, loss in transmitting over the grid, extraction of gas, refining of petrol, etc etc. But is isn’t *far* lower at all.

Partly true. With our current energy mix, the carbon emissions of ICE vehicles is still many fold that of any electric vehicle charged at any time of day.

By 2030 (assuming the Tories are kicked out) all electric vehicle charging will use renewable energy only.

Needs a lot of work going into grid upgrades and resilience though (again, will happen if Tories are moved on).

Even sooner than 2030 it will be possible for all electric cars to be charged at off peak times without using fossil fuels.

Genuinely interested, do you have a source for this? One of the key things putting me off an EV is the spurious carbon emission claims. It is currently very rare for the marginal gereation of the UK grid to be renewable. So if I choose to put say 10kwh into an EV, that additional 10kwh gets generated by burning more gas, not by solar panels or wind turbines managing to squeeze out an extra 10kwh. Even when the UK grid is being powered 50% by renewables, generating extra power must be done 100% by burning more gas.

So charging an EV is (almost) never done using renewable power. Even if you have a green electricity provider, that just meant that some notional allocation of who bought what power got shifted about. Charging your EV caused additional power to be generated by burning gas.

I even have solar panels, but if I use the power they generate to charge an EV, it means less going to the grid, so more gas must be burned to make up the shortfall.

With all the extra wind and solar coming online, and flexible EV charging helping to align demand with times of excess generation I see how this problem will resolve itself over time, but I have never seen any thoughtful estimates of how long it will take. Months? years? decades?

Obviously the answer is tyres. BITD, you just bought a Fire XC Pro in size 2.1, and if you were feeling fancy, chose one of the 4 coloured stripes.

But now. Blimey. Couple of days to figure out how a Wicked Will is different to a Nobby Nic. Then you need to choose a width. Then a compound. Then a carcass. And figure out if tubeless ready is even a thing any more or if TTL is the new thing, and what even is tubeless ready because surely all tyres get run tubeless nowadays.  Then realise that you current tyres are the OEM version or whatnot and so aren’t as good as proper ones, so now you don’t want to even put those old tyres on your pub bike because you have convinced yourself that anything without at least 6 compounds is a deathtrap.

Then you notice the price of tyres nowadays and go and have a little frustrated cry.

Strong field this year

Spurs probably all have different size holes, I used M12 bolts on mine but it was tight and they needed tapping through with a mallet.