Cumbria coal mine go-ahead

andrewmcleod

Well-known member
Until we stop using fossil fuels to generate power then no transport system or industrial process is “green”. Every additional process using power is adding to demand. If you build your own wind farm that is still power that could be fed to the grid, it is just displacement. At the moment we are burning coal for power (double the emissions of gas per kW.hr), so every new electric car is coal fired.

I can’t be bothered with the maths (have to paint), but I somehow doubt that the emissions per mile of an electric car power by coal are better than a petrol/hybrid car by the time you add up the efficiency losses. I already thought gas fired was suspect, and that has many decades to go at this rate.
Note - CO2e is greenhouse gas equivalent as CO2 - i.e. the amount of CO2 that would produce the same amount of greenhouse warming/climate change as the actual gases released (because many processes release other more potent greenhouse gases like methane).

In 2010 electricity has a greenhouse gas equivalent of 482g CO2e per kWh. In 2020 it was only 242g CO2e per kWh (it went up slightly to 265g CO2e per kWh in 2021). I assume those figures include transmission losses, but even if they don't that's only 9% loss. So electricity has been partly decarbonised and continues to be decarbonised.
Those figures are actually higher than others, e.g.:
which quotes 235g CO2e per kWh for 2019 UK generation at the point of consumption (i.e. including transmission losses) - 231g CO2e per kWh if you include imports. That doesn't include emissions before generation though e.g. in mining/transport.

An electric car will typically use 15 kWh per 100km. A petrol car will typically need 5.5l of petrol per 100 km.
Petrol is apparently 8.76 kWh / litre, so therefore the petrol cars use around 48 kWh per 100km. This is not unreasonable, as electric cars are massively more efficient than petrol cars (albeit actually generating that electricity is typically less efficient).

Petrol releases about 2.3 kg CO2 per litre burnt, so our 5.5l of petrol will release 12.65 kg of CO2 for that 100km drive.
The electric car, running off 265g CO2e per kWh UK electricity, releases 3.98kg CO2e.

That's massively less CO2, and looking at the trend of UK electricity carbon impact over the last 10 years (i.e. steeply decreasing) suggests that driving an electric car is better right now for the planet and will get even better in the future.
 

mikem

Well-known member
Except we don't have enough power capacity to keep those cars charged & the government aren't building / planning infrastructure at a rate to keep pace (not to mention a global recession slowing it down). It also doesn't reflect whether there are differences in production / disposal of vehicles
 

andrewmcleod

Well-known member
Except we don't have enough power capacity to keep those cars charged & the government aren't building / planning infrastructure at a rate to keep pace (not to mention a global recession slowing it down). It also doesn't reflect whether there are differences in production / disposal of vehicles
Why would we have the power capacity to keep cars that don't yet exist charged?

It's a problem, but hardly an unsolveable one.
 

grahams

Well-known member
Currently (sorry) the grid has massive spare capacity through most of the day as we are no longer using incandescent light bulbs, CRT televisions, wasteful fridges etc etc. The problem is that electricity requirement vary enormously hence the relatively low overnight rates. Octopus' rates for example, are 7.5p for 4 hours overnight and 39.25p for the remaining 20 hours. Doubtless these rates will equalise when EVs become common, in which case the answer is to install solar panels and charge from those.
 

Chocolate fireguard

Active member
Currently (sorry) the grid has massive spare capacity through most of the day as we are no longer using incandescent light bulbs, CRT televisions, wasteful fridges etc etc. The problem is that electricity requirement vary enormously hence the relatively low overnight rates. Octopus' rates for example, are 7.5p for 4 hours overnight and 39.25p for the remaining 20 hours. Doubtless these rates will equalise when EVs become common, in which case the answer is to install solar panels and charge from those.
Yes you could do that. On average.
You might, if you are lucky, get solar insolation of 1000kWh/square metre/year.
And you might get 25% of that as electrical power from your photovoltaic panels.
Your car, needing 15kWh to do 100km, would need 1500kWh for a (slightly below average?) 10000km per year.
So 6 square metres of panel would do. Perfectly reasonable.
But very little of that solar energy arrives in the coldest months of the year (hardly seems fair, does it?), so you are back to drawing from the grid, at the same time as the COP of all those heat pumps falls to below 2 (when using electricity produced with an efficiency of 35%, at best) and people also plug in the backup fan heaters.
That's when the coal-fired power stations get lit up.
Yes things will get sorted eventually, but in the next few years if everybody with a boiler to replace got a heat pump, and everybody's new car was electric this country's carbon emissions would increase significantly.
 

Cantclimbtom

Well-known member
... ...but I somehow doubt that the emissions per mile of an electric car power by coal are better than a petrol/hybrid car by the time you add up the efficiency losses... ....
I was a sceptic of electric cars until this time last year. My thinking was that the electricity they use gets generated by gas fired power station or wherever rather than internal combustion so all you're doing is moving the point of carbon emissions from the car to the power station. I don't have the figures to hand but someone who did -- at the time showed me some back-of-a-fag-packet type calcs that looked at the efficiency of electricity generation, transmission, batteries motors and whatnot and then the efficiencies of oil extraction, refining, transportation and the car itself.

I was gobsmacked. Until they showed me, I hadn't looked at the efficiency of internal combustion or power stations and just make some assumptions - in my case my figures were way out. Just for example look at what proportion of energy in the fuel is actually used to power an e.g. petrol car versus what goes to heat.

I'd just *assumed* without looking at any figures maybe the car would be 30-40% efficient or something and maybe a power station was a little bit better. But as soon as it was pointed out to me that a gas fired power station is 55-60% efficient and a petrol engine is more like 20-25% efficient (it's a huge heat producer that just happens to get some work out of it where it can) then actually the figures need to be examined in detail and it isn't just moving the point of emissions, electric cars can very likely reduce CO2 emissions.
 

mikem

Well-known member
It has spare capacity at certain times of day, but they don't have the facility to store large amounts of energy - enough electric cars would improve this, plus in house storage, but battery technology is not carbon neutral. & as more vehicles come into use, more will need to recharge during the working day, as they don't have the range for continuous use.

In winter 2020 we got close to demand exceeding supply & they've just stood down 2 coal fired power stations that were prepared to be used this week if required:

Power consumption is now c.85% of what it was in 2000, but we've closed down most of the coal production since then:

We are also net importing power from France & just compare these figures with the ones I posted before about wind percentage (over 37% in November, down to almost zero recently, when we need more):
 

Fjell

Well-known member
Note - CO2e is greenhouse gas equivalent as CO2 - i.e. the amount of CO2 that would produce the same amount of greenhouse warming/climate change as the actual gases released (because many processes release other more potent greenhouse gases like methane).

In 2010 electricity has a greenhouse gas equivalent of 482g CO2e per kWh. In 2020 it was only 242g CO2e per kWh (it went up slightly to 265g CO2e per kWh in 2021). I assume those figures include transmission losses, but even if they don't that's only 9% loss. So electricity has been partly decarbonised and continues to be decarbonised.
Those figures are actually higher than others, e.g.:
which quotes 235g CO2e per kWh for 2019 UK generation at the point of consumption (i.e. including transmission losses) - 231g CO2e per kWh if you include imports. That doesn't include emissions before generation though e.g. in mining/transport.

An electric car will typically use 15 kWh per 100km. A petrol car will typically need 5.5l of petrol per 100 km.
Petrol is apparently 8.76 kWh / litre, so therefore the petrol cars use around 48 kWh per 100km. This is not unreasonable, as electric cars are massively more efficient than petrol cars (albeit actually generating that electricity is typically less efficient).

Petrol releases about 2.3 kg CO2 per litre burnt, so our 5.5l of petrol will release 12.65 kg of CO2 for that 100km drive.
The electric car, running off 265g CO2e per kWh UK electricity, releases 3.98kg CO2e.

That's massively less CO2, and looking at the trend of UK electricity carbon impact over the last 10 years (i.e. steeply decreasing) suggests that driving an electric car is better right now for the planet and will get even better in the future.
You need to run the figures at the margin.
Note - CO2e is greenhouse gas equivalent as CO2 - i.e. the amount of CO2 that would produce the same amount of greenhouse warming/climate change as the actual gases released (because many processes release other more potent greenhouse gases like methane).

In 2010 electricity has a greenhouse gas equivalent of 482g CO2e per kWh. In 2020 it was only 242g CO2e per kWh (it went up slightly to 265g CO2e per kWh in 2021). I assume those figures include transmission losses, but even if they don't that's only 9% loss. So electricity has been partly decarbonised and continues to be decarbonised.
Those figures are actually higher than others, e.g.:
[URL

An electric car will typically use 15 kWh per 100km. A petrol car will typically need 5.5l of petrol per 100 km.
Petrol is apparently 8.76 kWh / litre, so therefore the petrol cars use around 48 kWh per 100km. This is not unreasonable, as electric cars are massively more efficient than petrol cars (albeit actually generating that electricity is typically less efficient).

Petrol releases about 2.3 kg CO2 per litre burnt, so our 5.5l of petrol will release 12.65 kg of CO2 for that 100km drive.
The electric car, running off 265g CO2e per kWh UK electricity, releases 3.98kg CO2e.

That's massively less CO2, and looking at the trend of UK electricity carbon impact over the last 10 years (i.e. steeply decreasing) suggests that driving an electric car is better right now for the planet and will get even better in the future.
You need to run the calcs at the margin. Gas-fired is about 450g/kW.hr. Coal is over double that. For some decades to come gas will be the margin, assuming we can actually avoid coal in the short term as demand increases and our nuclear capacity diminishes.
My rough calcs previously said that if the UK was burning coal at the margin then every extra electric car was CO2 negative, and it might just be OK for gas. Which I think is about right. The only upside is building charging infrastructure which will take a while.
One of my little jobs going back 20+ years was calculating and reporting things like CO2 and NOx emmissions for our operations in a country. We were taxed on it, so it was a fiscal calculation.
We should already have 8-10 new nuclear plants in operation or construction, and we don’t. I see Macron just announced a similar scale of construction, but that’s also going to take a while.
I have lived in houses with an air con unit in every room and I am not going back to that. I prob need to drill two 100m+ deep wells in my drive (through Silurian rock) to hook up a ground source system and I would like to know it is worth it because there is no way it will be in monetary terms.
 

Wayland Smith

Active member
Possible alternative?

Breakthrough in nuclear fusion energy announced

https://www.bbc.co.uk/news/science-environment-63950962

BUT!

Remember in 1954 we were told that nuclear power would result in electricity so cheap that it could not be metered!

"The phrase was coined by Lewis Strauss, then chairman of the United States Atomic Energy Commission, who, in a 1954 speech to the National Association of Science Writers, said:
It is not too much to expect that our children will enjoy in their homes electrical energy too cheap to meter, will know of great periodic regional famines in the world only as matters of history, will travel effortlessly over the seas and under them and through the air with a minimum of danger and at great speeds, and will experience a lifespan far longer than ours, as disease yields and man comes to understand what causes him to age"

 

andrewmcleod

Well-known member
You need to run the figures at the margin.
Only if you are assuming that UK energy usage will increase and outpace renewable/low-carbon generation. This is a possibility but not by any means certain. Given the trend over the last 10 years (except this one), I'd rather suspect that despite the increase in consumption from electric cars that the carbon impact of electricity in the UK will continue to decline as we continue to shift to renewables and possibly even that the UK's overall consumption will continue to decline (slowly).
 

Speleofish

Active member
I can't help thinking a better descriptor would have been "Gaping Gill" or "Frozen Deep" rather than "cathedral" -sized when talking about underground cavities...
 
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