UK Carbon emissions per kWh.  Surprising. - Page 1
Forum section: electronics / general

author: paulca
author_rank: Super Contributor
timestamp: October 12, 2022, 03:57:27 pm
content: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1083857/2022-ghg-cf-methodology-paper.pdfIt's a long read, but the parts I went looking for were the conversion ratios between burning methane (LPNG) for heat and using resistive heating elements (for example). CO2 / kWhe versus CO2 / kWhtThere are tables and tables and tables and they all seem to give different values depending on which perspective they are looking at it from. The surprising thing is how rapidly the ratio has been falling.I find as you get older time seems to go faster and it's easy to get out of date, but the figures they are proposing for the UK fuel mix are something around 170g/kWh burning methane, 190g/kWh burning propane and 191g/kWh electricity.I'm like, what? (watt?). How? When?The UK has a fuel mix of about 40-45% natural gas for electric generation. CCGT plants are about 60%-70% thermally efficient and the turbine generators are, what?, 90% efficient? Then (from the report) about 8% grid loss.I'm probably butchering the maths, but for each kWh electric, 0.45kWh is generated from gas. The overall generation efficiency is 60%*90%*92% = 0.496. So to generate 0.45kWh it will need to consume roughly 0.9 kWh of gas.That works out. Doesn't it? That 1kWh of electricity, in the UK, currently "costs" 1 kWh of gas. That would not eat into the GOP of heat pumps that much.I suppose I'm admitting I was wrong for quite a while. I thought it was just 3:1 * carbon fuel mix %.Either that or there is a large amount of greenwashing going on, or my maths or assumed figures (for generation efficiencies for example) are way out. The others are from the paper.

author: IanB
author_rank: Super Contributor
timestamp: October 12, 2022, 04:22:33 pm
content: I read your post over and over again, but I can't understand what you are asking. What is your question?

author: tom66
author_rank: Super Contributor
timestamp: October 12, 2022, 04:46:55 pm
content: The UK grid is so clean that you can drive a Tesla Model X SUV (a ridiculous vehicle that weighs about 2.5 tonnes) and come ahead of the emissions profile of a moped running on petrolMoped on petrol ~120mpg: emissions per gallon of petrol ~10.9kg so 1 mile ~90g CO2eqModel X on ordinary UK grid electricity at 200g/kWh: 2.5 miles/kWh in worst typical case so 1 mile ~80g CO2eqIgnoring tyres/maintenance for simplicity (Model X probably loses when you consider those, but I expect only just!)Heat pumps would make sense because their COP is high. 1kWh electricity may require about 1kWh of gas (assuming your calculation is correct) but COP of 3 is achievable easily. Meanwhile average gas boiler manages about 80% efficiency in typical installation.

author: jonpaul
author_rank: Super Contributor
timestamp: October 13, 2022, 06:44:31 am
content: the question seems irrelevantThe main CO2 and warming source is animals grown to be slautered and eaten, politicians and governmentsNon Western /US UK countries will continue to use coal, gas, oil, frac for decades or forever, to keep the governments in power.Real solution is nuclear powerjon

author: SiliconWizard
author_rank: Super Contributor
timestamp: October 13, 2022, 07:56:51 pm
content: Methane is the most problematic greenhouse gas.https://www.sciencelearn.org.nz/resources/3132-methane-a-greenhouse-gasSure the poor cows emit a lot of it. As natural gas, this gets released in the atmosphere as is only if there are uh... leaks.But otherwise, burning natural gas is a lot less pollution than burning other kinds of fossile fuels. (Natural gas is mostly methane.)https://group.met.com/en/mind-the-fyouture/mindthefyouture/natural-gas-vs-coal

author: james_s
author_rank: Super Contributor
timestamp: October 13, 2022, 08:35:43 pm
content: It's too bad we can't easily harness all that methane that cows produce. It seems less damaging to the environment to burn it than to release it into the atmosphere, and it's useful stuff too.

author: tom66
author_rank: Super Contributor
timestamp: October 13, 2022, 08:45:14 pm
content: There are farms around here that collect the, err, "cow leavings" and recycle it to produce biogas. I recall the problem with this, besides the cost per kWh, is that most of the methane comes from the burp and not the opposite end. So you need to put a mask on a cow then, to capture the methane. Good luck with that.

author: IanB
author_rank: Super Contributor
timestamp: October 13, 2022, 08:49:54 pm
content: Quote from: tom66 on October 13, 2022, 08:45:14 pmThe waste can be digested (composted) to produce methane gas and leave a nitrogenous fertilizer behind. This may not scale to large amounts of energy, but it works for small scale energy production.

author: Gyro
author_rank: Super Contributor
timestamp: October 13, 2022, 08:54:14 pm
content: Quote from: tom66 on October 13, 2022, 08:45:14 pmhttps://www.eevblog.com/forum/dodgy-technology/holy-cow!/

author: tszaboo
author_rank: Super Contributor
timestamp: October 13, 2022, 09:29:47 pm
content: Quote from: IanB on October 13, 2022, 08:49:54 pm1.) I believe recent studies found that adding like 10% of algae into the diet of cows makes them emit almost no methane.2.) So actually, all the vegan people should be glad that we eat meat. The more meat we eat the less cow remains, the better it is for the environment. This is simple math.OP: Also this trend looks good.

author: tom66
author_rank: Super Contributor
timestamp: October 13, 2022, 10:03:42 pm
content: I don't generally agree with much of what the UK government has done but they have really got the transition to renewables right - it's happening with rapid pace. I'd like to see more joined-up thinking in the area of storage (to go fully renewable, we need *days* of storage capacity) and smart consumption (spearheading some kind of smart device standard would be great, we need dishwashers and washing machines etc that run at the best time)

author: themadhippy
author_rank: Super Contributor
timestamp: October 13, 2022, 10:30:34 pm
content: Quoteeven though there trying to stop farmers from building new solar farms?They make the excuse the land is needed for food production,but then another report comes out asking farmers start growing more biofuel products to get burnt in power stations

author: SiliconWizard
author_rank: Super Contributor
timestamp: October 13, 2022, 10:37:04 pm
content: It seems to be working very well indeed.

author: tom66
author_rank: Super Contributor
timestamp: October 13, 2022, 11:27:16 pm
content: Quote from: themadhippy on October 13, 2022, 10:30:34 pmPerhaps this current iteration of the government notwithstanding then - though given opinion polls do we think they will make Xmas?!

author: paulca
author_rank: Super Contributor
timestamp: October 14, 2022, 02:33:10 pm
content: The UK just moved all it's industry and manufacturing to other countries to emitt the CO2 for them over there.