By Paul Homewood
h/t Ian Magness
More naive reporting from Matt Oliver:
The promise of underground riches is nothing new in Cornwall. But on Thursday, the region will plumb new depths in the quest to harness Britain’s natural resources.
For the first time, the United Downs deep geothermal power plant will start generating 24/7 electricity at a site near Redruth.
With an output of around three megawatts, enough to power roughly 10,000 homes, the plant cannot exactly be described as game-changing.
Yet experts believe it will help pave the way for similar projects across Britain aimed at tapping into the vast thermal resources below our feet.
The United Downs project, developed by Geothermal Engineering Ltd (GEL), will draw water at temperatures of around 190C from underground reservoirs that sit approximately five kilometres beneath the surface.
It takes advantage of a natural fault line using two wells, one that draws water up and one that pumps it back into the granite rock formations. Water that is brought above ground is run through a heat exchanger which uses another liquid with a lower boiling point to make steam and drive a turbine.
The result is power that is nearly always on – whatever the weather – save for short maintenance periods, says Ryan Law, the chief executive of GEL.
“Once you have done your drilling and the rest of it, the plant then runs 24/7 for about 96pc of the year,” he says.
In renewable energy, these kinds of numbers are virtually unheard of. Utility-scale solar tends to only push 25pc of the year while wind farms tend to land somewhere between 20pc and 40pc.
Full story here.
I’m not sure who these “experts” are. They would not be paid by GEL, by some chance?
The article also contains serious errors, not least the claim that solar power works at 25% efficiency. The true number is half that.
Bot the biggest error is this:
Matt Oliver obviously does not realise that £119/MWh is at 2012 prices! The current strike price is £170.50/MWh, three times the price of gas power:
Economically attractive, he says! What a joke. It is only viable because of the £3 million a year CfD subsidy plus that £1.8 million bung. And all for a miniscule contribution to UK electricity supply. The 3 MW quoted might generate 25,000 MWh a year, compared to total UK demand of 300,000,000 MWh.
But it gets much worse! The process has been causing earth tremors, as Oliver reports:
Like fracking, however, this kind of drilling can cause unnerving mini-earthquakes.
In Britain, ministers effectively outlawed fracking for oil and gas when they limited operations that create tremors of more than a 0.5 magnitude.
There are no such rules for geothermal, even though it has caused mini-tremors that were three times more powerful than this, with the industry instead regulated based on its surface vibrations. Law argues that this is more sensible because it measures the actual effects above ground.
So it’s OK to have earthquakes three times as powerful as from fracking, because geothermal is “good” and fracking “bad”.
FOOTNOTE
I have left comments for Matt Oliver, pointing out his CfD strike price error, but so far the article still has not been corrected.
There has been a geothermal power station in Southampon for years. It is quite small and supplies power to the port. It is insufficient to provide shore power to the many cruise ships and container ships that visit the port. I think only 2 berths currently have shore power available. In part, this is because the destruction Calshot (oil) and Didcot (coal) power stations have left the Hampshire area short of grid supply. This has resulted in Southampton being one of the worst towns in the country for air pollution. Story tip: This may be an interesting feature to follow up on the blog. e.g. Could the geothermal power be increased?
Depends on what exactly heats it below.
In most cases output probably is not even close to the practical limit, but both plain costs and maintenance would have a bad case of diminishing returns.
The subsidies could mitigate this somewhat… but without fine-tuning this would only lead to more non-viable money sinks, just like those sludge bombs instead of methane infrastructure and the rest of industry powered by the Watermelon regulations.
The Southampton geothermal power station doesn’t supply electricity to anywhere. It does provide free heating to much of the city centre and surrounding council houses.
It’s two tier everything with Labour from self-determination through to fracking.
The limit of 0.5 was always a cynical ploy to kill fracking off at birth…
Ed Davey: I’m proud to have stopped fracking, despite energy crisis
In 2012, he introduced a strict regulation that means companies have to halt work if they trigger tremors over 0.5 magnitude. – iowaclimate
For some small degree of context
1 kg of flour dropping to the floor 1.194
A 2.5 kg bag of potatoes dropping 1.98
2 people jumping 1.374
A football being bounced (softly) 0.845. Liverpool ac
It was a political decision – even though there was and is an energy crisis. They’ll be alright, Jack. They’ll see to that.
To that you can add:-
My wife slamming the back door : the whole house shakes (so it must be a higher value than those).
Have you considered a brick built house?
That is a brick built house, you haven’t seen his wife!
This is true. Is she like… Brunhilde?
Well, 0.5 is ridiculous.
Worse, the problem is not whether it’s 0.5 or 1.5 but rather dynamics. The stupid arbitrary notches the bureaucrats love so much are deceptive on both ends.
If a large mass was rearranged, there were tolerable tremors, and then they end once everything is settled to a new equilibrium — it’s one thing. But if they continue — why?
Small tremors as such are a good sign: energy is dumped in small portions before any more could accumulate. But if this happens because cracks keep propagating, there may be a larger shift waiting to happen.
There is no doubt this project is a seriously commendable feat of engineering, the genesis of which was “The Hot Rocks Project” under the auspices of the Camborne School of Mines and the endeavour has been decades in its development.
But will it ever be a go-to form of generation in the United Kingdom?
Highly unlikely, despite the effective 24/7 generation capability.
Capital costs per MW for combined-cycle gas is in the order of £1 million per MW; it’s £3.7 million for offshore wind; and it’s £750,000 for solar.
But, for this project, it’s in the order of £15.5 million per MW.
And, without the considerable subsidies of various forms, it is undoubtedly highly accurate to observe the project would . . . never have got off the ground.
Regarding “EARTHQUAKES!!” . . . give me a bloody break – blasting vibrations from what we hope will be renewed mining operations at the nearby South Crofty Mine will be rather more noticeable while being equally likely to cause no surface damage whatever.
That said, the reason for the government’s banning of fracking is hypocrisy of the tallest order and nothing less than bloody laughable.
With the caveat that capital costs should be divided by maximum likely capacity factor. CCGT should be capable of sustaining 90%, so figure £1.1 million. Offshore wind is likely 33%, so figure £11 million, solar might be good for 16%, so figure £4.5 million plus battery costs. With a claimed capacity factor of 96%, the £16 million per MW for geothermal doesn’t sound all that wacko compared to other renewables.
No argument from me on the UK’s banning of frac’ing being ridiculous.
“With an output of around three megawatts, enough to power roughly 10,000 homes, the plant cannot exactly be described as game-changing.”
300W per household. Fridge + TV + a few lights – maybe, and not all homes at once. Oh yeah, you can probably charge your phone too.
This is a silly way to describe it.
For 3,000 homes that would still be only 1kW per house. Hardly enough, I’d have thought, particularly if they all put the kettle on simultaneously…
Fantasy figures.
Why do we measure electricity generation in terms of household usage? Why not measure it terms of Aluminum Smelters?
By the way, they have nearly killed off Tomago Smelter in NSW, Australia.
We don’t–they do.
Innumeracy rules.
When I run my A/C in summer my usage averages 2KW/hour…47KWh/day
How does the 6th form describe it?
‘Magic beneath the surface’: pioneering geothermal plant launched in Cornwall
Expensive magic.
300W per household at 230V?
Using P=EI I only get 1.3 amps. I don’t think it’s powering even that much.
I’m wondering what the lower boiling point fluid is that is used to drive the turbines and why it is not specifically called out. Is it isopentane, pentane, a fluorinated refrigerant?
Even plain water boils at 100°C (212°F)
Good posting by Paul, and good report by Matt. Earthquakes/tremors at 0.5 to 1.5? The lowest felt by humans is 2.0 (above shallow source) or 2.5 (close to medium depth source). The Jurassic dinosaur Seismosaurus could beat this easily. Never mind.
Need a good scare story, geologists need not apply.
Locals have reported some vibration and rattling windows.
Some sources say largest tremors were 1.7 local magnitude, some up to 2.3, direct or induced.
It’s incorrect to say they operate without limit though.
“Cornwall Council imposed a maximum PGV limit of 8.5 mm/s for a single event, based on existing British Standards (BS 6472-2:2008) for blasting/quarrying.
“Caution” State Trigger: Operations enter a “caution” state if events with a PGV greater than 0.5 mm/s are detected during the day.
Operational Protocol: If events exceed these conservative limits, operations are closely monitored, and if further significant events occur, operations will cease until the reservoir stabilizes.
Performance: During testing in 2020, the maximum PGV recorded was 0.8 mm/s, which is more than ten times less than the 8.5 mm/s limit, despite some events being felt by locals.” (8.5 = about 2.2 local magnitude when measured at a short hypocentral distance)
If lubricating a fault produces small tremors, it is evidence that a delayed and much stronger tremor is avoided.
Rubbish. These aren’t fault based tremors.
Lol, haters still active. Downvoting without the intellect to explain.
The water may be 190C now, but that won’t last long once they start cycling water through the system.
Not efficiency, “% of the year”.
Presumably when it’s worth the trouble of plugging in at all. Which mostly should be far below peak possible output, of course. So half of this sounds about right.
“So it’s OK to have earthquakes three times as powerful as from fracking, because geothermal is ‘good’ and fracking ‘bad’.”
It’s like wind farm bird kills and whale kills, and Ivanpah “solar” smoking-bird kills all over again – for greenies, it’s OK to kill wildlife because, well, I don’t know why – don’t make no sense to me. As President Trump said about democrats, “These people are crazy”. The problem for the rest of us it that somehow they have been able to control the narrative that killing birds/whales == “Green” energy.
Seems Communism is so classless(it has no class at all) that even their animal killings and desasters
are more equal than those caused by everyone else.
When you extract heat from a heat reservoir it gets colder. The cold water pumped into the well to replace the hot water taken out has to be heated to the same temperature as the water taken out. If that takes too much time, inevitably the source will cool off and becomes useless. So the amount of energy you can extract depends not only on the temperature of the source but more importantly on the speed at which the extracted heat is replenished. Don’t be shocked if in Cornwall that recovering time may turn out to be too long for the amount of heat they want to extract.
Giggle. Do geothermal at Yellowstone.
Or you could build a safe, clean, reliable and affordable nuclear power plant and have pier for many many decades.
“So it’s OK to have earthquakes three times as powerful as from fracking, because geothermal is “good” and fracking “bad”” – this is consistent with what human behaviour experts reveal: that humans mostly make decisions based on Emotions, & the Rational part of our brain is used merely to justify & rationalize the Emotional decisions made. And then there’s Propaganda…
Geothermal works well where there is wet hot rock (Iceland, New Zealand, California) and can work well in dry hot rock. As has become usual though, the British do half measures. Generating electricity with a low temperature working fluid cuts the Carnot efficiency in half. It would be more efficient to provide process heat and space heating. The Swiss were drilling deeper for greater heat, but produced swarms of tiny earthquakes so frightened people stopped the project. Ignorant people are easily frightened.