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EM. Where do you get the 20 year lifetime figure from? This must be a pure guess.

You also ignore the thermal energy output of the scheme which is considerably greater than produced electricity.

An additional component not so far analysed here is the return on investment (either financial or energy). I'm willing to wager that conventional gas wells would be far more efficient, perhaps even tight gas wells. Remember you need to drill at least two wells for a geothermal scheme, commonly three.

Jul 21, 2017 at 2:37 PM | Unregistered CommenterSupertroll

Well, no more so than you, Entropic man. I am learning from an expert at data manipulation.

Let’s cut to the chase, and see what it looks like since 1901, shall we?

Oooh, look! 0.9°C in 115 years – less than 0.8°C per century. Not so scary, now, is it? And at the rate it has been rising since 2001, it will only have risen by less than 1°C by 2100 – and that is assuming the trend remains upwards, and there are no drops in the interim, as was observed during the last century… and the century before that. Why worry?

Jul 21, 2017 at 2:22 PM | Registered CommenterRadical Rodent


No good sceptic worries about the quality of the environment when there is money to be made. Ask Donald Trump in the White House or Scott Pruitt at the EPA.

Jul 21, 2017 at 2:16 PM | Unregistered CommenterEntropic man

Golf Charlie

From the published figures the Redruth geothermal plant is rated at 1.3MW. Over a twenty year life it would produce 228,000MWh. We calculated earlier that it would produce 40 million kg of CO2 over that time.

That gives a lifetime CO2 output of 175kg CO2/MWh. Add on a typical 5kg/MWh for its construction you get a total of 180kg/MWh.

For a gas plant the Parliamentary report quotes 500kg/MWh in operation. Add-on the 5kg/MWh for construction and you get 505kg/MWh.

The geothermal plant produces 180/505 * 100 = 36% of the output from a gas plant.

As Supertroll pointed out, it rather depends on what you are comparing. I did not see the National Geographic article. What proportion of flash steam, dry steam and binary generation were they using?

And yes, a flash steam geothermal plant should pay carbon tax.

Jul 21, 2017 at 2:04 PM | Unregistered CommenterEntropic man

Radical rodent

You naughty cherrypicker! You should be comparing like with like, not an El Nino year with an ENSO neutral year.

If you want to start with the 1941 El Nino peak at 0.4C you should be comparing it with the 2016 El Nino peak of 1.3C.

If you want to end with ENSO neutral 2017 at 0.8C you should be comparing it with the post 1941 ENSO neutral years at 0C.

You also claim that the CO2 produced during construction is ignored. More bullshit.

When you build electrical generation plants the construction cost in CO2 is comparable across all forms of generation. To this you add the CO2 produced in operation. The correct unit is the amount of CO2 used in the construction and operation divided by the lifetime output of the plant.: kg CO2/MWh.

There are lifetime figures available from the parliamentary report at http//>postpn268

Renewables vary from wind and hydro at 5kg CO2/MWh to 60kg/MWh for PV. Nuclear is also 5kg/MWh. These are front loaded because most of the total lifetime CO2 is produced during construction.

Fossil fuel plants produce 1000kg/MWh coal and 500kg/MWh for gas. These are end loaded since most of the lifetimen CO2 is produced during operation.

This is why I laugh when you talk about "facts". So much of what you write is demonstrably wrong.

Jul 21, 2017 at 1:39 PM | Unregistered CommenterEntropic man

Gwen. Steam and superheated steam geothermal fields are confined to volcanic terrains. Groundwaters in such settings are in part derived from (or are otherwise contaminated by) magmatic sources that include carbon dioxide, hydrogen sulphide and magmatic water. Carbon dioxide may be so abundant that gas fields composed almost entirely of the gas do occur (they have some value providing CO2 for tertiary recovery of oilfields). Thus CO2 released by geothermal plants comes from the geothermal fluids.
If geothermal fluids used in binary systems are returned to the subsurface, the contained CO2 is never released. Steam/superheated steam plants usually allow any water to flash to steam so releasing CO2 to the atmosphere. Geothermal plants I have visited in California and New Zealand are noisy, stinky places you would not want for neighbours. My granddaughter says the same about a plant she visited in Iceland. So not so environmentally friendly.

Jul 21, 2017 at 1:25 PM | Unregistered CommenterSupertroll

Jul 21, 2017 at 12:26 PM | stewgreen

Jul 21, 2017 at 11:01 AM | Supertroll

Jul 21, 2017 at 12:01 PM | Radical Rodent

Thank you!

But, I am still no clearer about this statement from the National Geographic article!
"Geothermal fields produce only about one-sixth of the carbon dioxide that a relatively clean natural-gas-fueled power plant produces".

Is this CO2 coming out of the ground as an operational running "cost", and should it be subject to a Carbon Tax?

The Green Blob were the ones who thought Carbon Taxes were a good idea

Jul 21, 2017 at 1:02 PM | Unregistered Commentergolf charlie

@Robert Christopher said : 'CrossRail route was previously unelectrified, so that is part of the £16bn cost.'
OK that surprised me cos although no rail is electrified on the south/north of the Humber we just assume all London track is electrified.
- So yes thru the entire length of CrossRail each journey has the EXTRA utility of being electrified and lower local emissions.
So the new UTILITY we get from CR is a few new tunnels and electrification.
Now that's fair enough if we recover that £16bn from peoples ticket cost which also has to include all the running costs aswell.

(RC argues that you can't write off infrastructure cot over 10 years it should be 100 years. Well hang on that means in today's ticket prices we should have a component from the last 100 years infrastructure. eg Reading and Paddington stations have been renovated in last few years eg Reading cost £425m non Crossrail budget)

Crossrail may well be convenient for London commuters, but I bet what they pay won't ever pay for it all.
Main suspicion is that Northern taxpayers pay for London commuters privileges
Does that matter ? Cos I'm thinking the way it happens in London is that the gov spends £10bn on ridiculous infrastructure gimmicks, but then property prices rise by £20bn and everyone is happy long as the music goes on and the game doesn't stop.

I'm really uncomfortable with the way UK economy relies so much on rising property prices rather than profits from selling goods/services.

Jul 21, 2017 at 12:31 PM | Registered Commenterstewgreen

@RR Spot on
+1 for critical thinking there.

That's the problem we have with typical green thinking
They've quick to over-estimate one side of the balance (green +ves, or FossilFuel -ves)
... yet brush over the other side of the balance (green -ves, or FF+ves)

Jul 21, 2017 at 12:26 PM | Registered Commenterstewgreen

golf charlie:

It can be extracted without burning a fossil fuel such as coal, gas, or oil.
Except of course, for the drilling. And the fracking. Oh, and the pumping. Other than that, no fossil fuels are required (and let’s ignore those used in the construction of all the tools and machinery used to enable the process, too, as well as burned in transporting these to the site, and those transporting the work-force hither and thither).

Some people do live in little bubbles of unawareness.

Jul 21, 2017 at 12:01 PM | Registered CommenterRadical Rodent

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