Aberthaw Power Station and Decarbonisation

[whole diary]

[Red Squirrel]

Rolls-Royce and other key players think it might make sense in aeroplanes - see this Flight Global article. With three times the energy density of jet fuel, coupled with the fact that adapting jet engines to burn it is not that much of a leap, it could well make sense in that appllcation. I have heard it argued that it may even be safer than jet fuel, because if it leaks out of the tanks it'll be blown away before if can catch fire, unlike jet fuel which sticks to things and then burns...

By the way, does anyone else share my suspicion that we've moved on a bit from talking about Aberthaw Power Station..? Shall I split this thread?

[broadgage]

Yes it might be worth either splitting this thread, or perhaps editing the title to include "energy production and storage" or some similar wording.

[stuving]

Yes it might be worth either splitting this thread, or perhaps editing the title to include "energy production and storage" or some similar wording.

I reckoned it was all about decarbonisation, one way or another.

[Red Squirrel]

OK, I've added ' and Decarbonisation' to the OP^▸ (Original Poster / topic starter).

[Bmblbzzz]

But seriously. 50MW of superfluous renewable energy can produce one tonne of hydrogen per hour, which will provide a maximum of 39 MWh of energy, less the energy needed to compress the 1 tonne in the first place. I read something from VW, who know all about measuring engine statistics (ahem) a couple of years ago that said the energy translated into actual motive power in a hydrogen car is about a third of the energy in the tank, so your 50MWh to produce a tonne of gas becomes 13MWh in the car. They didn't think it was worth it - whether that was to boost the image of their clean diesels by bad-mouthing the alternatives is not something I know.

TBF^▸ (To Be Fair) though that's about the same as in a diesel or petrol car. An electric car does much better, I understand. And a pedal cycle is surprisingly bad in this respect but that's presumably in part because the energy produced in respiration has to do trivial things like keep the rider's heart beating.

[TonyK]

TBF^▸ (To Be Fair) though that's about the same as in a diesel or petrol car. An electric car does much better, I understand. And a pedal cycle is surprisingly bad in this respect but that's presumably in part because the energy produced in respiration has to do trivial things like keep the rider's heart beating.

I don't disagree. It's just that this is not put across in the original claim, of 50 MW producing 39 tonnes H₂ in an hour in a way that doesn't make it look as though you can stick that 50 MWh in the tank, and head for Barnard Castle.

I'm not claiming scientific or mathematical accuracy, but I thought I would try to work out some sort of rough numbers. For a pure electric car full of batteries, so far as I can tell, 25KWh will get you about 100 miles without extra drain on the batteries like aircon, lots of things charging because of kids in the back seats etc. Cost wise, that is good news.at around 3.75p per mile, compared to about 13p per mile for a petrol car doing 40 mpg at ?1.13 per litre. The best figure I can get for a hydrogen car seems to be about 17.4p per mile, or at least was in 2017 when the Evening Standard article was published.

Another way to look at is that if that 50MWh is produced by either 25 onshore or 10 offshore wind turbines, an hour's production will produce enough hydrogen to send 1,000 cars on a journey of about 15,000 miles at 30% efficiency. But it will produce sufficient electricity to send 1,000 pure electric cars a distance of 20,000 miles, which seems a better use of the power without taking other factors into account.

[stuving]

Why does everyone keep going on about hydrogen used as a transport fuel?

[onthecushions]

Because although the shortest distance between two points is a straight line, we always seek a more direct route.

Just the prejudice of a superannuated thermodynamicist.

OTC

[stuving]

Batteries or fuel cells connected via static inverters contribut to INSTABILITY.

Why? If they replace physical inertia, its absence certainly does. But in principle a BESS^▸ (Battery Energy Storage Systems) (battery plus 4-quadrant converter) can provide virtual or synthetic inertia. All you need is to add the right ... software!

Work continues on this, though most of it is analysis or simulation. PG&E in California have at least reported some experiments with a 1 MWhr unit and a real grid.

EPIC 2.05 - Inertia Response Emulation for DG Impact Improvement

This project explored the capabilities of inverter-based energy resources to provide a set of functions related to system inertia which support the electric system. The project demonstrated via transmission system modeling and Power-Hardware-In-Loop testing that advanced inverter control methods can provide active power support that improves the system?s frequency response in the face of reduced conventional inertia from synchronous machine generators. Inverter control methods were explored including inertia-like response (derivative control) and grid-forming (voltage source) modes for respective benefits in bulk system and isolated distribution system use cases.

Our TSO^▸ (The Stationary Office (now OPSI)) is working on it, though I can't find evidence of any real hardware.

It's not just a matter of doing the maths and trying to match the effects of real inertia. In some ways a different power flow profile from real inertia is an advantage, and of course there may be power limits a big generators doesn't have. There are other changes going on too, such as how the voltage response is affected by all these inverters doing their own thing. But we'll see - some time soon.

[ellendune]

Because although the shortest distance between two points is a straight line, we always seek a more direct route.

But the shortest distance between any two places on the earth's surface is along a great circle! Unless you are going to dig a hole!

[onthecushions]

But the shortest distance between any two places on the earth's surface is along a great circle! Unless you are going to dig a hole!

Very true.

It's better to go round in great circles than to get stuck on a r(h)um(b) line.

OTC

[Bmblbzzz]

Because although the shortest distance between two points is a straight line, we always seek a more direct route.

But the shortest distance between any two places on the earth's surface is along a great circle! Unless you are going to dig a hole!

Set the controls for the heart of the earth, Mr Chekhov.

[Red Squirrel]

Roger, Mr Waters...

[TonyK]

Roger, Mr Waters...

My copy has them set in the opposite direction.

[broadgage]

As has already been said, there is not any overnight surplus of renewably generated electricity.
As more wind turbines are erected, less natural gas is being burnt, but SOME gas is still used.

The day when there WILL be a surplus of renewable electricity is however getting nearer. During the last few hours, electricity from natural gas has dropped to only 3 or 4 Gw, an unusually low figure. A 50% increase in wind turbine capacity could see gas drop to zero.
Not all the time of course but under favourable conditions.

For the least few days, electricity from wind has been the largest input to the grid, not continually, but nearly so.