The Alternative Green Energy Thread

QrizB

I'm not sure where you get 2.5% from? Unless you're only counting wind and ignoring other sources?

The figures from Electric Insights (the site you linked, thank you) show that yesterday, 21/07/21, fossil fuels generated 390GWh, just over 50% of the total day's demand of 740GWh. Solar (7.3%), wind (2.3%) and biomass (8.7%) together generated 150GWh, roughly 18% of the day's demand.

So if, as you suggest, we quadrupled our solar, wind and biomass capacity (plus some short-term storage to smooth it) we would have had an extra 450GWh and would have been able to get through the day without FF.

QrizB

Sorry, I missed your question about cost.

1. Solar. The UK has 13.5GW of solar PV installed. The CAPEX cost of solar PV is around 45p/watt so adding another 50GW would cost £23Bn, more or less, or about 1/4 of HS2 (or 2/3rds of NHS Test & Trace).
2. Offshore wind. The UK has 24.1GW of wind power. The CAPEX cost of offshore wind is around £1.60/watt so adding 72GW would cost £115Bn, about as much as HS2.
3. Biomass. The UK has about 2.5GW of biomass power. The CAPEX cost of biomass including carbon captiure is around £3.50/watt so adding 7.5GW of biomass would cost around £26Bn, another 1/4 of an HS2.

So it would cost £164Bn.

The flip side is that, even allowing for those CAPEX costs, electricity should then be cheaper; see the LCOE figures in the BEIS report I used.

(Source doc for my price data, 2025 prices.)

PS I'm not for one minute suggesting that this is the most sensible energy split, I've not done any sort of analysis beyond "what do we have today and adding 3x more".

JKenH

QrizB said:

I'm not sure where you get 2.5% from? Unless you're only counting wind and ignoring other sources?

The figures from Electric Insights (the site you linked, thank you) show that yesterday, 21/07/21, fossil fuels generated 390GWh, just over 50% of the total day's demand of 740GWh. Solar (7.3%), wind (2.3%) and biomass (8.7%) together generated 150GWh, roughly 18% of the day's demand.

So if, as you suggest, we quadrupled our solar, wind and biomass capacity (plus some short-term storage to smooth it) we would have had an extra 450GWh and would have been able to get through the day without FF.

Sorry I meant weather dependent renewables. The jury is out on biomass - how clean is it really?

The 2.5% was a rounding up of the 2.3% wind contribution. Solar helps in summer but we can have anticyclonic days in winter with virtually no wind and very little solar. Perhaps I am being a bit pessimistic but on 3rd March, wind contributed 2.4% and Solar 0.9% so 3.3%  (1.24GWh) leaving fossil fuels to pick up 62% or 23GWh. Presumably other sources were running at maximum so if renewables were to pick up that fossil fuel capacity we would need around 18 x our current renewables (weather related) capacity. Virtually all our biomass generation is from Drax and I doubt we are going to be building many more of those plants. We won’t be building 18 x our current wind turbine or solar fleet so there is a big gap for storage to fill.

JKenH

QrizB said:

Sorry, I missed your question about cost.

1. Solar. The UK has 13.5GW of solar PV installed. The CAPEX cost of solar PV is around 45p/watt so adding another 50GW would cost £23Bn, more or less, or about 1/4 of HS2 (or 2/3rds of NHS Test & Trace).
2. Offshore wind. The UK has 24.1GW of wind power. The CAPEX cost of offshore wind is around £1.60/watt so adding 72GW would cost £115Bn, about as much as HS2.
3. Biomass. The UK has about 2.5GW of biomass power. The CAPEX cost of biomass including carbon captiure is around £3.50/watt so adding 7.5GW of biomass would cost around £26Bn, another 1/4 of an HS2.

So it would cost £164Bn.

The flip side is that, even allowing for those CAPEX costs, electricity should then be cheaper; see the LCOE figures in the BEIS report I used.

(Source doc for my price data, 2025 prices.)

PS I'm not for one minute suggesting that this is the most sensible energy split, I've not done any sort of analysis beyond "what do we have today and adding 3x more".

That sounds like a big number but tbh I’ve no idea how it translates to our bills. 

If our demand for power is say 30GW and wind and solar can currently just about approach that on a perfect day for both then increasing solar and wind will eventually produce an oversupply much of the time. In a competitive market as supply increases prices will fall until an equilibrium is reached when there will be no new entrants to the market. This is likely to occur long before sufficient capacity exists for wind or solar to be able to meet demand on a still or dark day. 

I know it is often said that the cheapest way forward is just to overbuild renewables so much that even on the worst days they can cope but in a free market this is never likely to happen. Eventually the market price of electricity drops so much that  only the cheapest generators survive and as new installations are built old ones are retired as they are no longer competitive. My view FWIW is that it will be more cost effective to build storage now than just keep on increasing weather dependent renewables capacity. Once sufficient storage is in place, be it batteries, hydrogen or whatever there will be a market for what is currently excess wind/solar and that in turn will incentivise more renewable generation. A balance is needed between storage and generation and currently we are adding generation faster than storage.

JKenH

Warning over winter power crunch

Britain must prepare for low energy supplies this winter as two nuclear plants shut down and workers return to the office, the business behind the power network has warned.

Low wind speeds and surging demand in Europe may also squeeze the amount of electricity available as the months get colder, according to National Grid Electricity System Operator (ESO).

There is also uncertainty over how much energy will come from remaining coal-fired power stations as they start to shut down.

National Grid ESO said: "While we remain confident there is sufficient supply to meet peak demand, we should prepare for some tight periods during the winter. We have a well-functioning market that responds to market signals and the ESO may need to use its tools to manage these periods."

The power system is getting less predictable as it moves from relying on large, fossil-fuelled plants to more wind and solar power stations, as well as cables linking to the continent which can be used to import and export power.

https://www.telegraph.co.uk/business/2021/07/22/centrica-opts-keep-nuclear-power-stake/

QrizB

JKenH said:

I know it is often said that the cheapest way forward is just to overbuild renewables so much that even on the worst days they can cope but in a free market this is never likely to happen. Eventually the market price of electricity drops so much that  only the cheapest generators survive and as new installations are built old ones are retired as they are no longer competitive. My view FWIW is that it will be more cost effective to build storage now than just keep on increasing weather dependent renewables capacity. Once sufficient storage is in place, be it batteries, hydrogen or whatever there will be a market for what is currently excess wind/solar and that in turn will incentivise more renewable generation. A balance is needed between storage and generation and currently we are adding generation faster than storage.

It seems to me to be a chicken-and-egg situation. Currently, on all but the windiest days, we're still burning NG in CCGTs to meet base load. Energy prices remain high enough that it's worth building more renewables (just look at Agile Octopus, there hasn't been a negative price period since one half-hour in May, and it's been over 10p for eight weeks straight). Storage relies on the old market truism of buying low and selling high and currently there's hardly any "low".

Once there's enough weather-dependent renewables that energy is regularly available at bargain-basement prices (ideally free), there will be the incentive to store that surplus for those days when it's wanted. Exactly what form that storage takes is something I can only speculate on; batteries are great on the small-to-medium scale but I don't think anyone has built a 1 GWp / 10 GWh array that could replace a CCGT, at least not yet.

(Just thinking out loud, a 20' shipping container full of batteries contains 800kWh. A modern container ship holds 20,000 containers so a single vessel would make a 16GWh battery. That's the size of array you're looking at to make a "battery storage power station" worthy of the name. At current battery prices of $100/kWh it would cost £1.6Bn.)

Cardew

QrizB said:

(Just thinking out loud, a 20' shipping container full of batteries contains 800kWh. A modern container ship holds 20,000 containers so a single vessel would make a 16GWh battery. That's the size of array you're looking at to make a "battery storage power station" worthy of the name. At current battery prices of $100/kWh it would cost £1.6Bn.)

Interesting discussion.

The security implications for guarding these 'battery storage power stations' are huge.

JKenH

QrizB said:

JKenH said:

I know it is often said that the cheapest way forward is just to overbuild renewables so much that even on the worst days they can cope but in a free market this is never likely to happen. Eventually the market price of electricity drops so much that  only the cheapest generators survive and as new installations are built old ones are retired as they are no longer competitive. My view FWIW is that it will be more cost effective to build storage now than just keep on increasing weather dependent renewables capacity. Once sufficient storage is in place, be it batteries, hydrogen or whatever there will be a market for what is currently excess wind/solar and that in turn will incentivise more renewable generation. A balance is needed between storage and generation and currently we are adding generation faster than storage.

It seems to me to be a chicken-and-egg situation. Currently, on all but the windiest days, we're still burning NG in CCGTs to meet base load. Energy prices remain high enough that it's worth building more renewables (just look at Agile Octopus, there hasn't been a negative price period since one half-hour in May, and it's been over 10p for eight weeks straight). Storage relies on the old market truism of buying low and selling high and currently there's hardly any "low".

Once there's enough weather-dependent renewables that energy is regularly available at bargain-basement prices (ideally free), there will be the incentive to store that surplus for those days when it's wanted. Exactly what form that storage takes is something I can only speculate on; batteries are great on the small-to-medium scale but I don't think anyone has built a 1 GWp / 10 GWh array that could replace a CCGT, at least not yet.

(Just thinking out loud, a 20' shipping container full of batteries contains 800kWh. A modern container ship holds 20,000 containers so a single vessel would make a 16GWh battery. That's the size of array you're looking at to make a "battery storage power station" worthy of the name. At current battery prices of $100/kWh it would cost £1.6Bn.)

There is a battery now up and running at 250MW in Arizona but the storage capacity is around 1.5 GWH - about 6 hrs. Batteries are great at dealing with short term peaks and troughs but we would need quite a few of your tankers (great idea btw) moored offshore to provide a few days storage for those dark still days in winter. 

Despite being in the middle of summer and just having had several days with excellent solar we are still having to burn coal; in fact coal generation has exceeded wind some days. It’s like a child leaving home, full of confidence yet having to keep coming back to mum and dad because things aren’t quite working out as their immature mind thought it would.

It doesn’t matter if some days wind and solar can produce 60% of our energy if other days they can only manage 3%. We have to plan for the worst contingency and this is where (currently) fossil fuels win hands down. Now I know we can’t continue burning coal in the long run but our present policy of expanding renewables without commensurate storage is reaching the point of ever diminishing returns in terms of CO2 saved - we have picked all the low hanging fruit we can eat and if we want to pick more we need a basket to put it in.

A bit like running a car engine for a short time, emissions from starting and stopping fossil fuel plants can be greater than running gas plants continuously. In the short term we would probably be better off retiring the coal plants and replacing them with CCGT and running them optimally. It is unfortunate that nuclear plants are being retired early as this is only exaggerating the impact of low renewable days. If nuclear was performing as planned then we wouldn’t be running coal. It’s not all the fault of renewables that supply margins are currently so tight but the journey towards renewables is throwing up more and more of these tight supply days. 

Don’t get me wrong; I am not arguing for long term fossil fuel generation but in the short term until we have effective inter day/week/month and eventually seasonal storage we need to recognise the role of CCGT in keeping the lights on.

In terms of market forces if you look at the price graph there are still peaks and troughs every day which battery storage ought to be able to moderate/modulate brilliantly once set up and there have been times this year when the wholesale price has exceeded £1000/MWh and peaked at £4000/MWh (£4/kWh). If you are supplying to meet these peaks it won’t matter too much if the buying price is £30 or £0. Yesterday’s prices ranged from around £60 to just over £200 so even opportunities for arbitrage there. The more renewables then the more price volatility and the more opportunities for arbitrage. 

JKenH

Future Energy Scenarios 2021

National Grid ESO has produced its FES 2021 report. I haven’t had chance to read this yet but thought someone might find it interesting. 

https://www.nationalgrideso.com/future-energy/future-energy-scenarios/fes-2021

ABrass

Cardew said:

QrizB said:

(Just thinking out loud, a 20' shipping container full of batteries contains 800kWh. A modern container ship holds 20,000 containers so a single vessel would make a 16GWh battery. That's the size of array you're looking at to make a "battery storage power station" worthy of the name. At current battery prices of $100/kWh it would cost £1.6Bn.)

Interesting discussion.

The security implications for guarding these 'battery storage power stations' are huge.

The security implications for guarding nuclear power stations are huge.

I doubt QrizB is suggesting using an actual boat, just giving an idea of scale. So in that case it'd be the cost to guard a lot of shipping containers in piles.