[alancalverd]

we could  just use wind and make a very substantial reservoir for future years if we install enough,

There's the weakness - there is no primary "reservoir" in renewables. On a hot or cold day the wind doesn't blow, and the sun only shines half the time. So even if you had a reservoir, like a huge battery farm, you would have to install enough wind power to supply peak demand and recharge the battery, from average wind. Problem is that power output depends on the cube of wind speed, so you need to install several times the peak demand capacity.

And then there's the problem that electricity only accounts for about 30% of UK energy consumption, so when we are fully decarbonised, peak demand will be about 3 times the present level. 

There just isn't enough wind!

[Petrochemicals]

we could  just use wind and make a very substantial reservoir for future years if we install enough,

There's the weakness - there is no primary "reservoir" in renewables. On a hot or cold day the wind doesn't blow, and the sun only shines half the time. So even if you had a reservoir, like a huge battery farm, you would have to install enough wind power to supply peak demand and recharge the battery, from average wind. Problem is that power output depends on the cube of wind speed, so you need to install several times the peak demand capacity.

And then there's the problem that electricity only accounts for about 30% of UK energy consumption, so when we are fully decarbonised, peak demand will be about 3 times the present level. 

There just isn't enough wind!

Round the UK if we made an effort and put turbines all over, made them so they generated during the heavy winds with variable resistance generators, converted the hydrogen close to the turbine and stored it we should have more than enough, if you look at the UK portion of the north Sea, what we have of the channel and what ridiculous amounts off Scotland north and West. I am unsure of how many years we could store  but offshore wind does about 33 percent of its plate capacity, so if we put in 200 gw we would be generating 2 years worth per year.

That however is mucho mucho gasso.

Edit: that is just to replace the electricity, times by 3 for inefficiencies.

[alancalverd]

So we need to install 600 GW of renewable electricity generators and triple the gas grid capacity. By no means impossible.

[Petrochemicals]

To replace everything, like for like, you require about 120 Hornsea 6gw arrays, double it for reserves and we may just squeeze them in Norway once again will be laughing, France Spain and Portugal will struggle but they have solar to fall back on, Denmark should just about manage, but any country like Germany will have no hope either with solar or wind.

[alancalverd]

double it for reserves

No, there are no reserves with renewables. The wind either blows or it doesn't. Any "reserve" must be a battery or gas store.

[Petrochemicals]

double it for reserves

Any "reserve" must be a battery or gas store.

Yes

[acsinuk (OP)]

But hydrogen is not a compressible gas so totally uneconomical to store unless you mix it with carbon to liquify it? 
Hydro is a possibility if we can dam a whole upland valley or 2 ??

[Petrochemicals]

Hydrogen storage is plausible, Germany already stores much of its gas, enough for 3 months winter usage I think, buying during summer when it is cheaper The UK government didn't think that this was worth it so we end up paying through the nose for it, especially when vladimit put in throws hit toys out of the pram.

The problem with hydrogen is that wind energy operates about a third of the time so the UK would need the UK energy usage is about 250 gw so wind would need at least 750gw, double that for storage capacity for a production peak of 1,500gw. That would be about 15,000,000,000 m3 of hydrogen an hour I think. Not impossible but a hydrogen generating and transport infrastructure of that scale is more problematic than the 150,000 wind turbines.

As for hydro storage it is not feasible long term, MGH tells us  1km3 of water 1000m high has 10,000,000,000,000,000 joules or roughly 3,000,000,000 kwh, long enough for 12 hours of UK usage. There are not may places on earth you can achieve such capacity.

[alancalverd]

But hydrogen is not a compressible gas

An incompressible gas? Amazing.

On this planet we distribute hydrogen compressed to 300 atmospheres, and it's still a gas, right down to 33K. What is the atmospheric pressure and temperature on your planet, I wonder? 

[alancalverd]

Germany already stores much of its gas,

From about 1750 to 1965, the UK stored and distributed town gas, consisting of 50% hydrogen, in huge low-pressure collapsible tanks ("gasometers") which have mostly been demolished  apart from those overlooking the Oval cricket ground, which are subject to a preservation order.

The gas grid already exists and has been developed and maintained continuously since the 18th century. It was converted from town gas to methane in the 1960s by simply altering the burners, district by district, with no need to dig up the roads, and gradually replacing the generating stations  and gas stores with banks of LPG bottles.

The high pressure grid runs at 69 bar and will carry pure hydrogen with no problem. Local compression to 300 bar for road transport is straightforward.

[alancalverd]

km3 of water 1000m high has 10,000,000,000,000,000 joules or roughly 3,000,000,000 kwh, long enough for 12 hours of UK usage. There are not may places on earth you can achieve such capacity.

And certainly  none in the UK - the highest point is only 1,345 m above sea level!

[jackyjoy123]

The push for electric cars feels a bit premature when we aren't fully set up with green energy to back it up. The grid's still heavily reliant on fossil fuels, and nuclear seems underutilized.

[Petrochemicals]

The push for electric cars feels a bit premature when we aren't fully set up with green energy to back it up. The grid's still heavily reliant on fossil fuels, and nuclear seems underutilized.

I agree, if the uk could manage to keep the wind turbines turning and store the energy for a short period rather than paying for them to be turned off it would signal that the infrastructure was becoming mature enough to handle extra demand.

[alancalverd]

The present problem is that we need to maintain fossil and nuclear stations to fill the gap, up to peak demand,  when the wind doesn't  blow, so we can't reduce their number but as they aren't always working to capacity, they are uneconomic.

When demand is low, it's not a good idea to run down the nukes because they take a long time to run up again, and as Chernobyl demonstrated,  the run down needs to be very carefully planned, so at times of low demand we pay wind farms not to generate power when it isn't needed, and there's little point in building more nukes than are required to supply the minimum base load - which we already have.

So from the consumer's point of view, introducing windfarms has just increased the cost of electricity, and from the investor's point of view neither nuclear nor fossil power is a good investment for the future.

[acsinuk (OP)]

We need to store energy quickly and retrieve at peak demand.  The answer is hydro assisted by nuclear .
But Hydro large scale.
Lock Ness is 16 metres above sea level 56 square km and contains ? billions of tons of water.
Loch Locky is 29 metre above sea level 16 square km and contains ? billion tons of water.
So if we drain 1 metre of water from Locky we move 16 thousand million cubic metres/tons down to Lock Ness.
We need to do this transfer in 12 hours and it needs to be a reversible process. i.e. Pumped storage.
There are other examples of Lochs with hydo stations between but these need upgrading to ?9 times the size reversible.

[Petrochemicals]

We need to store energy quickly and retrieve at peak demand.  The answer is hydro assisted by nuclear .
But Hydro large scale.
Lock Ness is 16 metres above sea level 56 square km and contains ? billions of tons of water.
Loch Locky is 29 metre above sea level 16 square km and contains ? billion tons of water.
So if we drain 1 metre of water from Locky we move 16 thousand million cubic metres/tons down to Lock Ness.
We need to do this transfer in 12 hours and it needs to be a reversible process. i.e. Pumped storage.
There are other examples of Lochs with hydo stations between but these need upgrading to ?9 times the size reversible.

The point you are missing is that at present the uk uses 250gwh of energy per hour. Now we may be able to reduce this somewhat by electric heat pumps and electric cars, and install 125 gwh of nulcear capacity but we will then have a massivley skewed electricity demand in the winter, (a squint at my gas metre tells me that in the winter 4 months I have used about 800kwh of gas and the summer 4 months under 50kwh). That will still be quite some hydro electric storage. This dam in the alps could store 2,000 gwh if it had storage at the bottom.

https://en.m.wikipedia.org/wiki/Grande_Dixence_Dam#:~:text=The%20Grande%20Dixence%20Dam%20(French,the%20tallest%20dam%20in%20Europe.

[Petrochemicals]

When demand is low, it's not a good idea to run down the nukes because they take a long time to run up again, and as Chernobyl demonstrated,  the run down needs to be very carefully planned, so at times of low demand we pay wind farms not to generate power when it isn't needed, and there's little point in building more nukes than are required to supply the minimum base load - which we already have.

Yes and i remember asking a question on here about whether nuclear plants still degrage and loose life span even when not generating, the consensus seemed to be yes. If you have them on 50 percent of the time the cost of your electricity doubles, from what is already expensive.

[alancalverd]

We need to store energy quickly and retrieve at peak demand.

No need to store it quickly, but we need to be able to supply mean and peak for up to 5 days at a time when the wind doesn't blow.

It is true that the British Isles are rarely completely becalmed, but power output from a windmill depends on the cube of the wind speed and a machine that can genrate its rated power for say 80% of the time, effectively generates nothing at all for at least 10%. And these are the hottest and coldest days (persistent anticyclone) when electricity supply is most critical.

Occasional sharp peaks are already met by pumped storage, but only for the 20 - 30 minutes it takes to fire up the fossil plants. The beauty of hydrogen storage is that you can modify existing gas stations to use hydrogen with very little extra investment, giving you flexible response and guaranteed fast runup times to continuous working at minimal cost.

Emptying a sea loch is in the realm of tidal power, which despite being around in principle and in a few mechanical tide mills for thousands of years, has never been shown to be economic on the scale of a national grid.

[acsinuk (OP)]

First things first we need to have 22Gw of nuclear to supply the night minimum load and have just found this article from IET.

https://eandt.theiet.org/2024/07/30/small-modular-reactor-designs-approved-first-step-towards-uk-nuclear-power-expansion

As 10% of the nuclear plant is normally out of service for regular maintenance we need 24Gw to cover the 22Gw night load which will leave 20Gw to top up the day load using wind, solar, tidal and hydro/storage to complete a green grid by 2050.

It is achievable if we push the government to prioritise green grid and backpedal on electrifying transport .

[alancalverd]

Hydro storage is useless for the UK. We have no significant mountain valleys, and the little ones we do have are intensively farmed and somewhat populated.

Direct wind and solar are useless because they can't meet peak loads when they occur, only if the wind is blowing at the optimum speed or the sun is shining. 

Tidal hasn't produced useful power anywhere in the last 60 years, and any substantial modification to allow controllable tidal power will flood huge areas of productive farmland and essential wetlands.

Re: mini-nukes

the regulatory judgements do not guarantee that Rolls-Royce will be granted a site licence or the environmental permits needed to construct a power station based on the designs.

Nuclear power is not an investable business.

I can see no realistic alternative to wind farms with hydrogen storage and distribution.