Blade inspectors carry out work recently in the North Sea - Antonie Robson
© Antonie Robson
Last year, the Biden administration set an ambitious new goal for the USA: to deploy 30 gigawatts (GW) of offshore wind capacity by the year 2030, increasing US offshore capacity more than seven hundred times over. The UK already has 15 GW of offshore wind, more than 300 times as much as the USA: and our experience should be a terrible warning to Americans.
The UK’s electricity prices are the highest since records began in 1920 and are now amongst the highest in all Europe. One reason for this is obvious: slightly less than half our electricity comes from gas-burning Combined Cycle Gas Turbines (CCGTs) and gas now costs £90 per megawatt-hour (MWh), nearly five times higher than normal. CCGTs are cheap to build (around £650m per GW) and operate. In normal times they would generate electricity at a total cost of £40 per MWh. That’s now risen to nearly £150/MWh, thanks to Vladimir Putin and his impact on the gas market.
But that’s not the whole story. The other reason why British electricity is so expensive is because we have so much wind power: particularly, so much offshore wind power. Bad though the current situation is, we would be an even worse state if we had built even more offshore wind, as the British government plans to.
As an example, the offshore wind farms Hornsea Two and Moray East were completed in 2022 with capital costs of £2.77 billion per GW and £2.75bn/GW, more than four times the cost of CCGT capacity. They’re expensive to maintain, which is not surprising since offshore windfarms have all their many generators mounted at the top of 200-metre tall masts far away from land. Estimates of maintenance costs are as high as £200m per GW installed, per annum. The nominal cost of offshore wind generation is £170/MWh – noticeably higher than that for CCGTs, even in these dire times of high gas prices.
The other factor to bear in mind is that not only is wind capacity extremely expensive to build, wind farms do not deliver anything like their rated capacity over time. This is bad news for the customer, because the higher the capacity factor – that is, the higher the percentage of the rated capacity the powerplant actually delivers over time – the cheaper the energy. In 2022 the UK’s onshore and offshore windfarms operated with a capacity factor of 33 per cent. In 2021 it was only 29 per cent.
It gets worse. Like most other renewable generation technologies, wind power is unpredictably intermittent and highly variable. Also, since wind turbines are not synchronously connected to the grid, they provide no “grid inertia” – more on that shortly. Wind turbines cannot be asked to deliver energy when it is required, and their output changes rapidly. These failings must be mitigated and costed, and users have to pay for these costs on top of the price of the electricity.
In 2021 the UK annual grid balancing costs reached £4.19 billion, £150 per household. For context, back in 1995 when we didn’t have much wind power the balancing cost for the grid was a mere £250 million per annum. A large, and growing, contribution to these costs is constraint management, as when a wind farm producing electricity which isn’t wanted – perhaps when it is windy in the middle of the night – is paid not to put that electricity into the grid.
The problems and costs don’t stop there. Our transmission grid system was originally designed to link generation centres close to sources of fuel (coal, gas) and load centres such as cities. Now our generation sites are moving further away from load centres. Our grid transmission system has to be expanded to connect the new renewable generators, which is bad enough when they are on a remote hilltop and worse still when they are out at sea. The National Grid estimates that on current plans this work will cost £46 billion – £1,533 per household – to 2030.
Then there’s grid inertia. The British grid is termed an island grid, which means that we are solely responsible for controlling the grid frequency between tight limits so that things plugged into the grid will work as expected. Frequency control becomes easier as the inertia of the grid system increases. Grid system inertia is a key measure of how resilient the system is in response to transient changes. Inertia is the sum of the energy stored within the rotating mass of the machines (generators and motors) connected directly to the system. Low system inertia increases the risk of rapid system changes, which may then lead to disconnection of load or generation and then system instability. Apart from tree-burning biomass stations and hydro generation, renewables plants bring no inertia to the grid: as the proportion of renewables rises, system inertia falls and the risk of major problems such as blackouts increases.
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to keep energy bills down for homes and businesses.
We have attempted to reduce the issue of intermittency by expanding our connections to the European electricity grid – the hope being that the wind will be blowing somewhere else even if it is not blowing here – but we’re still exposed to periods when wind generation across the whole of Europe falls near to nothing. And these connections do not help with inertia and stability either because few of the connections to the continent are synchronous connections.
In 1995 the problem of grid frequency stability required provision of rapidly responding generators capable of changing their combined output at a rate of 0.13 GW per second in order to deal with fluctuations. With the arrival of so much unpredictable wind power, that figure has now increased almost tenfold to 1.15 GW per second!
Extra services like very rapid response gas generators, required in order to make it possible to connect renewables to the grid, add between £30/MWh and £50/MWh to renewables’ cost. Thus the true cost to the customer of offshore wind generators is actually between £200/MWh and £220/MWh, much more than CCGTs even in these times of ruinously high gas prices.
Phasing out CCGT production will therefore increase domestic electricity prices painfully.
But it seems that CCGTs will be phased out much sooner than planned. The government has proposed an expansion to 60 GW of offshore wind by 2030 (capital expenditure £122 billion) and solar to 70 GW by 2035 (capital expenditure to 2030 £30 billion).
This is extremely unwise: we still have no way of storing electricity at scale and the planned transitions of home heating and transport to electrical power are progressing weakly and may yet stall completely. Creating such a large solar generation fleet raises the nightmare scenario of early summer mornings, with little demand and the vast majority of generation being solar with zero inertia: massive grid collapses would be all but a certainty. Vast amounts of energy will be generated only to be expensively constrained off and probably wasted, and the scenario of unmet demand – with attendant blackouts – will become unavoidable.
The UK grid is simply not able to cope with the proposed amounts of renewables.
And we simply cannot afford all this. If we add the costs of an even more extended National Grid, this programme of wind and solar generation expansion will cost £232 billion – more than £8,000 per household this decade – all to be paid for by the suffering energy user. It should be emphasised that these figures do not include the costs of the huge energy storage industry which will also be necessary, whatever that may turn out to be: hydrogen or ammonia or something even more dangerous and expensive. Heat pumps and switching to electric vehicles could lift total costs above £1 trillion.
Truly, Americans should look at the British renewables disaster and give thanks that today they have hardly any offshore wind. And they might, looking at the UK, recoil with horror from the plans of the Biden administration: especially as most US offshore wind will need to be floating offshore wind rather than built on the seabed, and so even more expensive.
If either nation would like to reduce carbon emissions and/or reduce its dependence on fossil fuels supplied by unsavoury overseas regimes, an immediate measure would be to build new, modern, high efficiency CCGT plant which would immediately cut the need for gas and reduce emissions without requiring vast, expensive alterations to the grid and special measures so that they don’t cause it to collapse. We should also begin building new nuclear plant with some genuine urgency, as that is the only genuine, affordable, practical way to seriously cut emissions and achieve secure energy supplies.
Dr Capell Aris PhD has spent his career in the electricity generation sector. He is a former Fellow of the Institute of Engineering and Technology
The other factor to bear in mind is that not only is wind capacity extremely expensive to build, wind farms do not deliver anything like their rated capacity over time. This is bad news for the customer, because the higher the capacity factor – that is, the higher the percentage of the rated capacity the powerplant actually delivers over time – the cheaper the energy. In 2022 the UK’s onshore and offshore windfarms operated with a capacity factor of 33 per cent. In 2021 it was only 29 per cent.
It gets worse. Like most other renewable generation technologies, wind power is unpredictably intermittent and highly variable. Also, since wind turbines are not synchronously connected to the grid, they provide no “grid inertia” – more on that shortly. Wind turbines cannot be asked to deliver energy when it is required, and their output changes rapidly. These failings must be mitigated and costed, and users have to pay for these costs on top of the price of the electricity.
In 2021 the UK annual grid balancing costs reached £4.19 billion, £150 per household. For context, back in 1995 when we didn’t have much wind power the balancing cost for the grid was a mere £250 million per annum. A large, and growing, contribution to these costs is constraint management, as when a wind farm producing electricity which isn’t wanted – perhaps when it is windy in the middle of the night – is paid not to put that electricity into the grid.
The problems and costs don’t stop there. Our transmission grid system was originally designed to link generation centres close to sources of fuel (coal, gas) and load centres such as cities. Now our generation sites are moving further away from load centres. Our grid transmission system has to be expanded to connect the new renewable generators, which is bad enough when they are on a remote hilltop and worse still when they are out at sea. The National Grid estimates that on current plans this work will cost £46 billion – £1,533 per household – to 2030.
Then there’s grid inertia. The British grid is termed an island grid, which means that we are solely responsible for controlling the grid frequency between tight limits so that things plugged into the grid will work as expected. Frequency control becomes easier as the inertia of the grid system increases. Grid system inertia is a key measure of how resilient the system is in response to transient changes. Inertia is the sum of the energy stored within the rotating mass of the machines (generators and motors) connected directly to the system. Low system inertia increases the risk of rapid system changes, which may then lead to disconnection of load or generation and then system instability. Apart from tree-burning biomass stations and hydro generation, renewables plants bring no inertia to the grid: as the proportion of renewables rises, system inertia falls and the risk of major problems such as blackouts increases.
Related videoto keep energy bills down for homes and businesses.
We have attempted to reduce the issue of intermittency by expanding our connections to the European electricity grid – the hope being that the wind will be blowing somewhere else even if it is not blowing here – but we’re still exposed to periods when wind generation across the whole of Europe falls near to nothing. And these connections do not help with inertia and stability either because few of the connections to the continent are synchronous connections.
In 1995 the problem of grid frequency stability required provision of rapidly responding generators capable of changing their combined output at a rate of 0.13 GW per second in order to deal with fluctuations. With the arrival of so much unpredictable wind power, that figure has now increased almost tenfold to 1.15 GW per second!
Extra services like very rapid response gas generators, required in order to make it possible to connect renewables to the grid, add between £30/MWh and £50/MWh to renewables’ cost. Thus the true cost to the customer of offshore wind generators is actually between £200/MWh and £220/MWh, much more than CCGTs even in these times of ruinously high gas prices.
Phasing out CCGT production will therefore increase domestic electricity prices painfully.
But it seems that CCGTs will be phased out much sooner than planned. The government has proposed an expansion to 60 GW of offshore wind by 2030 (capital expenditure £122 billion) and solar to 70 GW by 2035 (capital expenditure to 2030 £30 billion).
This is extremely unwise: we still have no way of storing electricity at scale and the planned transitions of home heating and transport to electrical power are progressing weakly and may yet stall completely. Creating such a large solar generation fleet raises the nightmare scenario of early summer mornings, with little demand and the vast majority of generation being solar with zero inertia: massive grid collapses would be all but a certainty. Vast amounts of energy will be generated only to be expensively constrained off and probably wasted, and the scenario of unmet demand – with attendant blackouts – will become unavoidable.
The UK grid is simply not able to cope with the proposed amounts of renewables.
And we simply cannot afford all this. If we add the costs of an even more extended National Grid, this programme of wind and solar generation expansion will cost £232 billion – more than £8,000 per household this decade – all to be paid for by the suffering energy user. It should be emphasised that these figures do not include the costs of the huge energy storage industry which will also be necessary, whatever that may turn out to be: hydrogen or ammonia or something even more dangerous and expensive. Heat pumps and switching to electric vehicles could lift total costs above £1 trillion.
Truly, Americans should look at the British renewables disaster and give thanks that today they have hardly any offshore wind. And they might, looking at the UK, recoil with horror from the plans of the Biden administration: especially as most US offshore wind will need to be floating offshore wind rather than built on the seabed, and so even more expensive.
If either nation would like to reduce carbon emissions and/or reduce its dependence on fossil fuels supplied by unsavoury overseas regimes, an immediate measure would be to build new, modern, high efficiency CCGT plant which would immediately cut the need for gas and reduce emissions without requiring vast, expensive alterations to the grid and special measures so that they don’t cause it to collapse. We should also begin building new nuclear plant with some genuine urgency, as that is the only genuine, affordable, practical way to seriously cut emissions and achieve secure energy supplies.
Dr Capell Aris PhD has spent his career in the electricity generation sector. He is a former Fellow of the Institute of Engineering and Technology
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