Hot Air About Hydrogen
The UK Government's Net Zero plans run into yet more trouble.
As the OECD starts making predictions about the global cost of net zero (short version, expensive) the UK government’s net zero project is in more trouble. A key hydrogen heating project has been cancelled, nominally due to problems sourcing hydrogen in sufficient quantity. An earlier proposed trial was abandoned due to public concerns about safety and the terms. An Englishman’s home is still his castle, as those who seek to alter domestic heating by imperious legislation are re-learning.
The UK is a cold and wet country. Its houses need heating for much of the year. Keeping homes warm consumes around 250 TWh[1] of natural gas per year. That’s 17% of the UK’s entire energy consumption. Burning that fuel produces 11% of the UK’s greenhouse gas emissions (2022 figures). The overwhelming majority of homes are heated by gas or oil; replacing all that fossil fuel is one of the biggest challenges to net zero.
Unfortunately the UK’s housing stock is ancient. As the chart below shows (data from Statista). 20% of the UK’s 24 million houses are over 100 years old. Over 35% of it was built for heating by coal, meaning lots of chimneys.
Many older houses have been subdivided into flats. Many lack cavity walls. Many have limited scope for adequate insulation. Many have large windows as they were built before gas or electric light was available. Most have already been converted at least once from coal to gas heating. Few are airtight. 97% of the UK’s private have an EPC rating of C or worse. Making them more energy efficient costs money – who pays? The government is broke; homeowners may not find increased energy efficiency is affordable or calculate that it delivers the best return on investment of their limited funds.
In any case the need for domestic heating will not go away. Net zero requires replacing gas as a fuel. There are several approaches, all of which now have their advocates, lobbyists and opponents.
Biomethane
Natural gas is methane. It is possible to manufacture methane from organic matter in a way which becomes carbon neutral, using an anaerobic digester. This uses bacteria to turn organic matter into biomethane and CO2 in about equal amounts. The gasses can be separated, the CO2 sent to storage and the biomethane injected into the grid. Typical feeds stocks include food waste, silage and cattle manure. The UK has about 700 such digesters, typically delivering 0.5 to 2 MW of methane. Anaerobic digesters are proven technology that would seamlessly replace current methane with biomethane. The same grid, boilers etc would work.
The CO2 produced from burning the bio-methane is considered as green as it came directly from the organic matter. Replacement organic matter is growing, extracting more CO2 from the atmosphere.
The only problem is one of scale; delivering the 275 TWh require to heat homes would need some 100,000 more digesters and would require about 70% of the UK’s arable land to grow the fuel crops.[2] That rather begs the question of where the population would get its food.
Heat Pumps
Heat pumps come in two flavours – air source and ground source. Both take energy from the air (or ground) and deliver it into a house in a manner exactly analogous to a fridge. The only energy that they need is to run the pump, which comes out at about a third of the energy transferred. This reduction is a major boon for the net zero project (although caveats apply).
Air source heat pumps diminishes as air temperature falls, so the pump has to run more. At around minus 15oC they are running flat out so additional heating will be required. Very few houses in the UK experience such lows, but the climate might change.
Underground temperatures are constant and warmer so ground source heat pumps can work to much lower temperatures. They require extensive trenching or drilling, which is expensive and not all dwellings have the necessary access. There are an increasing number of GSHP heat networks in the UK and it’s a viable option for new developments, but not for most of the 24 million older dwellings.
Heat pumps deliver heat into the house at a lower temperature than a gas boiler. To compensate larger radiators and pipework may be needed. Replacing them requires significant works and cost.
And of course heat pumps need electricity. Their thermodynamic genius may reduce the input energy by 70%, but that still leaves an annual demand of around 75 TWh. The UK consumed 275 TWh of electricity in 2022, so that’s a 30% increase on existing generation. The entire nuclear industry delivered just 50 TWh. All the wind and solar farms between them delivered 93 TWh.
Few homes need heating in the summer so the vast majority of that 75TWh will be needed in the six months of winter. As electricity cannot be stored in volume, replacing gas with heat pumps would require some six Sizewell Cs running 24/7 or pretty much every wind farm to be operating at capacity all day and night throughout the winter.
That 75 TWh represents a near doubling of domestic electricity demand, which means at least a doubling of the current required by every house. Some houses will need upgrades to their supply cabling, as will the electrical distribution infrastructure. That won’t be easy or cheap.
Hydrogen
The huge advantage of hydrogen over heat pumps is that it can use much of the already installed gas distribution infrastructure and can deliver about as much heat[3].
Opponents of hydrogen (many of whom are heat pump advocates) cite the small size of the of the hydrogen molecule, which makes it “leaky.” Perhaps, but until North Sea gas came on line in the 1970s the UK’s domestic gas supply was “town gas”, which was some 40% hydrogen.[4] Most gas boilers can already operate with up to 20% hydrogen, as can most of the gas grid.[5] Moving to 100% hydrogen is relatively simple in terms of technical risk and implementation. The high pressure bit of the gas grid needs replacing and redundant metal pipes need to be decommissioned. There are costs to this which are in the £50 to £70 billion range.
The tricky bit is getting the hydrogen. The small amount of hydrogen that industry uses is generally produced from methane (i.e. natural gas) which releases CO2. This process is known as “grey hydrogen.” Until and unless CO2 capture becomes a reality (thereby delivering “blue hydrogen”) this approach is self-defeating in climate change terms. In 2022 the UK produced about 27 TWh of grey hydrogen.
The other production approach is electrolysis, which takes electricity and produces “green hydrogen.” IF (big “if”) the electricity is emissions free so is the hydrogen. The plant that does this is called an electrolyser. They have an efficiency of about 80%, that is 10 TWh of electricity would yield 8 TWh of gas. That means that producing 275 TWh of hydrogen to heat the UK’s houses requires a dozen Sizewell Cs running all year to make hydrogen.
Which leads to the second great advantage of hydrogen, which is that it can be stored. This means that wind farms that are currently idle when there is more wind than electricity demand can be put to work powering electrolysers, thereby making hydrogen for winter use. Hydrogen is stored in the same way as natural gas – in salt caverns. There is plenty of capacity for such storage in the UK. There is a whole discussion about pressure, leakage and volume but the reality is this is all known science. The volume of hydrogen to be stored is significant and depends of course on whether you’re making it from wind, solar or nuclear means.
There are two challenges that hydrogen faces, one real and one imagined. The real one is that current electrolysers are small and expensive. Producing 75TWh of hydrogen that the UK requires would require 380 of the largest 25MW electrolysers, as well as the dozen Sizewell Cs to run them. It can be done, but it won’t be cheap in the first instance –there is an argument to be made that costs will fall as more are made.
The imagined challenge is that the public think hydrogen is dangerous, which of course it is if it is allowed to mix with oxygen and someone strikes a match. That’s also true for natural gas, but the public take for granted that they can use it to heat their homes safely. The combination of maladministration, inept PR, scaremongering, ignorance and stupidity that caused the Whitby and now the Redcar trials to be scrapped is an exemplar of the chaos that is the UK’s net zero programme.
Economics
While wind may be free, wind power is expensive as it creates a need for other power stations when the wind doesn’t blow. Power stations that don’t run at capacity are more expensive than ones which do and preferring wind to gas delivers just that effect, as the chart below shows:
Which makes electricity more expensive, as the chart below shows:
Increasing energy costs create inflation as everything that you consume has required energy to be created and delivered to you. That inflation is usually countered by raised interest rates, which in turn increase the cost of capital which in turn makes a new power station more expensive, leading to increases in energy costs. The UK’s obsession with net zero in general and wind power in particular is driving it into an economic doom loop.
What’s The Answer?
Successive governments have brought this on their own heads. Rather than engage with the public, net zero was cooked up by Ed Milliband and implemented by statutory order by Theresa May in pretty much her last act as Prime Minister. The government has implemented ill-considered targets which are neither achievable nor affordable, as I show in my book. The approach is that of the Soviet Union and like the USSR is heading for technical failure and economic disaster.
The UK only accounts for 1% of global emissions (on a territorial basis. If, as is likely, the rest of the world lags in the “race to net zero” then the UK’s self-sacrifice will have been a futile gesture. There is no merit in being at the head of a column of zealot lemmings. Better to prepare for global failure and build sea defences.
The current reality of net zero is simple. On 2022 figures the UK consumed 2,022 TWh of energy of all sorts. Of this just 183 TWh was green energy. Anyone serious about net zero would be building nuclear power stations. Urgently, at the rate of about one Sizewell C (or equivalent) per year for 30 years. For all the headlines made about the amount of wind power the UK has installed, wind delivered less than 50% of the UK’s clean energy and just under 7.5% of the UK’s likely demand in a net zero world. It wasn’t cheap, either.
Any responsible government would pause and reflect on the technical and financial challenges of delivering net zero and establish what benefits, if any, they bring compared to (say) improved sea defences. No party with a seat in Westminster is proposing such a review – instead the repeat the sound bites of the fanatics and treat the pronouncements of the CCC and the IPCC as statements of fact. None challenge “the science” of climate change, although that is far from settled. None considers the disastrous impact of runaway energy costs. That’s not just economic folly, cold (hypothermia)kills.
The only party that is prepared to challenge the narrative and implementation of net zero is Reform, but they have no seats in Westminster.
Yet.
[1] A TWh is a terawatt hour, which is one billion kilowatt hours. The average UK house uses 2,700 kilowatt hours a year.
[2] That figure would be reduced to about 25% if grassland was also used to make grass silage. Not all permanent grassland is capable of producing silage in industrial quantities and currently the grass is used to feed cattle and sheep.
[3] Methane (natural gas) and hydrogen have similar Wobbe Indexes. The Wobbe Index is a guide to the ability of one combustible gas to substitute for another.
[4] It was made from coal. It’s components also included methane, (inert) nitrogen and (highly toxic) carbon monoxide. Putting one’s head in a gas oven was a common method of suicide.
[5] Arup (a very reputable engineering firm) reported on this. https://nic.org.uk/app/uploads/Arup-Future-of-UK-Gas-Networks-18-October-2023.pdf
Dear Mr Benham-Crosswell, I have seen your articles for some time at TCW (conservativewoman.co.uk) and greatly appreciate your pragmatic, informed approach to every subject. This article is exceptional. Thank you.