The Economic Case For Hydrogen In Domestic Heating
The title of this post, is the same as that of this article on The Chemical Engineer.
The Wikipedia entry for The Chemical Engineer has this introductory paragraph.
The Chemical Engineer is a monthly chemical engineering technical and news magazine published by the Institution of Chemical Engineers (IChemE). It has technical articles of interest to practitioners and educators, and also addresses current events in world of chemical engineering including research, international business news and government policy as it affects the chemical engineering community. The magazine is sent to all members of the IChemE and is included in the cost of membership. Some parts of the magazine are available free online, including recent news and a series of biographies “Chemical Engineers who Changed the World”, although the core and the archive magazine is available only with a subscription. The online magazine also has freely available podcasts.
It is a source on the Internet, where anything non-scientifically correct will be unlikely to appear.
The article has two introductory sub-headings.
Despite its thermodynamic disadvantages, global energy technology specialist Thomas Brewer believes hydrogen has an economic and efficient role in domestic heating. It forced him to deviate from his usual mantra of ‘efficiency above all else’ to get there, though
The work of decarbonisation by chemical engineers is about how we can cost effectively enable our organisations’ transition away from fossil fuels. This requires foresight. A decision chemical engineers make on a project with a 20-year lifespan will still be operational in 2045, when in most global locations, internal combustion engine (ICE) vehicles will probably be in the minority and grid electricity will be mostly renewable.
This is the first actual paragraph.
It is unsurprising, therefore, that chemical engineers are researching and debating the prospects of the future of energy availability from renewables, and the likely role and cost of hydrogen. There is much public noise surrounding the conversation about heat pumps vs hydrogen for domestic heating. I have noticed how few articles are written from an unbiased perspective, how very few reports talk about the whole solution, and authors avoid quantifying the financial impact of their proposed solution. I couldn’t find an unbiased study with any financial logic, so, I built a model to assess the options, for my own interests. I found the results so intriguing that I wanted to share them.
In other words, let the data do the talking and accept what it tells you.
These are some extracts from the article.
On Curtailment
The article says this on curtailment of wind energy, because you are generating too much.
Efficient electrical energy storage is expensive, which has traditionally led renewable system designers to include curtailment as a part of their design. Curtailment involves oversizing the wind supply to be higher than the grid connection to reduce the need for as much energy storage, and deliberately wasting the occasional electrical excess. The system design becomes an economical balance between oversizing the renewable generation and paying for additional electrical storage. Within the UK grid in 2023, curtailment is a small factor. As electrification and wind power become more mainstream, the financial decision between investing in excess wind vs electrical storage will lead curtailment to become a more significant factor.
Curtailment is to me a practice, that should be consigned to the dustbin of history.
To eliminate it, as much storage as is needed storage must be provided.
Eliminate Naked Flames In The Kitchen
The article says this about eliminating naked gas flames (natural gas or hydrogen) in the kitchen.
Figure 1 shows that the recommended standard of hydrogen gas installation if removing kitchen gas cooking would result in less injuries than the existing natural gas installation if cooking were converted to induction heating. Kitchen leaks are more likely than boiler leaks due to the number of valves and connections, regardless of the gas type. NOx emissions in the home because of naked flames in the kitchen are also of concern to the health of the occupants and hydrogen naked flames have a higher NOx emission than natural gas; another reason to eliminate naked flame cooking.
When I was financing the development of what became the Respimat inhaler, I did my due scientific diligence and found research from a Russell Group University, that naked flames (including smoking) were a cause of asthma, especially in children.
My recommendation is that, at an appropriate time in the near future, you replace your gas cooker with an electric one. My ginger-haired Glaswegian friend, who is a chef, who’s had Michelin stars would recommend an electric induction cooker.
Pumped Storage
The article says this about building more pumped storage.
The pumped storage assumption is based on the SSE proposal for Coire Glas, a 30 GWh £1.5bn storage system in Scotland which will more than double the UK’s current pumped storage capacity. The capital cost of this pumped storage system is about £50/kWh which will be delivered at about 80% efficiency. Pumped storage is a good balance between low cost and high efficiency. However, it requires natural resources. The Mott MacDonald report, Storage cost and technical assumptions for BEIS (Department for Business, Energy and Industrial Strategy) suggests the equivalent of four Coire Glas-scale installations in the UK by 2050. The model optimistically assumes that ten more similar additional Coire Glas-size pumped storage schemes could be installed.
This page on the Strathclyde University web site, gives these GWh figures for the possible amounts of pumped-storage that can be added to existing hydroelectric schemes.
Strathclyde’s total for extra storage is over 500 GWh.
Distributed Batteries
The article says this about distributed batteries.
A distributed battery assumption could be configured with multiple 10 kWh batteries which typically cost about £3,000 installed, near or in homes with a heat pump. This could be coupled with larger battery storage systems like the £30m Chapel Farm 99 MWh battery installation near Luton, commissioned in 2023. The small battery systems at each home are similar to the proposed virtual power plants using electric vehicle battery capacity to help balance the grid. Placing these batteries at locations with grid limitations could reduce the costs of upgrading the grid system. This is a more expensive energy storage scheme than pump storage and for the purposes of the model it is assumed that battery storage schemes are limitless. In both cases cited, the cost is £300/kWh. Battery efficiency varies significantly with temperature, and typically ranges from about 90% to 97%. As the system design needs to be focused on the coldest periods, the model is optimistically assuming 93% efficiency, which would require many of the batteries to be in a heated environment.
New lower-cost alternative batteries are also being developed.
Hydrogen Generation
The article says this about hydrogen generation.
Alternatively, the electricity generated from wind energy could be used in the electrolysis of water to produce hydrogen. While the fully installed electrolysis equipment costs about £2,100/kW, hydrogen storage in specially built cylinders is relatively cheap at about £23/kWh. The model, however, assumes salt mine storage which the US DoE in their report, Grid Energy Storage Technology Cost, calculate at a total system cost for hydrogen of $2/kWh. Electrolysis is the least efficient energy storage option, with a conversion efficiency of 75%, including compression. The waste heat from this conversion loss is useful for industrial heating, or in a district heating system. This has been ignored for simplicity.
Pumped storage, distributed batteries and hydrogen electrolysers distributed all over the UK, will mop up all the spare electricity and release it to heat pumps and for charging cars as necessary.
The hydrogen will be used for heating, to decarbonise difficult-to-decarbonise industries and provide fuel for hydrogen-powered vehicles, railways and shipping.
Curtailment will be a thing of the past.
The UK Offshore Wind Potential
The article says this about the UK offshore wind potential.
The UK government target for wind generation by 2030 is 50 GW. The UK offshore wind potential is reliable and available and has been estimated to be as high as 2,200 GW. There are, however, a few low wind periods that can last for several days.
I am not going to argue with 2,200 GW, but I will say that a lot of that will be used to generate hydrogen offshore.
Conclusions
This is the article’s main conclusion.
A wind-based supply for heating will mean that large quantities of potentially unused electricity will be available for more than 90% of the year, for potentially very low cost. While this could appear wasteful, it provides further synergistical opportunities for the decarbonisation of other interruptible energy duties, such as production of hydrogen for road transport or supplying heat via heat pumps for interruptible industries.
The sensitivity analysis shows that these conclusions are robust even with significant variation in the assumptions on equipment cost, efficiency, and other electricity source options.
This is also said about the most cost-effective solution.
A cost-effective national heat pump-only solution is about £500bn (50%) more expensive than a hydrogen-only boiler solution. The most cost-effective system is a combination of the two, £100bn cheaper than the hydrogen-only solution, and £600bn cheaper than the heat pump-only solution.
A cost-effective national heat pump-only solution has a system efficiency 40% lower than the hydrogen-only solution, requiring more than 750 GW of installed wind capacity. A hydrogen boiler solution requires less than 500 GW but the most efficient system, however, is a combination of the two.
The conclusions mean that everybody will be able to use the most appropriate solution for their circumstances for both heating their housing or powering their vehicles, as there will be massive supplies of affordable electricity and hydrogen.
How Will Everything Be Paid For?
Just as Germany and others built its industry on cheap Russian gas, it will now choose to use the plentiful and reliable UK electricity and hydrogen to rebuild its industry.
The Anonymous Widower 
It’s FAR cheaper to curtail than to store.
Electrolysers have high capital costs. They currently don’t make financial sense even when run at 100% duty. If run only during curtailment, you’d get sub-1% utilisation today.
Large scale subsidy-free green hydrogen production will only come when electricity prices are negative for 10, 20, maybe 30+% of the time. 5 years ago I calculated the economics would work once we hit 145GW of installed wind capacity; situation likely hasn’t change much since.
At that point it’ll be one of the only technologies that can provide a practical large-scale zero-carbon seasonal energy store (initially just diluting mains gas, later storing in disused gas fields). Albeit at rather poor energy efficiency.
Comment by Mark | February 7, 2024 |