Month: December 2021

Future Heat for Everyone and the Role of Hydrogen

By Ellie Martin

The 2021 Sustainable Gas Institute Annual Lecture was delivered on 3 December and focused on hydrogen’s role in heating. It was contextualized by the challenges to decarbonizing heat, a comparison of hydrogen boilers and heat pumps, the importance of listening to consumers, and the steps that need to be taken to achieve net-zero gas with the help of hydrogen. Content was delivered by the engaging Dr. Angela Needle, who serves as strategy director at Cadent Gas, founder of the Women’s Utility Network, and VP of the Hydrogen UK Trade Association.

Challenges to Gas Alternatives

Given the impending state of climate change and a 300 TWh yearly dependence on natural gas for domestic heating, it is clear that decarbonizing gas is key to achieving net zero emissions for the UK by 2050. Fortunately, a few alternatives to natural gas are inching across the market – namely heat pumps, district heating, and now potentially hydrogen. Current gas boilers are reliable, easily tucked into cupboards and other discrete areas, easy to control and adjust, and generally problem-free. These are some big shoes to fill. What’s more, over £11,000 per home would be needed to cover the energy efficiency improvements, appliance replacements, and electricity and gas network changes necessary for net zero gas. On top of this, homes in the UK are quite literally the worst in Europe when it comes to retaining heat. UK homes lose an average of 3°C over five hours (surpassing all European neighbors), with 61% of EPC ratings falling at or below the D level.

There’s also the difficulty of determining who owns buildings, with the UK moving towards outright ownership. This is a huge challenge to achieving net zero because homeowners are the hardest to reach when it comes to government policy. Diversity in ownership types also presents an issue: solutions will need to be tailored to each property instead of adopting a one-size-fits-all policy.

Dr Angela Needle

Heat Pumps vs. Hydrogen Boilers

An all-hands-on-deck approach will likely be required for natural gas replacements, particularly during the early stages of development when it is unclear which technology will turn out to be the best investment. While hydrogen boilers and heat pumps are often unfairly pitted against each other, there are some key differences between the two that bear mentioning.

One of the most obvious advantages to heat pumps is that they’re currently deployable and proven to work. They’re also highly efficient and thus a good fit for well-insulated homes, and the low energy requirements afforded by these high efficiencies can produce lower running costs. Downsides to this technology include its high upfront cost, supply chain limitations, and the need for consumers to change their behavior.

On the flip side, hydrogen boilers are expected to cost around the same amount as gas boilers and could fit in the same exact spaces, and thus the switch would require less adaptation by consumers. They don’t need to rely on electricity at critical times of the day due to the capacity for storage, and they don’t produce any carbon monoxide. However, hydrogen boilers are not yet commercially available and could temporarily increase gas prices during the initial scale-up stages. Another issue is public perception, namely safety concerns regarding flammability and a general view that these systems are inefficient because energy is required to make hydrogen, and hydrogen is required to make heat.

Since the two options excel in different areas, one technology might be a better fit for a given context. For this reason, it is important to approach deployment from an individual building level in addition to a national level. Resilience network planning will also be key to ensuring constant delivery, even in extreme circumstances like disruptive storms.

The Importance of Consumers

Decarbonizing gas is going to require a highly inclusive approach that considers technical, economic, and consumer perspectives. This last bit is especially important, as consumers tend to be left by the wayside when it comes to big picture solutions. And despite reports that 75% of the public is concerned about climate change, there is still a massive gap between public intent and public action – for example, only 39% of people have reported considering a switch from natural gas heating. Because the effort required to implement new technologies can be a major barrier to uptake, it is crucial for governments to make it easy for consumers to commit to action. A key part of this involves educating consumers with the help of trusted advisors, such as local tradespersons and NGOs, as opposed to energy suppliers or natural gas companies (for whom consumers are typically much less responsive).

Planning the Future

 Cadent is working on a range of projects related to net zero gas, and I was particularly impressed by their implementation approach, which is essentially this: don’t expect people to be comfortable with technologies they have to imagine, show them what’s possible. For example, one project is developing in-home applications for hydrogen: whether an odorant needs to be added, where hydrogen accumulates if it leaks, and how readily combustible it is, among other questions. An exciting product of this work is a hydrogen show home that has cropped up in Gateshead. The house features hydrogen boilers, stoves, and fires that boast a beautiful orange flame (to book a visit, email ). Project “H21” is testing the feasibility of 100% hydrogen supply up and down the UK’s current gas network, and another scheme involves blends of hydrogen and natural gas that can provide CO2 emissions reductions of around 6% and could serve as a key stepping-stone in scaling up and encouraging public acceptance of 100% hydrogen in the near future. Residents who participated in this project consistently reported that they couldn’t tell the difference between regular and blended boilers.

So how much hydrogen do we theoretically need? According to predictive models, this number varies from 23 to 182 TWh depending on the interplay between customer acceptance of hydrogen and the adoption of heat pumps. While it’s difficult to plan for a future that has so much uncertainty, the gas sector can prepare by ensuring hydrogen is as safe, well-planned, and easy to implement as possible for when the time comes to deploy. If companies like Cadent continue to innovate in this direction, hydrogen has my full support.

Ellie Martin is a master’s student in Imperial’s Sustainable Energy Futures course. Her undergraduate background is in Biochemistry and Molecular Biology at the University of Miami, and she’s interested in developing energy technologies through the intersection of engineering and molecular science.

Methane removal from the atmosphere- could it help us reach our climate goals?

By Dr Jasmin Cooper

Methane is the second most important greenhouse gas and because of this, over 100 countries have pledged to cut their emissions of this potent greenhouse gas. All efforts so far to cut methane from the atmosphere have focused on reducing emissions, targeting sectors such as oil and gas, agriculture and waste management. While this is effective in reducing the amount of methane present in the atmosphere, they cannot reduce methane emissions to zero. Also, these actions could be hindered by methane emissions from thawing permafrost caused by current increases in global temperatures. Therefore, there may be the need to remove methane from the atmosphere, but this is an area with little ongoing research and many data gaps.

Unlike carbon dioxide which can be removed directly from the atmosphere, methane removal centres on enhancing the conversion of it into carbon dioxide, or other chemicals. The reasoning for this is because of methane’s strength as a greenhouse gas; 82.5 ± 25.8 times as powerful as carbon dioxide over 20-year time horizon and 29.8 ±11 times as powerful over 100-year time horizon (1). Therefore, by converting it into a less potent greenhouse gas, its global warming impacts are greatly reduced.

The methods which can be used to remove methane focus on increasing the size of existing methane sinks (natural systems which remove it from the atmosphere) or other ways of converting it into carbon dioxide and other chemicals:

Enhancing methane sinks


The main sink for methane is the reaction with hydroxyl (OH) radicals in the atmosphere, which coverts it into carbon dioxide. Therefore, methods of increasing the amount of OH radicals in the atmosphere would enhance the rate of methane removal. Iron-salts have been found to enhance OH radical formation from sea water by mimicking the reaction of mineral dust (2). By applying iron-salts to sea water, the formation of OH radical and Cl is enhanced, both of which react with methane.


The other sink for methane is microbes in the soil, which contain enzymes that can oxidise methane into carbon dioxide (3, 4). By increasing the concentration of these microbes in the soil or using them in equipment designed to remove methane from air e.g. biotrickling filtration (3), the concentration of methane in the atmosphere can be reduced.

Direct oxidation and conversion into other chemicals


Methane can be converted into carbon dioxide without OH radicals. Methane can react with oxygen in the presence of a catalyst, in a reaction similar to combustion, to produce water and carbon dioxide. Many catalysts can be used including photocatalysts, metal catalysts with zeolites and porous polymer networks (3). These are used in air contactors, like those used in direct air capture for carbon dioxide removal, where air flows through the materials containing the catalyst. Methane can also be oxidised to form methanol (3). It is also possible to directly converted methane into chemicals such as ethane and ethylene in the presence of a catalyst (5) and platinum-based catalysts have been found to be effective for this.

Barriers to methane removal

While it is possible to remove methane from the atmosphere, its direct removal is an area with little ongoing research. Reasons for this are that the concentration of methane in the atmosphere is much lower than carbon dioxide (~200 times lower; 1.88 ppm methane versus 410 ppm carbon dioxide). Therefore, it is more energy intensive to remove methane from the atmosphere because large volumes of air need to be processed to remove significant amounts of methane. Other reasons for why little scientific interest have been placed on methane removal is that it is currently much more effective to reduce the concentration of methane in the atmosphere by emissions abatement e.g., reducing venting and flaring in oil and gas or waste management practices in agriculture.

Could it help us reach our climate goals?

Overall, methane removal from the atmosphere could play a role in meeting future climate targets but this is dependent on how successful methane emission reduction initiatives are, as well as other decarbonisation strategies e.g. phasing out fossil fuels and ramping up renewable electricity. Methane removal is not a substitute for methane emissions abatement but could be complimentary to it if further sharper and deeper cuts to methane are needed to reach Paris Agreement goals. If net-zero pledges are successful and more initiatives like the Global Methane Pledge Methane are established, then methane removal is unlikely to play a role in future decarbonisation strategies.


  1. IPCC. AR6 Climate Change 2021: The Physical Science Basis. Geneva, CH: Intergovernmental Panel on Climate Change (IPCC); 2021.
  2. Oeste FD, de Richter R, Ming T, Caillol S. Climate engineering by mimicking natural dust climate control: the iron salt aerosol method. Earth Syst Dynam. 2017;8(1):1-54.
  3. Jackson RB, Abernethy S, Canadell JG, Cargnello M, Davis SJ, Féron S, et al. Atmospheric methane removal: a research agenda. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences. 2021;379(2210):20200454.
  4. Lawton TJ, Rosenzweig AC. Methane-Oxidizing Enzymes: An Upstream Problem in Biological Gas-to-Liquids Conversion. Journal of the American Chemical Society. 2016;138(30):9327-40.
  5. Li Z, Xiao Y, Chowdhury PR, Wu Z, Ma T, Chen JZ, et al. Direct methane activation by atomically thin platinum nanolayers on two-dimensional metal carbides. Nature Catalysis. 2021;4(10):882-91.




Will the global methane pledge make an impact in meeting climate goals?

By Luke Dubey

In the first week of COP26 a ground-breaking methane pledge was announced by the US and the EU. Very quickly over 100 countries, representing 70% of the global GDP and almost 50% of anthropogenic methane emissions had signed up. The pledge agrees to cut methane emissions by at least 30% by 2030 compared to 2020 levels. It is estimated that delivering on the pledge would reduce warming by at least 0.2°C by 2050. So how is this going to be achieved, will it work, and why are over half of the emissions not covered?

Each country that has signed the pledge can decide how to reduce its emissions. This could be through new technology, regulations, switching fuels or changing practices. Due to the completely different emission profiles of each country, emissions reductions will take a completely different form. For example, the EU is a large consumer of gas, but a low producer compared to the US which has very high gas production. The strategies in place for one country will be very different to another. Due to how recently the pledge was announced, most countries do not have a detailed outline of how they plan to reduce their emissions. But these will be required very rapidly as 8 years is a short time for such a large emission reductions.

Thus far, only the US has a detailed national action plan on how to cut emissions within their borders. The US action plan was published in November 2021 following the announcement of the pledge at COP26 by President Joe Biden, and outlined their strategy to cut emissions. The action plan has considerable focus on the oil and gas sector, aiming to reduce emissions from sources covered by the action plan by 75%. This includes pipelines which will be covered by a new leak detection and repair rule which would establish standards to detect and eliminate leaks. Plugging wells, reducing flaring and venting and improving standards for new and existing oil and gas sources are also included. The action plan, should it be successful, will provide a playbook for reducing oil and gas sector emissions. Other emission sources are also covered in the action plan. For landfill emissions, a reduction in emissions via regulations and a drive to reduce the quantity of food in landfills, with the goal of 70% of emission captured from landfill. The agriculture sector is tackled via new technologies such as anaerobic methane digestors. The action plan has shown the 30% reduction can be achieved by slashing emissions from the lowest hanging fruit, in the USA’s case oil and gas and landfills, while providing jobs. This will allow the harder to abate sectors to survive while the technology to reduce their emissions becomes less expensive and more feasible to implement.

If the US has shown (in theory) how drastic emission reduction can be achieved, while also providing co-benefits to the economy, why have all countries not signed up? This is the main failing of the pledge. The 30% emission reduction, while significant enough to aid us on the path to 1.5°C (if all countries signed up) was a reduction too big for some of the world’s largest emitters such as China, Russia and India. Their omission is a huge blow to the 1.5°C target where methane emissions need to decrease by 25 – 53% for it to be achieved. Moreover, the 30% reduction in many countries is not enough to meet the IEA’s net zero pathway which sees a 75% methane reduction in energy use. So, it would seem that the pledge, by not being adopted by some of the largest emitters, will not be enough to meet Paris goals. However, should the signatories demonstrate that emissions can be reduced, while implementing a methane tax price (some in the US have suggested $1800/ton) then these countries, through purely economics may be persuaded to reduce emissions. Getting these high emitting countries onboard will be key to the long-term success of the pledge and will have a large impact in whether climate goals can be met.

Overall, the methane pledge must be seen as a positive as it is the first large scale attempt at tackling this potent greenhouse gas globally. The omission of many large emitters is a great loss but must be placed in the context of many unwilling participants at COP26. Should the reductions in emissions from the signatories be successful it will pave the way for other countries to join. This in turn will go a great way in meeting climate goals.