Hydrogen gas could play a major role in the future as a fuel source heating the UK's homes and businesses. HVP's Joe Dart reports.
Natural gas still plays an integral role in the heating industry – it powers the boilers that heat the nation’s homes after all. Gas will likely continue to be an important energy source for the foreseeable future but, much like other fossil fuels such as oil and coal, supply is dwindling and could run out entirely in the not too distant future.
On top of that, natural gas releases greenhouse gas emissions when burnt. According to the government’s Clean Growth Strategy, heating in buildings and industry creates around 32% of the UK’s total emissions, and nearly 70% of our heat is produced from natural gas.
The government has signed up to the Paris Climate Agreement, which will require the country to reduce its greenhouse gas emissions by at least 80% by 2050, when compared to 1990 levels. As a result, it is now exploring alternatives to burning natural gas when it comes to heating the UK.
There are two main options that the government is considering for decarbonising heat. The first is electrification, with households moving away from gas or oil boilers to electric heat pumps. The second is to decarbonise the gas grid by substituting natural gas with low carbon gases, such as hydrogen.
In recent years, much of the government’s focus has been on electrification, but the idea of introducing hydrogen into the gas grid is now gaining serious traction.
One major project which is showcasing the potential of hydrogen is the H21 Leeds City Gate feasibility study. H21 is a Northern Gas Networks (NGN) led project, in partnership with Wales & West Utilities, and part-funded by the Ofgem Network Innovation Allowance.
The basis for the study is to determine whether it is possible to convert our current distribution system in a large city from natural gas to 100% hydrogen.
“We used Leeds as a blueprint for conversion due to its size, energy demand and geographic location, but this blueprint could be adapted for any large UK city,” said Mark Horsley, Chief Executive at NGN.
The advantage of hydrogen over natural gas is that, when it is burned, it produces no carbon dioxide. This means that fewer harmful emissions are released when it is used as a fuel.
The final H21 study confirmed that the gas network in Leeds does in fact have the correct capacity for a full conversion to hydrogen, with minimal new energy infrastructure needed compared to alternatives, such as electrification.
The report also provides assurances that the conversion can happen with minimal disruption to customers. However, it is worth noting that if a switchover from natural gas to 100% hydrogen does occur, many existing gas-burning appliances will no longer function. That includes gas boilers, cookers and fires. In Leeds alone, approximately £1 billion has been earmarked to cover the cost of these appliance upgrades should the hydrogen switchover get the green light.
It sounds like a lot, but there are also serious costs attached to the electrification of heating. A 2016 KPMG report, 2050 Energy Scenarios, found that the cost of converting the UK to hydrogen gas could be at least £150 billion cheaper than electrification.
Martyn Bridges, Director of Technical Communication and Product Management at Worcester Bosch, says a switch to electrification would also result in far more invasive works for homeowners as, to work most effectively, heat pumps require a well-insulated home.
He said: “We know that [a leaky old property and a heat pump] isn’t a good combination, but a leaky old property and a high temperature heating by gas, oil, or hydrogen isn’t as much of an issue for the homeowner.”
Although the H21 strategy is proposing a straight swap from natural gas to hydrogen, there are other potential options involving hydrogen that could provide a solution.
One such option would be to enrich the gas grid with hydrogen. Most conventional gas boilers can still perform with a hydrogen blend of up to 20% in the natural gas network.
This sort of approach is already starting to be trialled in the UK. For example, the HyDeploy project will see the introduction of a 20% blend of hydrogen into Keele University’s gas network. The project is still in its preparatory phases, but a live trial is planned from April 2019 to March 2020.
Another option is to invest in fuel cell technology. This sort of technology is already commercially available within the heating sector. Viessmann manufactures the Vitovalor 300-P, which comprises two units, a fuel cell module and a peak load module, comprising an integral gas condensing boiler.
The way that the system works is that a fuel cell extracts the hydrogen from the gas supply and combines it with oxygen to generate both heat and electricity.
Christian Engelke, Technical Director at Viessmann, says that very little heat is lost or wasted in the process, and the product has a total efficiency of approximately 90%. An added benefit is that the Vitavalor can be installed in much the same way as a conventional boiler, requiring little additional training for the installer.
If the government takes the decision to back hydrogen as a solution for decarbonising heat, Christian is keen to stress that the Vitovalor could be a great way to immediately start reducing carbon emissions.
“In the short to medium term, get those machines out into the marketplace – they provide the least amount of disruption for all parties involved, and we are also fulfilling a government obligation to provide a solution to individual properties in terms of decentralisation electricity generation, which helps to balance the grid,” he said.
“The technology is commercially available, it’s reliable, [with] very little disruption to the homeowner. Yes, it’s a little more expensive, but it’s not much more expensive than a 4kw PV system.”
In addition, Christian says there are major questions over the sustainability of hydrogen that have yet to be answered. He explained: “We have to look up the supply chain to ask where the hydrogen we make comes from.”
Hydrogen can be a renewable fuel if it is produced through sources such as wind and solar, but in the vast majority of cases it will made from fossil fuels such as natural gas.
Mark from NGN expects that ‘green’ hydrogen – generated by renewable resources and electrolysis – will increase over time as the hydrogen economy grows and renewables play a greater role in electricity generation. However, for the time being at least, “the only way to produce hydrogen at the scale needed is through steam methane reforming or autothermal reforming: taking natural gas and separating the hydrogen and carbon”.
Looking forward, both Martyn of Worcester Bosch and Mark from NGN believe the next steps for hydrogen are reliant on whether the government is willing to take the plunge and starting investing heavily in the energy source. Mark said: “The main challenge for a switchover is a government policy decision on hydrogen.”
For Martyn, he fully expects to see hydrogen contributing to the future of decarbonising heat, but argues that we won’t see enough of a difference unless it’s blended into the gas network at high percentages, at least 40-50%.
“Once you’re getting to that sort of level, you might as well go the whole hog [to 100%]. So it’s very likely we’ll see a step change of more hydrogen,” he said.
However, Martyn suggests that enthusiasm needs to be tempered, at least in the short term, as a decision won’t likely be made before the next general election. He concluded: “I think there is sufficient evidence already on the table to set a timetable [for hydrogen] if they are really convinced that this is the answer.”