A new report published by the ACE Research and Energy Saving Trust for the Scottish government finds that the low carbon heat solutions widely available on the market today emit zero direct greenhouse gas, and can help slash the emissions of buildings.
Readily available low carbon heat solutions are found to emit zero in-building emissions, but there is a gap on the technologies’ wider emissions profile.
The UK is highly dependent on natural gas for heating buildings, leading to high emissions and high prices.
Accelerating the deployment of low carbon heating solutions will be key for the UK to reach net zero.
In-building GHG emissions and carbon heating solutions
Created for the Scottish Government’s ClimateXChange unit, the new report explores the extent to which there are any direct, in-building GHG emissions associated with low carbon heating solutions. The answer? Zero.
ACE Research, the research unit of the UK’s Association for Decentralised Energy (ADE), and Energy Saving Trust, an energy efficiency non-profit, set out to analyse a wide range of low carbon heating solutions to better inform future building regulations on the role they can play in getting buildings to net zero.
The report looks at solutions such as direct electric heaters, electric storage heaters, electric boilers, solar thermal technologies, heat pumps, heat networks and fuel cells.
The direct GHG emissions of these technologies, meaning the emissions generated by a heating system at point of use within total grounds of the building, were found to be zero. However, this does not take into account the wider upstream emissions in manufacturing and selling these technologies or external supply to power these solutions.
Kieran Sinclair, the heat policy manager at ADE explained that while it is widely understood the emissions impact of various fossil fuel combustion systems for heat, less research has been conducted on the impact of heating solutions considered to be low carbon.
“This research aims to fill that knowledge gap and help guide the legislation that is so critically needed to encourage the rapid development of truly low carbon heating solutions, such as the system of heat networks that will need to be quickly deployed to decarbonise the UK’s towns and cities by 2050”, Sinclair commented.
What are the low carbon heating systems available?
Currently, the main low carbon heating solutions deployed in the UK are solid biomass, heat pumps, and solar thermal.
Although biomass is the most popular solution in the UK as of today, it is also the solution the report found not to achieve zero emissions. While sustainably sourced biomass may often be considered to be carbon neutral since the material being burned has already absorbed carbon, this does not take into account the combustion of the materials.
Combustion of biomass results in the emissions of carbon, methane, and nitrous oxide. However, emissions from biomass are still significantly lower than the baseline emissions of other heating systems. Analysis found that most biomass heating technologies emit less than 2% of total natural gas boiler baseline emissions. However, this could vary greatly depending on the quality and source of the material.
The second most popular low carbon heating solution is heat pumps. A heat pump is any device that takes low temperature air from a renewable source such as ambient air, ground, or water, and raises the heat using a refrigerant cycle. This solution uses a relatively small amount of energy, and the only risk of direct in-building emissions is the risk of leakage of refrigerant, but this risk is considered negligible if the pump was installed and tested properly.
Solar thermal systems use heat from the sun to warm water, providing only heat for water and not for space heating. The only risks of GHG emissions associated with solar thermal systems are leakage of working fluids, but again, this risk is considered to be negligible.
The majority of other low carbon heating solutions are electric. This includes electric panel heaters, electric fan heaters, electric radiant heaters, electric storage heaters, and electric boilers.
While the report finds these solutions to emit zero in-building GHG emissions, this does not take into account the emissions related to the electricity grid powering the heating systems. If a country’s energy matrix is mainly renewable, then this will not impact the GHG emissions of these solutions. However, it is not the same story if the grid is mainly powered by fossil fuels like coal.
While all these low carbon heating solutions can be net zero in theory, there is a lack of data on the wider emissions impacts of installing, operating and decommissioning heating solutions within the wider systems.
What role does decarbonising heating play for net zero in buildings?
The UK’s Climate Change Committee found that heating and hot water for UK buildings make up around 40% of the country’s energy consumption and 20% of the GHG emissions. Mitigating and finding new solutions in the heating sector is therefore crucial in reducing overall emissions of buildings and energy use.
Currently, over 80% of UK homes rely on natural gas for heat, a much higher dependency compared to other countries due in part to the country’s natural gas reserves in the North Sea. The over dependency on natural gas for heating in the UK is not only an emissions problem, but could be an energy security problem in the future if they can no longer rely on their own supply and are pushed to import.
As the Ukraine-Russia crisis has highlighted, the supply of natural gas globally can be a turbulent and risky business – not to mention expensive for consumers. Consultancy Auxilione forecasts that due to the rising wholesale gas and electricity prices triggered by the Ukraine crisis, the energy bills for UK citizens will hit new records. Energy bills could jump from an annual rate of £1,971, to £3,635 just for the last three months of 2022 alone.
Reducing the reliance on natural gas and making the move to low carbon heating systems is therefore both a climate, social, and economic issue that impacts everyone.
The UK’s strategy to reduce heating emissions and natural gas reliance
To address this challenge, the UK published its Heat and Buildings Strategy in October 2021. The new strategy acknowledges that in order to achieve net zero in all buildings to stay aligned with the country’s wider net zero ambitions, decarbonisation of heat is a key priority.
The policy aims to phase out natural gas boilers by 2035, however no one will be forced to replace their existing boilers with cleaner, more efficient solutions. The strategy aims to drive down the cost of low carbon heating solutions like heat pumps, while exploring the potential to use hydrogen for heat by 2026.
The Secretary of State for Business, Energy and Industrial Strategy (BEIS), Kwasi Kwarteng, said in the new policy’s foreword that while the move to decarbonising heating will be complicated and rely on a combination of leading-edge technologies that may or may not mature, this also offers the country significant economic opportunities.
“The transition to low carbon buildings could add £6 billion gross value added and support 175,000 skilled, green jobs by 2030”, commented Kwarteng.
Decarbonising heat is certainly no easy task for a country so reliant on natural gas, but the UK will need to take big, decisive steps towards deploying the heating solutions that have already proven to be low carbon and integrate these into future – and existing – buildings in order to achieve net zero.