Direct greenhouse gas emissions from low and zero carbon heating systems

The Scottish Government is committed to ensuring that, from 2024, new buildings applying for a building warrant must use heating systems which produce zero direct GHG emissions at the point of use.

This analysis of direct, point-of-use greenhouse gas (GHG) emissions associated with zero carbon heating technologies considered a range of technologies, including:

• Zero direct emission technologies, including direct electric heaters, electric storage heaters, electric boilers, solar thermal and solar thermal storage, heat pumps and heat networks.
• Biomass combustion.
• Hydrogen combustion and fuel cells.

Key findings 

• Direct emissions from direct electric heaters, electric storage heaters, electric boilers, solar thermal technologies, heat pumps, heat networks and fuel cells are found to be negligible.
• Biomass combustion and hydrogen combustion offer significant emissions savings compared to fossil fuel-based heating, but with varying levels of direct GHG emissions that are important to be aware of.
• A common theme across different technologies is a lack of data and research on direct emissions from both manufacturers and independent researchers; therefore, further research is needed to fill gaps and improve understanding.
• For biomass combustion for heating, there may be an important role for education and awareness raising. Information could be provided to operators/users around types of fuel and fuel quality and how these impact emissions.
• As well as supporting improved air quality, controls on fuel quality are likely to result in reduced GHG emissions.