Heat pumps for low carbon heat in London

Etude were commissioned by the Greater London Authority (GLA) to undertake a study into the implications of a more widespread uptake of heat pump technologies in London’s new developments, driven by the decarbonisation of the electricity grid. You can download our full report on heat pumps in London from here.

Our ten key conclusions

1. Heat pumps are part of the solution

Heat pumps are very likely to play a growing role for the delivery of low carbon heat in London, both as part of low carbon heat networks (e.g. using waste heat as a source) and as building-only heating systems. New buildings offer an opportunity to generate faster changes in the market for this type of low carbon heat solution.

2. Heat pumps are already lower carbon than gas

When applying a more up-to-date carbon factor for electricity (e.g. 233 gCO2/kWh proposed in SAP 10) heat pumps are a substantially lower carbon system than gas-based solutions (e.g. gas boilers and/or gas-fired Combined Heat and Power) or direct electric options; and the electricity carbon factor is also expected to decrease further in the future.

3. Getting the most out of heat pumps is not yet widely understood by the industry

In order to deliver low carbon and affordable heat, the efficiency of heat pumps needs to be better understood by the building industry. The use of low temperature distribution systems and emitters, the method used to generate domestic hot water and the correct installation and commissioning of heat pump systems can all help to deliver low carbon emissions and operational energy costs. We should use SCOP or measured SFPs as the measure for efficiency. Heat pumps should not be seen as direct like-for-like replacement for gas-fired boilers or CHP.

4. Lifetime cost is competitive

Maintenance costs can form a substantial part of overall end-user heating costs in new developments and should be included in any evaluation of running costs of heat pumps. Efficient heat pumps offer a cost competitive form of heating.

5. There are a huge range of systems at a wide range of price points

It is very difficult to draw a simple conclusion on capital costs given the variety of systems and the range of costs within a single system type. However, on average, the capital costs of heat pumps are likely to be slightly higher than a ‘business as usual’ heating system with central gas boilers and a gas-fired CHP. A number of developments with heat pumps exist, which demonstrates that they are already viable in a commercial setting.

6. Capital cost is currently higher than other options

Potential additional capital costs compared with ‘business as usual’ are likely to be small in comparison to the total project costs though (0-3%) and should be seen in conjunction with their potential benefits including carbon and air quality. Research commissioned by the Government in 2016 also suggests that costs could reduce by 15-20% in future.

7. Plant space requirements and noise issues vary by system type

The impact of heat pumps on space and noise is very dependent on the system type and it requires consideration on a project-by-project basis.

8. Refrigerants are a manageable risk

The majority of refrigerants currently used in heat pumps have a high global warming potential and can present other risks. Regulatory frameworks are in place to address these concerns though and the industry appears to be working to mitigate these risks.

9. The suppliers can cope with the extra demand, design and installation need some help

Heat pump suppliers would be able to sustain an uptake in demand as they supply other European countries with much higher volumes of heat pumps installed annually. The industry as a whole needs to be capable of dealing with an increased demand.

10. Key challenges

The key considerations for a wider uptake of heat pumps include mechanical design (particularly supply temperatures and Domestic Hot Water (DHW) provision), architectural integration, installation quality, commissioning and maintenance. More work is required to ensure that they will not have unintended consequences, but none of these considerations are thought to be significant barriers. Heat pumps can also have the advantage of being ‘smart grid’ ready (therefore a demand side management opportunity).

Etude graphic showing the wide range of heat pump types available

Map of heat pump types