In October 2018 the Greater London Authority (GLA) issued an updated version of its benchmark guidance document on strategic planning application energy assessments, outlining how to comply with the requirements of the London Plan Policy 5.2 (and of course it’s also a useful basis for preparing energy assessments for planning authorities anywhere in the country). The updated version of the GLA’s energy assessment guidance document is applicable across all 32 London boroughs.

The biggest change is that the use of the revised SAP 10 carbon emissions factors is mandatory in both commercial and domestic developments from January 2019, despite a higher carbon emission factor for electricity – SAP 2012 – being stipulated in Part L of the current Building Regulations. This move reflects the decarbonisation of the grid, and is intended to inform a future update to the Building Regulations. 

But what does this updated energy assessment guidance mean for the choices developers make in terms of M&E design? The SAP 10 grid electricity emission factor is 0.233 kgCO2 per kWh, which is less than half the figure currently use in Building Regulations – 0.519 kgCO2 per kWh – which means that carbon savings from electricity generating technologies (such as PV and gas CHP) will be reduced, while technologies which use electricity to generate heat (such as heat pumps) will see their reported carbon savings increase. This will result in fewer schemes featuring CHP (particularly given the additional emphasis put on air quality), and more featuring heat pumps (particularly those using ‘green’ electricity from PV) and sources of secondary heat.

However, this doesn’t mean that gas boilers can be easily replaced with heat pumps, without any additional impact on scheme design. Most heat pump installations will include external condensers as part of a more economic air source system, and these need to be carefully positioned both in terms of air flow and noise impact. Ground source heat pump systems aren’t typically feasible in urban areas due to the limited footprint of buildings, and the high costs associated with the ground works. There are also other challenges with centralised heat pump systems with low water temperatures, so these do require more carefully planning than traditional gas-fired heating systems.

At AJ Energy one of our specialities is low-carbon M&E design, and given our long history of working with most of the boroughs in the Greater London Area, we’re well-placed to provide pre-planning services. To find out more, please call us on 01206 266755 or email