London Skyrise

GLA Energy Assessment Update –An Alternative Energy Strategy

At the end of October 2018, the GLA announced a major update to the Energy Planning guidance for major developments in London, in alignment with Sadiq Khan’s London Plan.

Under Policy 5.2 of the new London Plan, all major developments are required to submit a detailed energy assessment, to demonstrate how the targets for regulated CO2 emission reduction over and above current Part L Building Regulations will be met using the Mayor’s energy hierarchy:

  1. Be lean: use less energy
  2. Be clean: supply energy efficiently
  3. Be green: use renewable energy

The GLA has announced major updates to the Energy Planning guidance, which will come into force in January 2019, being renamed as the Energy Assessment guidance.

Carbon Emission Factor

The most significant change, is that planning applications will now be encouraged to use the updated SAP 10 carbon emission factors to assess the expected carbon performance of a new development using the Mayors energy hierarchy. Applications must still use the current Building Regulations methodology for estimating energy performance against Part L 2013 requirements, but will need to manually convert the outputs to SAP 10 emission factors for their submission.

This is to reflect the rapid decarbonisation of the electrical grid and the actual emissions associated with certain technologies. This will have a significant impact on products generating on-site electricity, which will see the impact of gas-engine CHP and Solar PV significantly reduced. In response to this, developments will need to employ alternative technologies to meet the 35% on-site carbon reduction figure.

SAP 10

In SAP 10, the Electrical Carbon Factor figure has been reduced from 0.519 KgCO2/kWh to 0.233 KgCO2/kWh. Meaning that electric heating solutions will now be more carbon efficient than gas, which has an intensity of 0.210 kgCO2/kWh, corrected to 0.247 kgCO2/kWh with a system efficiency of 85%.

Therefore, it is safe to say that heat pumps will now out perform any heating or hot water technology. A COP of just 3 will mean that heating and hot water production will have an emissions factor of 0.077 KgCO2/kWh. This will see a significant change in which products are specified into new buildings and reflects the Government’s commitment to transition to using low carbon energy.


Vauxhall Apartments


A New Energy Strategy

This is a significant update, especially for strategies being developed at the moment. Due to the time scales, there is an apparent need for applicants to understand what technologies are available to them in order to gain planning approval. Strategies must also continue to consider the overheating risk assessment and the potential requirement to connect to a future district energy system.

One such solution, which has already seen support from the GLA, is the Zeroth Energy System - created with an industry-leading developer for London high-rise apartments.

The revolutionary Zeroth Energy System uses an innovative, refrigerant free, water-to-water energy loop, running at 15-25°C, providing heating, cooling and hot water to apartments through in-dwelling heat pump technology. 

The Zeroth Energy System can be used with standalone Air Source Heat Pumps, but also be connected to district energy schemes, offering the greatest amount of flexibility to the building designers when compared with other solutions. Due to the unique operating temperatures the Zeroth Energy System will also help alleviate overheating issues currently experienced with traditional communal heating designs.

GDHV have considered the implication of this solution for the January 2019 deadline and the table below illustrates the potential impact of the system with the revised methodology. Using SAP models from a recently built development to the current London Plan, the Zeroth Energy System is modelled using ASHP’s with 300% efficiency.




The results of the analysis show a reduction in total carbon of 120,765kg or 45% when compared with the current methodology. This moves the overall reduction over the base case from 27% to 67% generously exceeding the 35% below requirement. Using the Zeroth Energy System for your London Energy Assessment, now offers an opportunity to scale back your carbon tax payments or find some additional capital cost savings by scaling back other energy saving strategies employed throughout the building.

Learn More

The GLA have stated that the Energy Assessment Guidance will remain in place until Government adopts new Building Regulations with updated emission factors, the consultation for which is expected early 2019, with implementation likely in 2020. At Glen Dimplex Heating and Ventilation, we have a team dedicated to understanding the built environment and its future, including how solutions such as the Zeroth Energy System comply with industry updates such as this.

To learn more about the London Plan and the Zeroth Energy System, contact us at to book an appointment with your regional Business Development Manager.