Earlier in the year, the GLA released an update to the guidance on preparing energy assessments. The updated document outlines the guidance for energy assessments carried out for new developments within London whilst intending to provide a transition between the current and new versions of the London Plan.
Below we outline:
- New Policy being implemented;
- Changes to current methodology that will now need to be applied; and
- Changes to building services as a result of the update.
New Policy
Be Seen
The guidance has expanded the London Plan energy hierarchy to include a new stage which requires all major development to ‘Be Seen’. i.e. to monitor and report its energy performance post-construction to ensure that the actual carbon performance of the development is aligned with the Mayor’s net zero carbon target.
A further document has been produced – ‘Be seen’ Energy Monitoring guidance – that explains the process that needs to be followed to comply with the ‘be seen’ post-construction monitoring requirement.
A spreadsheet document has also been provided to help outline the specific information required and provide a comparative baseline. It remains to be seen what the GLA will do with the data that they have gathered and how developers might be held to account.
Figure 1: The updated London Plan energy hierarchy including the ‘Be Seen’ stage.
Whole Life Carbon
There is now a requirement for all referable planning applications to fully capture a development’s carbon impact by calculating and reducing whole life-cycle carbon emissions. A further draft document has been produced – Whole Life-Cycle Carbon (WLC) Assessments guidance – that explains the process that needs to be followed to comply with the whole life carbon assessment criteria (Policy SI 2 of the New London Plan). This guidance document will be formally consulted on post publication of the London Plan. A WLC assessment template has also been provided to help outline the specific information required and provide a comparative baseline.
At present, there are no whole life carbon targets outlined within the new London Plan Policy SI2, however, the WLC guidance includes information on design principles as well as WLC benchmarks to aid planning applicants. Additionally, both RIBA and LETI have published targets for embodied carbon as well as operational energy which may also be adopted by the GLA as well as local planning authorities.
Changes to Current Methodology
Overheating Risk
Outline applications must now complete the Good Homes Alliance Early Stage Overheating Risk Tool to evaluate the risk of overheating to the development and advise on the steps required to mitigate the risk as the design progresses. This tool aims to promote early stage alterations to design, reducing the risk of overheating progressing into a major issue at detailed design.
In instances where air quality or noise concerns pose limitations to the opening of windows, applicants are now being required to submit two separate overheating analyses; one with openable windows and one with closed windows. This will ensure that passive measures have been maximised and the façade design has been optimised regardless of the constraints posed by the site’s location, and the proposed servicing strategy. Additionally, there is now a requirement for applicants to demonstrate that the assumptions of the overheating model are aligned with the noise and air quality assessments.
Applicants are encouraged to refer to relevant published guidance which draws together these areas including the Acoustics, Ventilation and Overheating Residential Design Guide.
Carbon Emission Factors
It is now expected that SAP 10 emission factors will be used for referable applications unless the application:
- is in a Heat Network Priority Area; and
- there is potential to connect to an existing network using gas-engine CHP or a new network using low-emission CHP (provided the heat network operator has, or is in the process of developing, a strategy to decarbonise the network and has shared it with the GLA)
If the application is a non-referable development, then it will be down to the borough’s discretion to decide which emission factors are used.
This major change precedes the expected change in carbon emissions with the upcoming update to building regulations Part L. The new emission factors have significantly reduced the carbon associated with electricity, promoting the use of electric systems over gas systems in buildings and in particular – heat pumps. This shift in policy favours the expansion and continued use of heat pumps, even though that approach is not widely supported by the industry. This denotes a significant risk given how influential GLA policy is, particularly after the previous promotion of CHP which, in hindsight, the GLA got wrong.
Carbon Offsetting
Boroughs are expected to use the recommended carbon offset price of £95 per tonne of carbon dioxide, or to set their own based on local viability evidence. This price is greater than the price adopted by the majority of boroughs currently apart from a few exceptions (such as Haringey and Lewisham).
Calculating regulated CO2 emissions for refurbishments
Applicants are now required to estimate the CO2 emission baseline performance of the existing building assuming a standardised notional specification for existing buildings, shown in Appendix 4 of the new guidance document (which is based on Approved Documents L1B and L2B as well as the Government’s Building Services Compliance Guidance).
This methodology replaces the previously vague approach whereby the performance of the existing building was estimated and often purposefully diminished to embellish the improvement in energy performance of the proposed development. This will provide a consistent baseline across all refurbishments.
However, in cases where the actual energy performance of the building element is more efficient than the notional specification (Appendix 4), this should be used instead.
Modular buildings, temporary construction, and co-living spaces
Modular buildings will now be expected to comply with the existing London Plan policies. The nature of modular buildings means that they will be expected to demonstrate high standards of energy efficiency while maximising on-site renewable energy opportunities. This policy aims to promote energy efficiency within modular buildings and promote the methodology moving forward. Developers of modular buildings will subsequently be forced to reassess whether their modular designs are in line with best practice and to take more of a site by site approach as opposed to ‘one size fits all’.
For temporary construction, applicants will be expected to maximise carbon savings in line with the existing London Plan policies. Developments comprising co-living spaces will be treated as residential uses for the purposes of complying with emerging London Plan Policy H16.
Air Quality Limits and Compliance
The new policy requires energy and air quality assessments to be aligned at an early design stage and during the development process, with the energy assessment displaying how the energy data has been carried across into the air quality assessment.
Changes to Building Services
The Heating Hierarchy
To comply with emerging London Plan Policy SI 3, developments in Heat Network Priority Areas (HNPAs) should have a communal low-temperature heating system and should select a heat source in accordance with the following heating hierarchy:
- a) connect to local existing or planned heat networks
- b) use zero-emission or local secondary heat sources (in conjunction with heat pump, if required)
- c) use low-emission combined heat and power (only where there is a case for CHP to enable the delivery of an area-wide heat network, meet the development’s electricity demand and provide demand response to the local electricity network)
- d) use ultra-low NOx gas boilers (CHP and ultra-low NOx gas boiler communal or district heating systems should be designed to ensure that they meet the requirements in Part B of the emerging London Plan Policy SI 1 Improving air quality)
Cost to Occupants
Applicants will be expected to consider the estimated costs to occupants of the proposed energy strategy and outline how they are committed to protecting the consumer from high prices. This is likely to adversely impact upon electrically driven developments over gas consuming developments, forcing design teams to think twice about how spaces are to be serviced.
It is unclear what will constitute unreasonably high costs, however, it is likely that a communal gas boiler will be considered as the baseline as it is within other GLA policy. The following parameters should be considered when estimating costs to occupants: Fuel used (including taxes, CCL etc.), Incentives (if applicable), Electricity sales (if applicable), Plant replacement, Overheads and Maintenance.
Heat Network Design
Network losses should be investigated at the earliest opportunity as they have significant implications on the efficiency of the network (both cost and CO2) and the thermal comfort of occupants.
Heat Pump Performance
Applicants will need to provide a diagram of the proposed location of the heat pumps and the associated condenser units. Where condenser units are installed internally there should be adequate access to air flow. For developments in Heat Network Priority Areas, the diagram should include the pipework which will be installed for future connection to a heat network.
Ambient Loop Heat Pumps
Ambient loop systems with heat pumps in individual units are regarded as individual heating systems and therefore would not be appropriate for developments in HNPAs.
If you would like to discuss these changes and how they impact on your existing or future projects please contact our Energy team.
