Why the London Plan is targeting zero carbon

Hywel Davies discusses the implications for new developments in the capital

The Housing and Planning Act made changes to legislation covering local authority and social housing, and addressing rogue landlords, with the aim of improving the supply of homes. There was also an unsuccessful attempt to attach a new commitment to the 2016 trajectory for ‘zero carbon’ homes – first adopted in 2007 – which attracted many headlines. But changes to carbon emissions targets in the London Plan – which now requires major new residential developments to be zero carbon – have attracted far less comment.

The Plan has been in place for some time, but it – and the more recent supplementary planning guidance, published in March 2016 – may have slipped past some, unnoticed.

David Cameron’s government abandoned the zero carbon homes policy in June 2015, but recent reviews of the London Plan have tested the continued inclusion of this requirement in the document, and it has been shown to meet the necessary viability requirements. So, for the capital at least, 2016 is the year of zero carbon housing.

Planning Policy 5.2 requires development proposals to make the fullest contribution to minimising carbon dioxide (CO2) emissions in accordance with the following hierarchy:

  • Be lean: use less energy
  • Be clean: supply energy efficiently
  • Be green: use renewable energy.

It also commits the Mayor of London to ‘work with boroughs and developers to ensure that major developments meet the following targets for CO2 emissions reduction in buildings’. The target for residential buildings is zero carbon from 2016. The policy requires major development proposals to include an energy assessment demonstrating how the targets are to be met on site, with at least the following details:

  • Calculation of energy demand and CO2 emissions covered by Building Regulations and, separately, from any other part of the development, including plant or equipment not covered by the Building Regulations, at each stage of the energy hierarchy
  • Proposals to reduce emissions through energy efficient design of the site, buildings and services, through the use of decentralised energy – such as district heating and cooling, and combined heat and power (CHP) where feasible – and to cut emissions through use of onsite renewable energy technologies
  • Where it is clearly demonstrated that the specific targets cannot be fully achieved onsite, any shortfall may be provided offsite or through a ‘cash in lieu’ contribution to the relevant borough, to be ring-fenced to secure CO2 savings elsewhere. Guidance is available on offsite carbon offsetting, based on a report for the Greater London Authority (GLA) by the National Energy Foundation.1

Zero carbon homes form part of major development applications in which the residential element achieves at least a 35% reduction in regulated CO2 emissions relative to Part L 2013 through onsite measures, and the remaining emissions are off-set through a cash payment to the relevant borough. This will be ring-fenced to secure delivery of CO2 savings elsewhere.

Technical implementation of this policy should be in line with the Mayor’s Energy Planning: GLA Guidance on preparing energy assessments (March 2016). The Mayor’s Housing Standard’s Viability Assessment assumed a carbon offset price of £60 per tonne of CO2 for a 30-year period and, if this figure is used, it will not be necessary to carry out a further viability assessment of the policy approach – or is that possible?

London, arguably, drives the UK economy in many ways. So will the London Plan become the driver of Building Regulations?

The supplementary guidance also addresses overheating, noting that more energy efficient homes may be at greater risk of this, and that an assessment of the risk is required. The guidance explicitly references CIBSE publications TM52 The limits of thermal comfort and TM49 Design Summer Years for London, saying they ‘can assist designers to take these considerations into account, alongside other industry guidance’.

With Building Regulations already devolved to the four home countries, it is arguable that the London Plan offers a fifth devolved set of regulations in all but name. The capital drives the UK economy in many ways – so will the Plan become the driver of Building Regulations, especially if Wales and Scotland seek to follow the GLA – and not the English – regulations in future? In this area, we already live in interesting times.


1 Review of carbon offsetting approaches in London, the National Energy Foundation, June 2016. bit.ly/2dDHADP

Hywel Davies is technical director at CIBSE