For major residential developments in Greater London of more than 10 units or 1,000sqm of GIFA (gross internal floor area) Policy 5.2 of the London Plan requires that CO2 emissions are to be reduced by a minimum of 35% on-site beyond Part L1A of the Building Regulations 2013 and that the remaining emissions, to 100%, are to be off-set through a cash in lieu contribution to the relevant borough.
Each borough applies its own rate: this is typically £1,800 per tonne of CO2 emissions over the lifetime of the development (taken to be 30 years).
In addressing the three principles of the Energy Hierarchy we will always seek to identify the most cost-effective way of securing the maximum CO2 emissions so as to keep the carbon off-set payment to a minimum while recognising that in certain circumstances the payment that may be due is less than the capital cost of installation of renewable energy.
We have worked on large-scale residential developments where on-site CO2 emissions were reduced by adopting a fabric first approach and a gas powered CHP plant thereby keeping carbon off-setting payments to a minimum.
Overheating and cooling are also required to be considered as part of the overall strategy to ensure that the dwellings are comfortable to live in.