Redefining zero carbon
The UK Green Building Council has devised a new definition of zero carbon for building based on off-site generation. It is spelled out in its report ‘The definition of zero carbon’ produced by its zero-carbon task group chaired by Mark Clare of Barratt Developments. The report releases new modelling that shows that the current definition is not achievable on up to 80% of new homes, so the definition of zero carbon needs to be changed if Government targets are to be achieved. The are three parts to the UK-GBC’s definition. 1. All new buildings must meet strict minimum energy-efficiency standards, both in terms of the building design and household appliances where supplied by developers. 2. All new buildings should seek to mitigate carbon emissions from energy use on or near the development. Where this is not possible, a minimum level of carbon mitigation must be met (e.g. 100% regulated energy). 3.Above this threshold, either:• off-site solutions could be allowed, without requiring private-wire networks, provided that they are demonstrably additional and have been built specifically to deliver the energy needs of the development;
• the developer can pay into a ‘community energy fund’ that will ensure equal or greater net carbon savings are delivered through new installation. The price of paying into the fund should be set at a margin above the cost of community-scale solutions so as to clearly incentivise the installation of on-site or local measures first. Paul King, chief executive of the UK-GBC, says, ‘Government’s level of ambition is spot on and should be supported 100%. This is not about dumbing down or abandoning the concept of zero carbon. This is about ensuring the same high level of carbon savings, but allowing developers more flexibility in how to get there to deliver mainstream, zero-carbon homes in the numbers required. ‘The solutions we are pointing to are designed to ensure energy-demand reduction always comes first and on- or near-site renewables should be the focus for meeting energy needs. ‘Our proposed definition recognises off-site renewables could play a part and also gives a big boost to community-scale technologies. This would have the added benefit of enabling much needed carbon reductions in the existing stock by enabling the distribution of low- or zero-carbon heat through district networks. The full report is available on the UK-GBC web site.
