The topic up for debate at the recent Round Table event at the Saint-Gobain Innovation Centre was ‘Zero Carbon – a lost cause?’ and it certainly provoked much discussion. At the table were many of the key players who were either involved in the creation of the original Zero Carbon definition, or charged with delivering it, in the form of the creation of construction products or the creation of the actual Zero Carbon houses themselves.

So, why so much debate?

The key problem with a discussion about Zero Carbon is that the target is still far from clear.

It has moved a long way from the initial ideas set out by the Labour Government in their consultation paper of 2006 ‘Building a Greener Future’ where it was stated that “Zero carbon means that, over a year, the net carbon emissions from energy use in the home would be zero”.

This original definition included all the energy, including that from non-regulated energy (white goods).  Since then, this has changed and only regulated energy (space heating and cooling, fixed lighting and ventilation) needs to be accounted for when building a Zero Carbon home. So, not really true zero carbon but at least this ties in with the way in which energy use in buildings is normally assessed through the Standard Assessment Procedure (SAP) and Code for Sustainable Homes.

A timetable for CO2 reduction was set out using Approved Document Part L (The Conservation of Fuel and Power) of the Building Regulations. The expected 25% reduction over 2006 levels did indeed occur in Part L 2010, however the further 25% reduction expected in Part L 2013 did not happen. We only got 6% (in 2014 as it was late, as well as unexpected) making the leap to Zero Carbon in 2016 rather bigger than anticipated and leaving Part L 2016 with much to do. We still await news of Part L 2016. Don’t hold your breath.

The Zero Carbon Hub did some fine work in proposing a Zero Carbon standard and many of you will be familiar with the Zero Carbon Triangle:



Source: Zero Carbon Policy.

The concept of Allowable Solutions was first introduced by Government in 2008 and this is really just a fancy term for carbon offsetting. It gives a developer options on ways to offset the residual carbon on a site to meet the carbon target.

So, job done then?  Zero Carbon defined?

Sadly, no.

An announcement in the Queen’s Speech gave us a new definition of Zero Carbon: Level 5 of the Code for Sustainable Homes but legislation will allow developers to build to Level 4 as long as they offset the gap to Level 5 using allowable solutions. Confused? You are not alone.

To further muddy the Zero Carbon puddle, it was also announced that homes built on ‘small sites’ would be exempt from the requirement to build to Zero Carbon.

If that wasn’t enough, a  proposal by the Tories  saying that they would also exempt 100,000 ‘starter homes’ from Zero Carbon  shows that the coming General Election could also make the quest for Zero Carbon a long and even more confusing journey.

I have, in previous blogs, likened the whole Zero Carbon journey to Middle Earth with references to the Dark Lord of Climate Change. However as the Zero Carbon target continues to unravel I fear there is less of Hobbit and more of ‘Bodge It’ about this sorry tale…