This “greenest government ever” has been letting out hints that “zero carbon homes” might mean something quite different by the time 2016 comes around. Already “allowable solutions” have been floated, meaning that not all of the carbon reductions need to come from on site. The number floated by the Zero Carbon Hub was 70% of the reductions to come from on-site measures – a combination of fabric energy efficiency (FEES) and on-site renewables.

Allowable solutions are essentially a form of carbon offset scheme. The remaining emissions from a new home are totted up, and emissions to that level are reduced elsewhere, whether that be by putting renewable energy on a different building or by making an existing building more efficient.

This it not necessarily a bad idea. There is a limited pot of money out there and on-site renewables are certainly not always the most efficient way to spend it. Of course, in the same way that carbon offset schemes need to meet a number of conditions before they become reputable, there are a number of conditions that need to be met before this new definition of zero carbon becomes anything more than a sell-out to the housebuilding industry.

Additional

The first and most important test of an offset scheme is “is this contributing reductions which would not have happened anyway?”. The greatest criticism levelled at schemes like the Clean Development Mechanism is that it was funding things like hydro-electric plants which were already a good investment. It is hard to make a case for projects like retro-fitting insulation being additional where there is already a business case to do insulate. On the other hand, as I talked about in the lock-in effect post, it may be that an additional pot of money could mean that the insulation can be installed to a greater depth than would otherwise have paid back.

Measurable

Another difficult question is measurability. It is not so hard to measure the energy savings made, or the energy generated by a renewable energy system. However it does cost money.

As a consultant with a background in academia, I happen to think that that is money spent on measurement and monitoring is well-spent. Rules of thumb and factors are all well and good, but they need to be checked against ongoing installations. Ideally there should be a central collection of the data generated (anonymised if need be) so that researchers can test their theories and government can be judged on the success of their policies.

How much more convincing would the late 2009 report from London South Bank on carbon savings under the London Plan have been if it had been based on more real-world measurements rather than estimates? Part two of the project is intended to do just that, but I’ve yet to see any sign of it despite the authors’ intention to publish early in 2010. I’ve emailed them so hopefully we can find out when it’s coming out.

Socially beneficial

With the loss of focus on the fuel poverty agenda we seem to have forgotten that one of the most important reasons for energy efficiency is that is means people can afford to heat their homes to a comfortable level. New homes built to Code level 3 cost a lot less to heat than old solid-walled properties. If we can start spending some of the money that would otherwise have pushed a new Code 3 home to a new Code 6 home on bringing existing homes up to a better standard then that is surely a win-win situation?

Further social benefits could be delivered by educational projects, for example renewable energy installations on schools, with built in meters so the performance of the kit can be monitored as a part of school science lessons.

Summary

These are just a few arguments for what would be needed from an offset scheme for zero carbon homes. At least from one that I could support. To restate:

1) The savings have to be additional. That means they have to be beyond what is currently a cost-effective investment.

2) The savings have to be measurable. That means careful monitoring and sharing information on what is and isn’t delivering.

3) The projects should have a social benefit. That means concentrating on alleviating fuel poverty and on educational projects

Only if these three conditions are met can I support any watering down of standards. There are other conditions such as requiring a minimum level of fabric energy efficiency, but in terms of the requirements for an offset scheme, these three are the conditions I hope to see met.