Saturday, 14 June 2014

Picking Through The Wreckage of Zero Carbon Homes

The policy that categorically does not do what it says on the tin




It all started out so well in those early years.  There was a sense of shared endeavour in the construction industry.  When, in 2006, the government announced that by 2016 all homes built in the UK would have zero net carbon emissions, no one thought it would be easy, but many in the industry were eager to rise to this inspirational challenge.

The concept was that we should stop building new homes that would only need to be upgraded later to be properly energy efficient. Building these homes fit for the future would stimulate a mass-market for energy efficiency measures and renewable energy technologies and result in tradespeople and designers developing skills that could be carried over into the upgrade of our existing stock of buildings.

Well, here we are in 2014 and how has it fared?

In the run up to the Queen’s Speech, Stephen Williams, a Liberal Democrat MP and minister at the Department of Communities and Local Government (DCLG), began briefing via the Lib Dem website that he’d ‘saved’ the Zero Carbon Homes (ZCH) policy from those nasty Tories.

From information in his article its possible to piece together how ZCH will work.  So let's peer through the smoke drifting around and have a look at the train wreck we’re left with.

It seems like all housing developers will have to build homes that are equivalent to the Code for Sustainable Homes level 4, which is only a 44% improvement on the so-called regulated carbon emissions of a 2006 home.

However, even this overstates the ‘achievement’.  As I have covered before in this blog, the definition of zero has been adjusted to include only regulated carbon emissions (those from heating and hard-wired lighting).  All energy used by plug in electrical appliances (white goods, gadgets, audio-visual) have been removed from consideration.

Add back in the average emissions from plug in electrical appliances and the picture is even less flattering.  The original vision of Zero Carbon Homes has been diluted to such an extent that the achievement of which Stephen Williams is so proud is that a home built in 2016 will be allowed to produce fully 71% of the carbon emissions of a home built in 2006.

The average energy bill for one of these ‘Zero Carbon’ homes will be similarly unimpressive.  I calculate that a 3 bed semi-detached ‘Zero Carbon’ home would have a combined energy bill of £800/year whereas one built to 2006 standards would have a combined energy bill of £1080/year.

The political sleight of hand that Mr Williams is using to justify his hyperbole was announced in the Queen’s Speech and is the creation of legislation to enable an element of ZCH called ‘Allowable Solutions’.   This could be better called ‘Buying Carbon Offsets’ because it means that instead of pushing the performance of the building itself from Code level 4 to Code level 5 (zero regulated carbon emissions), the developer can choose instead to pay into a government-managed fund.  What this fund will be used for is, as yet, undefined, but seems likely to be spent on upgrading existing buildings.

Allowable Solutions was first proposed as a means of helping more challenging homes (for example flats with limited roof area) make it over the line by allowing carbon offsetting for that difficult last little bit.  What was supposed to be the mint chocolate with the coffees has now become the main course of the meal, potentially accounting for 56% of the regulated emissions.

The circularity of this is mind-bending.  Instead of building efficient homes in the first place, we effectively collect a tax from the developer, leaving the house-buyer with largely unchanged energy bills and putting the money into a pot which may or may not at some unspecified future point be used to improve existing buildings.

The opportunities for double-counting the benefits are also clear.  It's hard to imagine ministers avoiding the temptation to take credit for both the new homes being zero carbon and for whatever measures the fund is spent on at the same time.

Furthermore, there is to be a provision for ‘small developments’ to be exempt from reaching Code 5.  Again, it is not yet clear what small means in this context, but Barbour ABI has estimated that if small means a development of 10 or more homes then around 10% of new homes would be exempted from the policy, whereas if developments of up to 50 homes were to be considered small, then this figure would be around a third of new homes.

Which Tin?


In his article, Stephen Williams says that Zero Carbon Homes “does exactly what it says on the tin”

This astonishing claim doesn’t even get close to passing the ‘reasonable person’ test.  Someone offered a home described as Zero Carbon would have a reasonable expectation that the carbon emissions from the home would be zero and energy bills would be extremely low.

After ten years of backtracking, what we’ve actually got is a policy where new homes will produce more than 70% of the emissions they started with, coupled to a carbon-tax that might apply to only 2/3 of new homes built, and energy bills for the house-holder reduced by only 30%.

This policy "does exactly what it says on the tin" only as long as the tin in question is labelled "Business as Usual for Property Developers"

DCLG has succumbed to the enticingly simple argument that a proper ZCH policy would impose higher costs on developers and slow the rate of new build, thus threatening the economic recovery. The reason this argument is bogus is that if build costs rise, then the price a property developer would be willing to pay for land will drop.  Building to higher standards simply reduces the wind-fall to the land owner.  The only time the burden of building to a higher performance falls to developers is when they have speculated that legislation will be watered down and over-paid for their land bank.

It is not clear that this “world-leading” policy even meets the wooly definition of the European Directive on the Energy Performance of Buildings that the UK must comply with by 2020.  This requires all housing to be ‘nearly zero carbon’.  It may be that this is tested in the European Commission, indeed a number of renewable energy associations are already considering just such a move.

All is not Lost


A properly designed structure for the Allowable Solutions might just get this train back on the rails.  The price per tonne of carbon should be set to encourage the use of now common on-site measures such as higher levels of thermal insulation, heat pumps, solar water heating and solar PV.

One opportunity would be to set the price per tonne in a tiered structure, with an increasing marginal cost.



Code 4 is a 44% reduction in the emissions compared to a 2006 home, leaving 56% emissions available to offset under Allowable Solutions.  What if the chunk from 44% to 72% was priced at £120 a tonne, and the chunk between 72% and 100% was priced at £30 a tonne. Developers would have a strong incentive to drive efficiency up towards the 72% level (broadly equivalent to the old 'carbon compliance' level) using improvements to the building.

A developer who built to business as usual (Code 4) and paid the entire carbon offset would have an average cost to bear of £75/tonne.  By contrast a developer that improved insulation levels or installed renewable energy on the homes to bring down emissions below 28% of 2006 levels could reduce their average cost of carbon offsets down to £30/tonne.

A policy designed like this would be responsive to a changing market. If the housing market continued to improve and government decided that landowners could bear more of the costs of the policy, then the relative width of the bands could be adjusted.

Come on Mr Williams, all is not yet lost. You've still got time to make the reality of Zero Carbon Homes match your rhetoric.

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