Confusion over "zero carbon" homes

Will the proposed code for sustainable homes prove as much of a white elephant as home information packs, or will it be mired in confusion like the introduction of Part L? TiC finds an industry plagued by uncertainty.

ANNOUNCED in a blaze of glory in April 2007, the Code for Sustainable Homes (CSH) was intended to launch the nation into a green utopia.

Providing an assessment measure for new dwellings against their environmental impact, the code uses a 1 to 6 star rating system. The government’s target is for all new housing to meet the highest level of the code, zero carbon by 2016.

Initial hope came in June at the Building Research Establishment’s (BRE) Offsite exhibition, where two timber-built homes were said to have attained the highest ratings of the code.

Offsite Ruling
In the long awaited guidance that followed the launch of the code more than six months ago, the Department for Communities and Local Government (DCLG) caught the housebuilding industry unawares in October, ruling that offsite renewable energy sources, such as wind farms, would not be eligible for code Level 6 homes unless directly connected to the development by “private wire” arrangement.

It was a blow to the industry that believed for a long time that developments would be able to purchase green power from offshore generation.

The Treasury was then sucked into defining its version of a Level 6 home following the Prime Minister’s pledge to offer stamp duty relief on new zero carbon dwellings in this year’s budget report. It aligned its definition to exclude offsite renewables for zero carbon dwellings.

A spokesperson from the Treasury told TiC that allowing offsite renewables would undermine the robustness of the zero carbon standard. “It would not represent value for money to the tax payer,” said the spokesperson. “Allowable electricity includes electricity generated from external renewables conveyed to the home by a private wire.”

The issue seems to be a matter of heated debate between the two departments. When asked about the decision to exclude the use of offsite renewables, a DCLG spokeswoman said: “It is something the Treasury stipulated because of the way it calculates stamp duty.”

An impossible goal?
Despite not ever issuing an exact definition of a true carbon zero dwelling, there is a feeling within the industry that the Government has moved the preverbal goal posts.

Bill Gething, partner at Feilden Clegg Bradley Architects is under no illusion why the Treasury has made it so difficult to achieve a Level 6 home. “The Treasury doesn’t want to lose any money in stamp duty,” he said. “They’ve made it so difficult to achieve that it’s just silly. I’m sure these definitions will evolve over time as there appears much more sophisticated ways of being able to do it.”

Trada’s codes and regulations consultant, Rupert Scott, said the government’s inability to define the term “zero carbon” early on has caused the uncertainty.

“We had all sorts of articles, many of which originated from the government coining this phrase zero carbon. They produced the Code for Sustainable Homes in April, which referred to it, but they still hadn’t defined it properly.”

In terms of the government’s decision to exclude offsite renewables for zero carbon homes, Scott said logic must prevail. “It is impossible to come up with renewable energy systems which are on a single dwelling basis that have a sensible payback period on them. If there were some, then people would be flooding to buy them.”

Green intervention
The concern over the exclusion of offsite renewables has alerted the UK Green Building Council (UK-GBC), who has sprung a zero carbon task group to report to the 2016 Steering Group next spring.

The task group is led by Mark Clare, chief executive of Barratt Developments, who in October began construction of its Level 6 house on the BRE site in Watford.

UK-GBC chief executive Paul King didn’t want to pre-judge the outcome of the meeting
but said that the definition, which precludes near-site and offsite connection to a private wire is too restrictive.

King said the problem the government has with offsite renewable energy is that no one can verify if it isn’t being used two or three times.

The Renewables Obligation requires energy companies to produce an increased proportion of their energy from renewable energy sources.

“Currently we’re not meeting those targets,” said King. “If developers were to be commissioning new renewable energy, how do you make sure they are not actually supplying energy that should have been met by energy companies?”

King said that if the government continues to adopt this definition, it would be possible, but not the best way to go about it. “The issue of cost maybe higher and the limitations of the size of some sites will be insufficient to apply onsite energy
generation.”

The Carbon Challenge Steve Carr, head of policy and economics at English Partnerships, sits on the UK-GBC’s task group. In 2008, English Partnerships will begin delivering a number of zero carbon communities to test out the CSH. Carr said that English Partnership’s consultant has raised concerns over the alignment of the definitions.

“The intention was that the zero carbon stamp duty relief would be aligned to come in to Level 6 homes,” he said. “However, we’re not convinced the paths are closer enough together. There are differences between the stamp duty definition, as revised in the new order about to be laid before Parliament, and the code Level 6 definition for zero carbon. There are still differences between the two even though they’re meant to be aligned by this new stamp duty order.”

Carr said the code talks about using zero carbon technology, whereas the stamp duty relief talks about renewable electricity supply. “For stamp duty relief you wouldn’t be able to use biomass Combined Heat and Power,” he said. “Biomass wouldn’t count. It is not renewable energy technology for electricity technology, which is what they are talking about.”

Chris Twinn, Arup director of the sustainable building team, said the departments are doing their best to align the definitions. “It’s very easy to poke holes between the two because one talks in technical terms and the other in accounting terms and the terminology doesn’t necessarily match up.”

Lighthouse controversy
One home that would currently qualify for stamp duty relief is the Sheppard Robson and Arup-designed Lighthouse. Hailed as the future home at the BRE’s Offsite 07 exhibition its designers claimed it satisfied Level 6 of the code.

Nearly six months after the event the two homes, which were said to have reached the hghest levels of the code are yet to be signed off. Twinn said the team is on a learning curve.

“One item was overlooked, which happened to be a window of a certain kind,” he said. “The window was on a six weeks delivery, but it was waiting for that specialist component. These aren’t things you can just buy from your local wholesalers. Come 2016, all of that should be well sorted.”

Despite the hiccup, Alan Shingler, partner and head of sustainability at Sheppard Robson said the practice is expecting its full accreditation imminently.

“The Lighthouse has passed its theoretical assessment and we’re expecting the post construction assessment accreditation imminently.”

Shingler is adamant that it is not financially viable to achieve Level 6 of the code for the majority of residential developments without considering offsite renewable provision. “The highest capital cost in achieving Level 6 for small developments is the renewable technologies you apply on the building,” he said.

The Lighthouse has proven that it is technically feasible to achieve Level 6. All the electricity is developed onsite, but as Shingler said, for the individual house owner to achieve this, the owner would have to buy at least between 40m2 and 50m2 of photovoltaic cells.

“Let’s say you’ve got flats on an infill site which is four-storey high, you simply do not have enough area on the roof to generate electricity,” he said. “You need 40m2 for every single flat that’s on that four-storey block on that site.

“I think it works for large-scale developments but not for smaller developments. The problem is that the code, as it is written at the moment, makes no distinction or threshold for large and smallscale developments.”

By the time the UK-GBC reports back to the 2016 Steering Group next spring, it will have a body of evidence to suggest that the most practical solutions will be found at a broader community development scale. If there was no concern over proposals, why else would companies like Barratt, BRE, and English Partnerships be signed up to the task group?

Similarly schemes such as English Partnership’s Carbon Challenge will only work to refine the Level 6 definitions and the communities department said it is welcoming the industry’s involvement.

A DCLG spokeswoman said: “We would like to hear from the industry. If they wanted to make representation to government or officials about that then I’m sure it’s something we’d be happy to listen to. But the zero carbon timetable is to 2016, so the very point of that is that there is going to be some changes that need to be made along the way; we do appreciate that.”

Bill Gething was equally as positive. “They’ve taken a hard line to start with,” he said. “I think it will make sense when they pick up a bit more confidence about the numbers that will be able to achieve the standards. It must be remembered that they are doing a very difficult thing.”