Brighton and Hove City Council’s Environment Committee has approved radical sustainable supplementary construction planning guidance aimed at ensuring new developments achieve carbon-neutral status or offset CO2 emissions by upgrading Regency and other existing housing stock. Dr Paul K Hatchwell takes a look at what these radical plans will mean.
Brighton and Hove are slated for 11,000 new homes over the next twenty years, so the impact of the new proposals on the forthcoming Local Development Framework (LDF) would be large. However, the greatest benefits are likely to be felt in older buildings, given the City’s predominance of attractive Regency period, Victorian and often less attractive post-war housing stock.
Flexible approach
Following approval by the Environment Committee this month, BHCC sustainability officer Francesca Iliffe told SB that the proposed Supplementary Planning Document on Sustainable Building Design (SPD) would mean “every residential development over three units and above, and every other development of 235m2 and above should be zero carbon”. Conversions and residential extensions over the threshold would also be affected.
The plans are not prescriptive as to how emissions are reduced, providing for flexibility of responses from developers linked to local planning requirements. They encourage use of renewables such as solar, wind, hydroelectric power, but also permit low carbon energy sources such as gas-fired combined heat and power/district heating, and other forms of energy efficiency.
The plans stipulate that at least 20% of energy overall should come from low or zero carbon technology, in line with the Merton Rule, affecting medium and large scale commercial developments, residential extensions, conversions and changes of use above the threshold.
In addition to this, Iliffe points out that “we are asking for zero carbon in all new build [homes over the thresholds], though we recognise that not all developments will be able to achieve this”.
In the latter case, developers must offset excess emissions by enabling reductions elsewhere, notably through s.106 agreements feeding into a BHCC fund to upgrade energy performance in older building stock, with buildings of ten years old or more eligible for grants.
The Council has also developed a Calculator for Offsite Reduction in CO2 Emissions, based partly on BRE work (see figure). It implies that the various measures would cost developers around £2,000 to £2,500 per ton CO2 avoided per annum, depending on whether solar thermal installations are included.
Between them, the new developments will also have to contribute 64,000 new trees across the district over the next 50 years, aimed particularly at countering the growing threat from urban heat island effects and need for air conditioning, based on s.106 agreements and suggested contributions of £14,000/ha, or £215/dwelling.
Urgent upgrade
Iliffe stresses that the Council, which signed the Nottingham Declaration in 2004, aims to cut emissions by 3.5% annually. Given the “very low rate of incoming new developments”, at 0.3% compared to the national average of 1%, she points out that the most important aspect of greenhouse gas mitigation policy in Brighton and Hove is the need to address poor performance in existing housing stock. She adds that a similar offset fund for refurbishment has already worked well in Milton Keynes.
Another challenge is the difficulty of retrofitting measures such as cavity wall insulation in older buildings.
*Sustainable Building Design: Appendix 1 - Supplementary Planning Document (SPD),
Brighton & Hove City Council, September 2007
http://peace.brighton-hove.gov.uk/Intranet/CommitteeMgt.NSF/0/A6228986CE724F7B80257345003E80AA/$File/Item+14+2+Draft+Sustainble+Building+Design+SPD.doc
Brighton & Hove’s SPD on Sustainable Building Design
The Supplementary Planning Document (SPD) on Sustainable Building Design proposed by BHCC planners and guided by the Sustainability Commission following extensive stakeholder consultation, has already been subjected to a Sustainability Appraisal. It will eventually form a part of the new LDF.
The SPD is “composed of a written statement detailing requirements and dedicated pages in Brighton & Hove City Council’s website containing supporting information and advice on how to meet requirements”. The final version is expected to be ready for approval by March, 2008, which would then make it a material legal consideration in all new planning applications.
The aim of the SPD is to: “provide detailed, up to date, clear advice to various user-groups on relevant sustainable design policies; improve the environmental performance of the city’s new build and existing buildings; and make sure all developments in Brighton & Hove achieve the highest possible standards of sustainable building design”.
The statement, split into three parts, covers “the concept of sustainable building design and the legislative and planning background”, the “requirements by development type”. The final section annexed covers “supporting information including one-page summary of requirements; calculator for contributions to improve environmental performance of existing housing stock; implementation and monitoring; detailed policy guide; and glossary”.
A key element of the SPD, shortly to be out for consultation in line with PPS12, involves a Brighton and Hove Sustainability Checklist, to be tailored for local use from the regional sustainability checklist approved by SEEDA. The checklist will be developed by BRE, with SEEDA, South East Regional Assembly (SEERA) and City Council funding, in time for consultation in October/November, 2007.