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Guest blogger Ian Hopkins, Sales and Marketing Director for ENER-G Combined Power tells us why CHP remains on the front line as a way to boost environmental performance scores under BREEAM despite 'major change' to the energy category of the assessment.
A revised environmental scorecard for buildings still values CHP, despite lower weighting for energy efficiency.
TheBuilding Research Establishment Environmental Assessment Method(BREEAM) is a means devised by consultancy, the Building Research Establishment (BRE), to score the performance of non-domestic buildings under a range of environmental and sustainability criteria.
It covers nine areas, including building management, water use, transport issues and - crucially for combined heat and power considerations - energy and carbon emissions. Its aim is to go beyond regulatory obligations and keep in step with advances in technology and best practice.
BREEAM is highly rated by developers, designers and building managers as a way to demonstrate the environmental credentials of their buildings.
Its scoring system is “transparent, flexible, easy to understand and supported by evidence-based science and research,” according to its deviser BRE. BREEAM has been reviewed for a second time this year - the first time since 2008. Inevitably, there are significant changes to energy assessment.
Fundamentally the new scoring system has changed little. Credits are gained by outstripping a baseline building standard. Each section has an environmental weighting. The total of the weighted scores is translated into one of five ratings from “pass” to “outstanding.”
Change in climate
One area of “major change", according to BRE, is in the energy category.
The 2014 revision has ended the use of a single energy performance baseline throughout the UK. BREEAM will now use the national building regulations for Scotland, Wales and Northern Ireland to set a baseline for each of the devolved administrations. (Note - Previously, under BREEAM 2011 the Part L 2010 notional building was used as the baseline for all buildings assessed under BREEAM, regardless of their UK country location).
Another change is the end of a requirement - under the former low or zero carbon (LZC) technologies section (Ene04) - that some of the building’s energy was from renewable sources.
That obligation is now addressed in recently beefed up building regulations. Following on from those changes are:
● The weighting for energy under BREEAM has been reduced from 19% to 15%.
● The number of credits available under the reduction of energy use and carbon emission section (Ene01) has been cut from 15 to 12.
● LZC credit has been replaced with a Low Carbon Design credit that favours energy conservation from the building’s fabric. But there remains credit for an LZC feasibility study for a proposed building and implementation of its findings. In further detail, the section Ene04- Low Carbon Design has a total of 3 credits. And the section is split into two parts – 1) Passive Design (2 Credits) 2) Low or Zero Carbon Technologies (1 Credit). LZC percentage carbon reduction targets (which were part of BREEAM-2011- Ene-04 LZC issue) have now been removed from the new version.
● The weighting for Pollution remains unchanged at 10% and NOx emissions were reviewed, but no changes in NOx levels or credits were made.
Although each credit under ENE01 is now worth less, the criteria for acquiring them are basically unchanged, so achieving excellent is no more or less difficult.
For CHP compliance with the Low Carbon Design criteria it is necessary to consider:
● Annual energy generated from CHP
● Life cycle cost of the CHP including payback
● Local planning criteria, including land use and noise
● Feasibility of exporting heat and electricity
● Available grants
● All appropriate LZC technologies and reasons for excluding any of them
You should also consider possibilities for:
● Connecting the proposed building to an existing community CHP system or source of waste heat or power.
● Specifying a CHP system or source of heat or power waste, with the potential to export excess heat or power via a local community energy scheme.
Ian Hopkins is the Sales and Marketing Director at ENER-G Combined Power. For more useful guidance, check out ENER-G Combined Power’s free e-magazine “Regenerate” is out. Click here to read it.