Camco

Energy In Buildings and Industry Magazine

Dr Robert Cohen is Technical Director at Camco, a member of the CLG’s Technical Steering Group for DECs and creator of the EPLabel software which generates DECs online

EiBi Magazine February 2009, pp.43-44Size: 146k
Type: pdf
http://www.eibi.co.uk

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The energy label began life in the consumer white goods market in the early 1990s when the familiar rainbow gradings were introduced to differentiate lower energy products from cheaper but less efficient competition. Soon products became considerably better and no more expensive. As energy use crept up the political agenda, the concept was extended to new cars and now it is being applied to buildings. Today such labels are rightly seen as a badge of quality, as energy efficiency usually equates with better design, higher effectiveness and less noise.

Most labels are based on laboratory measurements of energy use, combined with calculations which assume a typical usage pattern, and generally use a seven-point scale from A to G to present a headline energy rating.

For buildings, a theoretical calculation based on the building’s fabric, installed HVAC and lighting systems and a standardised use is effective at estimating the relative impact of measures to improve fabric or plant. This is applied for the Energy Performance Certificate (EPC) needed when a building is constructed, sold or let so buyers and renters can compare options on a standard basis.

However, labels for occupied non-domestic buildings which are based on theoretical calculations (‘asset ratings’) can be both expensive to perform and of limited accuracy. In practice, these models cannot capture either the effects of buildings and services which do not behave exactly as designed, or the complexities of the occupier’s equipment, operation and maintenance regime. Nor can they account for controls that don’t work properly or any lack of understanding by users.

With combating climate change becoming ever more paramount, addressing real outcomes and reducing the credibility gap between calculated and actual performance is essential. For non-domestic buildings, the UK therefore introduced an energy label based on the total measured energy used in a year (an ‘operational rating’). This Display Energy Certificate (DEC) is required to be on prominent display in all public buildings with a floor area over 1,000 m2 and must be renewed every year. It shows energy efficiency based on CO2 emissions compared with a benchmark, total CO2 emissions per year, and how these have changed over the preceding three years.

Buildings are responsible for 70 per cent or more of the CO2 emissions of most public authorities, and so DECs feed well into the present requirement to collect the energy and CO2 data making up National Indicator (NI) 185. They also complement a third policy instrument, the Carbon Reduction Commitment (CRC).

The key purpose of the DEC is to make energy performance visible at the level where action can be taken and improvement, or deterioration, becomes transparent and meaningful. For some, holding up the mirror to their own performance and exposing it to public scrutiny can be a painful reality check after decades of lip service and greenwash. But it is long past the time when such sensitivities can continue to distract us all from curbing the emissions the atmosphere actually receives.

At the time of writing around 10,000 DECs have been lodged, which is about 15% of the total anticipated. A slow but gradual compliance rate has a silver lining: distributing DEC activity throughout the year avoids a single overwhelming surge to meet the 2008 deadlines and its annual echo when DECs are renewed. Canny public authorities may bide their time to synchronise their DECs with the reporting period of NI185 and/or the CRC.

More worrying than the present low uptake is that many public authorities view DECs as a compliance task, procuring them through contracts departments which have no remit to integrate them with existing energy management activities. The result can be a futile use of taxpayers’ money on a literal interpretation of the regulations, rather than a stimulus to improvement. For example, in some authorities an assessor will visit all sites to create a cursory advisory report, without incentive or capability to recognise actual reduction opportunities. Without customised measures, the resulting report has very limited value.

A more intelligent use of scarce resources is to obtain all the required DECs, but only a default and zero cost advisory report to fulfil the minimal legal obligations. A performance league table of the current stock can then identify the worst performing buildings and those with the highest carbon footprints. This makes it easy to prioritise those buildings most deserving of detailed follow up surveys and targeted energy investment. If a system of DECs is properly integrated into energy management activities, it will encourage the efforts of management and occupiers to tune-up their buildings, avoid waste, undertake investments that save real not just virtual carbon, and obtain public recognition of these efforts in the next year’s DEC.

Another reason for low DEC numbers is a transitional arrangement in England and Wales that allows a single DEC to be produced for a site or campus. Site-based DECs have much merit. The procedure captures the total carbon footprint of the site, aligns the DEC boundary with the available energy meters and subjects the whole site to energy efficiency scrutiny, while the standard methodology covers only those buildings over 1,000 m2 and omits the rest. Consequently, site-based DECs should be retained, not abandoned in 2009. Annually renewing the site DEC and providing individual certificates for buildings on the site over 1,000 m2 generates much needed continuity with the transitional arrangements. In addition, site DECs reveal how overall performance has improved year on year, can be displayed in public reception areas and give the most meaningful information to the public.

With climate change, energy security and peak oil combining to create a devastating outlook for the world as we know it, there is justification to examine how energy certificates can evolve from purely regulatory instruments to become a real stimulus for savings. In spite of this, DECs are not mentioned once in the 500 page tome recently issued by the Committee on Climate Change. With CLG dealing with energy use by buildings, and DECC responsible for energy supply and the environment, it begs the question whether there is any policy co-ordination that brings together supply and demand and can deal with the often woeful energy efficiency of tertiary sector buildings.

On 13 November 2008, the EC launched a ‘recast’ of the EU Directive behind building energy certificates, which could provide this policy development. But the current draft has a worrying bias. After about five years of debate about the importance of having both asset (calculated) and operational (measured) ratings across Europe, the recast appears to refocus an energy certificate on an asset rating and to ignore operational issues. This is particularly perverse as much of the CO2 arising from the use of buildings is a consequence of operational issues. The operational rating also captures the energy use by non-building related items, such as office equipment and electrical appliances, and forces management attention to fall on these, and not just the building itself. The only positive aspect of the draft recast in these respects is the proposal to reduce the threshold for public display from 1,000 to 250 m2.

A more progressive recast would require public authority and private buildings to display an energy certificate based on measured energy use and renewed each year. This is directly envisaged by the CEN Standards (EN 15603 and EN 15207) which underwrite building energy certification. Several countries including France and Germany already use operational ratings for the commercial sector. Without measured ratings, we only have virtual improvements (which post-occupancy experience reveals are normally optimistic) and only in the new and refurbished building stock. Improvement through fine-tuning, equipment purchasing, better control, management and maintenance, and the efforts of management, users and contractors will go completely unrecognised.

The mandatory, permanent display of an energy certificate in public buildings in Europe is a world first. Using an operational rating and renewing it each year makes the building’s energy use and CO2 emissions especially transparent and increases the incentive on both building managers and occupiers to run their buildings efficiently. In the UK, DECs are a vital component of new policy instruments needed to tackle the energy wastage in non-domestic buildings. However, with their limited resources, public authorities should prioritise their spending where it can achieve maximum benefits and beware wasting money on uninformative advisory reports.

DECs based on measured energy now need to be widened to the private sector and to smaller buildings. This can be instigated by an upcoming recast of the Energy Performance of Buildings Directive.

A low carbon economy will only emerge if both supply side and demand side measures are implemented in tandem. We need to make radical changes, not only to the specification of our buildings, but also to the ways in which we equip, use and manage them. By acting at the building and/or site level, DECs are a powerful complement to organisation-level initiatives like NI 185 and, in due course, the CRC. They disclose where and how emissions can be most easily reduced, and they track the success with which savings are being made.