Tackling carbon without straining the budget

The Carbon Plan is about the way government, both central  and local, can tackle the nation’s carbon footprint. Within that, it has a number of things to say about the role of the public sector. The Plan notes that: “While the public sector represents only around three per cent of the UK’s greenhouse gas emissions, it has a responsibility to lead the way in reducing them.”
It also reiterates some specific commitments. David Cameron said that carbon emissions from the government office estate would be cut by ten per cent within the year to 2011. A series of other environmental targets for 2015 are contained in the Greening Government’s Operations and Procurement programme. As one example of the activities being undertaken, departments taking part in the Energy Efficiency Whitehall competition are installing ‘nine innovative technologies’ in their buildings. These range from phase-change ceiling tiles that absorb heat during the day to behavioural change programmes.

Local government
And it is not just central Government. A week after the main announcement, Energy Secretary Chris Huhne signed a Memorandum of Understanding with the Vice-Chair of the Local Government Association, Richard Kemp, which set out how central and local government would work together to achieve the goals set out in the plan.
Yet this is all against a background of spending cuts and stretched resources. So how can public sector bodies make the most effective use of scarce resources and make the greatest reductions in emissions?         
If finance is tight, then renewable energy technologies may not be the most cost-effective way of approaching the issue.
One of the phrases currently much in favour is the ‘negawatt’ – i.e. the energy saved because it was not needed in the first place. Energy efficiency is all about ‘negawatts’ – reducing demand and therefore consumption. The ‘waste hierarchy’ that was much discussed a few years ago has ‘reduction’ as the first step in any effective resource management process. So reduction needs to be the first part of any energy or carbon reduction strategy as well.

Display Energy Certificates

Now many larger public buildings – those that are visited by a large number of the public – already have to measure their emissions and energy consumption. These buildings are required to have Display Energy Certificates (DECs) which provide an annual assessment of how efficiently the building is being operated and what the annual emissions are. They also indicate a typical rating for the type of building. As a snapshot of how the building is actually performing, they are more useful than one based on ‘designed performance’. This is because buildings very rarely match their specified performance levels. Equipment may not be calibrated correctly, there will be ‘drift’ over time and perhaps most importantly there are people in them who open windows and leave lights on.
DECs provide a simple but useful way of comparing improvements in energy performance year by year, as well as a simple way of constructing a league table of the worst performing assets across an organisation’s estate. This can be turned into a priority list for assessment and action.
DECs were a concept first set out in the Energy Performance of Buildings Directive (EPBD) which was then transposed (in Euro-speak) into national legislation. In England, Wales and Northern Ireland, the use of DECs based on actual operating performance [metered data] is mandatory and must be updated every year. This reflects the government’s understanding that DECs provide a very useful facilities management tool in helping to manage the building estate. A re-casting of the Directive has extended the scope of DECs to cover virtually all buildings (public and private sector) over 250m2 that are visited by the public. The new regulations start to take effect from 2012 with size thresholds reducing over the next few years, so a large proportion of public sector buildings will be required to have these certificates in the very near future.

Visual representation

DECs have other functions, especially in the central government estate. Some departments now have guidelines about the energy performance criteria of the office space they let or lease. DECs give a visual representation of performance in a series of coloured bands from A (excellent) to G (poor). Clearly, the decision to rent only buildings in band C or above helps reinforce an organisation’s green credentials, but it also means saving money as well. The difference in annual energy costs per square metre between one band and another can be around £3-4 at current energy prices. Multiply that up over a whole building and the figure can be substantial.

There are now a number of electronic systems which collect meter data and automatically produce approved DECs. That eliminates the cost of bringing in outside experts to compile and authorise them. For an organisation with a number of buildings that can result in a substantial saving in itself.
The DECs provide a list of typical projects which could save money – but these are generic and may not necessarily apply to the particular building that the DEC applies to.

Automatic Monitoring & Targeting (aM&T) systems do more than just compile DECs though. They provide much more fine-grained detail about how buildings are performing and will help energy and facilities managers target areas where consumption is excessive. By identifying and addressing excessive consumption, the overall building energy profile can be optimised with consequent savings in energy costs – and emissions.

Management and controls
There are a number of areas where energy can be used unnecessarily. It is spring time now and the clocks recently went forward. Among energy managers this is traditionally a time for extra checks. If the timeclocks controlling energy-consuming equipment have not switched over to BST, either automatically or by manual resetting, then the heating, lighting, etc, will be coming on later (perhaps leading to manual overrides and thermostat adjustment by chilly staff in the morning) and – importantly, switching off an hour later than usual when it is no longer really needed.
As the external temperature rises, heating demand will tail off and cooling demand will rise. It is essential to check the set-points for both systems and establish a dead zone of 2-3 degrees where neither is operating. Otherwise, the two systems may cycle on and off around these temperatures, effectively working against each other – and doubling energy consumption.
‘Drift’ has been mentioned before and M&T systems are essential is detecting this and addressing it. Also, when equipment breaks down, it does not necessarily switch off. If the settings become jammed or a temperature sensor fails, this can lead to the equipment being always on. This again should show up in the charts produced by the M&T system from the metered data.
These examples are all instances where the key issue is not so much the equipment itself but rather the effective management of energy. A low energy lightbulb will still waste energy if it is operating when it is not needed. Often the focus is on the purchase of energy-efficient equipment and effective management is forgotten. Yet the two go hand in hand and attention must be paid to both.

Take lighting as an example. Not all areas of a building have the same requirements. Those near windows can make use of daylight while the inner core of a building may need more artificial light. Storage areas (and conference rooms) may only need intermittent lighting, perhaps with occupancy sensors. It may be appropriate to use daylight sensors for window areas so that optimum use can be made of natural incoming light.
External security lighting may need both Passive Infra Red (PIR) and daylight senors.

On the other hand, in areas where people are working, a single strategy mechanically imposed control may not give the best results – for example, individuals can feel dis-empowered and this may affect motivation and productivity. Sensitivity is needed here. Task lamps may be appropriate where fine-detail work takes place, with lower background lighting for corridors and communal areas. Yet this will need some default timeswitching so that lights are not left on overnight or at weekends.

Managing energy use is not just about equipment; it involves looking at the whole picture and making sure that energy use meets the needs of the people in the buildings without wasting this valuable resource or contributing needlessly to climate change.

For more information:
Web: www.esta.org.uk

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