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Energy Bills

Alan Aldridge, executive director of the Energy Systems Trade Association (ESTA) outlines five ways to save on energy this winter

As the new academic year gets underway, the nights will be closing in and temperatures dropping. Compared with last year, though, energy prices will be much higher and likely to stay that way. With most educational establishments committed to out-of-hours activities as well, the energy bills this coming winter will be even more of a shock than last year. So, is there any way to reduce energy bills without sacrificing comfort or reducing services to users?

The days of being able to reduce energy bills through shrewd purchasing are largely over. Energy buyers are finding that offers from competing suppliers are generally similar. The other way is to actually reduce the amount used - and so reduce carbon emissions as well, an increasingly important priority given the threat of climate change. This can be done in two ways: by eliminating unnecessary consumption and by using the rest more efficiently.

New buildings and most refurbishment projects are governed by the building regulations - these set out the performance standards which must be met. The section dealing with energy performance is Part L. The latest version of these came into effect in April and represent a significant tightening of the regulations. In fact, buildings constructed to these standards will be about 20 per cent more energy efficient than those built to the previous code (28 per cent for air-conditioned structures).

The techniques and technologies used to achieve these savings are not just applicable to new buildings though - they are for the most part just as effective in existing buildings. ESTA has identified five key technologies which can deliver most of the necessary savings. Installing them in existing buildings such as schools and colleges will also deliver savings, cutting emissions and bills.

Identifying consumption
How much energy does your establishment use - and where? Where is there potential for reducing consumption? To answer these questions, it is necessary to measure what is happening on a continuing basis. Now, the technique of Monitoring & Targeting (or M&T) is very well-established, it is the backbone of energy management. However, it can be tedious and time-consuming to collect lots of data and feed it into the right analysis software package.

Just as many teaching and administration tasks - as well as scientific research projects - were transformed in the 1980s and 1990s by computerisation, so recent developments in M&T offer users a much simpler but more powerful means of keeping a check on energy use. Automatic monitoring and targeting (aM&T) systems include the meters themselves, automatic meter reading and data collection, waste analysis and alarms which alert users to excessive consumption. They are now tried and tested and the Government has recognised their effectiveness by giving a specific allowance for their use. A full aM&T system qualifies for a 5 per cent CO2 allowance under Part L for new build, non-domestic properties - it is officially accepted that, just by installing these systems, energy performance will improve.

In fact, ESTA’s calculations show that aM&T can deliver about 20 per cent of the performance boost required under the new regulations, so building operators will get a much greater benefit. There will clearly need to be some initial investment but the savings will soon recover these. Now, automatic meter reading must be installed in all new non-domestic buildings of more than 1000m2, so this will offset the investment in larger buildings anyway.

Controls
The amount of heating required in an entrance hall will be different from that in the classrooms or again in laboratories with large amounts of glazing. Effective control of the internal environment - maintaining comfort levels without wasting energy - will clearly require different strategies for these areas. Once again, the Government has recognised this by insisting that larger new buildings and those undergoing refurbishment have separate control strategies for different ‘zones’. There are a number of ways of doing this, from standalone controls in the different areas right up to full Building Energy Management Systems (BEMS). The exact choice will come down to the conditions in the specific building and the length of payback considerations.

Another area where effective control can make a significant difference to energy consumption is the boiler house. The boiler is usually the largest single energy-consuming piece of equipment in the whole site. If it is not working efficiently, there is a possibility of high energy wastage - meaning greater greenhouse gas emissions and higher bills, with the energy literally going ‘up the chimney’. Properly controlled boilers deliver heat to the building in the most efficient - and cost-effective - manner.

Lighting
Modern buildings are, by and large, well-insulated. The power required to run machinery and provide the lighting therefore represents a large proportion of the overall energy supply. So inefficient lighting can account for a large percentage of energy wastage. As most of this waste energy is emitted from lights in the form of heat, it can also lead to overheating in air-conditioned buildings, resulting in more energy being needed for cooling.

While the use of low energy light fittings and lamps will reduce energy consumption and excess heat loss, proper control of lighting will have a major impact on this area of energy usage. Low energy lights left on all night may not waste as much energy as their conventional tungsten-filament counterparts - but it is waste all the same!

The most basic form of controls are timeswitches that turn off the lights at a given time: this could be after the building closes in the evening for instance. Occupancy sensors switch lights on when people enter a room and switch them off after a certain amount of time has passed since the last movement is registered: toilets, storerooms and corridors fall are suitable locations for these controls. Daylight-linked controls adjust the amount of artificial light depending on the strength of the daylight in the room. All these devices can be linked into a building lighting control strategy or be used in their own specific locations.
ESTA’s calculations show that lighting controls can account for up to 15 per cent savings on total building energy use.

Power factor
Inefficient electrical equipment loses some of the power supplied as waste heat. The ratio between the power supplied and the ‘useful’ power consumed is called the power factor - ideally, the two figures should be almost identical and the power factor will be 1.0. Power factor correction equipment will help to correct some of the inefficiencies and give equipment better power factor.

A lot of electrical equipment that uses motors (including air conditioning) is relatively inefficient under certain conditions. When the motor is running at full speed the equipment is at its most efficient. At lower speeds, or part-load, the motor may still use just as much energy. Clearly, this is wasteful and costly. The introduction of variable speed drives (VSDs) does away with this problem because their energy consumption varies with output. So when installing or replacing motor-driven equipment, machinery incorporating VSDs may offer significant savings in running costs.

These five items - aM&T, controls, lighting controls, power factor and variable speed drives - can deliver significant energy savings and give environmental benefits too. With education budgets already stretched, these savings can help to ease the pain of still rising energy prices.

The Energy Systems Trade Association (ESTA) encourages demand-side energy efficiency of buildings, building services and process services. The Association has more than 100 members, all committed to promoting energy efficient systems and practices