Providing construction sites with temporary power can be challenging, especially when working in densely populated residential locations. Ben Vincent, UK national accounts manager at temporary power generation company Aggreko, offers a six-point guide.
1. Fluctuating power demands
Construction sites often have variable power demands, with higher demand during operational hours. There are several options that can reduce generator inefficiencies connected to these fluctuations.
- Hybrid power units can be used in tandem with a generator. The generator meets larger peak-time power requirements and charges the Hybrid’s battery. Then the Hybrid takes over during periods of lower demand, reducing the need for the generator to operate at an inefficient, low load. With the Hybrid unit subsidising generator power, fuel consumption is reduced, improving the fuel efficiency vs power output and reducing operational costs.
- If base power demands are too high for a hybrid option, construction managers could consider “load-on-demand” generation. This scalable solution uses smaller kVA [kilo-volt amp] generators to power the same peak demand as one larger unit, but with the option of turning surplus generators off when the site’s demand falls. The generators switch on and off automatically so only produce as much power as the site needs. An uninterruptable power supply is guaranteed even during generator maintenance.
2. Noise control
Local authorities require construction sites to use the most practical measures possible to control noise and vibration, as defined in Section 72 of the Control of Pollution Act 1974. This means adhering to recommendations and good practice laid down in British Standard 5228-1 2:2009: Code of practice for noise and vibration control on construction and open sites. Controlling noise levels is particularly important in residential areas and many local authorities insist on total quiet during unsocial hours. There are a number of ways of minimising the noise caused by site power generation, including:
- Super-silent generators can be acoustically optimised to bring the decibel count down to a hush sound.
- Acoustic curtains that can be fitted to the fencing surrounding generators to reduce noise levels by up to 10%.
- Hybrid power units that can be used as a silent power alternative to generators when only low electrical loads are needed.
- Load-on-demand solutions can ensure noise levels will fall when the site’s power demand drops and fewer generators are needed.
3. Security
For remote locations, unmanned areas, or sites in crime hotspots, the security of generators and supporting equipment can be an issue. When faced with this challenge find a generator supplier who can provide secure-containerised generators. These unbranded containers can house a range of generator sizes, their fuel tank and distribution equipment – offering protection from theft and vandalism.
4. Site-wide power on large projects
Rather than using multiple, lower voltage generators around a large construction site, it is often worth considering a high voltage (HV) solution. This involves setting up a generator with a transformer to distribute HV power across the site to small distribution boards or transformers where the power voltage is reduced back down for use. This solution requires one set up and saves space. Since only one fuel delivery is required it can minimise access issues and may provide improved fuel efficiency.
5. Emissions reduction
There are a number of greener options to consider when selecting power generators:
- Gas-fuelled generators can cut emissions by up to 40%, compared to diesel, and have the potential to be much more cost effective.
- Using biodiesel to power generators can offer a cleaner, greener alternative to conventional diesel.
- Use diesel generators with particulate filtration units. These can dramatically reduce emissions, achieving a reduction in particulate matter (PM10) of 85 to 90%.
- Hybrid power units, that are operated by large batteries, produce zero emissions and are suitable when load demands are low.
- Using smaller generators to load share, rather than a single larger generator, will also help reduce emissions and save fuel.
6. Space and access restrictions
The size, shape and footprint of generators vary widely, as does fuel capacity. When space is a problem consider the following options:
- When possible, select generator sets with an integrated fuel tank, which is a major space saver.
- A large fuel tank will reduce fuel deliveries to site, both minimising transport disruption and reducing the carbon footprint via travel miles.
- Don’t overlook site access for refuelling requirements. Some generator hire suppliers offer a fuel management service, to alleviate the hassle of ordering and delivering fuel to ensure continuous power on site.
