Amey PLC - Sherard Building

Amey PLC, Sherard House – powerPerfected

Amey PLC supports both public and private organisations that serve the public and meet the needs of the 21^st Century citizen. They support the delivery of the highest public policy objectives in education and transport, social cohesion and community development. Amey consider their corporate responsibility and environmental impact to be a high priority. In recent years they have seen improvement against their peers with environmental responsibility and have gained an international standard for environmental management systems. 

The Challenge, the solution and the savings

After Amey sent their annual electricity consumption details, it was possible to give a provisional quote for a powerPerfector unit and the energy savings that would be expected. Like most office buildings, Sherard House has a broad a mix of electrical loads, consisting mainly of lighting, HVAC and computers. A voltage logger was then sent for one week, which recorded the voltage level in the building by connecting to it in to a regular mains socket. It was found that the average voltage at the Amey was 243.0 volts (V), 23V higher than the nominal supply required in the UK. After a survey of the site by a powerPerfector approved contractor, the installation took place. The installation was completed on a weekend when there would be no disturbance to the building. There was no noticeable change to the operation of the building, although continuous carbon savings were instantly being made every day at Sherard House. 

Topline results

The first graph below shows the half hourly kWh consumption from 1 June 2007 to 22 June 2009. The kWh consumption before the installation is shown in red and the kWh consumption after the installation is shown in green. The graph shows that there is seasonal variation in the electricity consumption. The times of highest consumption coincide with the coldest times of the year. It can also be seen that consumption at the times around the Christmas and New Year periods is lower that other times, which would be due to lower occupancy of the building at the time. 

An established method used to quantify energy savings in the context of seasonal variations is known as a “degree days” analysis. Degree days are based on Met Office temperature data, and give a measure of how hard heating or cooling equipment must work to compensate for external temperature. By plotting the weekly kWh consumption against Degree Days and fitting a trend line to this data, it is possible to determine the expected level of electricity consumption for a given number of degree days. The deviation of the weekly kWh consumption values recorded after installation from this trend line shows how actual consumption compares to the expected level each week, and hence quantifies the savings attributable to the installation of the powerPerfector unit. A comparison of these points with the expected level for temperature shows a 15% reduction in average kWh consumption.

Voltage Power Optimisation. The less obvious benefits

Reduced maintenance, longer life
All electrical equipment has an optimum voltage at which it works best. A powerPerfected supply delivers that optimum and reduces the strain on your electrical equipment, leaving it to work more reliably and for longer.

Better quality power supply
Some things you may have accepted for years, but product faults can turn out to be caused by a poor quality power supply. For instance, the life of incandescent light bulbs is almost doubled when the supply voltage is optimised. Now imagine that in relation to an IT network or an expensive piece of manufacturing equipment.

Missing the penalty kick
Power factor penalty charges – which are now uncapped in the UK – can be avoided if your power factor is above 0.95. If your power factor is at around 0.9 at the moment, powerPerfector could remove your exposure to these charges by improving the electrical efficiency of your site.

Lower harmonic distortion and reduced neutral currents
powerPerfectors are able to filter harmonics on the mains incomer. Harmonic distortion is on the increase and can lead to random failures of electronic equipment – particularly computers.

Protection
Common transients – very brief spikes in voltage from the grid – are eliminated by powerPerfector. Transients at this level can cause catastrophic damage to equipment, but smaller, more common transient events will also shorten the life expectancy of electrical equipment over time.