The National Archives / powerPerfector

[Tristan_Parker]

The National Archives is the UK government's official archive, containing over 1,000 years of history. Its role is to give detailed guidance to government departments and the public sector on information management and advise others about the care of historical archives.

After receiving the annual electricity consumption details for The National Archives, it was possible to give a provisional quote for a powerPerfector unit and to outline the potential for energy savings. Four voltage loggers were then sent on to two of The National Archives’ buildings, for ten and 14 days respectively, to record the voltage level by connecting them to a regular mains socket. It was found that the average voltage was 246 volts (V) at both sites, 16V higher than the nominal supply in the UK.

Analysis following the installation showed that there was an average reduction in kWh consumption of 12.2% attributable to the powerPerfector installations, equating to annual carbon dioxide emissions saving of 774,507 kg.

powerPerfector is the world’s only Voltage Power Optimiser, giving energy, carbon and cost savings by efficiently optimising a site’s supply voltage. By optimising the voltage, electrical equipment runs more efficiently and consumes less energy. The declared electricity supply in the United Kingdom is now, as a result of European Harmonisation, 230V with a tolerance of +10% to -10%. This means that effective voltage can be anywhere between 207V and 253V depending on local conditions.

Most electrical equipment manufactured for Europe and the UK is rated at 220V and operates more efficiently at this level. Forcing appliances to operate at a higher voltage in the UK (242V is the average supply level) leads to significantly higher energy consumption, increased heat losses and a reduced lifespan. As a result of equipment specification and the range of voltage supply, there is an opportunity to achieve cost savings by optimising voltage at source and at the same time improving the operation and lifespan of a site’s electrical infrastructure. It is estimated that 90% of sites in the UK are operating at too high a voltage and could therefore benefit from installing a powerPerfector.

Savings summary for The National Archives:
• Predicted reduction in average kWh consumption: 11.5%
• Actual reduction in average kWh consumption: 12.2%
• Projected annual carbon dioxide emissions savings: 774,507 kg
• Projected annual financial savings: £122,594

Four powerPerfector units were installed in two National Archives buildings in September 2009. A 1 MVA and a 1.5 MVA powerPerfector unit were installed on 6 September 2009 – the 1 MVA unit was at a 0% optimisation setting and will not be affecting voltage levels until the optimisation setting is changed, while the 1.5 MVA unit is at a 7% optimisation setting. A further 1 MVA and 1.5 MVA unit were installed on 13 September 2009, at a 6% and 7% optimisation setting respectively.

A report put together after analysis of the half-hourly data for the site found that there was an average reduction in kWh consumption of 12.2%, compared to expected levels, above the predicted 11.5%. This equates to an annual carbon dioxide saving of 774,507kg and annual financial savings of £122,594. Since one of the four units is currently at a 0% optimisation, it is expected that further energy savings will be achieved once the unit has been changed to the correct optimisation setting.

The amount by which the energy consumption has been reduced since the installation of the powerPerfector was found to be an average of 12.2%. This reduction in kWh consumption equates to an annual reduction in CO2 emissions of approximately 868,358kg, with further energy savings expected to be achieved when the unit currently at 0% optimisation is at the correct setting

The powerPerfector is also ensuring that the site operates at a higher level of efficiency, as well as benefiting from improved power quality and protection from transients of up to 25,000V.

Although the ability of voltage power optimisation (VPO) technology to reduce energy (kWh) consumption on a site is well documented, the technology also provides a range of other benefits, all of which contribute to creating a more efficient, robust and reliable electrical supply for a site, providing further financial benefits on top of the reduced energy costs. These benefits include: reduced maintenance burden; an improved power factor; lower harmonic distortion; reduced neutral currents; improved phase voltage balance; and improved protection for a site and its electrical supply.

Representatives from powerPerfector will be hosting discussion groups on ‘voltage power optimisation’ and ‘energy performance measurement and verification’ at the Low Carbon Best Practice Exchange, held in London on June 10. For more information, visit: http://www.carbon-innovation.com/london.php