Voltage optimisation meets energy storage
The excess power represented by a mains voltage that is too high for a building’s requirements can now be stored for future use. Dr Alex Mardapittas of Powerstar explains.
Energy storage is emerging as one of the best solutions to address the twin problems of high demand for electricity plus the volatility of power supplies as more electricity generated by renewables comes onto the grid. An optimised system will balance supply and demand by allowing any excess energy to be stored locally and used at peak times for maximum financial benefit. The potential for savings is immense. Imperial College London’s Energy Futures Lab has estimated that energy storage technologies could generate savings of £10 billion a year by 2050 in the UK.
Energy storage is the key feature of a system developed by Powerstar that combines energy storage with voltage optimisation and renewables, offering the user greater control and flexibility over their energy supply and facilitating a strategy which maximises savings.
Called Powerstar Virtue, it uses the Powerstar voltage-optimisation technology to harness the induced negative power feedback to the supply and charge a storage medium. It can make savings in electricity costs by avoiding grid connection during times of high tariffs and reverting to the energy stored during times of low demand.
On-site renewable generation can also be integrated with the solution to combine the energy saved from the voltage-optimisation system with that generated from the renewable energy source. Users can switch to the stored supply at any time, ensuring a constant and reliable energy supply.
As forecasting of available power is simple, Powerstar Virtue allows users to become a virtual power station (VPS) and make informed decisions on how much power will be available at all times and, as a result, decide when to use stored energy to maximise the benefits. The system can act as a full facility UPS (uninterrupted power supply) for up to two hours and thanks to its modular nature, additional storage modules can be fitted post-installation to match any future needs of the site.
The system also increases the monetary benefits from national and DNO (Distribution Network Operator) incentivised programmes such as STOR, EDR and FDR.
Installing the system also provides a significant additional benefit, as it eliminates the need for inverters on renewable installations, which can further help towards reducing costs and improving return on investment.
Sites will also benefit from the many additional advantages of voltage optimisation — reduced harmonics, voltage phase balancing and improved power factor, along with reduced maintenance costs and a longer lifetime for electrical equipment.
Powerstar Virtue is integrated with either a Powerstar MAX or Powerstar HV Max voltage-optimisation system. Both are well established technologies that have been saving private and public sector organisations money by reducing electricity spend and cutting carbon emissions, as well as prolonging the life of electrical equipment,.
Powerstar’s system achieves savings by matching the voltage of incoming electricity supply to the requirements of on-site electrical equipment and returning any excess back to the grid. It achieves this by generating induced negative power feedback, which flows towards the grid and is subtracted from the incoming power.
Between 70 and 80% of the savings achieved through this approach to voltage optimisation are through the induced negative power feedback, which is generated as a result of the design of the technology. The remaining 20 to 30% of the savings are gained from the improvement in equipment efficiencies due to appliances operating at a voltage more suited to their operating requirements.
A study into voltage optimisation by the University of Warwick concluded, ‘The overall power consumption is reduced because the negative power is induced as feedback power to the source. This power can be considered as being generated from the load site.’
Making savings on LED lighting is particularly challenging, but Powerstar has been proven to achieve this, as a tender awarded by the University of Melbourne confirmed. The system has also demonstrated that significant savings (6 to 10%) can be achieved when modern variable-speed drives (VSDs) are connected.
Powerstar systems have been designed, sourced and manufactured in the UK for over a decade, delivering average energy savings of 12% to 15% and improving power quality. A primary reason for a recent installation at St John’s Catholic Academy in County Durham was when a survey identified the cause of regular equipment failures, which included computers, motors and swimming pool pumps, as a power-quality issue.
Applying the correct voltage to the site’s electrical equipment has eliminated these electrical failures. The installation has also significantly reduced maintenance costs and resulted in electricity savings of over £8000 per annum and 42 t of CO2 emissions.
Storing energy savings for use at a time when tariffs are high is a natural and obvious progression. Storage is also crucial if we want a significant part of our energy to come from renewable sources. This new system makes a virtue out of that necessity, providing the energy user with greater control and flexibility over their energy supply to avoid energy wastage and maximise savings.
Dr Alex Mardapittas is managing director of Powerstar.