Making Microgrids workable
Supplying electricity to islands and other remote areas has always been a challenge. The growing popularity of Renewable Energy Sources (RES), such as solar energy, has been cause for optimism. RES are well-suited to remote environments since the electricity is generated locally. In such circumstances, energy generated by RES can be supplied to the local community via low voltage distribution networks known as Microgrids. The University of Manchester was charged with assessing the problem of allocation losses in Microgrids in the framework of an R&D project sponsored by the Energy, Environment and Sustainable Development Programme. Allocation losses arise from the fact that energy distribution is not a 100% efficient process with between 5 and 10% lost to heat and other sinks. The British engineers aimed to find out how well the methods established for estimating losses in traditional electricity grids apply to Microgrids. All conventional numerical techniques were examined, including: proportional allocation and marginal allocation as well as variations on these two techniques, plus impedance matrix and, finally, Optimal Power Flow (OPF). One problem common to most of the aforementioned techniques, the choice of reference node, was resolved by assigning equal losses to each generator on the Microgrid. In addition, a good deal of effort was spent on analysing the financial parameters associated with Microgrids. An important outcome of the research was the creation of an application to determine how to set tariffs in order to achieve a desirable rate of return on investment. The development and use of these tools will help promote the adoption of Microgrids as a technically and economically viable solution for delivering electricity.
