Maintaining supply reliability of small isolated power systems using renewable energy

The application of renewable energy in electric power systems is growing rapidly due to enhanced public concerns for adverse environmental impacts and escalation in energy costs associated with the use of conventional energy sources. Photovoltaics and wind energy sources are being increasingly recognised as cost effective generation sources in small isolated power systems (SIPS) primarily supplied by costly diesel fuel. A relatively high renewable energy penetration can significantly reduce the system fuel costs but can also have considerable impact on the system reliability. Small isolated systems routinely plan their generating facilities using deterministic adequacy techniques that cannot incorporate the highly erratic behaviour of renewable energy sources. Existing probabilistic risk methods are not generally accepted in SIPS evaluation despite their utilisation in most large power utilities. Deterministic and probabilistic techniques are combined using a system well-being approach to provide useful reliability indices for SIPS containing renewable energy. An evaluation of the contribution from photovoltaics and wind energy sources to SIPS reliability is presented