Case Study of a Hybrid Wind/Photovoltaic/Diesel Power System at a Radio Repeater Site

The use of the wind as a viable alternate for power generation became a reality for B.C. Telephone in 1982 at the Swindle Island Microwave site in Northern British Columbia. With diesel fuel costs approaching $5 per gallon delivered to a site which is accessed only by helicopter, the cost savings for fuel is estimated at over $14,000 annually at 25% duty cycle on the diesel generator. The power system consists of two 2000 watt wind generators connected to a 3000 A.H. battery designed for cyclic discharge applications. An 8.0kw diesel generator via two 50 amp chargers supply the 700 watt radio load and recharge the station battery in a cyclic mode in periods of low wind as well as provide power for lighting and test equipment as required during routine maintenance visits to the site. The system has been in operation in a trial mode for 18 months and was cut into service in the spring of 1984. During this period, several "teething" problems have surfaced and subsequently been resolved, including the destruction of the two wind generators blades and tail assemblies. At present, there are plans to retrofit a photovoltaic array to the power system to complement the wind generation plant. The paper will discuss the pro\´s and con\´s of wind generation as well as engineering considerations relating to site selection, system sizing, control and auxillary equipment as well as maintenance requirements and cost effectiveness.