Cellular telephone service is a rapidly expanding and very competitive business in Romania. MobiFon, an affiliate of Air Touch, is a leading service provider and an operator of numerous off-grid cell sites throughout Romania. These sites have typically been powered by diesel generators. But diesel generators are often expensive to run and several diesels must be installed at each site to ensure uninterrupted service.
In the late summer of 1998 MobiFon contracted Bergey Windpower to design, supply, and assist in the installation of a hybrid wind /solar system retrofit to an existing GSM cellular site with a load of ~ 2 kW continuous.
BWC provided MobiFon with four design options representing different renewable energy supply fractions (100% being all renewable energy, 0% being all diesel energy) and costs. MobiFon settled on a 100% (nominal) renewable system consisting of 15 kW of wind (2 x 7.5 kW), 5 kW of solar, a modest battery bank, and a 4.5 kW sine wave inverter.
BWC assisted MobiFon with the local construction of the 24 m (80 ft.) by supplying construction drawings and parts lists and helped MobiFon find suitable batteries in Europe. The U.S. equipment was all air freighted to Romania to meet MobiFon's tight installation schedule due to the onset of winter.
The system was installed in November, 1998 and has provided 100% power availability since commissioning. The diesel back-ups have not been necessary. As a result of this positive experience, MobiFon has installed smaller wind/solar hybrid systems at three additional sites and they plan more installations in the future.