A second green cell site was activated in 2009 on Chambers Island in Door County. The cliffs lining Door County's rugged shoreline were blocking the signals from mainland towers, leaving many area residents with limited cellular service, as well as leaving emergency personnel with limited radio coverage. The green cell site runs on batteries charged by solar panels at the base of the tower and a wind turbine installed on tower. A propane generator is available as a back-up source of power if there is inadequate wind or sun to charge the batteries.