Richmond Hill’s new wastewater-treatment plant could be partially powered by solar energy when it opens for business in 2015.City officials discussed the possibilities of using solar UV panels to help supply some of the new plant’s energy with Coastal Electric engineer Chris Fettes. Coastal is providing the power to the $24 million membrane-bioreactor plant being built at Sterling Creek. The plant will open with the capacity to treat 3 million gallons of wastewater a day — which is twice as large as the current plant — and can be expanded to treat 4 million gallons per day.