The Chelmsford (Mass.) Water District serves 26,000 customers on a $5.3 million annual budget. Managers expect 2,300 photovoltaic panels to supply more than half the energy their 3-mgd treatment plant needs every year. Photos: MassDEP, Division of Municipal Services
Connector boxes collect the DC current from groups of panels and send it to the inverter box to be converted to AC power.