The ambitious solar project that could save the town $2.3 million over the next 20 years grew a bit Aug. 15 when the Board of Selectmen approved a reimbursable deposit to include Wilton High School in the plan.The selectmen at their meeting in town hall authorized a town check of $4,268 to be paid to Eversource, the power company, as a deposit on the system of more than 100 panels that will be built on the roof of the high school and on the field house.It is the latest chapter in the town\u2019s movement toward being green. On May 8, the town entered an agreement with the solar company known as Kingspan.The company said it can generate 290,862 kilowatts, more than other competitors, for the job. Connecticut Green Bank will technically own the system. Kingspan will build it, and the system owner will subcontract the operation and maintenance to another company.The impact to the roof of the buildings will be minimal, because no bolts are used to hold the solar arrays in place. Rather, sandbag ballasts will be used.The plan is to install solar panels on the roofs at Miller-Driscoll School, Middlebrook School and now Wilton High School. The idea is to sell electricity to the town for 20 years at fixed rates that are lower than current and expected electric rates.The roofs would be generating solar power by October.