For those concerned about sustainable energy, the news recently out of East Hampton Town Hall is a nice surprise. Officials and three private companies are racing to put together a proposal to be presented to the state Public Service Electric and Gas Company, PSEG Long Island, for large-scale solar installations at town-owned sites. Taken together, the project could produce on the order of 40 megawatts of electricity, enough to power as many as 8,000 houses.