Expect to see more bonds backed by Property Assessed Clean Energy Loans that earn top marks from credit rating agencies.So far, a single deal, from Ygrene Energy Fund, has earned a triple-A rating, and only from a single rating agency, Morningstar Credit Ratings. Kroll Bond Rating Agency, by comparison, assigned an AA to the senior tranche of the deal, which was completed in 2016.But Ygrene and two other PACE providers represented at the Structured Finance Industry Groups annual conference in Las Vegas are hopeful that others will follow suit.Lain Gutierrez, a senior vice president at DBRS, was encouraging. Weve seen the performance levels, and they are very stellar performers, he said.