Massachusetts loses its claim to being the most energy-efficient state By David Abel Globe Staff,Updated December 17, 2020, 6:15 p.m. Email to a Friend This was the first year Massachusetts wasn't ranked the most energy-efficient state in the country in nine years.Eyematrix - stock.adobe.com For nine years in a row, Massachusetts ranked as the most energy-efficient state in the country, according to a closely watched annual report. But not this year. The state dropped to No. 2, behind California, according to the American Council for an Energy-Efficient Economy, a nonprofit based in Washington D.C. While the reasons for the lost bragging rights are somewhat technical â Massachusetts was still lauded in the groupâs annual report card â the slight demotion has sparked calls to reform its energy efficiency programs, which are considered vital to the stateâs plans to effectively eliminate carbon emissions by 2050.