Long Island Solar Farm Photo: Brookhaven National Lab

Long Island Solar Farm
Photo: Brookhaven National Lab

Twenty-nine states have renewable energy mandates. California’s mandate calls for 33% renewable energy by 2020 while New York State mandates 50% of its electricity be renewable by 2030. It is one thing to set energy or electricity mandates and quite another to achieve them. New York is quite fortunate; today 26% of its electricity comes from renewable electricity sources. However, large hydroelectric facilities today provide 80% of NY’s renewable electricity electricity and, unless more hydropower is imported from Canada, an expanded contribution from large hydropower seems unlikely. So to meet this 50% mandate, solar and wind which today produce 5.2% of NY’s renewable electricity would have to expand 462% over the next 14 years or on average, about 33% per year assuming no growth in the electricity demand over the same period. So how do states achieve these mandates recognizing that enormous growth in renewable electricity is necessary?

Many jurisdictions will look to distributed energy and in particular solar photovoltaic (PV) panels as a major contributor. But not all solar PV are equal. When compared, in 2015 residential PV was significantly more expensive at $4.17/watt while utility scale PV cost $2.34/watt. While it is true that rooftop PV has significantly decreased in price and does offer benefits like carbon-free electricity, greater electricity independence, and reduced consequences when the grid is disrupted from extreme weather, human error, or cyber attacks, unless there is a breakthrough, it is likely to remain more expensive than utility PV. And if a state’s goal is to support renewable electricity at minimum cost, then pursuing the utility pathway seems to be preferable.

Actual PV electricity production in the U.S. appears to support this approach. In 2015, utility scale PV produced about 2/3’rds of 1% of the nation’s electricity or about twice as much as rooftop PV. Yet states continue emphasizing policies that support residential PV to meet clean energy goals. Expanding individual electricity independence, especially as various renewable electricity subsidies are phased out, comes with a cost that may not have been fully considered.