July 28, 2011 - Vermont's largest solar array compared to California's

Thursday, July 28, 2011

Solar energy projects come in a variety of shapes and sizes: photovoltaic (PV) or thermal, large or small.  A look at Vermont's new largest solar project, and how it compares to the largest solar project in the US under development in California, highlights the range of solar power projects.

Yesterday, Vermont Governor Peter Shumlin officially activated a 2.2-megawatt solar photovoltaic system in South Burlington, Vermont.  Located on a 25 acre site amidst farmland on the fringes of Burlington's metro area, the $12 million project owned by Chittenden County Solar Partners is projected to produce 2.91 million kWh annually.  This output will be sold to Vermont's Sustainably Priced Energy Development (SPEED) Program under a 25-year power purchase agreement.  This PPA, made possible by Vermont's standard offer law, lets sell the solar project sell its output to Vermont utilities at a guaranteed price set by state regulators: in this case, 30 cents per kilowatt-hour.  This is about twice the average retail price for all electricity sold to residential users in Vermont.  Developers note that long-term contracts with guaranteed pricing are often necessary in order to finance projects.  While the Vermont Public Service Board has since lowered the standard offer to 24 cents, the South Burlington project's contract guarantees it the contract price.

Meanwhile, the largest solar project under construction may be the Blythe Solar Power Project in Southern California.  When the project is complete at 968 MW, this solar thermal power station will dward the scale of a distributed photovoltaic project like AllEarth's in Vermont.

What these two projects have in common is that they will both operate by capturing usable energy from the sun.  Both are new, meaning there are jobs involved in designing, constructing, and operating them.  Both can be expected to displace fossil fuel-fired generation, and qualify as renewable under federal and state policy.

The differences are perhaps more striking.  The Blythe project is a massive centralized project, while one of the key features of the Vermont project is its distributed nature.  Not only can distributed generation projects avoid the need to build new large transmission lines just to get the project's power to market -- a significant issue for centralized projects like those in California -- but distributed generation can even enhance the strength of the existing grid by shoring up voltages and reducing line losses.  Combined with the different technologies involved and the different overall project scales, these two solar energy projects illustrate the broad range of projects falling under the solar power umbrella.

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