Renewable-energy growth has accelerated in 2016, but this may go down as a milestone year for one renewable-energy source in particular.

Together, all renewable-energy sources are expected to account for 8 percent of U.S. electricity-generation capacity in 2017, according to the Department of Energy, and solar energy is responsible for most of that growth.

For the first time ever, new solar-generating capacity is expected to exceed new generating capacity for wind and natural gas.

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The final tally won't be available until March, but enough new solar installations were expected to be completed in 2016 to outpace wind and natural gas, according to Scientific American.

A total of 9.5 gigawatts of solar-generating capacity were expected to be built in 2016, tripling the amount installed in 2015, the magazine said, citing Energy Department data.

That amount would exceed the anticipated 8.0 GW of natural gas capacity, and 6.8 GW of wind capacity.

No new coal power plants were planned in 2016.

While solar could turn out to be the largest source of new generating capacity in 2016, it still represents a fairly small share of the overall U.S. generating mix.

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Utility-scale solar power accounts for about 1 percent of U.S. electricity, according to the Energy Information Administration (EIA).

The EIA expects solar capacity to continue growing, anticipating an increase of more than 30 percent in 2017.

Solar growth has been helped by federal subsidies, as well as a rapid drop in prices over the past few years.

Photovoltaic solar power field at Volkswagen plant in Chattanooga, Tennessee

Photovoltaic solar power field at Volkswagen plant in Chattanooga, Tennessee

Even without subsidies, solar is now in fact the cheapest form of electricity in the U.S., according to a recent study by investment bank and research firm Lazard.

Its annual Levelized Cost of Electricity analysis estimated the cost of utility-scale thin-film PV  to range from $46 to $56 per megawatt-hour, while wind was estimated at $32 to $62 per MWh, and natural gas at $48 to $78 per MWh.

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Wind and natural gas made significant strides in 2016 as well.

The nation's first offshore wind farm began operation this year, and it is anticipated that 2016 will be the first full year in which natural gas will account for a larger share of electricity generation than coal.


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