How bright is the future of solar power?

In the United States today, large “utility-scale” solar power projects account for more than 4,700 megawatts of electricity-generating capacity.

And 27,000 megawatts of large-scale solar are under development, which means that the industrial-solar sector is on its way to providing enough electricity for more than 5 million homes.

These are impressive numbers, but the question now is: Will this growth continue? Much of the expansion of utility-scale solar power — which consists of large, ground-mounted arrays of photovoltaic panels or another technology called “concentrating solar power” — has been due to two factors: state renewable energy portfolio standards that require utilities to produce a certain amount of green energy, and federal tax credits set to be sharply reduced at the end of 2016.

As the overall solar industry pushes past 10,000 megawatts of installed power by the end of the year — including PV panels on the roofs of homes and businesses — some states soon will begin to achieve renewable energy targets mandated by state portfolio standards, which could dampen demand for utility-scale solar projects. Given that and the uncertainty over federal tax credits, will the large solar plants starting to dot the Southwestern U.S. and elsewhere keep cropping up? Or will utility-scale solar fizzle out even as the need to push all forms of renewable energy forward becomes more urgent?

What’s next for utility-scale solar

Some renewable energy experts say the future of utility-scale solar is far from assured, in part because they believe distributed solar — meaning panels on individual buildings — will become increasingly dominant as the price of PV panels continues to fall.

Other analysts say that both distributed solar and utility-scale solar will play an important role in U.S. electricity generation. Today, solar power is just 1 percent of the total installed electricity capacity in the U.S. But experts believe that several trends could solidify the position of industrial-scale solar going forward. The first is the rapidly declining cost and increasing efficiency of photovoltaic and other solar technologies. The second is the likelihood that state and federal policies — including renewable energy portfolio standard (RPS) mandates, which now exist in 29 states and the District of Columbia, and a major federal tax incentive — will be extended or expanded.

A SunShot Initiative solar project at Sandia National Laboratories in Albuquerque, N.M. (Credit: Sandia National Laboratories/Randy Montoya)

In addition, the federal government has big plans for utility-scale solar. The U.S. Department of Energy’s SunShot Initiative, an effort to bring the cost of solar down, projects a scenario where costs continue to drop dramatically and 329,000 megawatts of solar power are integrated into the power supply [PDF] by 2030, representing 13.8 percent of total electricity demand in the U.S. Of that, the Department of Energy estimates, 209,000 megawatts, or almost two-thirds, could be utility-scale solar if prices for solar technology continue to fall.

“Ultimately, the real beauty of solar is that every building, every car park is covered,” said Dan Kammen, a professor of energy at the University of California, Berkeley. “So in the decades ahead, we’ll go to more and more distributed. But to enable the transition, I think we will see more of these bigger facilities still being installed.”

According to Cory Honeyman, a solar analyst at GTM Research, utility-scale photovoltaics alone accounted for only 0.25 percent of the total U.S. electricity capacity at the end of 2012. By the end of 2016, he says, that number will jump to 1.6 percent, more than a 500 percent increase.

Solar challenges and incentives

Building big solar is expensive and tough, as projects face significant regulatory hurdles. Large solar plants such as Ivanpah, Solana and the California Valley Solar Ranch are getting built in a few states because it is financially feasible based on existing policies. “Utility companies don’t tend to do these things voluntarily,” said Martin Pasqualetti, a professor and expert on energy policy at Arizona State University in Tempe.

Today, utility companies generally buy the power from big solar plants to fulfill RPS mandates. California, for example, is requiring that 33 percent of the state’s electricity needs come from renewables by 2020. Utilities can take a significant chunk out of their RPS mandates by buying all the power produced at a 100-megawatt plant, as they’re doing at numerous installations in the sunny parts of the country, including California, Nevada and Arizona.

California Valley Solar Ranch The utilities are buying up that power to avoid substantial financial penalties. “These RPS standards with penalties for non-compliance created this demand,” Honeyman said.

Because the utilities have an incentive to buy the power, the solar plants’ developers can secure financing to build them. The high-profile, 377-megawatt Ivanpah plant — ramping up to full capacity in California’s Mojave Desert right now — cost $2.2 billion, and other big projects are similarly expensive. Major loans from the Department of Energy help many of them pay those lofty costs.

The other policy helping the projects along is the federal investment tax credit, or ITC, which offers a 30 percent credit for facilities that come online by the end of 2016. But what happens if the tax credits are not extended and RPS mandates are fulfilled — and potentially not extended or amended?

Those policy shifts are the backdrop for the fact that the impressive pipeline of projects under construction or development is starting to run out of steam. Honeyman, of GTM Research, said that the slowdown is happening faster than anticipated. Some of the largest projects listed by the Solar Energy Industries Assocation (SEIA) — such as the 1,200-megawatt Sterling Project and the 750-megawatt McCoy Solar Energy Center, both in early development stages in California — have no entry under “electricity purchaser.” A project that can’t promise an opening date before 2017, when tax credits are scheduled to drop to 10 percent, may struggle to find a purchaser for its electricity.

Up on the solar rooftop

Rooftop solar faces fewer uncertainties and is expanding rapidly, with 488 megawatts installed in 2012, 62 percent more than the previous year. Individual incentives at the state and federal level, along with innovative solar leasing models where a building or house owner pays nothing up front, are pushing rooftop solar along just fine. But utilities generally aren’t enthusiastic about such “distributed generation,” because they make no money off those sources of power.

“Ultimately we’re likely to see solar as very distributed, because we might as well take advantage of our urban landscape and cover our built surfaces,” said Kammen, who frequently has testified to Congress on renewable energy issues. “But utilities are much more comfortable with large, central station power plants, and they demonstrate again and again that they’re not really that well positioned