A lot of people didn’t see the shale oil and gas revolution coming, and now a new report says many are failing to anticipate a coming energy explosion that will transform the energy sector to a similar extent.

Plummeting module prices and rising module efficiencies are driving a solar boom so big it may face only one obstacle: Its own success.

“The comparison is that the magnitude of the impact solar can have on the market is similar to the impact shale gas has had,” said Wood Mackenzie Research Director Prajit Ghosh. “The economics of solar is already competitive in many parts of the U.S. and that will only get better.”

There are many parallels between the energy revolution created by shale resource development and what is now happening in solar, said Ghosh, lead author of the consultancy's recently-released report, "Solar: The Next Shale?" An example is that rigs became more productive in shale in the same way that module efficiencies are driving the solar boom.

The comparison is more qualitative than quantitative but both the shale revolution and today’s solar boom are technology driven, Ghosh added.

A Net Cost Analysis verifies solar’s value

Dissatisfied with levelized cost of energy (LCOE) studies showing solar’s competitiveness, Ghosh’s Wood Mackenzie team worked up a Net Cost Analysis (NCA) for comparison.

“LCOE doesn’t account for the fact that solar only produces energy during the day when there is no cloud cover,” Ghosh explained. “It doesn’t account for the revenue side.”

The Wood Mackenzie team created an annual revenue model for all U.S. and Canadian transmission load pockets that included a full range of factors, including varying supply-demand profiles, solar and wind resource profiles, and gas supply profiles. It then created annual revenue for a specifically defined solar facility at a known cost.

The difference between the revenues and the cost in the NCA confirmed LCOE analyses of solar’s rapidly expanding price competitiveness. In larger scale solar, 19 states will be at grid parity and competitive with natural gas generation by 2020 and 38 states will be there by 2030, according to the study. By 2025, states will be approaching grid parity in residential rooftop solar as well.

“An NCA for California solar shows the economics went from no-reason-to-build in 2009 to 10% of peak solar market share in 2014 and 2015 that approaches 14% to 15% in some months,” Ghosh said.

How solar displacing gas could stunt solar's growth

The NCA also showed how solar threatens solar’s growth.

“The regulatory support for shale exploration was in place to accommodate the impact of shale gas,” Ghosh said. “The power market structures are not.”

As the cost of solar falls, due to economies of scale and efficiencies, more is installed. With this increased market penetration, solar both displaces gas – which takes market share away – and also decreases the price the market pays for gas as capacity, Ghosh explained.

“This is not just a forecast, it is actually happening,” he said, noting the drastic drop in solar’s net cost curve and the rising gas cost curve shown in the Wood Mackenzie study.

In particular, natural gas revenue in the high-price capacity market is lost.

“The economic incentive for new gas plants is no longer there,” Ghosh said. “But to integrate more solar, the market has to have something to run when solar is not available. There either must be a technology, like battery storage, or an incentive to build flexible natural gas, like California’s flexible resource adequacy product.”

Accommodating such integration costs will either diminish the solar value proposition or impede growth, Ghosh believes. The more likely outcome will be a slowed pace of growth as integration costs are socialized. Grid operations and infrastructure will be affected. And other technologies, like wind and battery storage, could be factors.

“It depends on the market,” Ghosh said. “In ERCOT, the cost of the transmission build out to support wind was socialized. And there are a lot of mutual benefits in solar and wind profiles. In other markets, there might be a generally good profile showing wind could back up solar but it might not be a perfect correlation.”

Solar's biggest threat: Poor rate designs

In distributed and rooftop solar, Ghosh said, the economics are not as clear as in large scale solar because of many nuances and varying incentives.

The expanding battle in states over net energy metering (NEM) and rate design is a central question. Retail rate NEM was introduced in the 20th century as a convenience, not a calculation. It was intended to grow solar and it did.

But as rooftop solar owners’ electricity bills go down, their payments for bill infrastructure charges are reduced proportionally, Ghosh explained. “As solar rooftops proliferate, some utilities and regulators say those costs are being shifted to non-solar-owners.”

As a result, there is now much anti-NEM legislation and rate design review that will be decided in 2015, he said. “Watch those cases to know how the economics of rooftop solar will go.”

If utilities are successful at implementing rate design changes that capture fixed charges, it could curtail economic rooftop solar, Ghosh said. “But 20th century rate design with net energy metering does not account for the fixed cost in an appropriate manner and that rate design has to be changed.”

If the cost is not paid for appropriately, the problem multiplies, he said. “As solar gets more economic and more customers move away from the grid, it could cause a rate increase loop. The more rates increase, the more customers will want to leave. And it gets worse and worse for the utilities.”

Kicker: More cost reductions coming

There is every indication the cost of solar will continue to go down, Ghosh said. Module efficiency, the biggest driver of cost reductions, continues to improve. As prices get better, competition increases and that will push out market inefficiencies like value pricing and grow new opportunities like building integrated photovoltaics.

Finally, solar is not one technology. Just as thin film created competition that produced higher efficiency silicon-based modules, perovskite now may be a silicon replacement.

“It is not at all market ready,” Ghosh said. “But its efficiency has increased from 2% to 20%, a learning curve we have not seen historically. Given the rate of change of these technologies, we have to pay attention.”