Industry observers disagreed Aug. 18 about a US National Renewable Energy Laboratory preliminary analysis that shows solar deployments must accelerate by three to four times current rates to achieve a largely carbon-free American power sector by 2035.

　　”President Biden’s goal to achieve a carbon pollution-free power sector by 2035, in conjunction with a proposal for historic investments in US infrastructure, are critical steps toward combatting the climate crisis and reducing greenhouse gas emissions at the right pace and scale,” the Department of Energy said in its issue brief, “Investing in a Clean Energy Future: solar Energy Research, Deployment and Workforce Priorities.””Solar is the fastest-growing source of new electricity generation in the nation–growing 4,000 percent over the past decade–and will play an important role in reaching the administration’s goals,” the DOE said in the brief, released Aug. 17.

　　Energy Information Administration data shows total solar capacity, including large-scale and distributed generation, more than tripled from 2015’s 23.5 GW to 2020’s 75.8 GW, but S&P Global Platts Analytics forecasts indicate that five-year growth rate would decline to 1.5 times by 2035.

　　That 2035 total–413.3 GW–is quite large, but if deployments accelerated at triple the 2020 rate, as advocated as a minimum in the issue brief, that total would reach 755.8 GW by 2035.

　　Policy changes neededMatthew Williams, an energy transition analyst at Platts Analytics, said reaching such an ambitious goal will require “additional policy forces.”

　　”The recent $3.5 trillion budget resolution earmarks a [clean-energy-standard]-style program, called the Clean Electricity Payment Plan, which could become a primary driver,” Williams said. “While details have not been released, we believe the design of the CEPP will likely take the form of a system of payments and fees applying to electricity suppliers [which] will incentivize suppliers to meet annual clean electricity goals, with the overall goal to hit 80% by 2030.”

　　Other factors that would be “vital in order for the net-zero 2035 goal to be met” include additional research and development funding, generous tax credits and domestic supply chain investment, Williams said.

　　Morris Greenberg, Platts Analytics senior manager of North American power analytics, said that while the estimate of required solar deployment acceleration is “not unreasonable, “it definitely presents challenges requiring diversification and expansion of supply sources.”

　　”Given sufficient time to scale up the size of the industry, it should be possible to reach targeted rates of solar additions without substantial increases in unit costs though that may not be true of required storage additions … given expected growth in [electric vehicle] demand and current battery chemistry,” Greenberg said.

　　Gregory Wetstone, American Council on Renewable Energy president and CEO, said “seizing this growth opportunity will require rapid transformation of the power sector and significant investment in a 21st century grid. “But the payoff will be both climate protection and greater economic prosperity,” he said

　　Grid reliabilityCampbell Faulkner, senior vice president and chief data analyst at OTC Global Holdings, an interdealer commodity broker, called the DOE issue brief “a political piece devoid of any real analysis that utilizes a bunch of rosy predictions written by policy folks who know nothing about how the electric power grid actually operates.”

　　”Grid reliability is decreasing, and this is a function of growing demand coupled with fewer controllable units being built due to a policy focus on lower average electricity prices,” Faulkner said. “There is an implicit good caused by renewable sources being added to various dispatch stacks due to their low running costs. But, when high load times do come, there often are not enough dispatchable units available across the NERC regions.”

　　However, the US appetite for renewable power is growing, with or without policy incentives, he said.

　　”Consequently, consumers should begin getting used to more frequent outages and persistent issues with reliability, all for lower average electricity costs,” Faulkner said.

　　However, Platts Analytics’ Greenberg said, “With proper planning, reliability need not degrade, but the need for incremental storage would be another factor that may present challenges in reaching the target in 2035.”

　　Scott Miller, Western Power Trading Forum executive director, said: “Batteries are going to be important but I cannot imagine they will be procured at such a level as to fill the gap when the system is still at peak and when the sun goes down as is now being experienced in California and increasingly in the West.”

　　Another factor is transmission, and the brief does not address the need for it to support moving power from areas with surplus energy to those without it, Miller said.

　　”Finally, as it pertains the increasingly arid (drought stricken) West, I don’t know what assumptions they are making about the availability of hydro,” Miller said in an email. “It appears that drought is more the norm now than in previous years and I don’t know what NREL’s assumptions are in this regard. Thus, the NREL analysis may be correct, but that depends on other assumptions about what else composes the future grid.”

　　Greenberg said his group’s long-term forecast did not consider 2035 a likely target for a zero-carbon power sector, “and though it is included in the budget reconciliation package, there are likely major hurdles before it becomes law.”

　　”Even if passed, there may be cost containment provisions that delay compliance, and there is a chance of repeal by a future congress/administration,” Greenberg said.