How Energy Modelling Keeps Underestimating Solar’s Potential
Energy modelling organizations from the International Energy Agency (IEA) to Greenpeace have been consistently underestimating the contribution solar electricity can make to the post-carbon transition, according to a new analysis in the journal Nature Energy.
In a summary for Carbon Brief republished on Resilience.org, lead author Felix Creutzig, a professor at Germany’s Mercator Research Institute on Global Commons and Climate Change, says that may be because solar adoption has taken off so incredibly fast. The unexpectedly rapid uptake is driving cost reductions that now have solar competing and winning against fossil fuels in markets as diverse as Mexico, Dubai, and Chile.
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“These dynamics have so far been poorly captured by energy system models, which tended to represent the complex mix of different climate policies in a simplified and stylized way—for example, as a single, economy-wide carbon price,” he writes. “These models also assume that society will always seek to minimize costs, ignoring the potential role of personal preferences.”
The result is that even Greenpeace and the German Advisory Council on Global Change (WGBU) separately projected solar growth curves through 2015 that fell short of the eventual reality. “The IEA, a key reference for all modellers, predicted growth rates of 16 to 32% per year between 1998 and 2010,” he writes. “In fact, real growth ranged from 20 to 72%, with the annual average at 38%. This difference caused huge under-predictions of how much solar would be installed.”
In energy future scenarios produced by Greenpeace between 2007 and 2010, he adds, “initially high growth rates were expected to fall to 24 to 32% per year, a rate that has been surpassed by real-world development.”
The biggest problem with failing to anticipate the year-by-year potential, Creutzig notes, is that the error multiples over time: While compound annual growth of 19% translates into 470% growth over a decade, 38% growth produces a 2,500% increase in capacity in 10 years.
On that basis, where the Intergovernmental Panel on Climate Change sees solar delivering five to 17% of global electricity supply in 2050, the Nature Energy study puts the potential at 30 to 50%, with no subsidies required.
“In other words, our electricity systems will be transformed from relying on consistent, ‘baseload’ coal to variable solar,” he writes. “This offers a somewhat bright outlook for climate change mitigation, but would also change the landscape of, and demands on, global electricity markets.”
Creutzig opens his article with a reference to researchers who are putting their time into carbon capture and storage or nuclear technology—partly, perhaps, because the potential of renewables has been so consistently understated. Which means the modelling failure “could be a serious problem for the industry and, maybe, the planet,” the Washington Post observes.
“If policy-makers believe solar is growing more slowly than it actually is, they may be less likely to prioritize the kinds of research and development that will help better integrate renewables onto the grid, such as improving battery storage technology,” writes climate specialist Chelsea Harvey. “This could lead us to continue relying on more carbon-intensive energy sources.”
“I think the most important risk is that the regulatory environment does not adapt in time to a rising share in solar energy,” Creutzig told Harvey.