Veteran energy and climate writer David Roberts is out with a provocative look at whether it’s realistic to power the global economy with 100% renewable energy, and whether deep decarbonization is possible by 2100.
His conclusions: We can’t be sure 100% RE is realistic, but that doesn’t mean backing away from the all-out effort to make it happen. And while deep decarbonization is doable by the end of this century, it’ll be some time before we’ll know whether carbon capture and storage (CCS) and nuclear are essential pieces of the puzzle.
In a column for Vox, Roberts reviews recent scholarship on how to achieve the 80 to 100% decarbonization required to hit the targets in the Paris agreement, a process that is “going to involve an enormous amount of electrification.” That’s a big problem, he says, because solar and wind energy are not dispatchable for grid operators, and the current best candidate for dispatchable power is nuclear, CCS proposed by some as a critical solution-in-waiting.
All of which triggers a raging debate, Roberts says, about whether it’s possible or advisable to try to decarbonize the grid without those two technologies.
Thinking through that question, he confirms that balancing variable renewable energy (VRE) without nuclear and CCS will require “a lot of new transmission, a lot of new storage, a lot of demand management, and a lot of new hydro, biogas, geothermal, and whatever else we can think of.” (Those last four being, in fact, dispatchable.)
So the first step is still to move forward hard and fast on renewable energy, since “we have a solid understanding of how to push VRE up to around 60% of grid power.” While “the fight to get 5% up to 60 is going to be epic,” he notes that “political and social barriers will do more to slow that growth than any technical limitation, especially in the short- to mid-term.” Up to that point, “none of these potential future limitations are any reason to let up on the push” to install variable renewables, and avoid natural gas lock-in at all costs.
But any hope of avoiding use of nuclear or CCS means taking the problem of variability seriously, since “as VRE increases, it will begin to run into technical and economic problems,” so that variable renewables plus storage are unlikely to get the world economy into deep decarbonization territory.
Which is why, in an opinion that will be challenged by many, Roberts argues that “from a decarbonization perspective, allowing a nuclear power plant to close (before, say, literally any coal plant) is a self-inflicted wound.” He adds that “every megawatt of dispatchable, carbon-free power capacity that is operating safely should be zealously guarded,” which means utilities must “keep nuclear power plants open as long as possible.”
Finally, while CCS is “an environmental nightmare in every way other than carbon emissions, to say nothing of its wretched economics and dodgy politics,” he concludes that “we’re going to need CCS regardless, so we might as well figure it out.”
Roberts doesn’t toss out the idea of 100% renewables completely—he says anyone inclined to argue against the target should consider whether it’s reasonable “to demand that a new system must demonstrate in advance that it is fully prepared to substitute for today’s system.” And he warns against adopting or ruling out options based on literature reviews that are susceptible to common biases, or cost-minimizing models that rarely minimize all the costs, “consistently and woefully” underestimate the falling cost and rapid growth of renewable energy, and “leave out many environmental impacts, along with more intangible social benefits like community control, security, or independence.”
Roberts’ ultimate advice for the scientists in the room is to “basically research everything. Test, experiment, deploy, refine.” He urges anyone looking for the best path to deep decarbonization—whether or not it’s 100% renewable—to “keep an open mind, support a range of bet-hedging experiments and initiatives, and maintain a healthy allergy to dogma.”