Anyone familiar with this blog and our work on energy issues will not be surprised by my sincere support of nuclear power as the only realistic solution to climate change in the electricity (and possibly transport and industrial heat) arena. I’ve laid my cards on the table in the peer-reviewed literature (e.g., see here, here, here, here, here & here) and the standard media, and I’ve even joined the board of a new environmental NGO that supports nuclear.

And there is hope, despite the ever-increasing human population, rising consumerism, dwindling resources, and the ubiquity of ideologically driven and ethically compromised politicians. I am hopeful for several reasons, including rising safety and reliability standards of modern nuclear technology, the continued momentum of building new fission reactors in many countries, and even the beginnings of real conversations about nuclear power (or at least, the first steps toward this) in countries where nuclear energy is currently banned (e.g., Australia). I’m also heartened by the fact that nearly every conservation scientists with whom I speak is generally supportive, or at least non-resistant, to the idea of nuclear power as part of the climate change solution. An open letter by our colleagues attests to this. In fact, every day that passes brings new evidence that we cannot ignore this solution any longer.

Even despite the evidence in support of implementing a strong nuclear component into climate change-mitigation strategies, one of the most frequent arguments for not doing so is that society can achieve all of its energy needs and simultaneously combat climate change by constructing 100% renewable-energy pathways. While it is an easy mantra to repeat because it feels right intrinsically to nearly everyone with an environmental conscience, as a scientist I also had to ask if such a monumental task is even technically feasible.

Don’t get me wrong — I’m a huge fan of renewable energy and its development, purchase, and installation, but only if (and that’s a whopping, great if) it displaces electricity generation from fossil fuels. Therein lies the rub — while this can be achieved up to a certain point (a point that is entirely dependent on a region’s specific set of environmental, geographic, political, demographic, and economic conditions), it tends to fall apart when renewable penetrations become high. The main reason for this is the dispatchability limitations and storage requirements of renewables-generated electricity.

An energy source that is dispatchable is able to be called-up or withdrawn at any time in response to demand changes, which means that it has to be able to provide electricity at a moment’s notice in response to variable demand. While battery technology is improving and making this easier, better batteries alone are not the solution, especially from an environmental viewpoint.

But the plot thickens when one examines the entire breadth of feasibility1 requirements for renewable energy, which is exactly what we’ve just done in a new, comprehensive review of 100% renewable studies from around the world.

Led by my soon-to-be-completed PhD student, Benjamin Heard, we have just published the first empirical assessment of the feasibility of existing 100% renewable-energy plans from around the world. As we had originally suspected, the news is not good for the faithful of a 100% renewable future.

Conservation biologists will probably not wish me to go over every single detail of this rather technical review, but I will summarise the main criteria that we used to judge the studies. We required studies to demonstrate four essential criteria to be considered feasible: (1) capable of tracking realistic projections of demand, (2) electricity must be supplied to match demand at a fine temporal scale, (3) transmission must be able to deliver the electricity generated, (4) ancillary services (e.g., frequency control) must be maintained.

In short, not one of the 24 studies we examined met all criteria, and most failed the basic feasibility test so badly that even being generous didn’t improve their purported reality. More specifically from a conservation perspective, it turns out that most of the studies also relied on an insane amount of hydro and/or biomass sources to meet even their unrealistic projections. We know collectively as a conservation community that both of these sources are disastrous for species conservation, mainly in terms of habitat destruction (see et alia key studies on hydro, and biomass). In short, even if these studies hadn’t failed to meet the main feasibility criteria, we as conservation biologists should be highly dubious regardless based on the reliance of these destructive practices.

The result is a stark wake-up call to the sustainability community about how we can achieve sensible climate-change mitigation policies fast enough to combat our almost out-of-control climate disruption. It’s also another reason that I continue to solidify my support for next-generation nuclear technology as part of the mix. While I want to see renewables implemented, we cannot rely on them alone.

Instead of the ‘100% renewables‘ mantra, we should instead be chanting ‘0% carbon‘.

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1We differentiate feasibility and viability: feasible means ‘possible within the constraints of the physical universe’, so a demonstration of feasibility requires that evidence is presented that a proposed system will work with current or near-current technology at a specified reliability. On the other hand, viable means that the system is not only feasible, but realistic within the socio-economic constraints of society. Unless something is first established as feasible, there is no point in assessing its viability.

CJA Bradshaw