It was a strange summer in Glasgow. The city, like much of Scotland, is notorious for cloudy, blustery, and generally capricious weather, even in summer. But in parts of Scotland and northwestern Europe, the summer of 2021 was uncharacteristically warm, dry, and sunny, a boon for lockdown-weary citizens unable or unwilling to travel to favorite southern vacation spots. It was also eerily calm. Day after day, there was little or no wind, something very noticeable in a country with a reputation as the windiest place in Europe.
Scotland was experiencing a “wind drought”—something that may be more common than we think. And that sounds like bad news for the project to build a carbon-neutral future, an enterprise that hinges on renewable energy. Most renewables are intermittent, and while some forms like tide and sun are more or less predictable, others are not. The energy potential of wind, dammed water, and biomass depends heavily on climatic conditions. And if the climate is changing, as the science community unanimously agrees it is, this will have implications for the green energy revolution. Will climate change cancel renewable energy?
This is an important question, one you’d expect would have been near the top of the agenda at COP26, the climate confab in Glasgow. To be clear, there is no evidence that the wind drought was symptomatic of anthropogenic climate change. Climate science tells us that in northwestern Europe, westerly winds are generated by the North Atlantic Oscillation, a weather motor with two contra-rotating gears. One is a zone of low pressure (the Icelandic Low) spinning counterclockwise and the other is a zone of high pressure (the Azores High) spinning clockwise. When there is a large pressure difference between these systems, strong westerlies and cool wet summers result. When there is less difference in pressure, westerlies are weaker and wet windy weather shifts south. This was what happened this summer. An anomalous zone of high pressure appeared between Iceland and Scotland from April to September, a period some observers characterized as the least windy in the U.K. and parts of Ireland in 60 years.
But even if wind droughts are not connected to climate change, they are an illustrative example of how renewable energy is based on assumptions about how the world works, and the world is currently being thrown out of balance.
Take hydropower, which plays a crucial role in electricity systems. The people who manage electrical load essentially have one purpose: to maintain as perfect a balance of supply and demand as possible because imbalances can collapse the system. But nature doesn’t care about human demand, so intermittent renewables pose particular problems for load managers. When there is more intermittent energy than necessary or when it disappears when it is in demand (like when there’s a wind drought), grids can get stressed. In the former case, load managers shut off or store excess electricity. In latter cases, they call on other forms of generation to fill the gap.
Engineers favor hydropower for storing excess electricity and for filling the intermittent energy generation gap. And hydropower’s important enabling function in balancing electrical load illustrates the intimate relationship between changing climate and the ability of human beings to exploit renewable energy. Surplus electricity, including electricity produced in times of intermittent energy plenty, can be used to recover water that has flowed through a hydroelectric facility and pump it to a reservoir at higher elevation, where it can be stored and release to drive turbines when needed. This is known as pumped storage, an infrastructure often analogized as a giant watery battery. In the U.S., pumped storage accounts for 95 percent of utility-scale energy storage.
The problem is that not all countries have suitable hydropower resources and many that do have already fully developed them. In the West, moreover, big hydro, though it is a form of renewable energy, has long been out of favor on grounds it costs too much and causes too much environmental damage.
Also, worryingly, climate change is threatening existing hydro resources in some parts of the world, undermining the ability of load managers to cope with intermittent energy problems like wind droughts. The two decade-long water megadrought in the U.S. southwest is drying up the Colorado River and sapping the potential of the reservoirs and dams built astride it to store surplus intermittent renewable energy and bridge the generation gap.
The megadrought is also harming crops used for biofuels, another important renewable energy enterprise. Parched conditions stunt the yield of corn used for ethanol and also alter the biochemistry of switchgrass, a hardy crop that requires less water and energy, as well as cellulosic agricultural waste, in ways that make these substances less suitable as fuel.
The imbalances humans cause in natural systems trace directly to the imbalances humans have built into their energy policies. For all the hope invested in the green energy revolution, U.S. energy planners have only ever perceived renewables as a supplement to existing fossil and nuclear energy resources, not as a replacement for them. The Obama administration termed this policy “all of the above,” an expression that connotes big-tent political imperatives.
But the massive expansion both of oil and gas production and renewable capacity under the Obama administration had network effects that served to deepen the conundrums of renewable energy. In the late 2010s, the U.S. surpassed Russia and Saudi Arabia to become the world’s largest producer of crude oil thanks largely to the massive application of hydraulic fracturing, a water-intensive technology that damaged water tables and made arid areas even drier. All that fracked oil and gas generated massive quantities of greenhouse gases that exacerbated climate change, and the resulting weather effects like megadroughts in turn undermined the ability of load mangers to use hydro to integrate intermittent renewables into the energy conversion mix.
As dams become degraded by climate change and are decommissioned by planners, solar panels and especially wind turbines have come to be seen as metonymic of the sustainable energy future. And public policy has subsidized the installation of much more intermittent renewable capacity than can currently be used. In the U.S., excess solar and wind capacity is routinely shut off. In the U.K., the government pays owners of windfarms to switch off the surplus. Oddly, these subsidized constraint payments constitute a perverse incentive to invest in still more wind generation, provoking criticism that the push to renewables is yielding limited returns.
In the U.K., wind generation capacity is so overbuilt that even in this calmest of summers the government still paid out tens of millions of pounds to keep the turbines from turning. Some observers hope to store intermittent renewable energy in rechargeable batteries at scale, including the batteries in electric cars, but these approaches bring their own costs and complications.
Questions of counterproductive energy policies and the relationship between anthropogenic climate change and renewable energy were not discussed in any depth at elite forums at COP26. Yet the popular mood overwhelmingly favored such a conversation, as indicated by widespread protests and street theater that culminated in a massive demonstration during the global day of climate action in Glasgow. Activists like Greta Thunberg criticized government and industry for passivity and hypocrisy in the fight against climate change. Barack Obama’s admonitions for the world to do more and for youth to “stay angry” drew skeptical pushback that referenced the former president’s checkered energy record. British Prime Minister Boris Johnson may also have misread the room in his COP26 keynote address, where he compared climate change to a doomsday timebomb that James Bond is scrambling to defuse.
Johnson’s analogy both expressed the urgency of the crisis and mispresented it. Climate change is not a single cataclysmic event that can be solved by a single heroic act. Wind droughts and other weather anomalies remind us that nature and society are dynamically intertwined in ways that are not always obvious. Environments and infrastructures together comprise hybrid entities that are neither purely social nor purely natural and that operate according to their own sets of rules. The historian Richard White dubbed such entities “organic machines,” a frame of reference surely more appropriate than the Bond bomb in conceptualizing a world humans have badly unbalanced. It will be years before COP26’s practical legacy can be known but in the short term the gathering can mark a moment to begin reflecting on the sometimes paradoxical organic machines we are constructing in the name of planetary salvation. Humanity has accepted that harmony and balance are fundamental to healthy ecosystems and energy systems. Now it faces the challenge of grasping the implications of applying ecological principles across the spectrum of human activity.