A widely read cover story on the impact of global warming in a recent edition of New York magazine starts ominously: “It is, I promise, worse than you think.”
It goes on to predict temperatures in New York hotter than present-day Bahrain, unprecedented droughts wherever today’s food is produced, the release of diseases such as bubonic plague hitherto trapped under Siberian ice and permanent economic collapse.
In the face of such apocalyptic predictions, can the world take solace from those who argue that it can move, relatively quickly and painlessly, to 100% renewable energy?
At first glance the answer to that question looks depressingly obvious. Despite falling costs, wind and solar still produce only 5.5% of the world’s electricity. Hydropower is a much more significant source of renewable energy, but its costs are rising and investment is falling. Looking more broadly at energy demand, including that for domestic heating, transport and industry, the share of wind and solar is a minuscule 1.6%. It seems impossible to eliminate fossil fuels from the energy mix in the foreseeable future.
All energy transitions, such as that from coal to hydrocarbons in the 20th century, take many decades. It is the rate of change that guides where investments flow. That makes greens more optimistic.
During the past decade solar photovoltaics (PV) and wind energy have been on a roll as sources of electricity. Although investment dipped slightly last year, the International Energy Agency, a global forecaster, said recently that, for the first time, the amount of renewable capacity commissioned in 2016 almost matched that for other sources of power generation, such as coal and natural gas.
In some countries the two technologies—particularly solar PV in sunny places—are now cheaper than coal and gas. It is no longer uncommon for countries such as Denmark and Scotland to have periods when the equivalent of all their power comes from wind.
Ambitions are rising. The State Senate in California, a state that is close to hitting its goal of generating one-third of its power from renewables by 2020, has proposed raising the target to 60% by 2030, and Germany’s goal is to become 80% renewable by 2050.
Nonetheless, whether it is possible to produce all of a country’s electricity with nothing but wind, water and hydro is a subject of bitter debate.
In 2015 Mark Jacobson of Stanford University and others argued that electricity, transportation, heating/cooling and industry in America could be fully powered by wind, water and solar by 2050-2055, without the variability of the weather affecting users. Forswearing the use of natural gas, biofuels, nuclear power and stationary batteries, they said, weather modeling, hydrogen storage and flexible demand could ensure a stable supply at relatively low cost.
In June, however, Christopher Clack, founder of a company called Vibrant Clean Energy, and fellow researchers issued a stinging critique of Jacobson’s work in The Proceedings of the National Academy of Sciences, the journal in which Jacobson’s team had published their findings.
Clack and his associates argued that a narrow focus on wind, water and solar would make tackling climate change more difficult and expensive than it needs to be, not least because it ignored existing zero-carbon technologies such as nuclear power and bioenergy. They claimed that the models wrongly assumed that hydroelectricity output could continue for hours on end at many times the capacity available today, and pointed to the implausibility of replacing the current aviation system with yet-to-be-developed, hydrogen-powered planes. In their view, decarbonizing 80% of the electricity grid is possible at reasonable cost, provided that America improves its high-voltage transmission grid. Beyond that, however, is far from assured.
Others take a wider view. Amory Lovins of the Colorado-based Rocky Mountain Institute, a think tank, shrugged off the 100%-renewables dispute as a sideshow. He takes comfort from the fact that it is increasingly common for renewables sustainably to produce half a location’s electricity supply. He believes that the share can be scaled up with ease, possibly to 80%.
© 2017 Economist Newspaper Ltd., London (July 15). All rights reserved. Reprinted with permission.
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