Comments due by Nov. 24, 2017
A transition away from fossil fuels is necessary, but it
will not be painless. A WIDELY read cover story on the impact of global warming
in 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 like 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% (see chart). It seems impossible to
eliminate fossil fuels from the energy mix in the foreseeable future. Upgrade
your inbox Receive our Daily Dispatch and Editors' Picks newsletters. Enter
your e-mail address Sign up now But 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 on July 11th 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 like Denmark and Scotland to have periods when the equivalent of all
their power comes from wind. Ambitions are rising. The 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;
Germany’s goal is to become 80% renewable by 2050. But whether it is possible
to produce all of a country’s electricity with just wind, water and hydro is a
subject of bitter debate. In 2015 Mark Jacobson of Stanford University and
others argued that electricity, transport, heating/cooling, and industry in
America could be fully powered in 2050-55 by wind, water and solar, without the
variability of the weather affecting users. Forswearing the use of natural gas,
biofuels, nuclear power and stationary batteries, they said weather modelling,
hydrogen storage and flexible demand could ensure stable supply at relatively
low cost. But in June this year Christopher Clack, founder of Vibrant Clean
Energy, a firm, issued a stinging critique with fellow researchers in the
Proceedings of the National Academy of Sciences, the journal in which Mr
Jacobson et al had published their findings. They argued that a narrow focus on
wind, water and solar would make tackling climate change more difficult and
expensive than it needed to be, not least because it ignored existing
zero-carbon technologies such as nuclear power and bioenergy. They claimed 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-tobe-developed hydrogen-powered planes. In
their view, decarbonising 80% of the electricity grid is possible at reasonable
cost, provided America improves its highvoltage transmission grid. Beyond that
is anyone’s guess. Others take a wider view. Amory Lovins of the Colorado-based
Rocky Mountain Institute, a think-tank, shrugs 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%. But in
order to cut emissions drastically, he puts most emphasis on a tripling of
energy efficiency, by designing better buildings and factories and using
lighter materials, as well as by keeping some natural gas in the mix. He also
sees clean-energy batteries in electric vehicles displacing oil demand, as
petroleum did whale oil in the 19th century. Some sceptics raise concerns about
the economic ramifications if renewables’ penetration rises substantially. In
an article this month, Michael Kelly of Cambridge University focused on the
energy return on investment (EROI) of solar PV and wind turbines, meaning the
ratio between the amount of energy they produce to the amount of energy
invested to make them. He claimed that their EROI was substantially lower than
those of fossil fuels; using renewables to generate half of the world’s
electricity would leave less energy free to power other types of economic
activity. Critics note that his analysis is based on studies of PV returns in
Spain from more than half a decade ago. Since then solar and wind costs (a
proxy for EROI) have plunged, raising their returns. What is more, other
studies suggest returns from fossil-fuel-derived energy have fallen, and will
decline further as they incur increased costs associated with pollution and
climate change. A high share of renewables may be less efficient at powering
economic growth than fossil fuels were in their 20th century heyday. But if the
climate doomsayers are to be proved wrong, a clean-energy system must be part
of the solution.
