My colleague Cutler Cleveland, Professor at Boston University, has a new article in the online Encyclopedia of Earth that presents a really thoughtful and detailed analysis of the history of the world’s major energy transitions, what we can learn from them about the impending end of the oil age, the prospects and limitations of renewable energy sources on the horizon, and what we face in making the transition to the next age without a major disruption in society as we know it.
The outlook is sobering:
“The only renewable energy that exceeds annual global fossil fuel use is direct solar radiation, which is several orders of magnitudes larger than fossil fuel use. To date however, the delivery of electricity (photovoltaics) or heat (solar thermal) directly from solar energy represents a tiny fraction of our energy portfolio due to economic and technical constraints. Most other renewable energy flows could not meet current energy needs even if they were fully utilized. More importantly, there are important qualitative aspects to solar, wind, and biomass energy that pose unique challenges to their widespread utilization.”
This point underscores that the transition to a new energy age will require a “silver buckshot” approach rather than a silver bullet. It will take innovations on multiple fronts involving intensive investment in a variety of energy technologies, along with innovation in delivery and storage technologies. And, perhaps most important, conservation. Meaning essentially a remodeling of civilization to incorporate high energy use efficiency and reccycling into everything we do so that the energy is actually used to do useful work, rather than, for example, to power thousands of cars full of single individuals idling and inching along urban freeways. This may sound utopian and absurd, but many of the approaches necessary are already available, as discussed in the fascinating book, “Natural Capitalism: Creating the Next Industrial Revolution” by Hawken, Lovins, and Lovins.
The renewable energy source that is the current darling of the US Congress, corn ethanol, is not going to cut it, as argued in this cogent op-ed by Dave Tilman and Jason Hill. The main reason among several is that it competes for already scarce arable land used for food production:
“If every one of the 70 million acres on which corn was grown in 2006 was used for ethanol, the amount produced would displace only 12 percent of the U.S. gasoline market. Moreover, the ‘new’ (non-fossil) energy gained would be very small — just 2.4 percent of the market. Car tune-ups and proper tire air pressure would save more energy.”
Car tune-ups. Wow. Here’s the big-picture conclusion from Cutler Cleveland’s article:
“The debate about ‘peak oil’ aside, there are relatively abundant remaining supplies of fossil fuels. Their quality is declining, but not yet to the extent that increasing scarcity will help trigger a major energy transition like wood scarcity did in the 19th century. The costs of wind, solar and biomass have declined due to steady technical advances, but in key areas of energy quality—density, net energy, intermittency, flexibility, and so on—they remain inferior to conventional fuels. Thus, alternative energy sources are not likely to supplant fossil fuels in the short term without substantial and concerted policy intervention. The need to restrain carbon emissions may provide the political and social pressure to accelerate the transition to wind, biomass and solar, as this is one area where they clearly trump fossil fuels. Electricity from wind and solar sources may face competition from nuclear power, the sole established low-carbon power source with significant potential for expansion. If concerns about climate change drive a transition to renewable sources, it will be the first time in human history that energetic imperatives, especially the the economic advantages of higher-quality fuels, were not the principal impetus.”
The figure shows composition of U.S. energy use. (Source: Cutler Cleveland).