The Renewable Energy Transition:
Can It Really Happen?
It’s not too late to stabilize climate change, but doing
so requires decisive leadership now.
B Y D O N A L D W. A I T K E N , P H . D .
One can make a relatively straightforward case for a global transition to renewable energy resources; we need look no further than Joel Stronberg’s “View from Washington” column on the dwindling oil supply (see p. 12). We see evidence of a movement to this transition most notably in Germany and Japan, but the entire European Union (EU) is also on a path of meeting aggressive targets for the deployment of renewable energy technologies. The EU has wisely supported this effort by making these targets mandatory as a whole for the Union, but proportionately adjusted to the realities and economic status of the various member states. Some U.S. cities and states are also making up for a lack of leadership in Washington by adopting ambitious renewable energy goals. But can these goals be sustainable in the future under the constraints of market realities and governmental policies?
The answer is yes, but with the first caveat that if the renewable energy transition is to succeed, then markets, governmental policies and energy infrastructure are going to have to be adapted to the special needs and characteristics of the renewable energy technologies and their applications. The second caveat is that significant reductions in energy “intensity” (the amount of energy expenditure required per unit of gross domestic product in a society) are essential if renewable energy resources are to make large-percentage inroads into total global primary energy use.
In this article, I examine the leading environmental challenge that can be remediated by the renewable energy resources — climate change. Then I present growing numerical evidence of the recent gains in renewable energy developments and applications resulting from policies and markets in place, and projections into the future by the renewable energy industries. As I explain, all of this suggests that the world can indeed get onto, and stay on, a path that will generate the great transition to sustainable energy resources and technologies.
Carbon Reduction is Greatest Challenge
With Russia formally agreeing to sign on to the “Kyoto Accord” (the Kyoto Conference of Parties to the Climate Convention in 1997, COP-3), the world has taken the first truly international step toward curbing carbon dioxide emissions in order to reduce the environmental and ecological stresses likely to lead to huge negative consequences for almost all nations and peoples. Unfortunately, it is a small step. It will slow the growth of carbon dioxide in the world’s atmosphere, but neither stop that growth nor stabilize the atmospheric burden of carbon dioxide (CO2) at any level. Indeed, the evidence of the last two years is that the rate of increase of carbon dioxide in the Earth’s atmosphere may be accelerating.
Even Small Steps
Have Great
Potential
Solar domestic water heating has great potential for reducing carbon dioxide, a major contributor to global climate change. According to research at the University of Wisconsin's Solar Energy Laboratory, a typical household electric water heater annually produces about as much carbon dioxide as does the typical family's car. Using solar to displace the family's electric water heating would provide environmental benefit equivalent to doubling the fuel efficiency of the family car.
For more information on the study, access sel.me.wisc.edu.
If there is to be any hope of limiting the Earth’s temperature rise to 2 C (3.6 F), the “safest” maximum level according to scientific consensus, international governments must take much more serious steps. In particular, the atmospheric burden of carbon dioxide will probably have to be limited to the range of 550 parts per million (ppm) to 750 ppm at most. A scientific argument can also be made that the present level of CO2 may already be leading to shifts in climate that harm human food production and health worldwide and increase damage costs from major climate events (e.g., hurricanes), and that no more CO2 should be added to that atmospheric burden. Nevertheless, in view of present world energy systems’ resistance to change, we will probably have to accept that the 550- to 750-ppm limit to atmospheric CO2 concentration is likely our best feasible hope.
In their work at the National Renewable Energy Laboratory, Stanley Bull, Ph.D., and Lynn Billman have demonstrated that in order to stabilize atmospheric concentrations of carbon dioxide in the 550- to 770-ppm range, assuming a modest 1 percent increase in world energy demand per year, the world will have to adopt renewable energy sources for total primary energy (all energy uses) at a pace roughly equal to 10 percent by 2010, 20 percent by 2020 and 50 percent by 2050, or what we call the 10/20/50 percent path in the rest of this article. They show, in Figure 1, the challenge in meeting the rate of growth of “carbon-neutral” fuels in general and the renewable resources in particular, if an atmospheric limit of 550 ppm is to be achieved by 2100. Figure 2 illustrates the growth challenge for the renewable energy resources to 2030 under the 10/20/50 percent scenario, specifically delineating the assumed growth rates of each technology in this model. (Figures 1-4 are adapted from “The Climate Stabilization Challenge: Can Renewable Energy Sources Meet the Target?” by D. Aitken, L. Billman and S. Bull, Renewable Energy World, Vol. 7, No. 6, pp. 56-69, November/December 2004.)
Can Renewable Energy Meet this Challenge?
A number of authors have noted that the world’s societies could be run on a very small fraction of the total renewable energy capacity of the Earth, and therefore that a total renewable energy transition must be reasonable and hence only a matter of policy to accomplish. But other authors who have tried to quantify the explicit and practical requirement for renewable energy resources to meet this challenge have drawn more skeptical conclusions. Their work suggests that the inexorable growth of demand for primary energy, year after year, would ultimately swamp the maximum presumed potential of renewables for realistic development. Only those studies that include simultaneous aggressive energy-efficiency assumptions or policies avoid this apparent limit.
In spite of the fact that some “experts” were writing that it was a futile attempt, a number of governments began to adopt targets for renewable energy adoption (called renewable portfolio standards in the United States) that are remarkably close to the 10/20/50 percent path. For example, the EU target is for 12 percent EU-wide total energy from renewables by 2010, along with a 22.1 percent penetration by renewables into the electricity sector by that same year. Some countries, as well as 18 U.S. states, have adopted ambitious renewable portfolio standards for up to 20 percent of electricity from renewables by 2020 or earlier. Evidence suggests that RPS goals are setting achievable targets for the effective development of the renewable energy resource base. Still, these are not yet adopted worldwide goals. Present U.S. national policy stands in stark contrast to these realities.
Technological Potential Supports Goals
To complement those studies on renewable energy’s potential to fill the carbon-neutral energy supply gap, I examined renewable energy technologies in application or near-application today, to look at the rate of growth of those that are commercially available. As part of that effort, I invited the industries themselves to project the potential level of worldwide application of those technologies into the future, say the year 2020 or 2050. This assessment was one of the four objectives of “Transitioning to a Renewable Energy Future,” the white paper written by this author for the International Solar Energy Society (download the ISES paper at whitepaper.ises.org). The other three white paper tasks were to present a convincing argument for governments to promote the application of renewable energy policies with all possible urgency; to give confidence to governments that they could do so realistically, economically and in timely fashion; and to provide a discussion of proven and potential policies that would support this goal.
The ISES white paper examines each of the major renewable energy technologies in turn. In each case, experts in that particular field were polled for an estimate of the potential rate of growth of that technology or for the projected number of accumulated installations by 2020 or 2050. These projections are remarkably encouraging. Excerpted examples from the white paper (with world totals updated where possible to the end of 2003) follow:
Bioenergy: Bioenergy resources produced 11 percent of year 2000 world primary energy use of 417 exajoules (EJ), equal to 395 quads). Yet that amount was only about 18 percent of potential capacity (250 EJ), and the total could reach 450 EJ (426 quads) by 2050, or more than total world primary energy use today.
Geothermal energy: By 2010, a 10 percent rate of growth in the use of geothermal sources could yield a capability to produce 20,100 megawatts (MW) of electricity and 39,250 MW of useful thermal capacity. Twenty-seven countries utilize geothermal power. Another 25 could come online by 2020 or so. Ultimately, 39 countries could be 100 percent powered by geothermal energy, four more at 50 percent, five more at 20 percent and eight more countries at 10 percent.
Wind power: At the end of 2003, total installed world wind capacity was 40,301 MW, an installation rate that had been growing during the previous five years at 26.3 percent per year (see Figure 3). Germany now generates 6.8 percent of its electricity from wind power, Denmark obtains over 20 percent from wind and the Schleswig-Holstein area of Germany generates about 30 percent from wind. A goal of 12 percent of the world’s electricity demand from wind by 2020 appears to be within reach. So is a goal of 20 percent of Europe’s electricity demand by 2020. The European Wind Energy Association recently increased their 2010 goal from 50,000 MW to 75,000 MW of installed wind capacity in Europe. This development pace is consistent with the historical pace of development of hydroelectric and nuclear energy.
Evidence suggests that RPS goals are setting achievable targets for the effective development of the renewable energy resource base. Present U.S. national policy stands in stark contrast to these realities.
Direct use of solar energy: The most visible, most versatile of the technologies that make direct use of solar radiation is photovoltaic (PV) electricity generation. The worldwide PV production in 2003 of 744 MW of capacity continued a PV production growth rate of 38.5 percent since the start of this decade (see Figure 4). All signs suggest this rate may increase, as major large-scale expansions of production capability are underway worldwide, especially in Japan and Germany. If PV production continues to grow at about 30 percent per year, 260,000 MW of PV could be installed by 2020.
But there’s more to solar energy applications than just PV. For example, renewed interest in the worldwide solar thermal electric industry appears to support a goal of 100,000 MW of installed concentrating solar power technology by 2025. And well over 100 million square meters of solar thermal water heaters are installed worldwide, a figure poised to increase dramatically, especially in China.
Buildings: Energy-efficient buildings designed with integrated passive and active solar energy features, daylighting, natural cooling and PV (building-integrated PV, or BIPV) have just as much long-term potential as any of the renewable energy supply methods to contribute to reducing carbon dioxide emissions. Buildings account for over one-third of U.S. greenhouse gas emissions. We can simply and economically save 30 percent of the energy in existing buildings and 50 percent in new buildings, and head, as we are, toward zero-net-energy residential and small commercial buildings. When all buildings combine these attractive natural energy features with home fuel cells powered by hydrogen produced from renewable energy sources, then they will come close to zero-total-energy buildings.
Advance with Confidence
Based on analysis of the data and conclusions from the ISES white paper, it is reasonable to target an 18.5 percent penetration of renewable energy into the global energy mix by 2020 and 50 percent by 2050 — goals practically identical to the 10/20/50 percent target to stabilize carbon in the Earth’s atmosphere. In light of the present growth rates of the renewable energy industries and projections of their capability to achieve aggressive growth targets in the future, we can set long-term goals for a global renewable energy transition and have confidence that we can accomplish them. In doing so, we will stabilize the atmospheric burden of carbon dioxide, hence stabilizing the Earth’s temperature.
The more we can improve energy efficiency and reduce energy intensity, the more achievable will be our task. What we now need most is supportive policies and dynamic, informed leadership — city by city, state by state and nation by nation.
Donald W. Aitken, Ph.D., has been senior staff scientist for renewable energy with the Union of Concerned Scientists, as well as executive director of the U.S. Department of Energy’s Western Regional Solar Energy Center. He now consults on renewable energy policy and architecture. He has twice served as chair of the American Solar Energy Society’s board, and chaired two of ASES’s national solar energy conferences. He has also been secretary and vice president of the International Solar Energy Society. He is an ASES life member, fellow and recipient of the Charles Greeley Abbott Award. He can be reached at donaldaitken@earthlink.net, or visit his website at www.donaldaitkenassociates.com.
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