We recently examined how Australia can meet 100% of its electricity needs from renewable sources by 2020, and the Ecofys plan to meet nearly 100% of global energy needs with renewable sources by 2050. Here we will look at another similar, but perhaps even more ambitious plan.
Stanford's Mark Jacobson and UC Davis' Mark Delucchi (J&D) recently published a study in the journal Energy Policy examining the possibility of meeting all global energy needs with wind, water, and solar (WWS) power. They find that it would be plausible to produce all new energy from WWS in 2030, and replace all pre-existing energy with WWS by 2050.
In Part I of their study, J&D examine the technologies, energy resources, infrastructure, and materials necessary to provide all energy from WWS sources. They use the U.S. Department of Energy's Energy Information Administration (EIA) estimates of global power consumption. The EIA projects that by 2030, global power demand will increase to 17 trillion watts from the current consumption of 12.5 trillion watts, or an increase of about 36%. This is the global energy demand that the J&D plan must meet by 2030. J&D describe how they chose WWS technologies in their study:
"we consider only options that have been demonstrated in at least pilot projects and that can be scaled up as part of a global energy system without further major technology development. We avoid options that require substantial further technological development and that will not be ready to begin the scale-up process for several decades."
"In order to ensure that our energy system remains clean even with large increases in population and economic activity in the long run, we consider only those technologies that have essentially zero emissions of greenhouse gases and air pollutants per unit of output over the whole ‘‘lifecycle’’ of the system. Similarly, we consider only those technologies that have low impacts on wildlife, water pollution, and land, do not have significant waste-disposal or terrorism risks associated with them, and are based on primary resources that are indefinitely renewable or recyclable."
J&D note that these criteria exclude nuclear power from their study for two primary reasons. Firstly, expansion of nuclear power to additional countries also increases the number of nations which are able to obtain enriched uranium for potential nuclear weapons. Secondly, nuclear energy results in 9–25 times more carbon emissions than wind energy, due to the mining, refinement, and transportation of nuclear fuel; the much longer time involved in building a nuclear facility (approximately 4 times longer than WWS facilities); and larger building footprint. Additionally, the long planning-to-operation times for new nuclear power plants (11 to 19 years) make it an infeasible technology to rely on for a significant amount of new energy production by 2030.
For auto transportation, J&D propose a combination of battery electric vehicles, hydrogen fuel cell cars, and battery-hydrogen hybrids. For ships, they propose the use of hybrid hydrogen fuel cell-battery systems, and for aircraft, liquefied hydrogen combustion. The hydrogen fuel is produced through electrolysis using WWS energy. J&D note that electric cars are 5 times more efficient than internal combustion engine vehicles, so less energy is needed to fuel them.
For building water and air heating and cooling, J&D propose using air-and ground-source heat-pump water and air heaters and electric resistance water and air heaters. These technologies are in existence today.
In terms of electricity generation, J&D find that the available supply could more than meet the global demand.
"Wind in developable locations can power the world about 3–5 times over and solar, about 15–20 times over."
J&D find that water will be a relatively small contribution to overall energy production, since wave power is only practical near coastlines, and most areas suitable for hydroelectric power generation are already in use. Overall in 2030, J&D envision 50% of global power demand will be met by wind, 20% by concentrated solar thermal power, 14% by solar photovoltaic (PV) power plants, 6% by solar PV on rooftops, 4% each by geothermal and hydroelectric, and 1% each from waves and tides. This will require a major construction effort – nearly 4 million 5-megawatt wind turbines, and nearly 90,000 300-megawatt solar PV plus thermal power plants, for example. J&D note that we have all of the necessary resources and materials to meet these construction goals.
J&D also note that by transitioning to more efficient technologies (for example, battery electric vehicles over the internal combustion engine, electric heat pumps for homes, and solar thermal energy with storage to provide baseload power rather than fossil fuels and nuclear) we can actually reduce global power production by 30% compared to business-as-usual. Even though global energy demand is the same in either case, effectively we will need to produce less energy because less is wasted through inefficient fossil fuel burning.
In Part II of the study, J&D examine the variability of WWS energy, and the costs of their proposal. On the positive side, J&D note that WWS technologies suffer less downtime than traditional power sources. For example, the average US coal power plant was down 12.5% of the time for maintenance between 2000 and 2004, while wind turbines have a downtime of 0 to 5%, and commercial solar in the ballpark of 1%. The downside is that sunlight and windspeed aren't very reliable. J&D offer 7 suggestions for solving this problem:
J&D envision that a combination of most of these strategies will be used to ensure that there is always enough energy production to meet local and global demands.
As for costs, J&D project that when accounting for the costs associated with air pollution and climate change, all the WWS technologies they consider will be cheaper than conventional energy sources (including coal) by 2020 or 2030, and in fact onshore wind is already cheaper. U.S. Energy Secretary Steven Chu recently agreed with this assessment.
To accomplish this major conversion to WWS energy, J&D note that it will require that governments implement policies to mobilize infrastructure changes more rapidly than would occur if development were left mainly to the free market, but that we have all the manpower, materials, technology, and resources necessary to make it happen.
"With sensible broad-based policies and social changes, it may be possible to convert 25% of the current energy system to WWS in 10–15 years and 85% in 20–30 years, and 100% by 2050"
As with the Ecofys plan, we are given a roadmap to transition away from fossil fuels and towards renewables in a timely fashion. Again the question remains whether we have the will to make it happen.
Posted by dana1981 on Sunday, 27 March, 2011
 |
The Skeptical Science website by Skeptical Science is licensed under a Creative Commons Attribution 3.0 Unported License. |