The Feasibility of Powering the World with Wind, Water, and Solar Power

Jacobson and Delucchi (2011) address the pressing problem of climate change by proposing to produce all new power worldwide from wind, water and sunlight (WWS) by 2030 and to replace pre-existing energy sources with WWS by 2050. In this Part I of their two-part study, they assess the feasibility of doing so by calculating global end-use energy demand in a WWS world and comparing it to that of a world powered by fossil fuels as projected by the Energy Information Administration. They also examined worldwide capacity for WWS energy production and the limitations of materials used for the construction of WWS infrastructure. They estimated that about 3,800,000 5 MW wind turbines, 49,000 300 MW concentrated solar plants, 40,000 300 MW solar PV power plants, 1.7 billion 3kW rooftop PV systems, 5350 100 MW geothermal power plants, 270 new 1300 MW hydroelectric power plants, 720000 0.75 MW wave devices, and 490,000 1 MW tidal turbines can meet global energy demand in 2030 with a 1.0% increase in land use, and found that barriers are primarily social and political rather than technical or economic. —Lucinda Block
Jacobson, M. Z., Delucchi, M. A., 2011. Providing all global energy with wind, water and solar power, Part I: Technologies, energy resources, quantities and areas of infrastructure, and materials. Energy Policy 39, 1154–1169.

          Mark Z. Jacobson and Mark A. Delucchi found a decrease in global end-use energy demand in 2030 compared to the Energy Information Administration’s projections, which predicted demand will increase from 12.5 trillion watts (TW) to 17 TW in the year 2030 given an energy supply similar to today’s, constituted by 35% oil, 27% coal, 23% natural gas, 6% nuclear, and the rest from biomass, sunlight, wind, and geothermal. In the WWS scenario proposed by the authors, all end uses that can be electrified would use WWS power directly, and end uses that require combustion (like industrial processes) would use electrolytic hydrogen produced with WWS. Heating and cooling processes would employ electric heat pumps, and batteries, fuel cells, or a hybrid of the two would replace liquid fuels in non-aviation transportation. Aviation would use liquefied hydrogen to then be combusted. Jacobson and Delucchi calculated that an all WWS world would require approximately 30% less end-use power than the EIA projections for our current heavily fossil fuel-powered world. This is due to some increases in efficiency, for example, in the case of using electricity directly for heating or electric motors, as well as modest conservation measures (increases in efficiency through better insulation, more efficient lighting and heating, passive heating and cooling in buildings, and large-scale planning to reduce energy demand) and subtracting the energy requirements of petroleum refining.
          The authors investigated the availability of renewable resources that could potentially be exploited for power production in order to evaluate whether these could meet global energy demands in 2030. They found that wind and solar power in likely-developable locations could each provide enough power by themselves to meet global demands, with wind power potentially providing 3–5 times global demand and solar power potentially providing 15–20 times global demand. Concentrated solar power (CSP) could also meet global demand and has the ability to store energy for night usage, but it requires more land than PV and can use about 8 gal/kWh of water in a water-cooled plant, compared to almost no water for PV or wind. At the same time, air-cooled plants could be a viable alternative to water-cooled plants in areas of scarce water resources. Although other WWS technologies like wave power, geothermal and hydropower have much less energy potential (between 0.02 TW for tidal power and 1.6 TW for hydroelectric), Jacobson and Delucchi say they will be more abundant and economical than wind or solar in many locations and that since wind and solar power are variable, these other technologies could help stabilize electric power supply.
          In the WWS power generation scenario created by the authors, 50% of power will come from wind, 20% from CSP plants, 14% from solar PV plants, 6% from rooftop PV, 4% each from hydrothermal and geothermal plants, and 1% each from wave and tidal energy. Calculating combined footprint and spacing areas required for these technologies led Jacobson and Delucchi to the conclusion that their WWS scheme will require an additional 1.0% of global land area.
          The authors found that resource availability of bulk materials like steel and concrete is unlikely to constrain the development of WWS power systems. Some of the rarer materials used for WWS technologies include neodymium for electric motors and generators, platinum for fuel cells, and lithium in batteries, however, could present problems. Wind power is currently limited by neodymium requirements for permanent magnets in generators. Solar power is limited by silver reserves, although research suggests that opportunities exist to produce PV power with low cost and commonly available materials. Current neodymium requirements for electric motors similarly imply a need to develop alternative motors that do not use rare-earth elements. Global reserves of lithium are limited and in order to satisfy requirements for electric vehicles and other uses, a global recycling program is needed. Similarly, a platinum recycling program would be required in a scenario of producing 20 million hydrogen fuel cell vehicles per year, which could easily deplete platinum reserves in less than 100 years. Although Jacobson and Deluccchi expect the cost of recycling or replacing neodymium or platinum to be negligible, this is dependent on a drastic improvement in worldwide recycling infrastructure and in many cases finding viable alternatives to existing technologies.
          Jacobson and Delucchi find a world powered entirely by wind, water and solar power to be feasible, with a marked decrease in global end-use energy demand, a 1.0% increase in land use, and some need for technological substitutions and/or recycling programs for materials used in renewable energy construction. The authors recommend replacing all new energy with WWS by 2030 and all existing energy with WWS by 2050. The study does not provide a life-cycle analysis of implementation of the proposed WWS technologies. This would potentially be useful, as it would require a measured analysis of all environmental impacts, including impacts of natural resource extraction for new infrastructure. Interestingly, Jacobson and Delucchi neglect to consider factors like the CO2 emissions from the chemical process of making cement, which would be required on a large scale for the production of wind turbines in their scenario.
The authors have published Part II to this study, in which they consider reliability, system and transmission costs, and policies needed to implement worldwide WWS infrastructure. 

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