Wind, Water, and Solar Power for the World

We don’t need nuclear power, coal, or biofuels. We can get 100 percent of our energy from wind, water, and solar (WWS) power. And we can do it today—efficiently, reliably, safely, sustainably, and economically.

We can get to this WWS world by simply building a lot of new systems for the production, transmission, and use of energy. One scenario that Stanford engineering professor Mark Jacobson and I developed, projecting to 2030, includes:

• 3.8 million wind turbines, 5 megawatts each, supplying 50 percent of the projected total global power demand
• 49 000 solar thermal power plants, 300 MW each, supplying 20 percent
• 40 000 solar photovoltaic (PV) power plants supplying 14 percent
• 1.7 billion rooftop PV systems, 3 kilowatts each, supplying 6 percent
• 5350 geothermal power plants, 100 MW each, supplying 4 percent
• 900 hydroelectric power plants, 1300 MW each, of which 70 percent are already in place, supplying 4 percent
• 720 000 ocean-wave devices, 0.75 MW each, supplying 1 percent
• 490 000 tidal turbines, 1 MW each, supplying 1 percent.

We also need to greatly expand the transmission infrastructure in order to create the large supergrids that will span many regions and often several countries and even continents. And we need to expand production of battery-electric and hydrogen fuel cell vehicles, ships that run on hydrogen fuel cell and battery combinations, liquefied hydrogen aircraft, air- and ground-source heat pumps, electric resistance heating, and hydrogen for high-temperature processes.

To make a WWS world work, we also need to reduce demand. Reducing demand by improving the efficiency of devices that use power, or substituting low-energy activities and technologies for high-energy ones—for example, telecommuting instead of driving—directly reduces the pressure to produce energy.

Because a massive deployment of WWS technologies requires an upgraded and expanded transmission grid and the smart integration of the grid with battery-electric vehicles and hydrogen fuel cell vehicles—using both types of these vehicles for distributed electricity storage—governments need to carefully fund, plan, and manage a long-term, large-scale restructuring of the electricity transmission and distribution system. In much of the world, we’ll need international cooperation in planning and building supergrids that span across multiple countries, because many individual countries just aren’t big enough to permit enough geographic dispersion of generators to mitigate local variability in wind and solar intensity. The Desertec project proposes a supergrid to link Europe and North Africa, and 10 northern European countries are beginning to plan a North Sea supergrid for offshore wind power. Africa, Asia and Southeast Asia, Australia/Tasmania, China, the Middle East, North America, South America, and Russia will need supergrids as well.

Although this is an enormous undertaking, it does not need to be done overnight, and there are plenty of examples in recent history of successful large-scale infrastructure, industrial, and engineering projects.

During World War II, the United States transformed motor vehicle production facilities to produce over 300 000 aircraft, and the rest of the world was able to produce over 500 000 aircraft. In 1956, the United States began work on the Interstate Highway System, which now extends for about 47 000 miles (around 75 000 kilometers) and is considered one of the largest public works project in history. The iconic Apollo program, widely considered one of the greatest engineering and technological accomplishments ever, put a man on the moon in less than 10 years. Although these projects obviously differ in important economic, political, and technical ways from the project we discuss, they do suggest that the large scale of a complete transformation of the energy system is not in itself an insurmountable barrier.

Efficient and Reliable: A 100-percent wind, water, and solar power system can deliver all of the world’s energy needs efficiently. Jacobson and I estimated the potential supply and compared those estimates with projections of energy demand made by the U.S. Energy Information Administration. We calculated that the amount of wind power and solar power available in locations that can likely be developed around the world, excluding Antarctica, exceeds the projected world demand for power in 2030 for all purposes by more than an order of magnitude. On top of that, Jacobson and I estimate that converting to a WWS energy infrastructure can actually reduce world power demand by more than 30 percent (based on projected energy consumption in the year 2030), primarily because electric motors have less energy loss than do combustion devices.

But, the naysayers will retort, what about reliability? Can these resources deliver power reliably? Indeed they can. While it is true that no single wind-power farm or solar-photovoltaic installation can reliably match total power demand in a region, it is also true—and often not recognized—that no individual coal or nuclear plant can either.

Indeed, any electricity system must be able to respond to changes in demand over seconds, minutes, hours, seasons, and years, and must be able to accommodate unanticipated changes in the availability of generation due to outages, for example. Today’s mainly fossil-fuel electricity system responds with backup systems, power plants brought online only during periods of peak demand, and spinning reserves—that is, the extra generating capacity available by increasing the power output from already operating generators.

A WWS electricity system handles changes in demand far differently. To start with, WWS technologies generally suffer less downtime than do current electric power technologies. However, they face inherently more variability; the maximum solar or wind power available at a single location varies over minutes, hours, and days, and this variation generally does not match the demand pattern over the same timescales.

Dealing with this short-term variability can be challenging, but it is doable. Including hydropower—which is relatively easy to turn on and off as needed—in the generating package helps, as does managing demand (for example, by shifting flexible loads to times when more generating capacity is available) and forecasting weather more precisely; these have little or no additional cost. A WWS system also needs to interconnect resources over wide regions, creating a supergrid that can span continents. And it will probably need to have decentralized energy storage in residences, using batteries in electric vehicles. Finally, WWS generation capacity should significantly exceed the maximum amount of demand in order to minimize the times when available WWS power runs short. Most of the time, this excess generation capacity could be used to provide power to produce hydrogen for end uses not well served by direct electric power, such as some kinds of marine, rail, off-road, and heavy-duty truck transport.

Economical and Safe: WWS power is economical. The private cost of generating electricity from onshore wind power is already less than the private cost of conventional fossil-fuel generation and is likely to be even lower in the future—less than US $0.05 per kilowatt-hour including some transmission costs, according to our calculations (this includes the fully amortized cost of capital and land).

By 2030, Jacobson and I estimate that the social cost (which includes the private or consumer cost, plus additional external costs: for example, the value of health damage from air pollution, which society bears but the individual consumer does not) of generating electricity from any WWS power source is likely to be less than the social cost of conventional fossil-fuel generation, and that includes the amortized cost of land acquisition, capital, and construction.

The cost of transmitting and managing—as opposed to generating—electricity will probably be somewhat higher in a wind, water, and solar system than in a conventional electricity system. In an intelligently designed and operated WWS system, the extra infrastructure and energy cost of sending electricity long distances over a supergrid and of vehicle-to-grid storage, along with demand management, hydropower, and weather forecasting, will probably add up to an average of $0.02/kWh generated. By comparison, conventional long-distance transmissions in the United States today cost about $0.01/kWh.

We don’t have to worry too much about the costs of the basic construction materials, because the supply of steel and concrete used in a wind, water, or solar power system is virtually unlimited—these materials are abundant and recyclable. The rarer materials, including neodymium (in electric motors and generators), platinum (in fuel cells), lithium (in batteries), and silver, tellurium, indium, and germanium (in different kinds of photovoltaic systems), are harder to get, more expensive, and limited in supply, so they will have to be reduced, recycled, or eventually replaced with less-scarce materials unless new sources emerge. However, the cost of reducing, recycling, or replacing neodymium, platinum, or the materials for photovoltaics is not likely to noticeably affect the economics of WWS systems.

WWS power is safe and sustainable. Wind, water, and solar power have essentially zero emissions of greenhouse gases and air pollutants over the whole life cycle of their systems. They do little to hurt wildlife, water quality, and terrestrial ecosystems; they are not catastrophic disasters waiting to happen in terms of waste disposal, terrorism, war, human error, or natural disasters; and they are based on natural resources and materials that are indefinitely renewable or recyclable.

Nuclear power, coal, and biofuels are anything but safe and sustainable. Biofuels and so-called clean coal systems still cause air pollution, water pollution, habitat destruction, and climate change; biofuels also contribute to higher food prices. Nuclear power already has had two catastrophic accidents, and even though the industry has improved the safety and performance of new reactors and has proposed even newer (but largely untested) ”inherently safe” reactor designs, the industry can’t guarantee that the reactors will be designed, built, and operated correctly. And catastrophic scenarios involving terrorist attacks are still conceivable. Furthermore, any nuclear-fuel cycle can contribute, even if very indirectly, to the proliferation of nuclear weapons.

With a wind-water-solar system, the risk of any such catastrophe is zero.

Finally, though critics envision sprawling solar installations or rows of wind turbines crowding out farms, a WWS power system won’t take a lot of land. The equivalent footprint area on the ground for enough WWS devices needed to power the world is about 0.74 percent of the global land area, and the spacing needed around wind turbines adds about 1.16 percent of global land area. However, the land used for such spacing is available for other purposes, including agriculture, ranching, and open space, and so is not ”used” in the way that land for biomass production or coal mining is used. Moreover, if we assume that one-half of wind devices will be placed over water, and recognize that all wave and tidal devices will be in water, that 70 percent of hydroelectric is already developed, and that rooftop solar power doesn’t require new land, then the additional footprint and spacing of devices on land will be only about 0.41 percent and 0.59 percent of the world land area, respectively.

The more extensive the supergrid, the less local fluctuations in power generation are a problem. However, more energy is lost in transmission, and infrastructure costs climb. Figuring out how to balance these factors in order to design the optimal grid and determine the best location of generation facilities will take additional research.

Getting in our way today is the fact that energy markets, institutions, and government policies support the production and use of fossil fuels. The world needs new policies to ensure that WWS systems develop quickly and broadly. The United States and other countries have adopted or discussed policies that stimulate production of renewable energy, including feed-in tariffs, which are subsidies to cover the difference between generation costs and wholesale electricity prices, investment subsidies, quotas requiring that a certain amount of generation be WWS power, and carbon and other environmental-damage taxes.

The obstacles to this transformation are primarily social and political, not technical or economic. If we continue to make decisions based on interest-group politics and muddle through with nuclear power, ”clean” coal, offshore oil production, and biofuels, then our energy system will continue to threaten the health and well-being of everyone on the planet. But with sensible broad-based policies and social changes, it indeed is possible to convert 25 percent of the current energy system to WWS in 10 to 15 years, 85 percent in 20 to 30 years, and 100 percent by 2050.