World can run on wind, water and sunlight, scientist says
In a fast-paced presentation, Jacobson outlined the results of an analysis of a variety of fuel sources, their associated environmental costs and how much of those sources would be needed to power the world.
The winners of Jacobson’s analysis, considered the cleanest power sources from a global warming, air pollution and land-use perspective, were wind, concentrated solar, geothermal, tidal, photovoltaic, wave and hydroelectric power.
Wind power, Jacobson said, could meet 50 percent of the world’s energy needs by 2030.
“Here’s one way to power the entire world for all purposes: This is with 50 percent wind, 40 percent solar and 10 percent everything else,” he said.
The energy sources not recommended, according to the analysis, included nuclear, coal — even with carbon capture and storage — natural gas and various biomass sources.
It’s not that some of those sources wouldn’t be an improvement on the current energy mix, Jacobson said, but that other existing energy sources were better.
“If we have a limited amount of money to spend, we want to spend it on the best technologies, not necessarily ones that are mediocre,” he said.
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Even with carbon capture, coal power results in 50 percent more carbon dioxide emissions per kilowatt-hour than wind and is 150 times more polluting of the air.
Nuclear produces nine to 25 times more pollution than wind, and the 10 to 19 years needed to permit and construct a nuclear plan is a big barrier.
Natural gas has 50 to 70 times more CO2 production than wind energy, and hydraulic fracturing leads to degradation of air, water and land, Jacobson said.
Jacobson calculated the total energy needs of the world in 2030 and how much of these alternative fuels would be needed to meet those needs.
The total amount of power needed if the world switched to a renewable mix was 11.5 terawatts by 2030.
This would require 3.8 million 5-megawatt wind turbines (there are currently about 300,000 wind turbines in the world).
Jacobson said that although he had ranked the energy technologies in terms of their ability to solve problems, not by cost, renewables also become more affordable over time.
This is because their fuel source is free, and they have much lower external costs, like pollution, he said. In the United States, premature deaths from air pollution-related causes cost $534 billion annually, or 3.3 percent of gross domestic product, he said.
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He estimated that onshore wind would cost 4 cents or less per kilowatt-hour by 2030, and offshore would cost 7 to 11 cents per kilowatt-hour. Solar photovoltaics should cost 5.5 cents a kilowatt-hour by 2030, he said.
By comparison, conventional sources of energy should cost between 14 and 19 cents per kilowatt-hour by that time, plus the added costs from pollution and other externalities, he said.
Jacobson’s talk came in the middle of a session on whether it would be possible to reduce global carbon dioxide emissions 80 percent by 2050.
Other presenters at the session, while saying they believe such a transition is possible, noted that reports outlining pathways for shifting the globe’s energy mix to renewables are often incomplete, are overly technical and lacking in detail, and omit the transportation sector.
Another problem with the transportation sector, which almost all the presenters agreed needs to switch to more efficient electric vehicles, lies in the transition of the heavy-duty vehicle fleet.
Heavy-duty vehicles require an energy-intensive liquid fuel, and biomass would be unable to meet those needs, said presenter Jeffery Greenblatt, a scientist at Lawrence Berkeley National Laboratory.
Hydrogen fuel cells may be able to meet the needs of the heavy-duty vehicle fleet, but that technology has yet to be proved.
“The technical challenges of hydrogen are still considerable,” Greenblatt said.