The world can be powered by renewable energy in 20-40 years - usingtechnology available right now, says Stanford researcher Mark Jacobson.
In a time of catastrophe oil spills, nuclear meltdowns, and waterpoisoned from natural gas fracking, citizens around the world are stillbeing told we must keep using these technologies to fuel our demand forenergy.
In the past, any one of these disasters would have been enough to shutthem down and pass laws to move toward clean alternatives, but not these days. We’re already giving out new permits for deep water offshoredrilling and even as Japan reels under a nuclear meltdown, we make plans for new nukes.
Contrary to what the fossil fuel and nuclear lobbieswould have the world believe – 100% renewable energy is within our reach – all we need is the public will, which unfortunately is in shortsupply today.
"Based on our findings, there are no technological or economicbarriers to converting the entire world to clean, renewable energysources," says Mark Jacobson, a professor of civil and environmentalengineering at Stanford University. "It is a question of whether we have the societal and political will."
He and co-author Mark Delucchi, from the University of California-Davis, published their paper in Energy Policy – they assess the costs, technology and material requirements to convert our society to renewable energy.
According to their plan, wind and solar can provide 90% of energy demand through electricity. Geothermal and hydroelectric sources would eachcontribute about 4% (70% of hydro is in place now), and wave/tidal would supply the remaining 2%.
Vehicles, ships and trains would be powered by electricity and hydrogenfuel cells. Aircraft would run on liquid hydrogen. Homes would be cooled and warmed with electric heaters and water would be preheated by thesun. Commercial processes would be powered by electricity and hydrogen.
Because all combustion processes would be converted to electricity,including hydrogen production, the plan would result in a 30% reductionin world energy demand. Electricity is much more efficient thancombustion.
They accomplish this feat without even considering reduced energy demand through energy efficient buildings and vehicles.
How do they do this cost effectively? By reducing energy demand and byfactoring in the savings that would accrue through lower health carecosts associated with air pollution from fossil fuels.
"When you actually account for all the costs to society – includingmedical costs – of the current fuel structure, the costs of our plan are relatively similar to what we have today," Jacobson says.
A major obstacle with widespread use of wind and solar energy isits variability – they don’t provide "base load" power, the minimumamount of energy that must be available to customers at any given hourof the day.
Jacobson says that can be overcome by packing them into a bundle. "Ifyou combine them as one commodity and use hydroelectric to fill in gaps, it is a lot easier to match demand," he says.
Since wind often peaks at night and sunlight peaks during the day, theyare complementary. Using hydro to fill in the gaps – as it does now- allows demand to be precisely met by supply in most cases. Otherrenewable sources such as geothermal and tidal power can also be used as supplements.
"One of the most promising methods of insuring that supply matchesdemand is using long-distance transmission to connect widely dispersedsites," says co-author Delucchi. Even if conditions are poor for wind or solar energy generation in one area on a given day, a few hundred miles away the winds could be blowing steadily and the sun shining.
"With a system that is 100 percent wind, water and solar, you can’t usenormal methods for matching supply and demand. You have to have whatpeople call a supergrid, with long-distance transmission and really good management," he said.
Another method of meeting demand could entail building a biggerrenewable energy infrastructure to match peak hourly demand anduse non-peak excess electricity to produce hydrogen for the industrialand transportation sectors.
Using pricing to control peak demands, a tool that is used today, would also help.
Are Their Enough Resources to Build All This?
They also examined whether the earth has enough resources to build out a renewable energy infrastructure. They concluded that even supplies ofrare earths and platinum are sufficient. Recycling could effectivelyextend the supply.
"For solar cells there are different materials, but there are so manychoices that if one becomes short, you can switch," Jacobson said."Major materials for wind energy are concrete and steel and there is noshortage of those."
Jacobson and Delucchi calculated the number of wind turbines needed toimplement their plan, as well as the number of solar plants, rooftopphotovoltaic cells, geothermal, hydroelectric, tidal and wave-energyinstallations.
They found that to power 100% of the world for all purposes from wind,water and solar, about 0.4% of the world’s land would be needed forsolar, about 0.6% for wind. Turbines need to be spaced out to preventinterference between them.
"Most of the land between wind turbines is available for other uses,such as pasture or farming," Jacobson said. "The actual footprintrequired by wind turbines to power half the world’s energy is less thanthe area of Manhattan." If half the wind farms were located offshore, asingle Manhattan would suffice.
Only about 1% of the wind turbines required are in place now, and less than that for solar.
"This really involves a large scale transformation," he said. "It wouldrequire an effort comparable to the Apollo moon project or constructingthe interstate highway system."
"But it is possible, without even having to go to new technologies,"Jacobson said. "We really need to just decide collectively that this is the direction we want to head as a society."
Adapted from article by Louis Bergeron, Stanford University News.