Entirely renewable California?

If a group of Stanford University researchers had their way, California would leave the age of fossil and nuclear fuels behind in just a few decades.

Led by engineering professor Mark Jacobson, the group outlined a $1.1 trillion (818 billion euro) plan this week to revamp the state's energy landscape. The scenario, published in a report, would see 80 to 85 percent of California's energy needs met by wind, hydroelectric and solar power by 2030, and 100 percent by 2050.

The study also put a concrete number on the state's energy needs, estimating that 603 gigawatts (GW) of new power generation would be required for a system that relies 100 percent on renewable energy.

"If implemented, the plan would eliminate air pollution mortality and global warming emissions from California, stabilize prices and create jobs - there is little downside," Jacobson said.

Economically feasible?

The researchers estimated that implementing the transition scenario would create roughly 220,000 more jobs in California than it would destroy, particularly in the fossil fuel and nuclear industries.

They also maintained cleaner air would mean 12,500 fewer premature deaths each year, while saving more than $100 billion in annual healthcare costs.

A transition to renewable energy would also relieve state coffers because there would be less coastal erosion and damage from extreme weather. That is, if other jurisdictions around the world follow suit in time to avoid major climate disruption.

"I think the most interesting finding is that the plan will reduce social costs related to air pollution and climate change by about $150 billion per year in 2050, and these savings will pay for all new energy generation in only seven years," said the study's co-author, Mark Delucchi.

The report said that building an economy powered by renewable energy would require higher up-front capital investments than those for fossil-fuelled infrastructure. But in the medium and long run, the absence of any fuel costs associated with renewable energy means that energy prices would be more stable.

Existing technology

The Stanford researchers' calculations showed that a future fully powered by renewable energy in California could be achieved using a mix of wind, water and solar energy and various capture, storage and transmission systems.

By 2050, the plan foresees a 100 percent clean-energy infrastructure that is composed of some 25,000 5-megawatt onshore wind turbines, 1,200 100-megawatt concentrated solar power (CSP) plants, 15 million 5-kilowat residential rooftop photovoltaic systems, 72 100-megawatt geothermal plants, 5,000 ¾-megawatt wave energy capture devices, and 3,400 1-megawatt tidal turbines.

"The technologies needed for a quick transition to an across-the-board, renewable-based statewide energy system are available today," said Anthony Ingraffea, another of the study's co-authors who is also an engineering professor at Cornell University in New York state.

Currently, most of California's energy comes from oil, natural gas, nuclear and small amounts of coal. Under the Stanford research group's scenario, 56 percent of the state's energy would come from solar, 35 percent from wind, and the remainder from a combination of hydroelectric, geothermal, tidal and wave energy.

All vehicles would run on battery-electric power or hydrogen fuel cells.

Home heating and air-conditioning would be provided using electricity-powered air, ground source heat pumps, geothermal heat, heat exchangers, and backup electric resistance heaters, wholly replacing natural gas and oil. The same would go for heating water.

High temperatures for industrial processes would be created using electrical heating equipment and hydrogen combustion.

In contrast, using a technology scenario different from the one by the Stanford researchers, some German researchers envision a "power-to-gas" system in which methane gas that is produced from the electrolysis of water and carbon dioxide would be used to store renewable energy collected from wind turbines and solar cells whenever there is an excess of immediate electricity demand.

However, in both California and Europe, there is still a large gap between low-carbon energy technology potential and the policy decisions that would be necessary to achieve a rapid transition to low-carbon energy.

A version of the Stanford study has already been released for New York state and the researchers are preparing similar plans for the 48 other US states.