State of the Planet

News from the Columbia Climate School

Charting the Course to a Renewable Energy Future

Ever since the dawn of the coal era some 200 years ago, scientists have known that fossil fuels—coal, oil and natural gas—would eventually be used up. More recently, the growing climate crisis has provided additional urgency to the quest for a more sustainable and ecologically friendly way to power modern society.

But even as environmentalists have pushed for greater investment in wind and solar energy, critics have insisted that renewable sources of power could never provide more than a fraction of world energy demand.

Evidence is mounting, however, that the critics are wrong.

Last March, a team of scientists led by Mark Jacobson at Stanford University published a study showing that with right mix of wind, solar and hydroelectric power, New York State could meet all of its energy from renewable resources within the state by 2030. The paper followed up on an earlier study by the team showing that the entire world could be powered by renewable energy by the same date. The New York study is the first of a series of planned regional analyses for the United States.

North Hoyle offshore wind farm. Source: Wikimedia Commons.
North Hoyle offshore wind farm in Wales, U.K. Source: Wikimedia Commons.

Significantly, the Jacobson plan calls not just for all-renewable electricity generation, but for the phase out of all fossil fuel consumption—including for building heating and cooling and for all transportation.The plan achieves this by replacing combustion engines with electric batteries and hydrogen fuel cells, and current building heating and cooling systems with heat pumps.

According to the plan, to meet New York’s total energy demand, the state would need to install about 271 gigawatts of renewable generation. About 40 percent of that would met by 12,700 new offshore wind turbines; the rest by a combination of onshore wind and an array of solar, hydroelectric, tidal and geothermal plants and installations.

“The technology is there,” says Vasilis Fthenakis, a senior research scientist at Columbia University’s department of Earth and Environmental Engineering.

Fthenakis would know: a few years ago he was the lead researcher on a paper outlining a similar plan to meet 69 percent of US electricity demand and 35 percent of its total energy needs with solar power by 2050, and 90 percent of total energy needs by 2100.

In contrast to the Jacobson plan, Fthenakis and his fellow researchers concentrate on building a large number of photovoltaic and thermoelectric solar power plants in the sunniest parts of the United States—chiefly the Southwest—and using high voltage direct current transmission to connect these power sources with the rest of the country.

“Jacobson’s biggest play is wind; in my scenarios, solar is the biggest,” says Fthenakis.

The largest photovoltaic power plant in the United States at Nellis Air Force Base in Nevada. The plant occupies 170 acres and has a 15 megawatt capacity.
The photovoltaic power plant at Nellis Air Force Base in Nevada was one of the largest in the United States when it was built. The plant occupies 170 acres and has a 15 megawatt capacity. Source: Wikimedia Commons.

According to his team’s analysis, the amount of land needed to power the entire United States with solar energy is less than what an equivalent amount of coal generation would require, if coal mining is factored in.

Professor Vasilis Fthenakis, Senior Research Scientist/Scholar and Adjunct Professor Director, Center for Life Cycle Analysis
Professor Vasilis Fthenakis, senior research scientist/scholar and adjunct professor, Columbia University Department of Earth and Environmental Engineering; and director, Center for Life Cycle Analysis.

Because conventional transmission suffers large power losses over long distances, Ftheankis’ plan would require the building of new high-voltage direct current lines to direct power from the Southwest to the rest of the country. China is currently building such lines to transmit electricity from its major power-producing regions to distant population centers.

To meet the challenges of intermittent power, the plan also calls for the building of new facilities that store energy by compressing air and pumping it into underground formations when sunlight is abundant, and releasing it to turn gas turbines and generate electricity when needed. Compressed energy storage today costs about half that of lead acid batteries; plants have been operating reliably in Germany and Alabama for decades.

Even though he believes it to be technically feasible, Fthenakis worries that Jacobson’s goal of 100 percent renewable by 2030 may be unrealistically aggressive, especially in light of the need to build an entirely new hydrogen fuel-cell infrastructure to replace fossil fuels for transportation.

He also points out that given the relatively small solar resource in the northeastern United States, Jacobson’s plan for New York requires an enormous build-out of offshore wind in a rapid timeframe—a build-out that may be untenable given many seaside residents’ feelings about wind turbines. “You have problems of acceptance,” he says. “You have the south shore of Long Island—in the Hamptons and so forth—where they are against it. People don’t want to see the 100-meter masts.”

Nevertheless, while the two plans may differ in their details and their approach to scale, overall, the message is the same. “I agree with Jacobson’s message that combinations of renewable energies that can satisfy total demand,” says Fthenakis.

Bianca Howard, a doctoral candidate in Columbia’s engineering department who has done high profile work on energy modeling in New York City, agrees. “I think that both Fthenakis’ paper and Jacobson’s paper are trying to illustrate that this is feasible, technically, with today’s technology. This can happen technically.”

“The question” she says, “is how do we get there in terms of policy, regulations … but we know what we need to do.”

Howard’s own work has focused on finding ways to ferret out the details of current energy use to better understand how a more sustainable energy system could meet demand. Last year Howard was the lead author on a study that produced a detailed map of New York City building energy consumption, down to the lot level.

In terms of getting to 100 renewables, Howard describes the process as a journey between two points.

Bianca Howard
Bianca Howard: “This can happen technically. The question is how do we get there in terms of policy.”

“We’re at point A and we need to get to point B. There are infinite lines that could connect the two. The modeling work is about trying to get an idea of where we are now, where the energy is being used, so that we can look at different methods to reduce that energy consumption and different ways to meet demand,” she says. “It’s figuring out where we are, so we can move toward the future.”

What’s interesting about the Jacobson team’s approach, says Howard, is that they have broken the transition down into different scales, from the globe to regions. This makes sense, given the political differences between regions.

“At least in the United States, we’re broken down by state, each state has it’s own policies, because that’s how our government is set up.” In New Jersey, for instance, state incentives have spurred more rapid solar installations than in neighboring New York.

Whatever the exact pathway, there are good indications that renewable energy has crossed a threshold that will soon make it unstoppable. Fthenakis’ analysis shows that the rapidly falling cost of solar power is likely to make solar electricity generation competitive with fossil-fuel-powered electricity throughout the country by 2020.

“There are things we can forecast, in terms of incremental technology improvements,” he says. He points out that his study, which used 2007 numbers, predicted the growing efficiency of photovoltaic technology. “Five years later we are exactly where we thought we would be,” in terms of efficiency improvements.

The fact that many of the current costs of solar power in the United States are the result of bureaucratic and regulatory red tape that could easily be reformed only bolsters this case. For example, says Fthenakis, “in Germany, solar is a lot less expensive.They have only one application, two pages,” in contrast with the maze of regulation and inspection that Americans go through for an installation. Reform of the solar permitting process in the United States could bring down costs quickly.

All of this suggests that is it only a matter of time before renewable energy takes over on economic grounds alone. “For peak shaving—the extra that you need for those hours of high demand—PV for southern California is already cheaper than natural gas,” says Fthenakis. “It’s happening.”

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