To shift the global economy from fossil fuels to renewable energy will require the construction of wind, solar, nuclear, and other installations on a vast scale, significantly altering the face of the planet. Can these new forms of energy approach the scale needed to meet the world’s energy demands?

From the dust-blown steppes of Inner Mongolia to the waters off Shanghai, China installed more wind turbines in the first half of 2010 than any other country — 7,800 megawatts of potential power production, or more than the United States, the European Union, and India combined. In fact, in northeast China alone, autumn and winter winds now produce some 17 billion kilowatt-hours of electricity, roughly 5.5 percent of the total power generation in the region. That’s up from 534 million kilowatt hours just five years ago.

But despite this rapid progress, wind energy still only generates a tiny fraction of China’s electricity. Indeed, even with aggressive government backing and green energy mandates, such “new energy” — including wind, solar, nuclear power plants, and biomass — accounts for less than 3 percent of China’s electricity production, compared to more than 70 percent provided by coal, which produces roughly 3 metric tons of carbon dioxide for every metric ton of the dirty, black rock burned. And as China’s economy continues to expand at a dizzying rate for the foreseeable future, wind and other renewable sources of energy will not even be able to keep pace with new demand, meaning fossil fuel burning will continue unabated.

This is hardly unique to China. In the U.S., electricity produced from the breeze has increased 13-fold in the past decade, yet still only provides 2.3 percent of the country’s electricity — compared to just under 50 percent provided by burning coal. Even Denmark, which has done more than any other country to boost wind power, struggles to integrate an intermittent generating resource into a grid whose customers expect the lights or the television to come on whenever they flick the switch.

As the world attempts to wean itself from fossil fuels — a result of the converging desires to combat climate change, improve energy security, and create green jobs — renewables such as the sun, wind, water, and hot rocks will play a larger role. So will energy sources, such as nuclear and natural gas, that are cleaner than the current favorites, coal and oil. The question is: Can any of these resources — or even all of them put together — begin to approach the scale needed to transform the world’s energy supply?

‘We need to replace all of the power-producing infrastructure that we have today within 40 years,’ says one expert.

And even if the world’s economies can muster the resources and willpower to wean themselves off fossil fuels, how many decades will it take? And can we move fast enough to stave off the potentially calamitous effects of climate change?

“Renewables are growing at fantastic rates compared to conventional resources,” says David Rogers, general manager for climate change at the oil giant, Chevron. But “while it’s growing like gangbusters, it’s starting from such a small base that by 2030 it still takes a small part of the energy space.”

To meet a proliferating set of international goals, such as Germany’s plan to derive 80 percent of its electricity from renewable sources by 2050, will require completely changing the present energy mix. Despite more than 21,000 wind turbines and 13 million square meters of solar installations, Germany still gets more than 50 percent of its electricity from burning fossil fuels, including lignite, the most polluting form of coal.

“In some real sense, we need to replace all of the power-producing infrastructure that we have today within 30 or 40 years,” says engineer Saul Griffith of California-based Other Lab, an engineering and design firm working on renewable energy projects, among other pursuits. “The options that we have that are non-carbon [dioxide] producing are nuclear power, solar power at a very large scale, wind power at a very large scale, and geothermal at a very large scale — and then perhaps biofuels or carbon sequestration on existing power plants.”

In fact, at the global level, in order to shift away from a world that gets 81 percent of its energy from fossil fuels and to cut emissions of carbon dioxide to just 14 gigatons per year, here is what the International Energy Agency says will have to be built every year between now and 2050: 35 coal-fired and 20 gas-fired power plants with carbon capture and storage; 30 nuclear power plants; 12,000 onshore wind turbines paired with 3,600 offshore ones; 45 geothermal power plants; 325 million square meters-worth of photovoltaics; and 55 solar-thermal power plants. That doesn’t even include the need to build electric cars and hydrogen fuel cell vehicles in order to shift transportation away from burning gasoline.

In addition, if the world’s economies hope to wean themselves from fossil fuels, they will have to significantly improve energy efficiency and begin to harness power from sources such as waste heat from factories.

One thing is certain: If the global economy does succeed in making the transition to renewable energy, the face of the planet will be significantly changed, with solar energy farms and wind turbines a common feature of many landscapes and seascapes.

“If 10 percent of the U.S. electricity generated in 2009… were to be produced by large wind farms, their area would have to cover at least 22,500 square kilometers, roughly the size of New Hampshire,” writes environmental scientist Vaclav Smil of the University of Manitoba in his book, Energy at the Crossroads. “These new energy infrastructures would have to be spread over areas ten to a thousand times larger than today’s infrastructure of fossil fuel extraction, combustion and electricity generation…. This is not an impossible feat, but one posing many regulatory, technical and logistic challenges.”

“Can we do this or not?” Chevron’s Rogers asks. “Even at the best time we ever had we only did 20 to 25 nuclear power plants in a year… We need 325 million square meters [of photovoltaics] annually. We’ve done maybe 10 percent of that in our best year, which was last year.”

But there is reason for guarded optimism. Even in the throes of the Great Recession, renewables accounted for more than 50 percent of newly installed generating capacity in the U.S. and the European Union, while China added 37 gigawatts of mostly wind and hydropower in 2009, according to the United Nations Environment Program.

“It’s not going to be easy to make an energy plan that adds up; but it is possible,” says physicist David MacKay of the University of Cambridge, an expert on scaling up renewable energy. “We need to make some choices and get building.”

When it comes to such a large-scale shift in energy supplies, few places face more of a challenge than the United States. Americans burn through nearly 6.4 billion barrels of oil and 1.1 billion metric tons of coal per year on our way to getting 83 percent of our energy fix from fossil fuels. Renewable resources, such as the sun, the wind, the flow of rivers and fuels derived from crops supply just 8 percent of our energy needs. Take away ethanol and hydropower, and the sun, the wind, and geothermal power supply less than 1 percent of the U.S.’s total energy use, including gasoline consumption.

Just to supply one-quarter of its current energy mix from a resource that emits far fewer greenhouse gases — nuclear power — the U.S. would need to build 1,000 one-gigawatt nuclear reactors by 2050. Yet construction has begun on only two nuclear reactors in the U.S. since 1974. And just to power an electric car and truck fleet to replace the U.S.’s current gas and ethanol-fueled one would require 500 new nuclear power plants. There are currently 442 reactors in the entire world, of which the U.S. has 104 — the most of any nation.

U.S. attempts to wean itself from fossil fuels have never fared well, yet the Obama administration has committed internationally to an 80 percent drop in greenhouse gas emissions by 2050. Either alternative energy supplies will need to ramp up from nearly zero to almost 100 percent in just four decades, or large-scale carbon capture and storage will be required, including pulling CO2 out of the air after it has been put there by all of our automobiles. In fact, simply removing one gigaton of carbon from the atmosphere would require 273 coal-fired power plants with complete carbon capture and storage. At present, there is one in the U.S., capturing just 1.5 percent of its emissions.

“We are talking about a transformation across the entire country,” Federal Energy Regulatory Commission (FERC) chairman Jon Wellinghoff said in an interview with Yale Environment 360. “We are talking about potentially tens of thousands of new transmission lines to ultimately move large amounts of wind, solar, and other resources to loads. We are talking about in the scale of billions of dollars of investments in smart-grid technologies, all the way from the consumer level up through to the transmission and generation level.”

Assuming the U.S. will require roughly 4 terrawatts of power by 2050 (a conservative estimate, given that we already use more than three), replacing all that fossil fuel would require at least 4 million wind turbines — necessitating building 12, three-megawatt wind turbines every hour for the next 30 years, according to Griffiths. The numbers are similar for solar — 160 billion square meters of photovoltaic cells or concentrating mirrors. “We need to be making a square yard of solar cells or mirrors every second for the next 40 years to install that much in North America,” Griffiths calculates.

It’s not just a matter of making the necessary equipment, it’s also a question of finding the space for it. A coal-fired power plant produces 100 to 1,000 watts per square meter, depending on the type of coal it burns and how that coal is mined. A typical photovoltaic system for turning sunlight into electricity produces just 9 watts per square meter, and wind provides only 1.5 watts per square meter.

The challenge is worse for smaller countries: the United Kingdom would have to cover its entire landmass with wind turbines to provide enough electricity for the current Briton’s average consumption — roughly 200 kilowatt-hours per day, according to MacKay, the Cambridge expert.

Although daunting, the challenges of installing new energy technologies on a mass scale are by no means impossible. In the first half of the 20th century, it took the U.S. 45 years to increase its use of oil until that fossil fuel represented 20 percent of the total energy used. At the same time, the U.S. built a sprawling gasoline-fueling station infrastructure, the rudiments of a national electricity grid, thousands of miles of telephone lines, airplanes and airports, interstate natural gas pipelines, and local delivery infrastructure for home heating — and rolled out all the appliances (refrigerators, radios, televisions, etc.) of the modern age — all in the same few decades, at the same time. In other words, the U.S. seems to have “scaled up,” in the parlance of engineers, pretty rapidly in the past.

Transforming the global economy to run on renewable energy would require a similarly massive effort. For example, to provide the energy equivalent of present global consumption would require covering 1 percent of the Earth’s surface with photovoltaic devices, according to chemist Nathan Lewis of the California Institute of Technology. That’s less than the land area currently covered by cities, but a huge chunk of territory nonetheless.

You can actually farm, you can actually graze, you can actually do things around that [wind] turbine versus if you are taking the top off a mountain to produce some coal,” FERC’s Wellinghoff notes. “Ultimately, we are going to have to accept the fact that wind turbines and solar systems are going to take up fairly large pieces of land. But, fortunately, we have a lot of land in this country and we have the ability to have dual use of that land.”

But the U.S. also leads the major nations of the world in per capita consumption of energy. The average American used 7.2 metric tons of oil-equivalent in 2009 (a number that, to be fair, has gotten slightly better of late, down from 8.5 in 2005.) That’s double the amount used by the average citizen in Europe, and five times the global average.

To put it another way, the average American uses 250 kilowatt-hours per day for “transportation, heating, manufacturing, electricity, and so forth,” writes MacKay. “That’s equivalent to every person having 250 40-watt light bulbs switched on all the time.” Energy efficiency might bring that consumption as low as 168 kwh per day, according to MacKay. But that still means each American would require 80 square meters of photovoltaic panels, plus biofuels from energy crops on 4,000 square meters of land. In addition, the U.S would need to build one 2-megawatt wind turbine for every 300 Americans, plus one 1-gigawatt nuclear power plant for every city the size of Boston.

On the grander scale, more than half of the energy used in the U.S. — 56.3 percent — is wasted. That’s a result of the essential inefficiency of burning coal in a power plant or gasoline in an automobile engine, or even transmitting electricity over vast distances.

Industry is beginning to make use of this waste — a steel plant in Indiana employs the waste heat from a coal coking plant to generate electricity, enough to help run its steel rolling machines in another adjacent facility. And while U.S. energy use has grown over the past four decades, three-quarters of that growth has been met through gains in energy efficiency, not by burning additional fossil fuels, according to a 2008 report from the American Council for an Energy-Efficient Economy (ACEEE). The energy used to produce every dollar of U.S. gross domestic product fell from 18,000 Btus in 1970 to just 8,900 Btus in 2008.

“The energy-related challenges of the 21st century require a dramatic shift in direction — from an emphasis on energy supply to an emphasis on energy efficiency,” says Jon “Skip” Laitner, ACEEE director of economic analysis. “The greatest American success story in dealing with energy in recent decades is also the least understood and the most invisible.”

In fact, researchers at Lawrence Berkeley National Laboratory estimate that waste heat from factories, oil refineries and other industrial facilities holds the potential for as much as 95 gigawatts (the equivalent of 95 nuclear power plants) of new electricity, which is cheaper to capture than building a new coal-fired power plant.

If this great energy transformation eventually comes, it will take decades to complete. But, as FERC’s Wellinghoff notes, “The scale is very large but, fortunately, it is something we can do incrementally and it is something that we have already started.”

If society’s efforts were turned in different directions, shifting from making fewer consumer products to making more devices to capture renewable energy, the transition might ultimately fuel itself. After all, beverage makers now produce some 300 billion aluminum cans per year, Griffiths notes, which is enough production capacity to manufacture 100 or 200 gigawatts of solar thermal annually. “So we could do 1 terrawatt of solar in 10 years if Pepsi and Coca-Cola and all the breweries became solar companies,” he says. “We have the industrial scale. We are just right now prioritizing what we want to make with it and we are making disposable aluminum cans instead of solar mirrors. That gives me reason for optimism. We can do it.”

http://e360.yale.edu/feature/green_energys_big_challenge__the_daunting_task_of_scaling_up_/2362/

By David Biello