National Geographic News
The Falls Dam hydroelectric reservoir with outlet drain in winter.

Hydroelectric reservoirs like this one in New Zealand provide sustainable power generation.

Photograph by Bill Hatcher, National Geographic

Ker Than

for National Geographic

Published June 26, 2013

The future appears to be bright for renewable energy sources like solar, wind, and water.

In fact, power generation from such renewables will exceed that of gas and nuclear by 2016, according to a report published Wednesday by the International Energy Agency (IEA).

"As their costs continue to fall, renewable power sources are increasingly standing on their own merits versus new fossil-fuel generation," IEA executive director Maria van der Hoeven said in a statement.

The report's publication comes on the heels of a speech Tuesday by U.S. President Barack Obama in which he unveiled a plan to combat climate change by limiting greenhouse gas emissions from fossil-fueled power plants and increasing federal reliance on renewable energy sources. (See related quiz: "What You Don't Know About Solar Power.")

"I'm setting a new goal," Obama said. "Your federal government will consume 20 percent of its electricity from renewable sources within the next seven years."

Business Is Booming

The IEA report, unveiled by Van der Hoeven as she delivered the keynote address at a Wall Street renewable energy finance forum in New York, analyzes market trends for renewable electricity in more than 20 countries and regions and predicted that renewable power will increase by 40 percent in the next five years.

The report predicts that renewables will make up almost a quarter of the global power mix by 2018, up from an estimated 20 percent in 2011.

Two main factors are driving the boom, according to the Paris-based IEA.

First, emerging markets in countries like China and India are increasingly turning to renewables to meet their fast-rising electricity demands. (See related: "Pictures: A Rare Look Inside China's Energy Machine.") Growth in these markets is expected to more than compensate for slower growth in Europe and the U.S.

Second, the cost of renewable energy sources has declined considerably. For example, wind competes well with new fossil-fuel power plants in a number of countries, including Brazil, Turkey, and New Zealand.

Hydropower—generated by falling or flowing water, like in dams—will remain the largest renewable power-generating source in the coming years and should account for more than two-thirds of the total global output from renewable sources by 2018, the IEA predicts.

The IEA also expects onshore wind power generation technologies, already widespread in 2012, to be deployed in 75 countries by 2018.

The use of biofuels, which generates energy from biological sources like municipal waste, is also expected to see modest growth in the near term. The IEA projects that more than 50 countries will be generating more than 100 megawatts of electricity using biofuels by 2018, up from 40 megawatts in 2012.

China is projected to be the leader in the adoption of many renewable energy technologies, including hydropower, onshore and offshore wind, solar, and biofuels.

Not So Sunny for Solar

The IEA is less optimistic in its outlook for solar energy production. According to the report, solar energy is expected to experience average annual growth rate of around 25 percent over the next five years—down from 45 percent annual growth for the period between 1998 and 2012.

"If we look at solar energy projections, we realize that these projections are not really promising," said Mohamed ElNozahy, an electrical and computer engineer at Canada's University of Waterloo.

"This is mainly attributed to the cost and technical challenges highlighted in my last review paper," said ElNozahy, who was not involved in the IEA report.

A recent paper co-authored by ElNozahy and published in the Journal of Renewable and Sustainable Energy highlighted numerous challenges for energy generated by solar cells before they can be smoothly integrated with existing electrical networks.

For example, power generation by solar cells—also known as photovoltaic (PV) cells—can vary dramatically in response to changing cloud cover or temperature. This causes dips in electrical output that can require costly equipment to regulate.

A Conservative Estimate?

Daniel Kammen, founder and director of the Renewable and Appropriate Energy Laboratory at the University of California, Berkeley, argued that the IEA's projections are somewhat conservative.

Kammen thinks the global shift to renewables and the adoption of policies and technologies to accelerate their deployment could occur faster than the IEA predicts due to growing awareness about health impacts of local pollution and the economic and environmental costs of climate change.

President Obama alluded to the impact of human health of global warming in his Tuesday speech.

"The IEA report notes but perhaps could give more weight to the very significant health and environmental costs that will result if this shift does not take place," Kammen said in an e-mail message.

Despite the momentum behind renewables, challenges remain, IEA's Van der Hoeven said.

For example, "worldwide subsidies for fossil fuels remain six times higher than economic incentives for renewables," she said.

Lorena M.
Lorena M.

I am off grid solar solar thermal wind and LED and I can tell you that my panels and whole system in fact has a ROI of 7 years. You can do it to and fortify your family against inflation. I know it a lot of places you can even get leasing for a grid tie and if you do that and sell back you offset your own run it like a business you only have to claim the power that you got credit for so small income to claim but you can write off a lease for your new small power producer business 100% ROI can be as low as 5 years in small places were the energy cost is above 20 cents a kW/hr. I went off grid for my house because I own a solar Business I can write it off anyway as a demo so this did not matter for me. For the average person make it a business get a system you can run on grid now but still use the same one off grid later. As soon as you have maximized your write off's close the small power producer business and go off grid.

Osmand Charpentier
Osmand Charpentier

The title is accurate and true: OCEANOGENIC POWER OF PANAMA: unexpected renewable energy, hydro, renewable, clean, cheap, scalable, easy to transport, and sufficient for the whole world for the next 300 years or more.

The current problem is envy, and human complexes, that whenever ridicule the greatness of our species, and delays our progress. Especially on the part of leaders and business men, that by being having a good time, can not ever be interested in solving human problems. There is nothing to bother: ¡I would too!

Ralfy Mann
Ralfy Mann

The catch is that renewable energy sources have lower energy returns, which means at best they might be able to meet basic needs but not maintain economic growth.

In addition, the components and infrastructure used for these sources require fuel and petrochemicals, especially in manufacturing and delivery.

Finally, given the fact that most human beings lack one or more basic needs, then the energy generated by these sources might not be enough.

Sirius Andreas
Sirius Andreas

The title of this article is a bit misleading unless one keeps in mind that its scope is limited to electrical power generation, rather than energy production in general. In terms of the latter, renewable energy is only responsible for a tiny fraction of the amount attributable to fossil fuels.

In other words, if we depended exclusively on renewables for energy, civilization as we know it now would collapse.

Sad to say, it seems as though we're fussing over very little. I demand more from the green revolution!

Osmand Charpentier
Osmand Charpentier

Let me inform, in the space of response to my comment, as proof that jealousy to humanity that must be mastered: after this written, wikipedia has allowed to an alleged student, and other cybernetic idlers, claiming silly reasons, and easy to correct, delete any reference to this energy in its online service.  

This is sadly censorship Third World style, paid with money produced from dirty fuels.

Lorena M.
Lorena M.

@Ralfy Mann I disagree even my 7yr old son got it when we went off grid and he learned to look and the energy meter read it then tell me the reading stating the sun is out and the meter is 49vdc can I please play on the play station? so if he gets is in one winter in Canada OFF the Grid I do think and adult will learn it too.

Hawk Eye
Hawk Eye

@Ralfy MannThat's what research, design, development, implementation processes are all about --- finding a better way.  We are on that path now.  It's a process that takes time.  


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