My dream is to make renewable energy affordable for all: Steven Chu

Steven Chu was awarded the 1997 Nobel Prize in physics jointly with compatriot William D Phillips and Claude Cohen-Tannoudji of France for "developing methods to cool and trap atoms with laser light". Chu is now better known as US President Barack Obama's former energy secretary, a post he resigned from in April to return to Stanford University. An advocate of sustainable development and renewable energy, Chu speaks to Narayani Ganesh on the sidelines of the Lindau Nobel Laureate Meetings with young researchers, 22 of who are from India. Excerpts:

What kind of solar energy business model would you suggest for India?

Solar energy being too expensive is not something one has to worry about. On a global scale, the Chinese made solar panels are cheaper but the difference is due to import duties pricing, shipping charges, taxes, licensing fee and so on. In a context where international prices are coming down and the technology is getting better and more reliable, you have to be concerned about installation cost and licensing fee. In the US, it also depends on where you are located. For example, the southern parts get more sunshine and in 10 years, you could get solar power generated at 8 cents an hour and that is not expensive.

Won't the utility companies — what we call electricity boards — be up in arms over consumers generating their own electricity on their rooftops?

In order for utility companies to be part of the solution you have to make them part of the business. It means if you have rooftop space at home, you can hire someone to install the panels from the utility company. In the US more and more solar projects are done this way — a company says you don't have to pay for anything; just pay for the electricity. Have a contract for five or ten years at a certain rate (about the same as normal electricity costs) — you don't have to bear the capital costs nor worry about maintenance. If utility companies are part of business, it would be good as they can borrow money at lower rates. It is a new business, a good business where they can make money.

What about storing solar energy?

As the technology gets better, energy storage too is possible, in batteries in your home. It is inexpensive — in 15 years maximum you can have storage inside home where it does not get up to 40 degrees Celsius. Utility companies, if they have to build a building to hold all batteries, will have to bear high costs. All they need is space. Which means they can offer you electricity at lower cost if they have local storage. So the consumer does not have to worry about inflation or equipment but just pay for the electricity. That is the business model I have been talking about to electrical companies this past year. If they know they can make money from solar energy generation on someone's roof, they would be most interested. And with batteries in homes, you would not have to worry about blackouts.

You gave up your post as Obama's energy secretary. Do you think scientists should stay away from politics?

I neither like nor dislike politics. It's just that I needed to get back to my research as a practicing scientist.

Obama has said he is concerned about climate change. But the US has a poor green track record...

He is certainly concerned, but the Congress has to pass the laws. We do need to change agricultural practices, reduce carbon emissions and ocean acidification. We need another green revolution but without the drawbacks of pesticides. High nutrition is important and to achieve that, we could explore safe GM food. My dream is to make renewable more affordable.

Source: http://economictimes.indiatimes.com 

Is Anything Stopping a Truly Massive Build-Out of Desert Solar Power?

The vast and glittering Ivanpah solar facility in California will soon start sending electrons to the grid, likely by the end of the summer. When all three of its units are operating by the end of the year, its 392-megawatt output will make it the largest concentrating solar power plant in the world, providing enough energy to power 140,000 homes. And it is pretty much smack in the middle of nowhere.

The appeal of building solar power plants in deserts like Ivanpah’s Mojave is obvious, especially when the mind-blowing statistics get thrown around, such as: The world’s deserts receive more energy beamed down from the sun in six hours than humankind uses in a year. Or, try this one: Cover around 4 percent of all deserts with solar panels, and you generate enough electricity to power the world. In other words, if we’re looking for energy—and of course, we are—those sandy sunny spots are a good place to start.

But statistics are one thing, building a few thousand gigawatts of solar power is quite another. Deserts are dusty, windblown and remote. So far, only a few hundred megawatts of utility-scale desert solar power have been built. Most projects are in the American Southwest, with a few in the Middle East and north Africa as well. Though progress has been slow and significant technical challenges remain, experts and industry leaders seem to agree that engineering difficulties alone are not holding us back from a big desert solar build-out. “From the technical side, I think we can do it. In fact, I know we can do it,” says Seth Darling, a solar researcher at Argonne National Laboratory near Chicago. “I don’t know that we can do it from a policy side, but I sure hope we can.”

Water and dust

 
On the engineering side, though, Darling says that there are one or two challenges that still could be “deal breakers,” at least for some technologies. The big one is water. Concentrating Solar Power (CSP) plants, like traditional power plants, need to be cooled to run, and cooling takes water—lots of it. And of course, if water were abundant in the desert, it wouldn’t be the desert. At Ivanpah, on-site wells supply the plant with water, but that solution won’t always be feasible. “I can’t think of any technical way around that unless a dry cooling technology that’s effective and affordable is developed,” Darling says. “No one has really come up with a way to do that.”

For photovoltaics (PV), water is only needed to clean the panels, which brings up the second large problem with desert solar: dust. Solar panels and mirrors need to be cleaned almost daily if efficiencies are to stay where they need to be. Dust is not transparent, so even just one gram of dust per square meter of solar panel area can reduce efficiency by around 40 percent. At that rate, it doesn’t take long in a dusty desert for the problem to become intractable.

In the desert near Abu Dhabi in the United Arab Emirates the Middle East’s first large CSP plant recently faced down the dust issue. In order to reach the 100-megawatt-capacity goal of the Shams 1 plant, developers had to add substantially more mirrors to the plant than planned due to dust in the atmosphere. Scott Burger, an analyst at Greentech Media’s GTM Research who focuses on the region, said the plant probably ended up costing three times the initial estimate, thanks in part to dealing with that dust. And now that it is built, Shams 1 sends a series of trucks up and down the lines of 250,000 mirrors every day, using robot arms to spray that precious water and clean away the dust.

The good news on the dust front, though, is that some water-free ideas exist for cleaning PV panels—they just haven’t been produced at large scale yet. The best possibilities are electrostatic cleaning, where a charge flowing over a panel can essentially push the dust out of the way (the technology was developed initially by NASA for lunar and Mars missions) or mechanical systems that would just brush off a panel once a day. For CSP plants where windblown dust and sand can permanently erode the mirrors, tilting them down out of an oncoming sandstorm is one way to keep the plants viable.

From deserts to market

 
And then there’s transmission, which Randy Hickok, the senior vice president of asset management at Ivanpah co-owner NRG Solar, says could be the biggest hurdle. “Traditionally power plants haven’t been in deserts, so you don’t have a lot of high-voltage transmission running to these out-of-the-way locations,” he says. “For a lot of your best solar resource, you don’t have available transmission, and siting transmission is not an easy task.” High-voltage lines can cost millions of dollars per mile.

But again, the technical side of this is not the deal breaker. Darling says we are perfectly capable of building long lines to remote locales, and with High-Voltage Direct Current (HVDC) the efficiency losses are quite low, on the order of only a few percent every thousand kilometers.

Hickok says that developers have rushed to build new facilities in locations where few upgrades to a transmission system are needed, but those “low-hanging fruit” possibilities get exhausted relatively quickly. The really big desert-solar ideas, like DESERTEC’s plan to power all of Europe with HVDC lines across the Mediterranean from north Africa, would require such a massive investment in transmission lines that they’re unlikely to move forward on meaningful timescales.

And even DESERTEC—which had led the calls for massive desert renewables development—has scaled back its planet-saving rhetoric in recent years as the challenge of getting started has grown. Thiemmo Gropp, director of DESERTEC, says the foundation’s main goal now is to help build some impressive pilot projects that will illustrate to the rest of the world that building big in the desert is doable. The group has partnered with Saudi Arabia, which hopes by 2030 to build an astonishing 54 gigawatts of renewable energy (41 GW from solar, essentially all of it in the vast Saudi desert) and is also on board with some initial projects in Morocco. Gropp agrees that the engineering challenges are not the primary obstacle, although of course the technology will continue to improve. “There are no serious hurdles,” he says. “Right now we have a car like in the 1920s or 1930s, we don’t have mass production of 2013; but it’s got an engine, it’s got 4 wheels, it works. I don’t see any technical principle hurdles.”

Out in the Mojave, Ivanpah is clearly a desert success story, but it can’t obscure the ongoing struggles that accompany it. BrightSource Energy, co-owner of the plant along with NRG Solar, has this year shelved a full gigawatt of other desert solar ideas. Many CSP plants have either been canceled or switched to more modest PV designs as panel prices have plummeted in recent years, showing again that the effort remains at the whims of fickle market dynamics. It is good to know, though, that whereas other planetary saviors (like, say, carbon capture and storage) languish in technological and cost purgatory, building solar power where the sun shines brightest doesn’t seem to worry those who are doing the building.

Source: http://www.scientificamerican.com

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Windiest or Sunniest Sites Not Necessarily Best for Wind and Solar

Setting up wind and solar farms in places where the wind blows mightiest or the sun shines brightest isn’t the wisest move if you’re looking to reap the most social benefits, researchers at Carnegie Mellon University have found.

They estimate that the environmental, health, and climate benefits of wind turbines and solar panels vary dramatically by location, ranging from US $10 to $100 per megawatt-hour (in 2010 dollars) of renewable energy generated. The results appeared last week in the journal Proceedings of the National Academy of Sciences.

Using a calculation that takes into account the type of conventional energy generators that wind and solar displace, the team was able to assess the amount of damage from carbon dioxide and other air pollutants—sulfur dioxide, nitrogen oxides, and particulate matter—that renewables actually prevent.

Sites with the highest renewable energy output don’t necessarily give the greatest social benefit, says Kyle Siler-Evans, a recent engineering and public policy graduate who helped perform the analysis. So while Arizona gets much more sun, a solar panel in Ohio offers 15 times as many health and environmental benefits because it replaces particularly polluting coal power plants in a higher population-density area. In fact, sunny Arizona is probably the worst location for a solar panel if you want to improve air quality and human health, the team found.

By the same reasoning, wind turbines in California are less beneficial because they replace relatively clean natural-gas-fired plants. By contrast, a turbine in less-windy West Virginia prevents 33 times as much health and environmental damage as one in California by reducing air pollutants. However, 30 percent of existing U.S. wind capacity is installed in California and Texas, while less than 5 percent is in Indiana, Ohio, and West Virginia.

The researchers at CMU, in Pittsburgh, looked at the hourly electricity generated by a 3-megawatt wind turbine at 33 000 locations and by a 1-kilowatt solar panel at 900 locations around the country. Separately, they calculated the health, environmental, and climate damage from 1400 fossil fuel plants for each hour from 2009 through 2011. To do this, they combined hourly plant-emissions data with a dollar value assigned to the damage from a metric ton of each pollutant. (For the dollar values, they used numbers that others had already generated. A social cost of $18.14 per metric ton of CO₂ came from an interagency working group report from the U.S. government, while the cost per metric ton from air pollutants came from a model developed by Yale University researchers.)

Finally, by combining the hourly renewable energy generation data with the emissions data, the researchers estimated the damage reduction achieved by replacing conventional generators with wind and solar.

Federal subsidies today provide incentives for builders to install wind and solar farms that produce the greatest amount of energy. Taking into account the location-specific benefits of wind and solar would be a wiser investment of government dollars, says Inês Azevedo, a professor of engineering and public policy at CMU. “Instead of valuing kilowatt-hours, [if] the policy mechanism…looked at metric tons of carbon dioxide avoided and health and environment damages avoided, we’d find that wind is oversubsidized in California and undersubsidized in Pennsylvania,” she says.

“This is a really nice way of rethinking our priorities in terms of where to deploy renewable technologies,” says Steven Davis, professor of earth system science at the University of California, Irvine. Davis adds that the analysis is robust, detailed, and geographically comprehensive, and he hopes that it catches the eye of policymakers.

Source: http://spectrum.ieee.org/

A Cheaper Option to Turn Carbon Dioxide Into Synthetic Fuel

Carbon capture and storage has been a political buzzword for years, even though it remains expensive and largely elusive on a commercial scale.

The first part of the equation, capturing carbon dioxide from power plants and other large emitters of carbon pollution, is the relatively easy part. The problem has been what to do with it. Injecting it underground is expensive, and turning it into fuel takes a lot of energy and often involves rare or toxic chemicals.

Researchers at the University of Delaware have taken a different approach, using an inexpensive catalyst that relies on electricity from solar energy to convert carbon dioxide (CO₂) into carbon monoxide (CO) that can be used for a range of industrial applications, including liquid fuel.

Gold and silver have traditionally been used as the catalyst to convert CO₂ into CO, but Joel Rosenthal, a chemist at the University of Delaware, found that the metal bismuth works just as well, if not better. “Despite its low cost, bismuth has been virtually ignored as a cathode material for CO₂ electrolysis,” Rosenthal wrote in a study that appeared in the June 19 issue of the Journal of the American Chemical Society.

An ounce of bismuth is 2000 times cheaper than an ounce of gold and found in many places as a byproduct of refining lead, tin and copper, according to Rosenthal. “Most catalysts do not selectively make one compound when combined with carbon dioxide — they make a whole slew,” Rosenthal said in a press release. “Our goal was to develop a catalyst that was extremely selective in producing carbon monoxide and to power the reaction using solar energy.”

Carbon monoxide is a valuable commodity chemical, said Rosenthal. It is used to make hydrogen gas, but also in the production of synthetic petroleum, which researchers are developing across the globe. 

Cheaply converting CO₂ to useful products that don’t require a lot of energy is an area of active research, especially as countries look to curb carbon emissions. Although the U.S. may never have a carbon tax, President Obama’s recently unveiled climate plan included provisions for the U.S. EPA to regulate greenhouse gas emissions from existing power plants, which will only increase the interest in CO₂ conversion research. Obama’s plan included $8 billion in loan guarantees for advanced fossil energy technologies, including carbon capture.

There are also many other researchers and burgeoning companies trying to find low-cost, low-energy solutions to CO₂ pollution. Skyonic, a company with a technology to turn CO₂ into baking soda, recently raised $128 million in venture capital. Researchers at the University of Texas at Arlington are converting CO₂ to liquid methanol using copper oxide nanowires and sunlight. Researchers at the University of Georgia have created a microorganism that feeds on CO₂ and can then be manipulated to make chemicals for fuels or plastics.

But for every breakthrough, there is far more work that needs to be done. University of Delaware’s Rosenthal said there are at least a dozen issues his lab needs to follow up on, which they will pursue this summer.

Source: http://spectrum.ieee.org/