Category Archives: solar

Surprising effect of light could change solar power generation

Professor Stephen Rand. Image from the University of Michigan

The University of Michigan has announced that researchers have discovered a surprising magnetic effect of light that could lead to solar power generation that doesn’t require the traditional semiconductor-based solar cells.

Stephen Rand, a professor in the departments of Electrical Engineering and Computer Science, Physics and Applied Physics and an author of a paper on the work, said the researchers had found a way to make an “optical battery.” This overturns a century-old tenet of physics.

Light has both electric and magnetic components. Until now, researchers thought the effects of the magnetic field were so weak that they could be ignored. But Rand and his colleagues discovered that, at the right intensity and when light is traveling through a non-conductive material, a magnetic effect can be generated that is 100 million times stronger than previously expected. This is equivalent to a strong electric effect.

“This could lead to a new kind of solar cell without semiconductors and without absorption to produce charge separation,” Rand said. “In solar cells, the light goes into a material, gets absorbed and creates heat. Here, we expect to have a very low heat load. Instead of the light being absorbed, energy is stored in the magnetic moment. Intense magnetization can be induced by intense light and then it is ultimately capable of providing a capacitive power source.”

This new technique could make solar power cheaper, the researchers say. They predict that with improved materials they could achieve 10 percent efficiency in converting solar power to useable energy. That’s equivalent to today’s commercial-grade solar cells.

The paper is titled “Optically-induced charge separation and terahertz emission in unbiased dielectrics” and has been published in the Journal of Applied Physics. You can read the University’s press release on their website.

Total and SunPower enter into strategic solar energy partnership

SunPower, the Silicon Valley-based solar manufacturer, has announced that it is entering into a strategic partnership with French oil and gas company Total. Under the terms of the agreement, Total will launch a friendly tender offer for up to 60 percent of both SunPower’s outstanding Class A Common and Class B Common shares. The offer price of $23.25 per share for each class represents a 46 percent premium over the Class A closing price and 49 percent premium over the Class B closing price. In addition, Total promises to provide SunPower with up to $1 billion of credit support over the next five years.

The boards of both companies have already approved the transaction, but the deal still needs approval from the anti-trust authorities of both the U.S. and the European Union. After the agreement is in place, the two companies will enter into a research and collaboration agreement focusing on advancing photovoltaic technologies in multiple research and development projects. With China currently leading in the increasingly competitive solar industry, the partnership should give a needed boost to the efforts of both Total and Sunpower.

“With Total’s $1 billion credit support agreement, solar research and development investments and the other resources available through its global network, we have taken the next step in positioning our business for continued growth and long-term success, ” said Tom Werner, SunPower’s CEO. “Our relationship with Total will improve our capital structure enabling SunPower to accelerate our power plant and commercial development businesses, and expand our manufacturing capacity with lower cash requirements.”

“The world future energy balance will be the result of a long-term transition in which renewable energies will take their place alongside conventional resources,” said Philippe Boisseau , President, Total Gas and Power Division. “Over the past years, Total has built up sizeable renewable energy activities. Today, Total is executing on its strategy to become a major integrated player in solar energy. We evaluated multiple solar investments for more than two years and concluded that SunPower is the right partner based on its people, world-leading technology and cost roadmap, vertical integration strategy and downstream footprint.”


The Atlantic has posted a special report on energy

The Atlantic has been posting a variety of stories and videos in a wide-ranging special report called “The Future of Energy.” Alexis Madrigal, senior editor at The Atlantic and author of Powering the Dream: The History and Promise of Green Technology, started the discussion each week by discussing an episode or question from the past that might help us frame our thoughts about what the future holds for our energy systems. Energy experts from a variety of disciplines were then invited to explore the topic and discuss the big ideas.

There are 3 topics posted in the collection: Part 1 – The Electric Car Solution, Part 2 – The New Nuclear Reality, and Part 3 – Big Solar vs. Environmentalists. The fantastic stories related to these topics offer a wide-ranging look at something that affects us all.

You can read the stories here.

Water energy that isn’t hydro

MIT’s Daniel Nocera and team have discovered a new process of electrolysis that might revolutionize the solar industry. Image from Fast Company.

Fast Company is reporting that The Tata Group and Sun Catalytix have joined forces to explore the potential for generating cheap energy directly from water. The founder of Sun Catalytix, MIT professor of chemistry and energy Daniel Nocera, and his team recently found a way to imitate plant photosynthesis by putting a silicon leaf, coated with a proprietary cobalt and phosphate solution,  into a jar of water. The Tata Group is betting that this is a huge breakthrough.

Attempts to replicate the tiny and efficient solar engines found in plants, which breathe (and generate energy in the process) by harnessing the sun’s rays to split water molecules, have been attempted numerous times over the past 100 years. Electrolysis, which can split water molecules by passing an electrical current through the water, is one such attempt. While electrolysis works, the amount of energy required, the need for pure water, and the potential for competing side reactions has made the approach less than ideal.

What Nocera and his team have done is to create a similar process as electrolysis, but without the need for large amounts of energy, the ability to use even waste water, and with less potential for side reactions. When the team plunged their experimental silicon leaf into a jar of water, they were able to generate power at an efficiency rate surpassing modern solar panels.Although the process is still in its very early, experimental phase, Nocera hopes to refine it enough to power a small home from a bottle-and-a-half of water.

The Tata Group, an Indian group of companies operating in a variety of business sectors, is committed to serving the societies they operate within. Part of this commitment is an interest in bringing resources to low-income and under-served sectors. They hope that Nocera’s discovery can lead to the development of refrigerator-sized power plants, bringing energy to the 3 billion people who currently have to do without.

Nocera estimates that if his solution works as expected and can be further developed, a swimming pool full of water would meet the world’s current daily electricity needs of 14 terawatts. Obviously such a discovery would be a tremendous game changer. We’re watching with interest to see what happens next.

You can watch a video about Sun Catalytix below.

Chu says wind, solar competitive with coal in decade

Secretary of Energy Steven Chu (left) meeting ...

Energy Secretary Chu and President Obama. Image via Wikipedia

In a March 23 event sponsored by the Pew Charitable trust in Washington DC, U.S. Energy Secretary Steven Chu said that wind and solar power may compete with fossil fuels within the next decade, without additional assistance from government subsidies.

Although the Obama administration has been encouraging investments in green energy, the main interest in developing alternative energies has been led by other countries like China. Chu emphasized the need for the U.S. to stay competitive, saying, “… the country and the companies who develop those renewable energy and resources that become cost competitive without subsidy all of a sudden have a world market. And, boy, we can’t lost that world market.”

So far, many members of the Republican Party have argued that reducing dependence on fossil fuels is unneeded and would be too expensive. Moreover, there are both technological and political impediments to bringing too many renewable resources onto the U.S. electrical grid at once. Much of this has to do with the fact that wind and solar aren’t considered a base-load resource; they can’t provide energy at the flip of a switch. There are also issues surrounding state-by-state subsidies of renewable projects (for instance, a taxpayer- supported project in Missouri can’t allow the proceeds and energy to go to Kansas).

Both parties have defended the use of nuclear energy, which provides base-load power without carbon emissions, but after events following the March 11 earthquake, tsunami, and nuclear crisis in Japan, it is unclear how much nuclear power the population can stomach. The lack of nuclear development leaves a large gap in the U.S. energy infrastructure that, at first glance, can only be filled by either natural gas or coal.

Chu didn’t clarify how wind and solar can become more competitive other than to say, “This is a race.”

Around the world in 80 days… in an electric car

I have a confession to make: the car that I drive is not electric. It’s a practical, nice looking Toyota Matrix. Not entirely unexpected for a person who teaches matrix computations at university regularly, of course, but I do feel pangs of guilt occasionally when driving around town. Honest, my next car will be electric. Especially after hearing, whilst driving that same Matrix,  a wonderful NPR “The World” segment last week on the recently completed Zero Emissions Race.

The three finalist of the Zero Race, from http://www.zero-race.com

Imagine driving 27,000 kilometers through 17 countries in 80 days in an electric vehicle. Three teams from Australia, Germany and Switzerland managed. The Australian team drove a three-wheeler that was dubbed “TREV”, the Germans an electric scooter and the Swiss a sort of high-tech motorcycle.

The race was organized by Louis Palmer, who some of you may remember as the “Solar Taxi Guy”, who toured around the world in a solar car three years ago.

The participants stopped off at the World Climate Conference in Cancun, Mexico last December. They drove through Europe, Russia, China, Canada and the United States, and finished with a track through Morocco and Spain.

I loved this “race”. It was not without its share of problems. It was difficult at times for the teams to charge their vehicles, particularly in Russia and China, where sometimes they had to wire directly into the power supply. And naturally, the race was not entirely emissions free. In places, electricity used for the vehicle was generated by fossil-fueled power plants.  But overall, it was a challenging, exciting adventure that managed to put a bright positive light on electric cars. I also loved that the Trev was designed by students at the University of South Australia in Adelaide.

For all of you interested in participating in such a race, there is another chance: The Zero Emissions Race Europe from September 3rd to the 25th. Let me know if you put a team together. I’d be happy to be the supply van. Me and my Matrix, but guilt free as we’d be helping to advance this future mode of transport.

Super solar skin: A glimpse of the future?

I was pleasantly surprised this morning when I opened the Stanford electronic newsletter. One of my colleagues, Zhenan Bao from Chemical Engineering, is developing an ultra-thin and stretchy material that can sense touch, detect chemicals and power itself with ultrathin and stretchable solar cells.

Photo from Stanford News, February 24, 2011

The skinny solar cells have a wavy stretchable structure, a bit like an accordion. Liquid metal electrodes are used that conform to the variable surface. It is not hard to imagine using these cells on fabrics. Fancy a solar cell suit?

The first solar PV cells were made of crystalline silicon. Such cells are relatively thick and stiff. Second generation PV cells are thin film cells, like the Cadmium-Tellerium cells produced by the US based company FirstSolar. A big advantage of thin film cells is that they are flexible and can be fitted to curved surfaces. To not only have flexible materials but also stretchable materials, like the solar skin developed by Bao and her colleagues, is very attractive. It can be fitted to moving parts without fear of cracking, wrinkling or breaking. The solar cells work also in stretched state.

I am not sure what the power density is of these solar cells, nor how much the power delivery is cut in stretched state. But, this is of course only a first prototype. My guess is that we’ll see very rapid developments in this area. The applications are just too attractive not to draw large investors.

We hope to organize an interview with Bao and ask her more about the underlying technology.

This is one of these research outcomes that makes science fiction science non-fiction. I love it.