May 9, 2008
Solar energy's presence is now felt. If its influence is to expand, however, researchers must innovate and develop tools to store the power.
That's the view from researchers at the Massachusetts's Institute of Technology who have received a substantial grant to make it all happen. Their overall goal is to improve today's mechanics, or to bring in disruptive technologies, that would greatly increase efficiencies and add value. As advances are made, prices will drop and give solar energy a chance to compete with conventional fuel sources.
Today's solar photovoltaic technologies have an efficiency rate of 10-15 percent. That compares to a thermal efficiency rate for a coal plant of 35 percent -- the amount of energy that ultimately gets converted to electricity. Solar is also more expensive, costing about 25 cents a kilowatt hour. That's compared to about 9 cents a kilowatt hour for natural gas and 5 cents a kilowatt hour for modern coal-burning plants, as well as 6 cents a kilowatt hour for wind energy if tax considerations are included.
"We think within the next decade that much of the critical, underlying science can be resolved," says Ernie Moniz, professor and director of the MIT Energy Initiative. "Then there are all kinds of external issues such as federal regulation and carbon pricing that will drive the rate of penetration. It will all serve to scale up manufacturing. Our job is to get rid of the key barriers and to create higher efficiencies that will lead to lower costs."
Solar power is also challenged by when, where and how often the sun shines. The American Southwest, for example, has twice the production potential of the Northeast, but that's where more people are located. Moreover, the sun only shines a third of the time even in the brightest locations, after factoring in darkness, dawn, dusk and clouds. That makes it difficult to cover the cost of paying off a capital-intensive technology.
That's where the MIT undertaking comes in. Its Solar Revolution Project, which is one of the largest solar energy clusters at any academic institution, is funded by an initial gift of $10 million by the Chesonis Family Foundation. Researchers there will explore new materials and systems that aspire to accelerate the availability of solar energy. Specifically, it will focus on three elements-capture, conversion and storage -- that will ultimately make solar power a viable, near-term energy source.
The key driver is climate change and what the project's sponsors say is an urgent need to develop carbon-free energy sources. Solar energy is clean, abundant and widespread. It can be used to increase electricity generating capacity while decreasing greenhouse gas emissions as compared to other energy conversion pathways. But until efficiencies are reached and the technologies are developed that can store the sun's energy, it will be limited to providing power during the hottest days.
"Yes, at large scale, the sun is the answer to the energy future of our planet," says Dan Nocera, W.M. Keck Professor of Energy at MIT. "The technologies are feasible, but they do not currently exist and hence the comment that you so often hear 'solar is the answer but it is far off in the future.' This is not the same as a pipedream."
Hitting Stride
Solar energy is promising and in fact, has received the greatest share of new capital flowing into green enterprises. Like all other fuel forms that include coal, natural gas and nuclear, solar has received some much needed tax breaks to penetrate the market and to become more competitive with other options. Last year, those breaks helped increase installations in the sector by 43 percent.
Winning new capital from venture capitalists and major manufacturers of generation technologies remains challenging. Such enterprises are stepping forward. The endeavor is no doubt helped by state mandates that are giving investors more confidence that they can earn handsome returns. California, for example, requires utilities to provide 20 percent of their fuel options in the form of green energy by 2010. That has motivated solar manufacturers from around the globe to start bidding on projects.
Solar energy now provides less than 1 percent of all energy needs in this country. Currently, 742 megawatts of solar cells are produced annually worldwide. Germany has 500 megawatts of solar energy already installed. That market, along with Japan's and the United States', accounts for 75 percent of the world's solar photovoltaic market. Globally, the market value tied to solar power is pegged at $4 billion.
Solar panels, which are distributed on rooftops, convert sunlight directly into electricity. Creating new components and processes is ongoing. Solar cells, for instance, used to be made up mostly of electronics. Now they are composed of silicon semiconductor materials. Plastics, polymers and bio-materials are also used. The question then becomes which of these can be produced at the least costs and with the greatest efficiencies.
"The cost of solar cells has already come down because of innovations in technology," says David Lee, CEO of BioSolar in Santa Clarita, Calif., which uses bio-based materials in its products. Not too long ago, solar power had cost $1 per kilowatt hour, he says, noting that "We need to reduce costs even further by providing cheaper components."
The next big step is to figure out how to harness the sun's energy. Batteries are one option. But they could be bested by using renewable energy as a catalyst to create pure hydrogen. That energy could then be used to power everything from cars to generators without creating any harmful emissions.
The more effort that goes into studying solar power, the sooner it will be adopted on a wider scale. Solar now has its legs. But researchers such as those at MIT hope that it will hit stride within a decade's time.
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