Sanyo's just announced that it's going to build a new factory in Japan dedicated to solar photovoltaic cell manufacture--the company plans to double its solar cell output to meet rising demand as the world slowly catches on to the idea of renewable energy. But in the light of some thinking about the rarity of chemical components, perhaps Sanyo actually shouldn't be planning a project like this at all.
The new Sanyo plant will produce more modern-tech photovoltaic (PV) cells than the company currently manufactures, with a higher power-output per incoming sunlight. The factory, planned for Osaka prefecture (along with a second factory which will make cheap PV cells for developing nations,) will effectively double the total power output from Sanyo-made solar cells to around 680 megawatts annually (for comparison, the Hoover Dam's peak power output is about 2 gigawatts.)
But while these plans are pretty admirable from an eco-friendly point of view, thanks to the environment-saving low-carbon-footprint nature of solar power, there's a growing body of scientific thought that's concerned about how renewable this, and other "renewable energy resources" actually are.
For high-power solar cells the issue boils down to a single element used in their manufacture: indium.
While PV cells are manufactured a little like any other semiconductor device on a silicon frame, the power efficiency of silicon-only cells is pretty limited. By doping the silicon with other elements and creating multi-junction devices, the efficiency can be pushed way up to around 40%. One element used for this purpose is indium, which is also used in indium gallium arsenide-based infrared detectors and mini lasers, and to make LCD screens.
But indium is actually an amazingly rare metal: It's present in very few mineral ores, and makes up just 0.25 parts per million of the earth's crust--compared to the 63,000 ppm of iron. Some researchers estimate that if we continue to use indium at the current rate there may be just a 10-year supply left.
There's a similar problem for fuel cell technology. Part of the magic that turns hydrogen into electricity in a fuel cell is the use of platinum as a catalyst: It promotes the chemical reaction that generates power and thus boosts the efficiency of the resulting cell.
But platinum, which is also a precious metal used decoratively and commonly elsewhere in electronics manufacturing, is thousands of times less abundant than even indium--it's present at around 0.003 parts per billion in the crust.
So if there's a radical rethink of the way we're exploiting the unrenewable and eco-harming energy resources of our planet, and a massive shift towards renewable energy resources, then the useful lifespan of both of these rare metals as electronic components is frighteningly short.
There are other chemical alternatives for use in both semiconductors and fuel cells, of course. Carbon nanotubes are looking like an increasingly useful supermaterial. Just last week researchers at Dayton University demonstrated they could be used to replace platinum as a catalyst in hydrogen fuel cells, and there's work to use nanotubes and graphene to create a better hydrogen fuel tank and a super-battery to store electrical power. Nanotubes are even showing potential as solar photovoltaic solar-cell materials.
Instead of building a factory to use up our precious indium resources at double the rate, perhaps Sanyo would be better off spending the money on researching carbon nanotube-based technology instead. After all, carbon makes up around 1,000 parts per million of the earth's crust, and there's plenty of it greenhousing-up the atmosphere as CO2.
[via Physorg, NewScientist]
Related Stories: | Topics:Innovation, Technology, solar cells, renewable energy, environment, sanyo, alt-power, solar power, platinum, fuel cells, eneloop, photovoltaic, indium, Science and Technology, Technology, Sanyo Electric Co. Ltd., Fuel Cells, Energy Technology |
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Recent Comments | 4 Total
February 10, 2009 at 12:58pm by Joshua Pearce
Rubbish – This article needed to be fact checked by someone remotely familiar with the photovoltaic industry.
First, the planned expansion for Sanyo's photovoltaic manufacturing plants will not use any indium at all – they are all silicon based technologies. The vast vast majority of the photovoltaic market is silicon based. In no way is the photovoltaic industry completely reliant on indium.
Second, some high efficiency solar cells do use indium – but not by doping silicon. These types of cells are a completely different technology for the high end part of the market – think military satellite not roof.
Third, using efficiency to compare photovoltaic technologies is incredibly naïve. Yes, every solar cell would be better if it were more efficient but a 40% solar cell is not necessarily the best. The way to compare solar cells is cost. Ideally cost per energy produced ($/kW-hr) because different technologies perform variably dependent on the environment. Usually they are compared in cost per peak power ($/W). So, for example, thin film amorphous silicon solar cells with relatively low efficiencies (10%) cost much less per unit power or per unit energy than anything with gallium in it.
The entire premise of the article is wrong. Why is Fast Company publishing such garbage? Retract it.
February 10, 2009 at 12:59pm by Kit Eaton
@joshua. The article doesn't state the "photovoltaic industry is completely reliant on indium". It merely highlights that some high-efficiency pv cells use indium in their manufacturing, which they do. And neither does it say that 40% efficiency is the best--it highlights that improving solar cell efficiency to 40% is possible. Comparing solar cell efficiency is a valid argument for this purpose. Sure, cost per energy produced is an interesting metric--but improvements on that scale are often achieved throughout a product's life in mass production. A thin film solar cell may well have a low cost per kWh price, but at 10% efficiency you simply need more square meterage to generate the same power output. That criteria is a key if you're talking about solar cell-powered portable gadgets with limited surface area, or indeed if you're talking about power generation on a massive scale. The push towards higher solar cell efficiency is going on in labs throughout the world--it's essentially a research issue for the time being. Simultaneously research into alternative material cells is going on, and that's an equally interesting area. It's horses for courses, ultimately--different solar cell technology will find applications in different equipment, as each technology matures. And remember that nearly all "high-end" tech makes its way into "low end" products eventually.
As such the central tenet that indium and platinum are rare metals that have a predicted short useful lifespan still holds--increased usage, in solar cells or whereever, will only reduce that life.
February 10, 2009 at 10:21pm by sangryul han
President Barack Obama recently asked Congress "to act without delay" to pass legislation to double alternative energy production in the next three years and build a new electricity "smart grid." This smart grid would be an updated digital version of the electric wires strung across our country in the past century. What makes it "smart" is that the lines would be buried and more efficient and would give homeowners feedback on how efficiently they were using the power inside their homes.
This new smart grid would cost about $400 billion over 10 years but would save between $46 billion and $117 billion over the next 20 years by reducing inefficiencies and power failures, according to the U.S. Department of Energy. It also would help to make us less dependent on imported energy and to reduce climate change. For example, if the smart grid were even 5 percent more efficient, it would keep as many carbon emissions from the atmosphere as eliminating 53 million cars.
A smart grid allows power from residential solar panels, small wind turbines, and plug-in electric vehicles to be fed into the grid. This would encourage the green energy industry by allowing small players, such as individual homes and small businesses, to sell power to their neighbors or back to the grid. It would provide another source of income for larger commercial businesses that have renewable or backup power systems that can provide clean energy for a price during peak demand, such as midday in July when the air conditioning is cranked.
Another brilliant feature of the proposed grid is the potential to use cars to store electricity and then feed it back into the grid during times of peak demand. "Vehicle to grid," or V2G, technology helps balance energy loads by "valley filling" (charging at night, when demand is low) and "peak shaving" (sending power back to the grid when demand is high). This would help utility companies keep voltage and regulation stabler. It would be especially useful when more of our power came from intermittent power sources, such as solar panels, which only produce power during the day.
Power outages are less problematic for a smart grid because it quickly can isolate the problemand create energy pathways around it. This makes a smart grid "self-healing" by reducing power outages and saving money. Buried power lines also would reduce outages caused by harsh winter storms, when tree branches are likely to down power lines. In my community, residents are concerned about proposed power lines that would stretch through the centers of many small downtowns and across lovely vistas. If these same lines were buried, there would be fewer objections from the community.
The smart grid could help consumers use that energy more wisely and save money, as well. A sensor in your home can tell you the price of electricity when the demand is highest. This allows you to set priorities so that you use more energy when the price is lower and less during peak demand. You also can find out which appliances are energy hogs and identify energy vampires that you may not have known about.
Austin, Texas, has been working on a smart grid since 2003, when its utility company first replaced a third of its manual meters with wireless smart meters. Austin currently manages 200,000 smart meters, smart thermostats and sensors across its service area and expects to be supporting 500,000 devices this year. Boulder, Colo., started a smart grid project in August 2008. The smart grid extends into homes through home automation network devices. These devices automatically set thermostats, reduce energy loads during peak times, and shut off lights in rooms when no one is in them.
By investing in our infrastructure, we also would stimulate economic growth and increase green jobs. Thousands of peoplewould be put to work across the country designing, building and installing smart grid technology. Having the grid in place wouldmake electric carsmore feasible and affordable. Renewable energy would become more viable, and demand would increase as more electric carswere added to the grid. It also would bring the price of homeand business-scaled renewable power systems down because the payback periods would decrease. Businesses may make tidy profits by selling excess power back to the grid.
Want to learn more about the smart grid? The U.S. Department of Energy has an easy-tounderstand publication you can download online called "The Smart Grid: An Introduction." The DOE is conducting a series of smart grid e-forums to discuss issues surrounding the smart grid, including costs, benefits, implementation and deployment. Thank you !