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New Material for More Efficient Solar Cells
PunkerTFC writes "Space.com has an article on a new material that could create relatively cheap solar cells which are up to 50% efficient. This is much better than the 25% efficient silicon solar cells (most common) or the 36% efficient multi-junction solar cells (very expensive). The material was created by "forcing oxygen into a zinc-manganese-tellurium crystal" creating more band gaps, which allow the cell to create electrical energy with three seperate frequencies of light. This could lead to cheap, high-output solar cells in the future, but it will take at least 3 years to assess the feasibility of the new technology, according to the researchers."
Solar cell technology seems to be getting more and more advanced. When will the time come when we are able to use it to effectively power a complete house?
We are there today. In fact, we where there several years ago. The trick is not to need more power than the solar cell generates... so obviously you can easily supply the energy a house needs from solar cells if your house don't need much energy. Say, if you live in the tropics or subtropics, there is no big deal to power everything electrical with solar cells today (even more so if you use natural gas for cooking and running the frigde). If you live above the arctic circle, the day will never arrive that solar cells are efficient enought - since when you need them the most (ie; in winter), the sun just isn't over the horisont... up here it's more a question of efficient storage of the electricity.
I'm more interested in getting really cheap solar cells than super efficiant ones - if I can put up ten cells produsing (say) 1kWh each for the same price I can put up two producing 4kWh each, the cheaper ones are the better choice - as well as making replacing broken arrays cheaper.
Off course, the day I can get solar cells that are both cheap and efficient, I'll pick them without a second thought ;)
Everything in the world is controlled by a small, evil group to which, unfortunately, no one you know belongs.
One alternate plan is to use cheap titanium dioxide to make less efficient solar cells that are significantly less expensive. Titanium dioxide is used to tint paint white and is available cheaply in bulk. While researchers are working on increasing the efficiency through nano particle techniques, do it yourselfers have made progress.
Solar sales are up 30-40% every year, and have been growing at such a steady pace for a long time.
Naturally, this is a positive feedback loop. Lower prices mean it's affordable for more niches, which means more people buy, which in turn scales larger. At this point, it's pretty much unstoppable. It is useful in too many niches, especially where customers aren't connected to a power grid.
There are now many countries that have more cell-phones than landline phones. It's likely that in 10 years, some countries will have more customers getting electricity from solar than from a central grid. Naysayers will say it's not ready... but then again, 15 years ago cell phones weren't either. What matters is not the absolute numbers, but the growth rate of the industry and the evolution of the technology.
Of course, as the market matures, more people are doing R&D to find cheaper ways to build PV systems, which is only going to accelerate this momentum.
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It's a question of what we can harness. Enough energy falls on the surface of the Earth every day from the Sun to supply the World's energy needs for weeks, we just can't harness it effectively.
Large scale solar farms in desert and offshore areas would be a very useful source of power for the future, even if it isn't used as a primary, continuous source. An offshore solar farm could be used to electrolyse seawater to produce hydrogen for fuel cells, for example - it is currently expensive to do this because you get out less energy than you put in. Using solar energy though, that doesn't matter because the sun is free (unless the US Patent Office grants someone a patent on "a large ball of gas and dust undergoing nuclear fusion that the Earth orbits around".
SCO will no doubt claim that the Sun also contains System V code. Darl McBride is welcome to visit the sun in an Apollo capsule to inspect it for himself. How he's going to get to the Sun's kernel is beyond me. He'd better pack some sunblock.
Then your wait is over. From the Renewable Energy Myths Debunked article at homepower.com:
Myth: It takes more energy to build PVs than they can ever produce.
Some skeptics of solar energy claim that it takes more energy to make a photovoltaic module (PV) than it can ever produce in its lifetime. The truth is that PVs typically recoup their embodied energy in two to four years. According to an article published by the National Renewable Energy Laboratory (NREL), today's single and multicrystalline modules have an energy payback of about four years, and thin-film modules about two years.
Most PV modules in the field are made from hyper-pure crystalline silicon. Purifying and crystallizing the silicon consumes the most energy in making these PVs. Thin-film PVs are made from considerably less semiconductor material, and therefore have less embodied energy in them. Most of the energy consumed is in the thin-film surface. The aluminum frame on any PV accounts for about six months of its payback time.
Solar energy is an amazing technology considering that PVs go on to produce clean, pollution-free energy for at least 25 to 30 years after they have achieved payback. For more information on energy payback, see the National Renewable Energy Laboratory's Web site (www.nrel.gov) and Karl Knapp & Theresa Jester's article titled "MPV Payback" in HP80.
I don't care if it's 90,000 hectares. That lake was not my doing.
And on that same page, they do mention that PV prices can go as low as "$3.58 Watt: thin film and $3.16 Watt: crystalline." $5.85 is an average, which includes PVs that are designed for different systems. In my case, I only care about cost per watt as I will have a sufficient surface, others have to worry about squeezing the most energy out of a limited space. Different needs, different models and different prices.
The most promising route will probably be solar rooftops, where solar cells are integrated with construction materials. For new construction or re-roofing, this makes a lot of sense because you don't have to pay much more for installation. With net metering, you also wouldn't need the expensive batteries. Of course, that assumes you're on the grid; if not, connection charges can be more than going the cost of going solar, including battery array.
Solar is still expensive for now, and this has led most people that consider it to use every trick in the book to lower their energy consumption. Better lighting, appliances, windows, insulation... if it cost less money to conserve than generate, it only makes sense to spend money on efficiency. You probably do not need 564kWh/month- you should be able to reduce that by at least a third, with a payback in under 2 years.
There are other applications too where cost alone is not a huge issue. If reliability is important, being able to have your own power supply, batteries, and a net metering arrangement with the grid could be a cheaper solution than most UPS, and give you far more autonomy.
While you may not see it as rosey, it's hard to argue with the fact that sales are still growing, year over year. And I can't think of anything that could stop that in the next 20 years: it's all but inevitable.
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