Clear Solar Cells Could Help Windows Generate Power 87
ckwu writes "The vast real estate of windows in office buildings and skyscrapers could be a fruitful field for harvesting solar energy—if lightweight solar cells could be made with a high enough conversion efficiency and appealing aesthetics. Now researchers at Oxford University report semitransparent solar cells that might do the trick. The team made solar cells using a perovskite, a class of mineral-like materials that have properties similar to inorganic semiconductors and show sunlight-to-electricity conversion efficiencies of more than 15%. The team deposited a thin film of perovskite onto glass so that the material formed tiny crystalline islands. The islands absorb photons and convert them to electrons, while light striking the empty areas passes through. The result was a semitransparent solar cell with a grayish tint."
It's not about places to put them. (Score:2, Insightful)
The challenges for solar cell adoption are:
Cost-effective manufacturing methods
The market price of silicon
Efficiency of conversion
Storing the energy for when it's required (or moving it to where it is helpful)
and Durability
When those problems are REALLY solved, we won't need to have dark windows to generate our energy needs. And we won't need to burn coal. But we're a long way from solving all of those problems.
Seems like a dumb idea (Score:2, Insightful)
Seriously, unless you can make these absorb energy only in wavelengths we actually don't want in the house, it seems like all we'd be doing is generating electricity, which we'd then burn trying to substitute the light we filtered out. If these capture either IR, or visible light (and they deffinately capture visible light), then we're just going to end up turning on more light bulbs, and heaters to compensate for them.
Re:It's not about places to put them. (Score:4, Insightful)
When those problems are REALLY solved, we won't need to have dark windows to generate our energy needs
I think the point of this was that windows are already darkened in office buildings. The solar cells are just a different darkening process that has a nice side-effect of actually generating energy.
Re:It's not about places to put them. (Score:5, Insightful)
Second, windows need not be "darkened" to provide solar power. Most of the energy in sunlight is not in the visible spectrum.
Re:It's not about places to put them. (Score:5, Insightful)
The challenges for solar cell adoption are:
Cost-effective manufacturing methods
The market price of silicon
Efficiency of conversion
Storing the energy for when it's required (or moving it to where it is helpful)
and Durability
The price of silicon isn't the biggest problem now. Solar cells are already at parity with coal in India [thinkprogress.org], and keep getting cheaper every year.
Efficiency is generally sufficient. A house's whole roof can generally power it.
Durability also isn't generally an issue. Solar cells usually last for upwards of 20 years.
The primary challenges now are:
Installation costs
Electrical connection costs (i.e. an inverter)
and Storage (or grid hookup costs)
Re:Pseudo Science... (Score:5, Insightful)
Speaking of pesky laws of physics, o hater of all things right and good...
According to Wikipedia, only about 44% of the sun's electromagnetic radiation that reaches the ground is in the visible light range. [wikipedia.org]. Photovoltaics are typically responsive to limited wavelength ranges. It would make perfect sense to tune semi-transparent photovoltaics to absorb radiation that falls outside the visible spectrum, while transmitting most of the visible light.
You get all the benefits of Low-E glass, plus electricity.
Re:It's not about places to put them. (Score:5, Insightful)
Re:Pseudo Science... (Score:4, Insightful)
We are beginning to design stuff into cars which continuously draws power, much like the numerous things in our homes that never turn completely off.
Solar cells built into car windshields can be used to mitigate the effects of a car not having its engine running. An owner of a solar-cell windshield equipped car will be able to return to his car, parked at an airport after it has sat unused for possibly several weeks, and have the battery fully charged upon his return. I have traveled and it has always been a concern to me whether the car will start after I have ignored it for a week.
Just a few hundred milliamperes going into the battery would have mitigated this concern.
I do agree with the posters who have already pointed out that using this for office building windows is a lot of wasted expensive effort for a negligible ( and likely negative sans tax credits ) return on investment, considering the cost of line power. A car in a parking lot usually has no line power available.