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Solar Power Becoming More Affordable
prostoalex writes "With both startups and large companies such as Boeing working on solar power, the technology is becoming more affordable, MIT Technology Review says. Solar power concentrators are all in rage now: 'The thinking behind concentrated solar power is simple. Because energy from the sun, although abundant, is diffuse, generating one gigawatt of power (the size of a typical utility-scale plant) using traditional photovoltaics requires a four-square-mile area of silicon, says Jerry Olson, a research scientist at the National Renewable Energy Laboratory, in Golden, CO. A concentrator system, he says, would replace most of the silicon with plastic or glass lenses or metal reflectors, requiring only as much semiconductor material as it would take to cover an area the size of a typical backyard. And because decreasing the amount of semiconductor needed makes it affordable to use much more efficient types of solar cells, the total footprint of the plant, including the reflectors or lenses, would be only two to two-and-a-half square miles.'"
But when will it become truly affordable for the masses? That's what most of us want to know. Wake me when it's time to disconnect from the petroleum/nuclear fired grid.
It's already happening in California. This deal is huge. It's between 300 and 900 Megawatts. And what's even more remarkable is that there is no federal or state funding for this project - not even a subsidy or tax break!
The solar electricity is simply profitable. Watch this closely.
Another interesting run is the Solar Tower project in Australia. I'm really excited by this one! Once built, the operating costs drop to near ZERO.
What few people realize is how much the price of electricity varies. So go get your utility bill. Call the nearest solar energy installation guys. You may find that it's profitable RIGHT NOW to put solar cells on your roof!
I have no problem with your religion until you decide it's reason to deprive others of the truth.
Such concentration systems are usually coupled with thermal applications:
-you increase the overall efficiency of the system (up to 80-90%) by getting both electricity and heat
-you heat water while cooling down cells, which improve their efficiency too (you can get as much as 30% with germanium)
http://www.solartecag.de/sites/innovation.htm
Just to point out: Those units in California are not photovoltaic. Those are solar-thermal Stirling generators.
Just a nitpick, really. I'm also quite excited about that project.
=Smidge=
Actually, a heat pump is a bad example, since you're putting energy in to move heat, not moving heat and getting energy out. With an engine, the amount of heat moved always has to be greater than energy out. Same with a heat pump - you actually can move more heat energy than you put power in. Hence coefficients of performance greater than 1.
-b.
You'd be amazed what can be done without proper design. Last year after the natural gas price spike, my wife went on a nut and turned the heat down to 55 for the winter. I'll admit it was a bit chilly at times and sweaters or sweatshirts became our casual dress around the house but by just opening and closing drape at the opportune times, we could keep the house above 65 during the day, above 62 during the evenings. We found it was more comfortable to shower with the bathroom door closed.
Apocalypse Cancelled, Sorry, No Ticket Refunds
Your model (a heat engine) doesn't really work for solar cells, although you are certainly correct that 100% efficiencies are unobtainable.u ll-spectrum-solar-cell.html
In solar cells, the point is that photons excite valence electrons across a barrier, giving them enough energy to create a current. There isn't really a classical analogy for this effect.
There's a limited discussion of solar cell efficiencies here, although it doesn't talk much about the underlying physics:
http://www.lbl.gov/Science-Articles/Archive/MSD-f
The upshot is, cells of a single type of material can only get up to about 30% efficiency, but we can stick several materials together to get past that barrier.
what's even more remarkable is that there is no federal or state funding for this project
The R&D was federally financed. I've done some work on it myself.
One of the advantages of this technology is that it is not solar. It's thermal. An external "combustion" engine is used to drive the generating turbine, thus any source of heat may be used.
One of the problems with solar power is that it is unreliable; innately. Some sort of storage/backuup system must be available to go online at all times. By using a heat engine to turn a generator instead of direct conversion to electricity, when the sun goes down you can just throw some buffalo chips (or whatever) in the firebox. There's no need for a completely redundant infrastructure.
KFG
You forget the five Solar Thermal plants at Kramer Junction which together produce 165 MW. SEGS III - VII, as they are called, have been in commercial operation for around twenty years now. These are definitely utility scale plants, not demonstration plants.
What a horribly foolish and short sighted statement. While it is true that solar works when the sun shines, it also works when it is cloudy, albeit producing less power. Therefore the average annual power production of solar is dependable on an annual basis.
Power storage for solar can come in many forms. For a solar-thermal system (i.e. a stirling engine generator) you can simply store the heat using one of many mediums. For a photovoltaic system you can store the power using batteries, capacitors, hydrogen, heat, or even gravity by pumping water uphill. While the last three require a hybrid power system to access the stored energy (PV->H2/heat/gravity->electricity) they are not new technologies. In most areas you won't want a single power generation system so you'd have multiple plants anyway. The solar-thermal systems are particularly compatible with stored power as they work under direct solar energy, stored heat, or any combustible fuel (coal, wood, ethanol, petroleum, etc). And a solar/hydrogen power plant would double as a power source for hydrogen vehicles.
While it is true that areas closer to the equator see more power generation capacity from solar, even areas farther away still benefit from solar's ability to mitigate peak demand in summer and winter.
The cost of solar (PV or thermal) eliminates the almost incalculable secondary costs of conventional fuels (impacts on asthmatics from particulates, acid rain, ecological damage from mining coal or spilling oil, etc).
I've been on slashdot so long I'm starting to get out of touch with the cool stuff if it ain't on slashdot.