Posted on 03/01/2006 5:25:16 AM PST by Mikey_1962
Energy security has become one of the hottest political topics in the last few years with the prospects of skyrocketing oil prices and shortages. Along with the looming dangers of climate change, the urgency of alternatives to CO2 emitting energy sources is becoming more obvious by the day. One of the most important actions to counter these challenges is the establishment of alternative energy sources such as solar energy. Latest research by South African scientists have taken us one step further to realising these goals.
Solar power has traditionally been differentiated into solar thermal and solar photovoltaic systems. The photo-voltaic effect is a phenomenon that depends on quantum physics, and allows specific materials to directly convert solar radiation to electricity. The photo-voltaic effect is used in solar panels, that have been powering spacecraft for decades and have recently been making their presence felt in supplying electricity to free-standing locations on earth, like telephone towers and pump systems on farms.
However, the panels available commercially today are almost all based on high-purity silicon as the photo-voltaic material, and these panels are much more expensive than the equivalent amount of coal, petrol or gas.
The only way to make photovoltaic energy more widely used, is to make devices (including solar panels) that are much cheaper than the current silicon-based devices. The most promising PV material identified to date is Copper-Indium-Gallium-Diselenide (CIGS).
CIGS is much more efficient than silicon at converting incident sunlight into an electric current: Less than one micron of CIGS absorbs more than 99% of available incident solar energy, compared to 350 microns of silicon to do the same job.
Despite the excitement around CIGS, significant cost savings compared to silicon were not achieved, despite 20 years of research. However, a new development has made the picture considerably brighter.
(Excerpt) Read more at scienceinafrica.co.za ...
That comes to about 2500 watts of useable power. About what it takes to drive a woman's hair dryer.
Lots of large batteries will be be required for peak loads and conventional backup power for cloudy days.
This is the system that is the farthest along that I've seen in terms of solar.
http://www.stirlingenergy.com/whatisastirlingengine.htm
It's my understanding is that california is planning to deploy to a massive array of these for multi-megawatt power production.
Powering your house off rooftop solar costs ~$7000 and used to be tax-deductable. Some energy companies pay you for excess energy production from your solar array, some don't. Here in Austin, TX - the municipal energy company rebates 75% of the cost if you hook your solar into the grid, so they get the excess energy. It's like a mini power plant for them. Without rebates or tax deductions, solar can pay itself off within 5 years or so.
Regarding geography, solar energy is effective at some level in most areas outside of the arctic circles. Near the coasts, you can expect increased production because of solar reflection off the ocean. Decreased power plant emissions increase solar emissions.
I think the stigma of solar energy is one of its ownly problems. Energy production doesn't have to be the responsibility of a large organization. Solar energy has been a worthwhile home investment since the mid-1980's, it just hasn't been a state/corporate solution and won't be for another 10 years.
The best way to gather solar energy, of course, is in space. A massive array could gather the energy and beam it down via microwaves to massive collection areas on the planet. It would be very effective - 40-50 years off though, and the collection arrays would have to be isolated.
Inevitably, if we try everything and it all generates power, that's good. When it comes to energy production, you don't need a unified solution. Nuclear, Wind, Solar, Biofuels - let's do it all. We can sort it out once we've ditched the coal plants and it's safe to eat fish again.
More info:
http://en.wikipedia.org/wiki/Solar_energy
There's a major solar facility going up in Cali using stirling engines. The article was posted here some months ago by moi.
"A typical middle-class suburban family needs only about 30 square metres (about the size of a living room) of solar panels to supply all of its electricity needs"
That depends on what country they are using to define a "typical middle-class suburbsn family", in some that would be a couple of light bulbs, a TV, and a refergerator.
I'm already in the final planning stages of a 5KW net-metered system w/3 day supply battery bank. I'm cutting thru the red tape now and plan to be on-line by late June or early July.
If quality of writing is any indication of veracity, this product is in trouble.
Where would you store the batteries to provide electricity at night?
Solar panels have been running about $5 a watt for decades in spite of constantly increasing sales. Mass production ought to kick in one of these days and drop the price to 5 cents a watt. Then we'll see a revolution in home power systems.
So before overhead and installation costs, it already costs $80 to turn on one light bulb.
Wake me when this is ready for commercialization.
If you want to build a solar panel, the materials you need are available only from companies who, in the end, pay Mobil Oil Corp. to get them.
What kind of batteries will you be using? According to the article below lithium ion batteries will soon be available for solar energy storage. Much better than lead acid.
In the future, off-grid buildings and electric vehicles will use all sorts of promising technologies to generate and store electrical power. In the foreseeable future however, batteries will remain the primary storage system for electrical energy.
Batteries are a crucial part of any off-grid building. Lead-acid batteries store electricity generated from wind, water, or solar generators. An inverter usually draws power from these batteries to power lights, appliances and other electrical devices. The battery “bank” is aptly named. You can never withdraw all of the electricity deposited into the bank due to battery issues and of course, system losses -- like many banks out there, it’s the service charges that get you.
Electric vehicles have traded lead-acid batteries for Nickel-Metal Hydride cells. NiMH cells are considerably lighter than lead-acid. This provides an immediate benefit to electric vehicles -- it means there is less vehicle to move. A drawback of NiMH is a widely-known problem of the memory effect -- this is when a NiMH battery begins to lose its ability to hold a charge, reducing a large capacity battery to a medium and then small capacity one over time. This memory effect means that NiMH batteries have a shorter life-span than lead-acid in most applications.
Lithium Ion batteries have all but dominated the small electronic device industries. Laptop computers, cellular phones, camcorders and other portable electronics. Li-Ion batteries are the smallest, lightest, and most dense energy storage system available today. Because of this density of energy, there have been sporadic incidents where a punctured Li-Ion cell can cause an undesired exothermic reaction, which in plain english, reminds us of the laptop bursting into flames incidents of a few years back. Even a small laptop battery has enough stored energy to cause damage or injury. Imagine an electric car, with hundreds of times the stored energy of a laptop battery being involved in a collision. This has been a great concern about scaling up Li-Ion batteries, yet the benefits of doing so have drawn companies into that field.
Valence Technology in Austin Texas has developed a high-capacity Lithium-Ion battery that brings the benefits of Li-Ion technology to the consumer yet has managed to remove the dangers associated with large Li-Ion batteries.
Valence Technology has developed their Saphion battery technology. This Lithium Ion battery has been designed to not only have similar form factor and greater capacities as typical lead-acid batteries, but most importantly to be completely safe, even in the event of a puncture. Their primary market is military communications where light weight, high capacity, and resistance to bursting into flame are highly desirable characteristics. On their website, they show a video demonstration of a traditional Li-Ion battery and a Saphion cell, both shot with a single round from an assault rifle. The traditional Li-Ion cell immediately bursts into flame, incinerating itself while the Saphion cell, even after a second hit, remains inert.
While Valence has courted the military as a customer, the Saphion batteries have made their way into the latest generation of Segway Human Transporters. Segway found that the Saphion battery enabled them to reduce weight, increase range and improve reliability of the battery system on the HT 180i and new off-road model.
While I look forward to one day being able to power my house, car, and boat from a cold fusion reactor, Stirling engine, or fuel cell, it is good to know that during the decade or so it will take to finish those technologies, people are working to improve a crucial component of electrical systems today.
The best way to gather solar energy, of course, is in space. A massive array could gather the energy and beam it down via microwaves to massive collection areas on the planet. It would be very effective - 40-50 years off though, and the collection arrays would have to be isolated.
I have read that proposal when I worked for Spectrolab back in the early 80's. Very interesting stuff but it dosen't address what I think is the core issue with energy generation. Supplying energy to the masses from a central generating source of some kind/any kind vs point of use generation. The only true energy independance will be when you generate what you need from where you are. Anything else will allow somebody else to control haow much and where it will go. I like the point of use idea myself.
You'll fry the songbirds and squirrels. So I was told by some utopists from L-5.
(AGM) Absorbed Glass Mat batteries, to start, hopefully new technology will have emerged by the time these kick.
http://www.beaconpower.com/products/EnergyStorageSystems/SmartEnergy6kWh.htm
What size (area) of solar panels is required to produce 5 kW?
Depends on the DC output of the panels. Mine will take up about 400 SF.
Bump for cool tech.
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