While high eff is nice, it\'s $/wt/life that is most important. By far the most cost effective solar is had by those paying the highest price for electricity, home, building owners both which have plenty of no cost room for them.
While I love the idea of photovoltaic electrical generation. Wouldn\'t it be a lot more effective to just put a few solar panels on top of every business and home? That could conceivably generated VASTLY more electrical output with less transmission loss even if the solar panels aren\'t that efficient? Just thinking out loud here.
The problem with commercially availability of solar cells is that they are not always created equal. I have had many individual cells that test differently between cells. Some cells are more efficient than others...even from the same batch!
Then there\'s the problem with crazing of the surface covering the solar cell. Some solar cells that use a polymer coating after being exposed to the sun for months on end will become cloudy and will start to craze and crack. Once this happens, the solar cell needs to be disposed of. I\'ve rarely had one of these cells last longer than 2 years. And now landfills will have to deal with the components of discarded solar cells...I wonder how many of those millions of solar powered garden lights that Walmart sells are thrown away when they are no longer working?
The building top concept is already being done just like the plants are already being done. The difference with a solar power plant is that anyone can use it by paying for that particular electricity if it is on the grid. If you lease a building for your business or rent in an apartment, or have a store in the mall, you can not install solar panels.
The higher efficiency will cost more just like anything bigger, faster, better would but it will also inspire other companies to improve and push down the cost of the lower efficiency panels. Just think DVD vs. blueray and remember how expensive DVD players were when they first came out. Now you can get a DVD-R for your computer for $20 BUCKS.
I agree with you in that $/wt/life and especially CO2 over life numbers are more important. Higher efficiency only equates to less surface area required for the same output. This can have possible benefits on production cost, CO2 emissions reduction from production, but in general it will normally always be marketed at a higher cost to consumers. This means it is less affordable, and less units are sold, and therefore less likely to drive market prices down. Besides surface area is generally not at a premium unless your powering a satellite. A cheaper less efficient cell is more likely to produce a positive impact on PV cell cost, but no-one is interested in earning less money per unit produced and so the obsessive race for higher efficiency continues.
It is partially true that you would save on transmission loses by placing the PV generation at the point of consumption. The only problem is that consumption doesn\'t always coincide with PV production, so you need to be able to import/export energy via the network or energy storage to offset this conundrum. Alternatively consume when the energy is available...but good luck teaching someone to do that! Plus in order to setup PV more effectively you would want to do it in an area of high solar influx (ie desert) and not ie Sweden where you could have up to 6 months without sunlight, plus overcast weather. It would seem that it is not as simple as installing solar on everyones roof to make it work all year round.
I still think the best way is to implement combined PV or Stirling Engine hot water power generation using concentrating solar dishes like this one: http://www.infiniacorp.com/360view.html
Firstly it uses the invisible infrared spectrum which accounts for nearly 70% of the radiation energy from the sun, (PV generally only uses the visible spectrum, with the infrared portion further decreasing PV performance by heating the semiconductor), plus it produces hot water for consumption as a side effect of cooling the stirling engine, if used as a local generation source on a household. Seeing that the world consumes more energy in households for heating, than any other energy consumed in the house, I think it would be more appropriate. BTW they solved some of the production cost dilemma by using polished alu foil for the collector, instead of semi-conductors, plus it tracks the sun which would even increase output of PV by up to 40%. Seems to be a few things already available that would increase the overall efficiency...all I can say to a 3-4% increase in PV is \"next article please!\"
Of course, Infinia is cute...but they would not bother with residential...nice dreaming.
Infinia plans to sell to residential once they work out the bugs. I worked on Infinia as a supplier for a while - they had many problems, then I later ran into one of their reps on vacation and she told me that none of the first batch sent to a solar farm in Spain worked on arrival. That was 10mo ago, so hopefully they got them working... The units are $30k each.
There are other Stirling dish makers too. They all claim more efficiency than PV, likely due to the IR benefit as jeffblogs said, but they do seem more complicated. The 3kw stirling engine cost as much to make as a Corvette engine. It has ridiculously tight tolerances to work efficiently and operates in 200 times atmospheric pressure. It\'s like putting an engine in a diver\'s oxygen tank.
I\'m not saying PV don\'t have issues, but further increases in efficiency and cost reduction in both systems (dish and PV panel) will determine who wins in the marketplace. The one that has the best $/kW/life numbers will be a likely source of our energy in the future.
Mark in MI
I am certain that distributed solar power -> having solar panels on roofs of most, if not every home and business (malls will have to get on board too, they have lots of roof and power requirements) is the way of the future. Power distribution is a big issue and distributed power at least patially, if not completely solves it. Every house can easily have solar hot water that requires NO PV cells, just black aluminum panels with tubes in/on them! It should be required on new construction in areas with a lot of sunlight.
Mark in MI
BTW, solar hot water would likely be supplemented by grid/gas water heating. Your water heater could have a smaller heating element to use less grid power. Likely, most people could eliminate the tank heater and just have a couple of under sink/under tub booster heaters for on-demand hot water if the tank is not hot enough. These are easy to install and run only when you turn on the faucet and need water hotter than the solar tank has.
Mark in MI
We don\'t need small, expensive, high-efficiency technology as much as we need CHEAP, VERSATILE and AESTHETIC solar collectors. Cheap, bulk cells that could replace shingles on roofs, conductive paints and coverings, etc.
I read where someone came up with inexpensive tape imprinted with solar cell collectors. Something like that could have LOTS of applications.
A few points to note:
• To the gentleman that complained he's only seen solar cells that lasted 2 years and then "crazing" caused them to haze and crack. He is likely thinking of cheap plastic solar panels used on some solar garden lights. The solar panels deployed on buildings and commercial generation stations are all made of special solar low-sulfur glass which does not have this problem and in general, solar panels are all warranted from 25-30 years. This is not a real problem when it comes to real solar panels. (Not to be confused with cells which are only a subcomponent of panels).
• Distributed generation in concept is a great solution for suburbia and rural areas, but this will not work for urban centers which have tall buildings with very small roof profiles. They will still have to get their power generated from outside the cities by utilities, so utility-scale solar is an important part of the mix, to be sure... Projects like the Brightsource Energy Ivanpah project not far from Las Vegas are the answer for greening power used to supply urban centers, rental properties which aren't likely to be upgraded except begrudgingly by their owners, and low-income households who can't afford any home improvement projects. In a state like CA which is by law required to upgrade its renewable energy mix to 20% by 2020, utility scale projects are perhaps the largest contributor towards reaching that goal, regardless of the type of technology deployed.