What if.. solar cells

[GregLocock]

Currently solar cells cost around $4 per peak watt. 1 peak watt of cell gives you around 7 Wh per day of electricity on a good day, or 4 Wh if it is poor weather.

There are several technologies coming up in the next five years that could see solar cells dropping to around $1 per watt. In fact even now the price is driven by high unsatisfied demand rather than production costs. My house uses 1500*24 Wh per day, so I'd need 9000 peak W of cells, which is almost viable at first sight, given that my current bill is around $800 pa.

So, how would your field be affected by cheaper solar power?

Can YOU think of a good diurnal storage technology that we haven't seen yet?



Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[GregLocock]

My house has say 60 m^2 of roof space. So if these new cheap cells manage a lousy 10% efficiency, and one sun is about 1500W, that is a 9000W nominal panel.

Which oddly enough if you refer to my first post, is just what I need.

That and a load of batteries (or whatever).

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[moltenmetal]

Greg: if the cells double as roofing, and stay waterproof at least as long as 25 year shingles, you may have something. Trouble is, most of those cells won't be pointed toward the sun unless your house has a very wonky roof. And if they wear out before they pay back, it's a poor investment. But if you tax fossil fuels to attribute their REAL costs of consumption to those who consume them, payback will be a lot faster.

I see the real problem with current solar cell technology to be their embodied energy. Are they finally generating ten times the energy in their lifetime that they take to make, transport to site and install? Then you can call solar a "green" technology- and not before. Windmills, on the other hand, don't suffer from this problem- because they deal with a concentrated form of the solar energy rather than depending on the solar flux directly.

Saw some articles recently about people trying to mimic biological photosynthesis as a means to generate/store solar energy, ie. using chemical photosensitizers. What they neglect to mention is sensitizer degradation. Unlike a tree, any device we build won't be able to make its own sensitizer to replace the amount that the sun de-activates, bleaches or otherwise destroys. The sun is tough on chromophores long-term. If the sensitizer costs more to replace than the energy you produce is worth, you don't have a process. Evolution has come up with a pretty good system- mind you, it had a couple hundred million years to do it.

 

[arunmrao]

A nice picture of a windfarm as it appears in BBC news today.this is certainly any day better than the coal yard or the ash pond that we get to see in a thermal power station.

http://news.bbc.co.uk/2/hi/in_pictures/6113552.stm

 

[CorBlimeyLimey]

Maybe offshore Wind farms would be better.

http://en.wikipedia.org/wiki/Image:DanishWindTurbines.jpg

The neighbours won't be bothered by noise pollution.
Birds are far less likely to fly into the blades ... except for Seagulls and Cormorants ... and that would be a good thing anyway.
Doesn't take away from useable property and gets away from the NIMBY element.

Maybe they could also double up with wave power.

 

[SomptingGuy]

Maybe oil companies could improve their green image by siting wind turbines on their offshore rigs?

 

[CorBlimeyLimey]

Oil companies have to have a "green image" before they they can improve it!!!

 

[0707]

GregLocock

I found this stuff that could be useful for you to solar energize your house

“A "typical home" in America can use either electricity or gas to provide heat -- heat for the house, the hot water, the clothes dryer and the stove/oven. If you were to power a house with solar electricity, you would certainly use gas appliances because solar electricity is so expensive. This means that what you would be powering with solar electricity are things like the refrigerator, the lights, the computer, the TV, stereo equipment, motors in things like furnace fans and the washer, etc. Let's say that all of those things average out to 600 watts on average. Over the course of 24 hours, you need 600 watts * 24 hours = 14,400 watt-hours per day.
From our calculations and assumptions above, we know that a solar panel can generate 70 milliwatts per square inch * 5 hours = 350 milliwatt hours per day. Therefore you need about 41,000 square inches of solar panel for the house. That's a solar panel that measures about 285 square feet (about 26 square meters). That would cost around $16,000 right now. Then, because the sun only shines part of the time, you would need to purchase a battery bank, an inverter, etc., and that often doubles the cost of the installation.
If you want to have a small room air conditioner in your bedroom, double everything.”

About your statement “solar powered car is never going to be practical” definitely you don’t like to be outrun by a snail.

 

[sms]

Somptingguy,

That is already being done. Shell for instance has a large wind energy business and is siteing windfarms on off shore locations, including old platforms.



-The future's so bright I gotta wear shades!

 

[KENAT]

Corblimey,

Don't count on off shore stopping Nimbys. Just ask Teddy Kennedy about the one planned off the north east coast of the US.

 

[arunmrao]

For the past few year Shell has been active in the Alternate energy resources arena. They have been conducting a few school programs too.

 

[dvd]

I have wondered what the environmental consequences of harvesting the wind are. What climate effects would there be is we took 75% of the energy out of winds that come on-shore? Will there be "wind rights" issues like there are "water rights" issues?

 

[KENAT]

I think I've posted this before, I think SMS asked a similar question.

My initial thought would be that a few thousand wind turbines wouldn't take any more energy out of the wind than the millions of trees that used to cover much of the worlds land area.

That's not to say it shouldn't be investigated but while one turbine probably takes more energy than 1 tree I doubt there'll ever be as many turbines as there were trees.

Plus I live out in the Mojave Desert and have stood down wind from vast swathes of turbines in the Mojave/Tehachapie area and believe me if they've taken 75% of the energy out then Bakersfield on the far side of the turbines would have been flattened by hurricane force winds.

 

[GregLocock]

Well, to get back on my hobbyhorse, burning ANY hydrocarbon in a stationary installation is daft. Hydrocarbons are uniquely portable sources of energy, we should be preserving them for use in transport etc, not burning them to heat water up at home. Gas, in cars, works really well. It is a high octane fuel, and burns very nicely. In aircraft it would not be quite as good, for a whole bunch of reasons.

Having said that, I am a hypocrite on this. My house is ALL electric, and my hot water is warmed by off-peak electricity. Ultimately (in Australia) that means my hot water is coal-fired, inefficiently. That is, the coal is burnt in a very high efficiency boiler, turned into electricity fairly efficiently, transmitted to me, somewhat efficiently, and then used to heat water fairly efficiently. I have a strong suspiscion that this is inefficient compared with a domestic coal fired boiler. But at current prices, why wouldn't I do it this way?



Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[Dinosaur]

Greg,

The answer in the US to your question, "Why burn any hydrocarbon in a stationary installation?" is ... because that's what the environmental movement wants us to do.

Leading up to the 1970s, much of the electric power not produced by hyrdoelectric means was produced by burning coal, heating water, running a turbine to turn a generator. Nuclear power was on the rise but environmentalists were convinced we would either blow ourselves up or live in a world of background radiation cause we didn't know how to dispose of the spent fuel rods.

At the same time, they discovered acid rain, a low acidic impurity in the atmosphere due to carbon release at coal fired plants eventually causing the formation of carbonic acid, in very low concentrations.

The environmental movement was able to shut down the development of nuclear power technology and insist that all coal fired plants be converted to oil fired plants which burned cleaner.

I agree, we should wake up and recognize gasoline and deisel should be used for ground transportation. Grades of petroleum that can not be used for transportaiton fuel should be used for other well suited purposes and we whould generate our power without petroleum when we can. If all the government regulations were eliminated that interfered with the proper allocation of resources, I wonder what the market solution would be?

 

[0707]

a grift to 2dye4

Continental SuperGrid

[image

http://www.aip.org/tip/INPHFA/vol-10/iss-5/images/20-4.jpg

]

Cheers

Luis

 

[moltenmetal]

Dinosaur: if the cost assigned to atmospheric discharges was zero, and government regulation were removed, the "free market" solution would be to burn the cheapest coal you could find. Or to burn hazardous waste or garbage.

There's a role for regulation and for taxation: the market doesn't price stuff properly, especially in situations where one person's consumption results in costs for others.

 

[dcasto]

agreed Molten, look at China.

A close second would be neclear if we didn't have all the regulations, look at Europe.

 

[LittleWheels]

Of course, reducing consumption will minimise the amount of solar cell area required. More efficient lighting, heating, etc are currently available with future improvements likely. Hot wire vs LED lighting anyone?

 

[Dinosaur]

I agree that there is a role for government regulation. For example, I work in transportation infrastructure (e.g. a highway department), and I believe speed limits need to be established and enforced. Many folks think that is an unnecessary encroachment into their freedom. In this free country, they have a right to their opinion even when it is wrong.

Likewise, I believe there are limits in polution that need to be established. My problem is that there are severe government restrictions in some aspects of energy that do not apply to other areas. This is an area where politics severely interferes with the proper allocation of resources.

For my part, I am outraged that China polutes the way it does while the environmental movement makes little to no fuss over their behavior. Likewise, the European community that uses a large amount of nuclear power and permits their automobiles to generate much more polution than US automakers are permitted in this country, points the finger at the US as the principle player in global polution problems. Environmental outrage directed at the US is dishonest given these facts.

If we could play by European rules, we would have much more nuclear power, reducing polution and the strain on global petroleum assets. When I ask for governmental regulatiions to be lifted in order to permit the proper allocation of resources, I am speaking of the arbitrary rules that have shut down the nuclear power industry, and other capricious rules that permit poluting by some folks but restrict poluting by others. Level the playing field and let engineers figure out where the resources should be used.

Dave, do you have a figure on lumens/watt on LED- incandescent-florsecent lights? I'd like to know how those compare. They are using a lot of LED matrix signal lights in my area now. I like them because they are redundant. I suspect they are also efficient. I just don't know to what degree.

 

[SomptingGuy]

LED lights? Can't give you any real numbers, but they have transformed the bicycle lighting industry. Rear, red lights have been available for a few years and only need one set of batteries for the whole Winter. Practical white lights came out over the last couple of years and are looking similar - my old "hot wire" front took 6 (!) batteries and lasted a week or so. My new LED takes 4 and just keeps going on and on.