Each photographic stop represents a power of 2, so 1 or 2 stops below direct sun light is more or less useless.
It should also be noted that PV panels generate electricity only when the photon has sufficient energy. Photons below this may increase the bolometric (total energy) of the sky, but only photons above the threshold will actually produce electricity.
eliminate it. You are always going to have excess capacity in any solar set
-up.
I didn't say that overcast didn't reduce non-concentrated solar panel outpu t, I just said that it didn't eliminate it.
Syliva Else was claiming that "there has to be backup for pretty much the e ntire solar power generation capacity" which is nuts. The peak solar power genera ting capacity - at noon on a sunny day - is going to be way higher than the network could absorb (at least not without some power storage system - eit her pumped or batteries - which currently seems to be much too expensive to be practical).
-- Bill Sloman, Sydney
Clouds don't change the spectrum of the incident light - they just reflect and scatter it. Thick cloud reduces the local albedo so that most of the energy gets scattered back into space. It looks dark from underneath, but white from above.
-- Bill Sloman, Sydney
And hence useless for any PV applications.
What is "eliminating" ? 0.1 %, 1 % or 10 % ?
The worst case scenario is about that.
Anyone designing such idiotic systems deserve to be shot.
There's gigatons of coal, oil, and natural gas, enough to last hundreds of years.
-- John Larkin Highland Technology, Inc picosecond timing laser drivers and controllers jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
How do you know this, John? Do you have a *reliable* reference for this assertion?
Look it up. There's tons of info online.
-- John Larkin Highland Technology, Inc picosecond timing laser drivers and controllers jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
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John Larkin Highland Technology, Inc picosecond timing laser drivers and controllers
jlarkin att highlandtechnology dott com
I put in a solar array and pay nothing for grid power. I would love to have a Tesla car, safest in the world, and use it's battery to back up my fridge when the grid goes down. Turns out that EV batteries are good for home grid backup. Just my $.02. Cheers, Harry
How much did you pay for the solar install?
How much did you used to pay for grid power?
How long will it take to get your money back?
Thats the economic view point. I could ask the same questions about energy investment.
Mark
Like the US Northeast is experiencing a lot lately. Blizzards that cover entire states, just when you need a lot of energy to keep from freezing to death.
How efficient is a solar panel under a cloud, that's covered in two feet of snow? How about a thermal concentrator?
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
There's a beautiful Tesla charging station in the parking lot of the Safeway in Truckee. I've never seen a car charging there. Shoppers park their gasoline cars in the charging slots when things are busy.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
Perception is everything. I still remember the alarmist headlines during the 1973-74 "energy crisis" proclaiming that we're running out of literally everything. There were predictions that we'll run out of gasoline by the next century. None of that happened, but the effect on the economy and public buying habits were spectacular.
It might be true that there are gigatons of various fuels in the ground (I have my doubts), but there are factors that might discourage or prevent the use of these fuels even if they were cheap and plentiful. Fears of global warming might put petroleum fuel consumption in an unfavorable position, as enforced by higher fuel taxes for research and CO2 mitigation. OPEC has provided a splendid example of inflexible commodity pricing by constricting the supply in order to maintain the prices. They're currently also doing a great job of temporarily lowering fuel prices until all the companies based on fracking and shale oil begin to fail. Fuel in the ground is useless unless all the middle men and governments between you and the fuel are cooperative.
Meanwhile, alternative fuels and sources have the potential for creating billionaires out of their proponents. All that's needed is to create the perception that petro fuels are evil, destructive, depleted, etc, and the alternative fuels and sources will appear quite attractive (by comparison).
Right now, such alternatives are in the early adopters stage, where consumers will buy into the new technologies for any imaginable reason except cost effectiveness. For example, an 80 year old semi-retired friend just blew $26,000 on grid tied solar installation in a marginal location. Based on my extrapolation of his current output and assuming a constant rate of increase in electric power rates, I calculated that he would break even in about 25 years. However, he proclaimed that this was of no concern, since the purpose of his "investment" in solar was a social and political statement that somehow cleansed his conscience from a lifetime burning the evil fossil fuels. I had much the same reaction when I calculated the alleged savings of buying a hybrid automobile.
Eventually, we'll run out of such early adopters and need to deal with the economic reality of alternative fuels. Of course, there will be cost reductions and efficiency improvements. My guess(tm) is that they will not be sufficient to make electric powered transportation cost competitive with petro fuels. The only obvious alternative will be to make petro fuels more expensive, which is what seems to be happening. That also saves the inconvenience of running out of fuels before the alternatives are ready.
I'm an avid reader of Home Power magazine. There's one technology which is never even mentioned, probably because it doesn't work. That's charging a battery pile from commercial AC power during off peak hours, and using the stored energy during peak hours, in order to prevent power consumption from going into the more expensive utility billing tiers. I've tinkered with the numbers for this using common lead-calcium stationary batteries and it's far from economical. I haven't bothered to do this for Li-Ion for the same reason that you don't see Li-Ion UPS power supplies on the market. A
100% fully charged Li-Ion battery has a reduced life expectancy. Reading between the lines, methinks this is what Elon Musk might be proposing for his home storage battery. Unless I missed some new battery technology, it won't work. That's one reason why I guessed that it might be a different battery technology.I guess we wait for the official announcement and proposal.
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
He is right about there being more than enough coal to keep the fires burning for a very long time. Fuel is not so much the problem as the oxidizer to burn it with. Well, let me remove my tongue from my mouth and say it's really not even the lack of enough oxygen, it's the issue of the waste products. Burn coal and you get many, many pollutants in the air such as SO2, NOx, Mercury, other heavy metals, arsenic, hydrocarons, CO and lets not forget.... CO2!
Yes, burning coal is a major source of that world famous greenhouse gas CO2. We will never see even a few percent of the total carbon resources burned because the damage to the environment will become so obvious that even the modern day dinosaurs will be able to see the asteroid coming and change our course. The only question is will we be able to turn the pilot wheel fast enough to avoid the iceberg (mixing my metaphors a bit here)?
-- Rick
I still say that Yellowstone will "heal" us all.
We deserve it too.
A gigaton of oil is the order of magnitude of the yearly consumption of the US alone!
Jeroen Belleman
Mount your solar panel vertically, aimed south, and the snow just reflects more sunlight onto it; you don't get less power, you get more. This is a winter question, right? With the sun low in the sky?
Right. The sunlight always sneaks in under the clouds.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
if you have time of use pricing, you can save a lot of money by use of simple timers and common sense to schedule the use of hot water heater/dryer/air cond...etc to off peak time.
No expensive batteries and inverters are needed.
I am waiting for time of use pricing to be offered in my area. They already took away the heating rate and I'm already paying for the smart meter.
Mark
Do you use electricity for heat and hot water? That's very inefficient.
We use natural gas for heat, hot water, cooking, and the clothes dryer. And we don't have a/c.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
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