It'd be nice. I wonder when it will get below, say, $1/KW.
Cheers! Rich
Not anytime soon. With the solar constant at about 1.3 kW/m^2 a dollar would have to buy almost a square meter of solar cells, even at 100 % efficiency.
Anno
You're dreaming, Rich. Gasoline generators are roughly $100/kW, and of course have considerably higher on-going costs. Solar is often pushing an order of magnitude greater -- you can bet that if you could purchase 10kW of solar panels for $1k, almost every house in the U.S. would be covered with them.
Present prices are about $7/watt. At $2/watt (a rough estimate) it'd start getting interesting (for end-users, who pay about 3x the utilities' cost-of-generation.
$2/watt wouldn't be interesting for utilities at all, of course, for the same reason: that would be 3x their current cost-of-generation!
Cheers, James Arthur
What do you estimate to be the current cost per watt over the life of a coal, oil, gas or nuclear fueled facility (build, operate, fuel and decommission)?
Andy writes:
Solar cells will ALWAYS be the energy source of the future.....
.... and you can quote me on that !!
Andy in Eureka, Texas
Stirling engines have an even more impressive history of being the technology of the future.
Get this: reflectors driving Stirling engines!
John
-- Many thanks,
Don Lancaster voice phone: (928)428-4073 Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552 rss:
Please visit my GURU's LAIR web site at
Hasn't more money been spent on fusion? It's always been 20-50 years off (about one career).
Marketeering at work. I wonder where the stock is being peddled.
-- Keith
"It's tough to make predictions, especially about the future." -- Yogi Berra
I'm afraid I have no easy answer--that question entails a bunch of assumptions about construction costs, interest rates, the price of oil, politics, etc. AIUI utilities are traditionally insulated from these factors by guaranteed profit provisions in the laws that govern them; it's kind of a cost-plus deal.
I've seen a really good treatment of the question for nuclear power on Wikipedia somewhere.
As a rough estimate of historical costs we can look at our power bills--mine indicates the local cost-of-generation is 4.3 cents / kWh, or $43 x 10^-6 per watt-hour.
Assuming that figure includes all maintenance, fuel, construction, decommissioning, the cost of money, etc., and that the plant lasts 30 years, the cost of producing 5 Wh/day (the average output of a 1w solar cell) comes to 5 * 43 x 10-6 * 30 * 365 = $2.35.
In fact, solar power won't be available every day, so solar cells' output could be matched for less cost, by whatever availability factor you wish to assume. Also, the cost of new plants may be higher (or lower) than historically, but this guess is at least a first-order approximation in today's dollars that includes historical inflation, etc.
Assuming a 20 year life and 300 day-per-year availability, a $6/watt solar cell costs $6/ (5 hours * 300 days * 20 years) = $200 x 10^-6 per watt-hour.
That solar-cell figure EXCLUDES two substantial costs: 1) maintenance, battery changes, etc., and 2) the cost of money (i.e., the interest cost on a large up-front investment).
Obviously I erred above when I said $2 was 3x the utilities' COG. I _should've_ said their COG is only 1/3rd of your bill, so their break- even point is 1/3rd of the consumer's break-even point.
Best wishes, James Arthur
James Arthur wrote: (snip)
Thank you for the elaboration.
In an effort to nail the thing down a little better I wrote a computer model last night. Assumptions make all the difference, but just for an example...
Assuming: (view in Courier) initial system cost = $3/watt solar cell + inverter cost = $2.50/watt battery cost per system watt = $0.50 (probably too low)
battery life = 8 years solar cell life = 25 years
inflation = 3.5% interest rate = 6%
value of electricity = $0.14/kWh, rising at inflation rate
300 solar days per year 94% of solar power delivered to loads (i.e., wiring+converter efficiency). 100% utilization of power generated (i.e. all is either used or sold for full retail price) 100% battery efficiencyResults: At the end of 25 years the system will be approximately used up. As a consumer you will have gotten the value of the electricity produced, and have $0.51 per watt in your pocket, a yield of about
0.6% on the investment.Comment: a system without batteries that sells excess power on the grid during daylight hours would cost less and return more.
With the same assumptions as above, a no-battery system would leave you with $4.79 per watt in your pocket after 25 years, which, including the value of kWh consumed, gives a yield of 4.38%
Cheers, James Arthur
I think the no battery, daylight grid booster approach will be the first way solar power will become practical on a large scale. I think there will have to be severe fuel restrictions (huge price increases or legal impediments on the burning of fossil fuels) before continuous output power plants will start to be replaced by solar/battery systems.
I agree. There's little advantage to the extra expense of dirty, nasty, lead-acid cell batteries unless you're off-grid. Being off- grid wrecks the economics though--you'd have no way to sell your excess power.
So, it seems that installed panels for $2/watt is where photovoltaics begin to be attractive as grid-boosters. My figures included *no* maintenance, failures, degradation, or breakage, so cheaper would be better.
The easiest, best, fastest, cheapest thing that can be done, however, is for Al Gore to just plain use less(*).
[1] According to thisCheers, James Arthur
computer
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The "no battery" method is quite common now. My daughter in the south west of Western Australia has just installed a grid connected system like this.
Personally, I would rather have a battery and sell any excess back to the grid during the day and have my own power after the sun goes down. I don't see any sense in having a solar power system if it doesn't give me power ALL the time, especially when the majority of household power is used after the sun goes down.
In the US, we have a big early-afternoon peak, mostly air conditioning. There's lots of excess, relative cheap generating capacity available at night.
John
The warmer states (WA, QLD,SA) would be similar to the where you are in the US with similar demand peaks due to aircon. Our local energy supplier has a system called SmartPower and it might be economical if you have a fairly heavy and constant demand for power during off-peak times, eg. swimming pool or aircon but for most users it wouldn't be worth it.
Retro-fitting a SmartPower meter is expensive especially if you have a
3 phase connection ($615) as I do. SmartPower subscribers have a summer-time variable tariff of 6.56c/kWh during weekends, 13.12c/kWh during morning and afternoon weekday off-peak periods and 20.22c/kWh during weekday peak periods. A normal subscriber has a standard flate rate of 13.94c/kWh year round.If I was not going to provide a battery I think it might be better to install a few additional panels so that I had excess energy to put back into the grid during summer peak periods. This would mean I would get rebates for any off peak power I would be drawing from the grid after sundown when the panels were not producing power.
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