The Wikipedia article has a nice table on national average capacity factors (about halfway down the article) http://en.wikipedia.org/wiki/Wind_power
--- On Mon, 9/7/09, James R. Frysinger <[email protected]> wrote: From: James R. Frysinger <[email protected]> Subject: [USMA:45760] Windfarms, was "Can journalists..." To: "U.S. Metric Association" <[email protected]> Date: Monday, September 7, 2009, 5:16 PM I've done the math using the published Kentish Flats numbers and found that 280 000 000 kWh over a year represents and average power level of just under 32 MW for the 10 km2 site. That's 3.2 W/m2, a few times the previously mentioned typical power generation site density. Of course, that's quite a windy part of the world, the brochure claiming a mean wind speed of 8.7 m/s at 70 m above mean sea level. I calculate the "90 MW" farm operates at 35.5 % capacity. Dare it be said, those figures are at the site and do not account for 10 km of line losses just getting to shore but still needing to reach the grid, which might deduct a few tenths of a percent of the power generated. Jim John M. Steele wrote: > The only one that seems completed and operating is Kentish Flats. It has > capacity of 82.5 MW installed. Its booklet forecasts 280 million kWh per > year, which is an average power slightly less than 32 MW, which is a capacity > factor of about 39%. > I can't find any actual data though. If it is actually delivering 280 >million kWh per year, that is pretty good. Many come up quite short to >forecast. Are you able to find any ACTUAL production data locally. > > --- On *Mon, 9/7/09, Martin Vlietstra /<[email protected]>/* wrote: > > > From: Martin Vlietstra <[email protected]> > Subject: [USMA:45755] Re: Can journalists be cured of their affliction? > To: "U.S. Metric Association" <[email protected]> > Date: Monday, September 7, 2009, 3:06 PM > > I looked at the figures shown below. I then looked at a UK website > - http://www.pmsc.org.uk/windfarms.htm. The scale of things is > quite different, and therefore so is the economics of the situatiom. > > > ------------------------------------------------------------------------ > > *From:* [email protected] [mailto:[email protected]] > *On Behalf Of *Stan Jakuba > *Sent:* 07 September 2009 02:11 > *To:* U.S. Metric Association > *Cc:* USMA > *Subject:* [USMA:45752] Re: Can journalists be cured of their > affliction? > > > Compare that Indiana "farmer's record" formulated by the usual > "green" (or greed?) propaganda with the real homeowner's record in > sunny Austin TX. Again, from my paper: > > As for the usefulness of PV for small installations, below is a cost > analysis of a plant representing a typical system installed on the > roof of a family house in central Texas . > > > Installed name-plate power . . . . > 3.24 kW > > Power actually measured over a year . . > . 0.44 kW > > Utilization (capacity) factor on 24/7 basis . . > 13.6 % > > Useful life of the structure . . . >. 20 years > > Electricity produced in that life span . . . > 280 GJ > > Sale (savings) of electricity in that life span will bring $7,700 > > Note: Supported by the net-metering law, the kWh rate is the utility > rate. > > Purchasing price, installed . . . >. $22,500 > > Note: This cost was subsidized whereby the owner paid only 1/3 of > that amount. > > Net gain (loss) at the end of the useful life: . > . $(14,800) or (66) % > > That percentage is based on the assumption that the repair and > maintenance cost will be zero, insurance premiums zero, net-metering > will last, and taxes forgiven. > > > Notice that if the owner had invested his purchase amount (that one > third) at a reasonable interest, say 5.5 %, he would have $22,000 by > that 20^th year. On the basis of all three thirds he would have > $67,000. Instead, in addition to the monetary loss (mostly to the > taxpayers as of now), the owner will be facing the pain of financing > the dismantling and disposal of the plant or replacing the PV panels > and some electric/electronic components should he decide to continue > making his own electricity. > > > The bottom line is: This “free” PV electricity would have to sell at > 240 $/GJ to break even instead of the 28 $/GJ (10 ¢/kWh) the owner > enjoys from the utility. In other words, a solar kWh costs almost > nine times more than the utility rate is, and the utility operates > at a profit while it buys fuel, cares for power lines, covers > operating labor costs, pays dividends, 401(k), etc. > > Source: /Gusher of Lies/, by Robert Bryce, pg 217. (PS: > This is an excellent energy book, but not SI.) > > > PV promoters claim that the cost of the PV collectors will come down > with time. Probably, but insufficiently, considering that, as > examples, coal-fired plants are built for 2 $/W, nuclear plants for > 1.4 $/W, gas turbine plants for 0.7 $/W vs. the GE PV plant at > 31 $/W. That gap is too wide to close significantly. Notice that > the above, roof-installed plant cost $51/W. > > > On related subject, I am attaching a table that had been > presented to this forum more than once before. It contains W/m² in > the middle column. The data have been collected over many years from > articles describing plants that were in operation for several yearly > cycles. These data are very hard to come by. Probably because the > owners do not want to admit how badly their investment turned out. > Calls for actual data are not returned from the people who > know. Invariably, one is referred "our website" which is, of course, > if it at all refers to a period of measurement, compares it to > "1/3rd of our operating cost) (what is it?) or powering 100 houses > (dog houses?, wood burning cottages?) and are written in the > style for school kids education. > > > BTW, I heartily recommend Prof. Hayden's > newsletter http://EnergyAdvocate.com <http://energyadvocate.com/> A >jewel among energy newsletters (although somewhat reluctant to use > W/m²) the articles are mostly metric, and, better yet, SI, although > not consistently. > > Stan Jakuba > > > ----- Original Message ----- > > *From:* John M. Steele > ><http://us.mc824.mail.yahoo.com/mc/[email protected]> > > > *To:* U.S. Metric Association > <http://us.mc824.mail.yahoo.com/mc/[email protected]> > > *Cc:* [email protected] > <http://us.mc824.mail.yahoo.com/mc/[email protected]> > > > *Sent:* 09 Sep 06, Sunday 16:29 > > *Subject:* [USMA:45749] Re: Can journalists be cured of their > affliction? > > > Probably not. The journalist didn't measure anything himself, > and probably didn't compute anything himself. He simply > reported pap, spoon-fed to him by the installer of the system > who has a very vested interest in making it sound good. > > > The 13.4 kW rating is almost certainly "high noon" power. The > area of the roof is is about 171 m². At high angle and > perpendicular incidence, sunlight is about 1 kW/m², and > affordable solar cells are about 10% efficient. If the roof > could be totally covered, perhaps 17 kW could be attained. >Given standard size panels, 13.4 kW peak is reasonable. > > > I estimate for a flat, non-tracking array, at optimum angle, he > will get the equivalent of 4 h of peak power per day, or 54 > kWh/day. (This will be "smeared" over more hours, but mostly > lower power in bell shaped curve). > > > My estimate is strongly at odds with the claim of saving $230000 > over 25 years at current electric rate of $0.116/kWh. The > implication of this statement is 217.3 kWh/day, roughly 4X my > estimate. Time will tell. Note that this estimate requires 16 > h of full power operation per day (average for the year. On > average, how long is a day. It's not all full power either). :) > > > As to the CO2 savings, the federal government uses a decade-old > figure of 1.34 lb/kWh. I note that 48240 lb is EXACTLY the CO2 > emission of 36000 kWh. However, the 36000 kWh number doesn't > seem to relate to either power estimate above. As an annual > estimate, it would apply to generating capability of 98.6 > kWh/day (call it 100) more or less the geometric mean of the two > estimate. > > > The article is a pile of environmental voo-doo (or doo-doo) > unlikely to translate to real results over the course of the > year. However, the real problem is not the reporter's math > ability but that all the "facts" came from the seller and there > was no fact-checking or critical view of (very dubious) data. > > > As to units, until we get AP to change the AP Style Guide, there > is not a snowball's chance in hell of the units being all SI. > > > > --- On *Sun, 9/6/09, James R. Frysinger /< > [email protected] >/* wrote: > > > From: James R. Frysinger < [email protected] > > Subject: [USMA:45748] Can journalists be cured of their > affliction? > To: "U.S. Metric Association" <[email protected]> > Cc: [email protected] > Date: Sunday, September 6, 2009, 2:23 PM > > > Journalists, as a rule, are terrible at dealing with > measurements. Case in point, > " Indiana Farmer Turns to Sun to Run Operation" > Saturday, September 05, 2009 > Associated Press > http://www.foxnews.com/story/0,2933,547042,00.html > > The story describes a solar photovoltaic installation on a > farm in Indiana . > > Comments: > "The 66- by 28-foot roof supports 60 photovoltaic solar > panels, each producing 224 watts of electricity. The panels > are aligned in four rows, or two sub-arrays, with each > sub-array producing 6.7 kilowatts, making the entire system > produce 13.4 kilowatts of electricity..." > The journalist should have said whether that claimed > power output was the ideal, peak value (the most likely > case) or the average over the length of a typical day. There > is a huge difference, especially since power output must be > zero at night! > > "The farm in southern Vigo County has at least 200 acres of > electric fencing to contain a herd of beefalo..." > Fencing is sold by length, not by area. Let's call 200 > acres 80 ha (close enough), or 800 000 m2. If the field is 1 > m by 800 000 m, then the fence around it would be 1600 km > long. If the field is square, then 3.6 km of fencing would > suffice. > > "The fencing itself uses 600 volts of power... > Power is measured in watts, not in volts. > > "The Lovealls' system will avoid the release of 48,240 > pounds of carbon dioxide into the atmosphere..." > Is that per day, per week, per year, over the life of > the system? There is a huge difference between 24 t of CO2 > per day and 24 t of CO2 per score of years! > Also, climatologists measure CO2 outputs in metric tons > (symbol t), not in pounds. And it's not terribly leading > edge to still be using feet, square feet, and acres. Since > the electrical units which were misused in this article are > SI units they should have stuck to the SI -- and should have > used it properly. > > Not as a matter of measurement ignorance, but a lack of > common sense: > "The solar panels are part of a "phase one" project, Roberts > said. A second phase for the Loveall farm will add more > solar panels, plus move an existing 66-foot wind turbine > next to the barn to produce wind power to allow the farm to > be 100 percent energy independent. The farm would remain > connected to Win Energy's power grid as a backup." > You betcha they need that backup! What happens at night > when the wind is not blowing hard enough to generate all > their needs? The fallacy ignored by the green crowd is that > systems such as this use the grid and its mainline nuclear > and fossil fuel plants to serve as their energy surge > reservoirs! > > Can journalists be cured of this affliction they have that > prevents them from understanding how to measure things? And > the news media wonders why we don't trust their reports! > > Jim > > -- James R. Frysinger > 632 Stony Point Mountain Road > Doyle , TN 38559-3030 > > (C) 931.212.0267 > (H) 931.657.3107 > (F) 931.657.3108 > > -- James R. Frysinger 632 Stony Point Mountain Road Doyle, TN 38559-3030 (C) 931.212.0267 (H) 931.657.3107 (F) 931.657.3108
