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100MW PV system for the Vatican

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$6.6/watt is way expensive, but if the electricity is over $.21/kw-hr, it will have a 20 year payout. Fartherdown the numbers on another project do not add up.

"More recently the Vatican has put words into actions.

The 5,000-square-meter roof of the Paul VI auditorium -- built in 1971 by Pier Luigi Nervi, the architect who designed Milan’s Pirelli Tower -- was covered with 2,400 solar panels to produce 300 kilowatt hours of energy a year, enough for 100 households, cutting carbon-dioxide emissions by about 225 tons. "

300 kw-hr?

 
A more reasonable stat would be 300,000 kW potential.
Leave it to reporters to screw up the numbers.

$6.6 isn't expensive, if its the installed cost. That would fit up with the MW project costs in the EU, given the panels have recently come down in price a bit. And I think Italy is paying what must be around 0.60 US per PV kWh, so the payout is much less than 20 years. In fact it may be 8 or 9 years, as insolation in the middle latitudes of Italy isn't too bad.

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"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)
 
Probably, someone switched to MWh, but the reporter missed that.

However, the reporter did correctly use kWh and energy.

TTFN

FAQ731-376
 
That correct use of the units was an accident. 300 kWh for 100 houses would be an average of 8.2 kWh/day. I use about 16 kWh/day and I don't use much electricity at all, so that doesn't make sense. But 300 kWp / 2400 panels is 125 Wp/panel; a reasonable Wp value for a typical normal size solar panel.

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"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)
 
I usually stop reading when I see that kind of stuff or something like "saves X kilowatts per year" or "enough power to run Y homes for a month".

Alan
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"It’s always fun to do the impossible." - Walt Disney
 
Not sure what the energy cost structure is like in Italy, but, running 8 kWh/day isn't necessarily far-fetched, if we assume low, or non, usage of A/C, smaller refrigerators, etc.

TTFN

FAQ731-376
 
No. I know it can't be that low. Spain's average is 15 kWh/d. That's 600W, not much more than a frige, 0.75 m3 water heater, an alarm clock, a few light bulbs at night and a TV mostly on standby. A lot of heat in the northern small towns is provided by LPG, no to little heat needed in the south. Average house/apt won't have air conditioning. Avg apt size is 85 m2. Italy is much the same, so no way its half.

300 kWp x 6 avg stdandard Sun h/day = 1800 kWh/d,
1800 kWh/d x 0.75 eff w/cable & inverter losses = 1350 kWh/d
1350kWh/d / 100 homes = 13.5 kWh/Home-d.

That's pretty much the same as the Spanish national average household consumption, with a lot of LPG usage for heat in the small towns.

It keeps looking like 300 kWp.

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)
 
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