Arizona Solar Power Project, Calculations

[kristopher]

From Bob Napiers' r-squared energy blog:

Arizona Solar Power Project, Calculations
The following guest post was written by Tom Standing, a "semi-retired, part-time civil engineer for the City of San Francisco." In Part 1, Tom takes on the calculations for a 280 MW solar thermal plant in Arizona that I looked at back in February. My conclusion from that essay was that the electrical demands of the U.S. could in theory be met on 10,000 square miles of land. Tom peels the onion a few more layers and puts the energy production into perspective.

While solar calculations are by no means second nature to me, I see no obvious errors in Tom's calculations. But I consider peer review to be a very useful component of my blog, and I know that Tom would appreciate any constructive criticisms. Part II will delve into France's solar ambitions.

<snip>

...Many questions come to mind in looking at the proposed Arizona plant. What precisely does the 280 MW refer to? Is it the plant’s output at capacity? Is it an annual average output? How much electricity will it generate annually? How will output vary during the day, or by season? How will output be affected by clouds?

There is important data available and a few fundamental design features that will answer these questions. Costs for construction, however, are not my strong suit. Other analysts will have much better information on costs. Cost of the plant will not change the results of my analysis.

1. Insolation Data...

2. Site Coverage with Solar Collectors...

3. Calculate Collector Area...

4. Model the Collection Array...

5. Calculate Insolation Striking the Collectors...

6. Assume 15% Conversion of Insolation to Useful Electricity...

7. Maximum Electrical Power Output...

8. Annual Energy Generated...

PV Potential...

Th author details how these steps are accomplished to find the power production of a given solar project.

http://i-r-squared.blogspot.com/2008/12/arizona-solar-power-project.html

[Fledermaus]

1. Thats for solar thermal not PV.

When done correctly, solar thermal or PV estimates for annual kwh are usually accurate +- 10%.

[kristopher]

3. The blogger addressed that

"PV Potential

I have not touched on PV, but there is much to discuss. NREL data is so extensive that there is almost no limit to analyses that could be done. For now, I should only refer you to an article that I published in the Oil and Gas Journal, June 25, 2001 issue. I graphically displayed annual insolation curves for a wide range of locations. At a glance the reader can see how insolation varies with latitude, longitude, and collector orientations. I also ran through sample calculations to see how much energy can be generated. An important finding is that insolation for most of the eastern half of the U.S. stays within a narrow range: 4.6 to 5.2 kWh/ (m2-day), with fixed collectors facing south, tilted at latitude for maximal exposure.

The above calculations are purely rational, using insolation data and general assumptions in design. Actual practice shows that solar installations typically generate 10 to 15% less energy than what the calculations show."

[Fledermaus]

6. You think so?

[kristopher]

7. He couldn't have been more specific.

[sam sarrha]

2. the new parabolic reflectors/vacuum tube collectors are said to need 300 square miles to produce 72%

.. the new laminated plastic sheet voltaic panels probably out do them now.. in cost pr megawatt

a percentage of total demand will have to be wind, to cover night time demand

[kristopher]

4. 72%? 72% of what? nt

[sam sarrha]

5. daytime electricity, that is what Clintons Solar project estimated.. W canceled it his first week in

office and sold the technology to a crony i heard