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Global Solar Power Capacity Surpasses 100,000 MW: Why is this significant?

August 4, 2013


J. Matthew Roney has recently published an article announcing, with great fanfare, that global solar power capacity surpassed 100,000 MW in 2012. The article can be found at the Energy Techling and Tree hugger websites:

The article seems to imply that there is some significance to the total published maximum capacity figures for the PV solar panel installations worldwide; however, it seems to me that (as is typical) there is significant information missing from this article and the real pertinent questions remain unasked and unanswered.

Some pertinent questions would be, “How much did this solar capacity really cost, and how much actual electricity (MW-hours) is it producing every year?” Passages from Roney’s article indicate the following regarding the solar PV capacity being installed:

The main policy driver that has allowed Germany and Italy to amass their world-leading solar capacity is the feed-in tariff (FIT), which guarantees renewable energy generators a long-term purchase price for the electricity they supply to the grid.”

“Renewable portfolio standards (RPS)—laws now in 29 states typically requiring that renewables account for a specified share of the electricity that utilities sell—have historically driven U.S. PV development. In California, the U.S. solar leader, utilities must get one third of their electricity from renewable sources by 2020. Federal tax credits and cash grants are also PV catalysts”

It seems we’re paying quite a bit of money from the public coffers to subsidize this PV capacity, why would we not discuss exactly how much it is costing and exactly how much electricity it is producing?

Another pertinent question might be, “How many different ways could we have spent less money, made more electricity, and eliminated more CO2 emissions; if we were not mandating PV production and subsidizing people who make money selling solar panels?”

Because of limited Capacity Factor (10-15%) a MW of solar capacity can, in general, only produce about one sixth of the electricity that a MW of other forms of generation like natural gas, on an annual basis. Please refer to my prior post on this subject, Specific Real Energy Production.  Considering this, discussing “progress” in terms of capacity is a bit misleading; as evidenced by the following quote from Roney’s article:

“Germany remains the world’s solar capital, home to nearly one third of global PV capacity. For the third straight year, Germany added more than 7,000 megawatts of PV in 2012, reaching 32,000 megawatts. Accounting for some 5 percent of national power use, the electricity flowing from Germany’s solar panels in 2012 was enough to supply more than 8 million homes.”

This information would have us believe that providing electricity for 8 million homes is something of great significance. However, information from Enerdata via the World Energy Council indicates that an average German home uses about 3.5 MWh/year (see chart below) and, using this figure for comparison, 32,000 MW of other forms of generation capable of capacity factors exceeding 85% would have been able to supply the needs of roughly 68 million homes, rather than 8 million homes. Suddenly, 8 million does not seem to be such a significant number of homes.

Global Electric Use

What is significant regarding the amount of supposed solar PV capacity that is now installed worldwide?  This is not the important information needed to judge the effectiveness of our energy strategy.

Why are we typically not asking the truly pertinent questions about how much it costs and what it really produces??

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