The total solar energy hitting Earth each year is
equivalent to
12.2 trillion watt-hours. That's over 20,000 times more
than the total energy all of humanity consumes each year.
And yet photovoltaic solar panels, the instruments that
convert solar radiation into electricity, produce only 0.7
percent of the energy the
world uses.
So what gives?
For one, cost: The
U.S. Department of Energy estimates an average cost of
$156.90 per megawatt-hour for solar, while conventional coal
costs an average of $99.60 per MW/h, nuclear costs an
average of $112.70 per MW/h, and various forms of natural
gas cost between $65.50 and $132 per MW/h. So from an
economic standpoint, solar is still uncompetitive.
And from a technical standpoint, solar is still tough to
store. "A major conundrum with solar panels has always been
how to keep the lights on when the sun isn't shining," says
Christoph Steitz and Stephen Jewkes at
Reuters.
But thanks to huge advances, solar's cost and technology
problems are increasingly closer to being solved.
(Bloomberg
& New Energy Finance)
The percentage of light turned into electricity by a
photovoltaic cell has increased from 8 percent in the
first Cadmium-Telluride cells in the mid-1970s to up to
44 percent in the most efficient cells today, with some
new designs theoretically having up to 51 percent
efficiency. That means you get a lot more bang for your
buck. And manufacturing costs have plunged as more companies
have entered the market, particularly in China. Prices have
fallen from around $4 per watt in 2008 to just $0.75
per watt last year to just $0.58 per watt today.
If the trend stays on track for another eight to 10
years, solar generated electricity in the U.S. will descend
to a level of $120 per MW/h — competitive with coal and
nuclear — by 2020, or even 2015 for the sunniest parts of
America. If prices continue to fall over the next 20 years,
solar costs will be half that of coal (and have the added
benefits of zero carbon emissions, zero mining costs, and
zero scarcity).
Scientists have made
huge advances in thermal storage as well, finding vastly
more efficient ways to store solar energy. (In one example,
solar energy is captured and then stored in beds of packed
rocks.)
Lower costs and better storage capacity would mean cheap,
decentralized, plentiful, sustainable energy production —
and massive relief to global markets that have been squeezed
in recent years by
the rising cost of fossil fuel extraction, a burden
passed on to the consumer. All else being equal, falling
energy prices mean more disposable income to save and
invest, or to spend.
The prospect of widespread falling energy costs could be
a basis for a period of strong economic growth. It could
help us replace our dependence on foreign oil with a robust,
decentralized electric grid, where energy is generated
closer to the point of use. This would mean a sustainable
energy supercycle — and new growth in other industries that
benefit from falling energy costs.
Indeed, a solar boom could prove wrong those who claim
that humanity has over-extended itself and that the era of
growth is over.
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http://theweek.com/article/index/244437/are-we-on-the-cusp-of-a-solar-energy-boom