Environmental Engineering Reference
In-Depth Information
11
Prospects for Solar and Renewable Power
The usage of renewable power is small at present, but it is growing rapidly. We saw in
Chapter 1 that of the 14.7 TW world total power consumption in 2009, the largest
renewable contribution was hydroelectric power at about 7.3%. The contributions of
wind and solar power were too small to be seen on the overall linear plot of Figure 1.1.
In Figure 1.2 (for the United States), out of a total renewable portion of 8%, only 1%
was solar and 9%was wind. Solar and wind account for less than 0.8% of U.S. power.
11.1
Rapid Growth in Solar and Wind Power
The present growth rates are extremely high. For example, solar electric installed
capacity in theUnited States is said to have increased at 74%per year since 2008 [146].
Investment overall in renewable energy, according to the Bloomberg New Energy
Finance report of 2011 ([146b], Figure 3), has increased at an average rate of 36% per
year in the period 2004
-
2010, with global investment in 2010 of $211 billion.
(To calibrate the size of this investment, taking the worlds energy consumption at
15 TW, a rough estimate of the value of the production capacity, at $1/W, is on the
order of $15 trillion, 71 times larger.)
Projections of these rates suggest a quickly changing global energy mix. Assuming
the renewable capacity grows at the same rate, 36% per year, as the investment, and
neglecting growth in nonrenewable energy, one can ask how long it would take to
reach 50 from 1%. The answer is 12.7 years, but this is a very uncertain extrapolation
to be sure.
Amore cautious limit on the ultimate contribution of photovoltaic capacity, as 15%
of worldwide electric power by 2050, has been offered by Maycock, a seasoned
participant and observer of the photovoltaic industry, as quoted by Yergin [147].
Mr. Maycock comments: 15% of the worlds electricity is a very big number. To
reach 15% will require trillions of dollars of investment. For a business that is now
doing sixty billion dollars a year, that is a very nice mountain to be challenged by.
This comment implies a lower growth rate: to go from 1% (roughly) to 15% in 38
years corresponds to a growth rate of 7.4% per year. The recent enormous growth
