Environmental Engineering Reference
In-Depth Information
by the factor 1000/205 comparing peak insolation to the average value. So, accu-
mulated peak capacity will need to be (500/0.205) GW
2439GW. The cost of
production lines to build this in 1 year is then $1220 billion, and cost for production
lines to build this capacity over 10 years is $122 billion. Again, the production cost for
the cells, assuming $0.3/Wp, is $2439 billion
¼
0.3/10
¼
$73.2 billion per year for
10 years. Total cost over 10 years is $(122
$0.845 trillion. If this
whole program were paid by the government, it would be $84.5 billion per year for
10 years. The $845 billion is approximately equal to 0.12 of the U.S. military budget
($708 billion in 2010) for a period of 10 years.
Income from this hypothetical investment can be estimated, and indeed exceeds
the cost over the 10 year period. The sales value of the produced electricity, whose
power ramps up from 0 to 500 GWover 10 years, at $0.1/kWh, is $0.1
þ
732) billion
¼
250 GW
10
365
24
3600/1000
3600
¼
$ 2.19 trillion. The return on the investment
beyond cost is $(2.19
$1.345 trillion, or 159% over 10 years. On a
yearly basis, the return can be calculated as
x
10
0.845) trillion
¼
1.047, or interest rate on
annual basis is 4.7%. This is a better return than a savings account, but would be
regarded as a very risky investment. And, as we know, banks are reluctant to lend
money unless there is a government guarantee, whichmight be available in the event
of a national realization of a state of emergency.
If a national energy emergency should appear, the realization that fossil fuels either
are running out or cannot be tolerated for their environmental consequences, leading
to a strong government commitment to favor solar energy over fossil fuel energy,
such large costs might be undertaken. These costs are several times larger than
existing subsidies [133] to energy industries, including oil and coal, but are much
smaller than military expenses. The long-term expectation of rising oil prices and
recognition of the dangers of coal burning to the climate will probably tilt the
economics toward solar and wind generation of electricity. A more benign and likely
scenario, suggested by the private investments now occurring in wind energy, is that
private capital will be attracted.
A large array of PV (photovoltaics) would normally convert the solar-produced
DC (using inverter technology) to conventional AC power on site and connect
directly to the power grid. Such a grid connection is conventional or required by
statute in many localities for a PV installation, but may be dif
cult for a large
remote installation. We might assume that energy storage, building up from the
present capacity in pumped hydropower, will eventually become a larger part of
the electric power grid. We will see later that more favorable costs, avoiding a large
part of the storage needed, can be found by a nearly equal combination of PVas we
have described and wind power (see Chapter 1). Wind power could be built on a
scale to cover the night-time demand and PV would provide the added power to
supply the peak demand during the day. In this case, the cost of the PV per watt
could be reduced almost by a factor 5, since the capacity would be needed only
during the middle of the day when the sun power is 1000W/m
2
. This approach
could greatly reduce the need for storage, but would likely require overcapacity in
wind power, to cover for a week of cloudy days.
¼
1.59, so
x
¼
