LARGE DAMS: Learning from the Past, Looking at the Future
Appendix B 131
opment with the environment. And at the core of this
challenge lies energy—the fuel of economic develop-
ment from time immemorial.
Who says energy says carbon. And carbon is now
the “most wanted” environmental culprit. Conversely,
displacement of carbon for the energy system may be
the largest single environmental challenge facing the
planet. Progress has been slow but sustained over
the past century. Since 1860, decarbonization has cut
the tons of carbon to units of energy produced by 40
percent. In 1920, coal still provided three-quarters of
global energy, and heavy smog lay over London and
Pittsburgh. Today, carbon is struggling to sustain its
market share of about 25 percent. The move from a
polluting carbon economy to a non-polluting hydro-
gen economy is underway. It will have to be acceler-
ated to keep global warming at bay.
Dams have a significant role to play in freeing the
energy system from carbon. When built on time and
on budget, they produce electric power at competitive
prices. Electricity can substitute for wood, coal,
kerosene and oil and therefore contribute to a clean-
er, safer, healthier environment.
With electricity, deadly wastes associated with
open fire and smoke in homes and workplaces
decline and with it exposure to pneumonia, TB, diph-
theria and other airborne diseases. Refrigeration also
becomes possible, and this cuts into waterborne gas-
trointestinal diseases—another major killer.
Electricity used to be based on coal alone. Hydro
is a viable alternative in certain situations. So is nat-
ural gas, which has increased its market share given
its flexibility, quick gestation, low capital costs and
the efficiency of combined cycle turbines. Natural
gas is carbon trim—four hydrogens for every carbon.
Coal uses one to two carbons per hydrogen. Oil uses
two hydrogens per carbon, while wood uses ten car-
bons per hydrogen. So only nuclear and hydro can
beat natural gas in the decarbonization game. But
nuclear involves high risks and heavy costs, while
hydro lies well within the technological reach of most
developing countries.
Hydro is renewable and domestic-resource-based.
By contrast, fossil fuels often require foreign
exchange. Furthermore, hydro projects are easy to
operate and maintain. No wonder then that two-
thirds of the large dams built in the 1980s were in
developing countries. The power market in develop-
ing countries is growing, and this is where the bulk
of unexploited sites lies. According to the World
Energy Council, a doubling of energy production for
hydro from 2,000 terawatt hours to 4,000 terawatt
hours per year from 1990 to 2020 is in store. This
implies a trebling of hydro capacity and, if it occurs,
would still leave 70 percent of the technically usable
potential untapped.
Such a development would contribute substantially
to reduced reliance on carbon as well as bring down
the currently high energy intensities of the develop-
ing world. Measured in tons of oil, for example per
U.S. dollar of GDP, Thailand resembles the United
States in the 1940s, while India is comparable to the
United States of a century ago. Keeping energy use
at current levels in developing countries is an envi-
ronmental fantasy that would confine them to perpet-
ual poverty. Per capita, LDC residents use only
1/15th of the energy consumed by a U.S. resident.
I will not talk about the extraordinarily important
use of dams for irrigation. But consider this simple
fact. By raising wheat yields fivefold during the past
few decades, Indian farmers have spared an area of
cropland equal to the state of California. This yield
revolution would not have taken place without sur-
face irrigation used in conjunction with ground water.
So there is a strong economic and environmental
case for large dams. But as dams are currently
designed, constructed and implemented, a strong
case can also be made against them. The damming
of a river can be a cataclysmic event in the life of a
riverine ecosystem. The construction of dams in
densely populated, environmentally sensitive, institu-
tionally weak areas can be very destructive.
Just as in real estate, location matters.
Consultation matters too. But it is not a panacea.
The protection of natural habitats and the resettle-
ment of people displaced by dams call for institutions
and implementation capacities that need nurturing
over many years, even decades. These are not chal-
lenges that can be met efficiently one project at a
time. The OED report suggests that 75 percent of
the dams reviewed did not meet current environmen-
tal/resettlement standards at completion and hypoth-
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