Environmental Engineering Reference
In-Depth Information
removal when the dam owner wanted to keep running it (Goldberg 1997). During the following
decade, more than 430 outdated dams were removed nationwide, and the number of recorded dam
removals grew each year (Fahlund 2011). Recently decommissioned small hydro facilities include
the 13.7 MWe Condit Dam in south-central Washington on the White Salmon River scheduled to
be breached in October 2011 (Pacificorp 2011), the 22 MWe Marmot Dam on the Sandy River in
Oregon (Romey 2007), the Smelt Hill Dam on the Presumpscot River in 2002, Brownville Dam
on the Pleasant River, Souadabscook Dam on the Penobscot River, and the East Machias Dam on
East Machias River (Griset 2010), all in Maine.
Reclamation
After the artificial structures have been removed, reclamation of rivers is largely a matter of get-
ting out of the way so nature can move in and take over the exposed land. Some reseeding may
be necessary to stabilize steep slopes on the sides of former reservoirs and prevent erosion from
heavy rainfall, and some desired fish species may be restocked to speed their reoccupation of
remote reaches of former reservoirs, but if the rivers below a former reservoir are unobstructed
by other dams, the fish will generally find their way upstream in large numbers within a year or
two, so the costs of reclamation are generally very low.
Dollar Costs of Utilizing Hydropower
The major advantage of hydroelectricity over other electricity-generating technologies is elimina-
tion of the cost of fuel. The cost of operating a hydroelectric plant is nearly immune to increases
in the cost of fossil fuels such as oil, natural gas, and coal, and no imported fuels are needed.
Hydroelectric plants have long economic lives, with some plants still in service after fifty or even
a hundred years. Operating labor cost is also usually low, as plants are automated and have few
personnel on site during normal operation. Although numerous small hydro plants have been
dismantled, no large hydro power plant has ever been decommissioned in the United States, so
cost estimates for decommissioning large facilities are not available. The costs of reclamation
are generally very low.
The market cost to consumers for hydroelectric energy consumed in calendar year 2009 was
estimated at a bit over $24.2 billion, and $22.8 billion in 2010 (calculated from USEIA 2011a,
Table 8.2c, Table 8.10). Federal subsidies and tax expenditures for hydroelectric energy were es-
timated at $216 million for FY2010, of which $215 million was for producing electricity (USEIA
2011b, xiii, xviii). The dollar costs of hydroelectricity can be broken down into two categories,
capital investment costs and operating costs. Capital investment costs are the largest, accounting
for almost 75 to 80 percent of the total lifecycle costs of a hydro power station. Operating costs
of hydroelectric power generation are considerably lower as hydro does not require any fuel
except for water, which is freely available. However, all mechanical equipment requires periodic
maintenance. The total dollar cost of a hydroelectric power plant is two to five cents per kilowatt/
hour, while that of small hydro power turbines is three to ten cents per kilowatt/hour. These costs
are comparable to the lowest fossil fuel and nuclear power generating technologies (Green World
Investor 2011).
Where a dam already serves multiple purposes such as flood control, irrigation, and provision
of municipal drinking water, a hydroelectric plant may be added with relatively low construc-
tion cost, providing a useful revenue stream to offset the costs of dam operation. For purposes
of evaluating energy technologies to develop future energy policies, it is worth noting that most
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