The Pros and Cons of Hydropower
There
are economic and environmental arguments for hydropower. Generally,
hydropower facilities have high capital costs but very low operating
costs. Over their lifetime, the total cost of producing power at a
hydroelectric facility is typically less than that for a fossil fuel or
nuclear plant. Hydropower facilities are dispatchable, i.e., their
owners can, within limits, increase or decrease power production to
reflect changes in electric demand.
Hydropower
is a renewable resource, relying on the natural cycle in which water
falls as precipitation, flows in rivers to lakes and oceans, and
evaporates from these water bodies back into the atmosphere. Hydropower
facilities produce no air pollution. They emit no carbon dioxide, and
their “cradle to grave” greenhouse gas emissions are less than most
other types of generation (this approach measures emissions associated
with facility construction and operation, as well as direct emissions).
Impoundment
facilities typically offer a variety of recreational opportunities,
notably fishing, swimming, and boating. The Federal Energy Regulatory
Commission, which regulates hydropower, generally requires these
facilities to provide public access to the reservoir to allow the public
to take advantage of these opportunities.
Argument Against
The
primary arguments against hydropower are environmental. Impoundment and
pumped storage facilities can cause serious environmental harm to
surrounding areas. They can alter the amount and quality (e.g., oxygen
level) of water flowing downstream, which affects plant life as well as
both aquatic and land-based animal species. Turbines kill fish in the
river, although this impact can be mitigated through the use of fish
ladders and similar structures. Dams block migratory routes,
particularly for anadromous fish such as salmon that live in the ocean
but come up rivers to spawn. The creation of new dams can destroy the
habitat of species, including forests. The destruction of forests
produces methane, a potent greenhouse gas. Dams also reduce sediment and
nutriment flow downstream and reduce the temperature of the water.
In
addition to these environmental impacts, impoundment facilities can
reduce the aesthetic value of streams, particularly wild rivers. As a
result of environmental and aesthetic concerns, a number of dams in New
England have been removed in recent years, including dams on the
Kennebec River in Maine and the Pawcatuck River in Rhode Island. In
contrast, run of river facilities have a smaller environmental impact,
and produce relatively little change in the stream channel and flow.
Hydropower is a renewable energy source that utilizes natural water flow, which is mostly unlimited. Comparing hydropower with some other renewable sources, it does the most damage on the environment. When building a dam for the hydropower plant, the water level above is significantly increased, while the ecology below the dam is changed dramatically. Building such a plant often comes with sacrifices.
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