Frank Mace, Associate
Project Manager
New York State Energy
Research and Development Authority Albany, NY
Description:
Hydropower, also called
water power or hydraulic power, is derived from the energy embedded in moving
water.
History is full of
examples of water wheels or water mills with associated mill ponds. These
systems functioned for thousands of years and provided power for the production
of flour, lumber, and textiles. Hydropower also provided power for irrigation
and cranes for loading and unloading cargo ships.
Most of us, however,
associate hydropower with the production of electricity or hydroelectricity—for
use in homes, public buildings, and commercial establishments.
Hydroelectric generation
stations, such as the one located at Niagara Falls, which was completed in
1886, take advantage of the natural falls. However, most hydroelectric projects
require a dam and an associated reservoir to provide what is called the
"head." The head is simply the pressure exerted by the weight of the
water, based upon elevation (or distance) between the top of the water and the
generating equipment. When the water is released and allowed to flow, it
provides the power necessary to drive the turbines.
The 1930's saw large scale
projects, such as the construction of Hoover Dam (creating Lake Mead), which
was completed in 1936 on the Arizona/Nevada border, and also saw the creation
of the Tennessee Valley Authority (TVA) in 1933. The TVA constructed dams and reservoirs for
flood control and hydroelectric power in seven states. In addition, these projects provided
much-needed employment during the Great Depression. The TVA also advanced
efforts in reforestation and malaria control and trained farmers in techniques
for improving crop yield and soil conservation.
The U. S. Army Corps of
Engineers provides a historical perspective on hydropower:
"Unlike the West,
where irrigation became the focus of attention, the East was more concerned
over hydropower development. Beginning in the early 1880's, when a plant in
Appleton, Wisconsin, first used falling water to produce electricity, the
construction of hydroelectric dams on the nation's waterways proliferated. These private dams threatened navigation and
forced Congress, acting through the Corps of Engineers, to regulate dam
construction. The Rivers and Harbors Acts of 1890 and 1899 required that dam
sites and plans be approved by the Secretary of War and the Corps of Engineers
before construction. The General Dam Act
of 1906 empowered the federal government to
compel dam owners to construct, operate, and maintain navigation facilities
without compensation whenever necessary at hydroelectric power sites."
See: U. S. Corps of Engineers: http://www.usace.army.mil/About/History/BriefHistoryoftheCorps/Mult
ipurposeWaterwayDevelopment.aspx.
The U. S. Army Corps of
Engineers also offer this explanation of the process of hydroelectric power:
"A hydraulic turbine
converts the energy of flowing water into mechanical energy. A hydroelectric
generator converts this mechanical energy into electricity. The operation of a generator is based on the
principles discovered by Faraday. He found that when a magnet is moved past a
conductor, it causes electricity to flow. In a large generator, electromagnets
are made by circulating direct current through loops of wire wound around
stacks of magnetic steel laminations. These are called field poles and are
mounted on the perimeter of the rotor. The rotor is attached to the turbine
shaft and rotates at a fixed speed. When the rotor turns, it causes the field
poles (the electromagnets) to move past the conductors mounted in the
stator.
This, in turn, causes
electricity to flow and a voltage to develop at the generator output terminals."
See: The U.S Department of the Interior, Bureau of Reclamation: http://ga.water.usgs.gov/edu/hyhowworks.html.
Dams and reservoirs are
expensive, create challenges to navigation and aquatic life, and take up
valuable real estate. More recently, we have seen the development of tidal
power, or dam-less power. One example of tidal power is located in the East
River in New York City. A New York State Energy Research and Development
Authority (NYSERDA) publication explains this process:
"Capturing the
natural ebb and flow of the tides has always been a challenge filled with
potential benefit. For the past century,
hydropower was created by building dams to channel water through powerhouses,
where giant turbines captured the power of the falling water. Recently,
increased attention to hydrogeneration has centered around a kinetic method of
hydropower. By using dozens of small generators in a section of the East River
off of Roosevelt Island, near midtown Manhattan, a project is demonstrating
kinetic generation. The Roosevelt Island project features tri- bladed turbines
capable of turning on their horizontal axes to capture both the ebb and flow of
the East River. Submerged prototypes have shown positive results, and
regulatory approval is underway for a section of river covering a little over
one acre. The potential is to generate 5 to 10 MW of electricity by 2010."
See: NYSERDA: General Reports, "Renewal—Tidal Power," p. 13: http://www.nyserda.ny.gov/en/Publications/NYSERDA-
General-Reports/~/media/Files/Publications/NYSERDA/05-
06%20Section%201.ashx.
Hydroelectric stations
are appropriate for any geographic location that has moving water. This form of
power is the most common renewable energy source worldwide and accounts for
almost half of all renewables in the United States. According to The Need Project (2008), hydropower produces 20 per
cent of the world's electricity; and in the United States, New York ranks third
in the use of hydropower for the generation of electricity: http://www.need.org/needpdf/infobook_activities/IntInfo/HydroI.pdf. Hydropower is the cheapest way to
generate electricity in the United States—cheaper than coal or nuclear
plants—and produces no air pollution because it does not burn fuel.
Benefits:
For consumers
Hydroelectric power
produces no air pollution, promoting a healthier living environment for
community residents.
The lower cost of
hydroelectric power makes homeownership and rental costs more affordable for
older people, individuals with disabilities, and families, supporting their
ability to remain living in their communities.
For the community
The lower cost of
hydroelectric power supports the activities of the business community and
lowers the operating costs of other community sectors, such as health care
facilities and schools.
Hydroelectric power is a
renewable energy source, reducing reliance on traditional non-renewable fuels.
Hydroelectric power
avoids fuel costs in the production of electricity, and, therefore, stabilizes
the cost of energy over the life of the plant.
The avoidance of fossil
fuels makes hydroelectric power more environmentally friendly and reduces
greenhouse gas emissions.
Lakes created by
hydroelectric dams can also contribute to flood control, irrigation, recreation,
and wildlife.
Impediments or barriers
to development or implementation:
Hydroelectric power is
dependent upon rainfall for the supply of flowing water.
Hydroelectric stations
must be sited in areas with moving water.
Hydroelectric generation
is a long-term investment.
Hydroelectric generation
may require the construction of a dam and reservoir.
Hydroelectric projects
may have an impact on aquatic life.
Resource—examples:
Higley Hydroelectric
Station, Lower Raquette River, St. Lawrence County, NY—as part of NYRSERDA’s
Renewable Portfolio standard, this station was re-powered to increase output
from 4.5Mw to 6.2 Mw:
http://www.nyserda.ny.gov/Page-Sections/Energy-and-Environmental-
Markets/Renewable-Portfolio-Standard/Project-Gallery.aspx.
Katie Horner (January 13,
2011), "Could East River Tides Help Power NYC," Water Matters—News
from the Columbia Water Center, State of the Planet On Line: http://blogs.ei.columbia.edu/2011/01/14/could-east-river-tides-help-
power-nyc/.
NYSERDA, General Reports,
"Tidal Power," p. 13: http://www.nyserda.ny.gov/en/Publications/NYSERDA-General-
Reports/~/media/Files/Publications/NYSERDA/05-06%20Section%201.ashx.
Resource—written and web:
U.S. Army Corps of
Engineers: http://www.usace.army.mil/Pages/default.aspx.
Hydropower - Renewable,
Reliable, Energy Independence for America: http://www.usace.army.mil/Portals/2/docs/civilworks/budget/strongpt/2012s
p_hydropower.pdf.
The U. S. Department of
the Interior, Bureau of Reclamation, "Managing Water in the West": http://www.usbr.gov/.
Resource—technical
assistance contact names:
Frank W Mace, LEED AP,
DGCP
Distributed Generation
Certified Professional NYSERDA
17 Columbia Circle
Albany, New York 12203-6399
(518) 862-1090, ext. 3433
e-mail: fwm@nyserda.org
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