“There’s a major reexamination of the value of hydropower
going on now, particularly over last three or four years.
The renewed interest is because of the push for renewable
portfolio standards in certain states and how to meet
those standards. Hydro is considered green by the states,
has a favorable standing with local communities and is
very popular. There has been increased attention and
a movement to harness what is potentially out there,”
said Doug Dixon, technical executive at the Electric
Power Research Institute (EPRI). Members of EPRI represent
more than 90 percent of the electricity generated and
delivered in the United States.
Today, conventional hydroelectric power represents
only 7.6 percent of all American electric generation,
but the potential waiting to be harnessed is
huge. Not in gigantic projects like the Hoover
Dam, but in a vast number of smaller, more diverse,
nationally distributed sources that cumulatively
could add up to big electricity production. Hydro
has advantages over solar and wind since it produces
full time. The next generation of water power
is likely to include:
Building additional capacity
or increasing efficiency at existing hydroelectric
Installing new power plants
on existing dams.
Building small-scale hydro plants
not requiring new dams or reservoirs.
Installing ocean-wave and tidal
Placing in-stream hydrokinetic
turbines in rivers.
Harnessing the power of constructed
waterways: canals, aqueducts, water supply system,
and effluent streams.
Hydropower was the earliest and cleanest source
of renewable energy, but not much was heard, if
anything, about it in speeches about renewable
energy from the presidential candidates. They would
talk about wind, solar, biomass, ethanol, electric
vehicles; even bring up controversial nuclear,
but barely any mention of hydro.
Fred Ayer, executive director of the Low Impact
Hydropower Institute (LIHI) characterized the situation
this way, “My sense is the public attitude about
hydro is mixed. People are conflicted. When they
think about it initially, they like the idea it’s
renewable. On the other hand, it has the potential
to cause serious damage when you insert dams into
free-flowing rivers. I don’t think you will see
many new dams built in the United States in the
Rather than build new dams, environmentalists are
lobbying to remove them from rivers that have migrating
fish such as the salmon in the Columbia River.
Besides storing potential energy to generate electricity,
people often lose sight of the vital role dams
play in flood control, irrigation and creating
lakes to store water supplies and for recreational
“I think our best hope for additional near term
hydro is the powering of non-powered dams. The
dam is already there and the environmental impact
has either been accepted or mitigated,” ventured
Doug Hall, program manager for water energy at
the Idaho National Laboratory (INL). Adding capacity
to existing hydro plants is another option. Replacing
older turbines with newer, more efficient ones
can gain significant power output with the same
water flow, by as much as 15 percent.
INL is a science-based, applied engineering national
laboratory that supports the United States’ Department
of Energy’s missions in nuclear and energy research,
science and national defense. It is also the leading
authority on hydropower’s potential. In 2004, with
the assistance of the United States Geological
Survey, INL completed a major water energy assessment
of all 20 hydrologic regions in the United States.
Anyone is interested in exploring the water power
potential in their area should visit http://hydropower.inel.gov/prospector/index.shtml.
There, the Virtual Power Prospector geographic
information system (GIS) application displays all
natural stream water energy resources in the United
States. By displaying maps of potential hydro sites
and existing infrastructure, detailed information
Based on this study and additional research, INL
released its Feasibility Assessment of the Water
Energy Resources of the United States for New Low
Power and Small Hydro Classes of Hydroelectric
Plants. For study purposes, low power was defined
as 1 megawatt or less and small hydro from 1 to
30 megawatts. INL estimated the power potential
for sites not requiring a dam or reservoir based
on using penstocks (a pipe that takes water from
a higher elevation to a turbine at a lower elevation).
“Using very conservative assumptions on how much
developable hydro power there is available; we
identified 130,000 sites in the States that represent
30,000 megawatts of annual average power. Today
there are about 2,300 hydroelectric plants in the
United States with a cumulative annual average
power of about 35,000 megawatts. So, there is the
theoretical potential of nearly doubling hydroelectric
production,” said Hall. Again, that is without
building new dams or reservoirs.
Worldwide during 2008, small hydro installations
grew by 28 percent over 2005 to raise the total
small hydro capacity to 85 gigawatts (GW). Over
70 percent, or 65 GW of new, small hydro was in
China, 3.5 GW in Japan, 3 GW in the States, 3 GW
in India and the balance in a number of other countries.
Using water energy that runs through pipes at irrigation
projects and water treatment plants is also a greatly
underutilized asset. An example of what can be
done is found at the Deer Island Wastewater Treatment
Plant in Boston. After wastewater is treated, and
before it discharges into a 9.5 mile outfall tunnel
into Massachusetts Bay, the water drives two, 1,000
kilowatt generators. In August, the project submitted
an application for certification to the Low Impact
Hydropower Institute. If certified as environmentally
responsible, the project may become eligible for
carbon trading credits, green energy bonds and
can be added to a renewable energy portfolio.
Microhydro, generally defined as less than 100
kilowatts, has experienced a revolution over the
past decade, particularly due to technology advances
in microturbines that require as little as a few
quarts or gallons of water per second to generate
electricity. Individuals, both on and off the grid
with access to even the smallest water flows are
generating their own electricity. Advances in micro
circuitry and dropping prices for charge controllers,
batteries and small inverters have made this possible.
“It’s a niche market, but one that is growing,”
said Denis Ledbetter, owner Lo Power Engineering.
His company manufactures microturbines costing
from $1,800 for a 50 watt unit to $2,150 for 1,500
watts. They use a multi-cupped Pelton design waterwheel
mounted inside a metal case that is driven by a
jet, or multiple jets of water. The turbine drives
a standard automotive alternator to charge a bank
of batteries. Once the batteries are charged, DC
power can be fed to an inverter for conversion
into AC for home use. Without labor, and depending
on the size and length of the penstock, complete
microturbine systems typically cost in the range
of $5,000 to $10,000 dollars.
A telltale sign of what’s happening in a variety
of hydro projects is the soaring increase in the
number of preliminary permits issued by the Federal
Energy Regulatory Commission (FERC). Part of the
increase is due to a pilot license program to encourage
hydrokinetic and wave energy projects.
A highlight example of FERCs expedited approach
is the 100 kW Hastings Minnesota project that was
commissioned last August to become the country’s
first federally licensed hydrokinetic power plant
that is grid-connected. Hydrokinetic is different
than a conventional hydroelectric. A turbine placed
in a river, man-made channel, tidal flow or ocean
current captures energy from moving water at low
speeds without requiring a dam or diversionary
structure to direct the flow.
FERC approved this first commercial hydrokinetic
project at Hastings in December 2008 and it came
online nine months later – lightspeed compared
to FERC’s traditional standards. This turbine,
installed in the flow of the Mississippi River,
is generating electricity around the clock except
for occasional maintenance. The project is also
a prototype for long-term study of the main environmental
objection, fish endangerment. A preliminary study
conducted by Normandeau Associates, a leading environmental
consulting firm, indicated an estimated 97.5 percent
fish survival rating for the turbine. Of course,
environmental studies will continue during the
demonstration phase and the project can be challenged
by any number of federal and state agencies or
private interests before it can be fully licensed.
Putting low-speed turbines in rivers holds promise
for putting clean, renewable electricity onto the
grid in a timely manner, if the environmental concerns
can be overcome. Infrastructure costs are comparatively
low. Turbines can be suspended from anchored barges
as done at Hastings, or mounted on the riverbed.
Transmission lines can be buried in river beds
and major rivers, the most suitable for hydrokinetic,
already have robust transmission infrastructure
along their banks. Large cities located on rivers
with high power demand could be the prime beneficiaries.
“The people at FERC are very aware of the criticism
of how long the licensing process takes. They will
tell you that if you have projects where no one
is particularly concerned about the impact, for
example, on man-made canals running downhill where
you need to slow down the flow of the water, those
kinds of projects could be licensed reasonably
quickly,” said Doug Hall at INL. A FERC license
typically takes from three to eight years. Because
FERC regulates the process, a project is open for
review by all the federal resource agencies as
well state and local agencies, groups or individuals.
This is not the case for wind and solar projects
since a FERC license is not required.
“The FERC process is too long, but they try to
meet everyone’s needs. Before 1969 we didn’t have
many environmental statutes in this country. In
the mid to late 80s, FERC started to pay closer
attention. The licensing process is certainly not
perfect but they are tremendously ahead of where
they were 50 years ago. They deal with a lot of
important issues that are not always easy to resolve.
It can be very time consuming and a very expensive
process,” said Fred Ayer at LIHI.
Another FERC sanctioned demonstration project is
the Roosevelt Island Tidal Energy (RITE) project
in New York City’s East River (a tidal estuary).
Over the past 2 years, Verdant Power operated 6
turbines, each with 16-foot diameter rotors to
demonstrate the system as an efficient source of
renewable energy. Over 9,000 turbine-hours of operation,
the system produced 70 megawatt hours that were
delivered to two end users. Bidirectionally powered
by both ebb and flow tides, turbines are automatically
controlled for continuous, unattended operation.
Now going into Phase 3, the company plans to build
greater capacity through 2012. Because tides run
like clockwork, electric production is predictable.
In January, defense contractor Lockheed Martin
announced a partnering agreement with Ocean Power
Technologies (OPT) to build utility-scale wave
generation projects on the Pacific coast. FERC
issued preliminary permits for four sites in California
and Oregon. These projects will use OPT’s PowerBuoy
technology that has been tested in several small
demonstration projects, including one with the
Navy in Hawaii.
Arrays of PowerBuoys will be anchored offshore.
Waves move a buoy up and down and a power take-off
system generates AC electricity that is sent to
shore on a seabed cable to the grid. Sensors on
the buoy monitor subsystems, ocean conditions and
real-time data is sent to shore. If waves become
too high, the system automatically stops power
production. When waves return to normal, power
The Energy Improvement and Extension Act of 2008,
included a new PCT for marine and hydrokinetic
facilities deriving energy from waves, tides; currents
in oceans, estuaries and tidal areas; free flowing
water in rivers, lakes and streams; free flowing
water in irrigation systems, canals, or other man-made
channels, or from differentials in ocean temperatures.
Such facilities must have a nameplate capacity
of at least 150 kilowatts and be in service before
January 1, 2012 – a very tight window for hydro
development. The corporate tax credit is 1.1 cents
per kilowatt hour.
Developers would be further encouraged to build
hydropower if they could bank on generous, long
term state tax benefits or incentives or renewable
energy incentives from utilities.
Everyone constantly decries our dependence on imported
oil when the United States has some of the most
abundant water resources on the planet. Moving
clean hydropower onto the grid in a responsible
environmental manner should be a high priority.