POWER October 2014 - 58

RENEWABLES
A New Day for North American
Hydropower?
Often overlooked in the dash toward wind and solar, hydropower remains a
major player in renewable generation. But recent trends suggest a shift
toward pumped storage and retrofitted generation may be in the works.
Thomas W. Overton, JD
C
an hydropower get some love?
Even fans of renewable energy
can be forgiven for having forgotten
about a resource that-up to now-
has produced more electricity than wind,
solar, biomass, and all other renewable
sources combined. Energy sector news is
dominated by reports about the latest big
solar plant coming online, ever-larger wind
turbine models coming on the market, and
seemingly never-ending battles over subsidies
and credits.
The limited public interest in hydropower
is understandable to some extent. Hydro is
a mostly low-tech, mostly familiar resource
that generally makes waves only of the watery
sort. The giant hydroelectric projects
of the 20th Century have become part of
the landscape in North America, and relatively
few more of those are likely to ever
get built. Wind and solar have seized not
just the headlines but also the generation
momentum: The U.S. Energy Information
Administration predicted in this year's Annual
Energy Outlook that 2014 will be the
first year ever in which total non-hydro renewable
generation will exceed total hydropower
generation.
That's a crown that hydro may struggle to
get back. Total U.S. hydroelectric capacity
(including pumped storage) increased about
1.3% between 2002 and 2012, a period in
which wind capacity increased more than
1,300% and solar increased nearly 800%.
Hydro has also missed out on a lot of
the support given to wind and solar. Focused
as many renewable subsidies are on
fostering new capacity, many incentives
specifically exclude existing hydroelectric
generation. The Environmental Protection
Agency's (EPA's) proposed carbon emissions
standards barely mention hydro,
leaving several hydro-heavy states feeling
left out. Nuclear generation gets a credit
to help keep existing plants operational in
the face of competition, but existing hydro
appears to get nothing. In fact, the EPA
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POWER | October 2014
didn't consider hydro at all in calculating
several states' baselines for renewable
generation (on the rationale that doing so
would disadvantage states with no or limited
hydro potential).
Forgotten But Not Gone
But counting hydro out would be a big mistake.
A common misconception is that hydro is
" built out " in North America-especially in
the U.S.- with nearly all large potential sites
already harnessed. In fact, in the U.S. alone
there is substantial undeveloped hydroelectric
potential, almost as much as is currently used
for generation. A study by the Oak Ridge National
Laboratory (ORNL) released in April
2014 found that there was more than 84 GW
of untapped potential nationwide, though this
included areas where hydro development is
prohibited. When excluding areas that are
within or close to National Parks, Wild and
Scenic Rivers, and Wilderness Areas, the
study found that there was still more than 65
GW of potential capacity that could generate
almost 350 TWh annually.
The potential capacity goes beyond
greenfield projects. An earlier ORNL report
from 2012 found that the more than
54,000 unpowered dams across the U.S.
represented substantial opportunities for
retrofitting generation at a fraction of the
cost-and hassle-of new dams. Though
most of these dams are too small or poorly
configured, the 600 or so most favorable
sites could be retrofitted with a total of
around 10 GW of capacity.
The highest potential was found in the
Ohio, Upper Mississippi, and ArkansasWhite-Red
river basins, where many U.S.
Army Corps of Engineers (USACE) navigational
locks could be fitted with generation
(Figure 1). The study identified 87 such sites
1. Untapped. The Emsworth Locks and Dams on the Ohio River in Pittsburgh are one of
many federally owned flood control and navigation sites at which hydro generation could be
added, according to a recent study. A Boston-based company is seeking approval to build a 24MW
run-of-river facility there. Source: U.S. Army Corps of Engineers

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POWER October 2014

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