POWER March 2021 - 24

SUSTAINABILITY
The Hydropower Industry's
Sustainability Conundrum
Hydropower makes up the majority of the world's renewable energy capacity, but
it's not necessarily an environmentally friendly form of power. However, groups are
working to improve hydropower technology to make it more sustainable in the long
term.
Aaron Larson
ou hear a lot of talk about sustainability
these days, but what
exactly does the word mean? According
to dictionary.com, one definition
is: " The quality of not being harmful
to the environment or depleting natural
resources, and thereby supporting longterm
ecological balance. " It's obviously
a worthwhile goal, but actually achieving
the objective is not as easy as it
sounds, especially for companies in the
hydropower industry.
The largest increase in the use of
renewable energy recently has come
from the rapid expansion of solar and
wind power. Nonetheless, hydropower
remains the world's largest source of
renewable energy, accounting for more
than half of the installed global renewable
energy capacity. During a webinar
hosted by the International Hydropower
Association (IHA) on Jan. 20, Roger Gill,
chair of the IHA's Hydropower Sustainability
Governance Council, said, " Wind
and solar have great potential, but they
also have limits. It seems to me that hydropower
is going to be always a major
part of the solution mix. "
Is Hydropower Sustainable?
However, some experts question whether
hydro is truly an environmentally
friendly form of power generation. There
are significant environmental impacts
associated with dams and hydropower
plant operations.
For example, flooding land for a
reservoir can destroy
hydroelectric
forests, wildlife habitat, agricultural
land, and scenic areas. In some instances,
entire communities have to
be relocated to make way for reservoirs
(Figure 1). While reservoirs can
provide benefits, such as flood control,
agricultural irrigation, and recreation,
they can also negatively affect
aquatic ecosystems.
It's well known that certain species
24
Y
of fish, such as salmon and shad, swim
up rivers and streams from the sea to
reproduce in spawning grounds in the
beds of rivers and streams. Dams can
block their natural migration paths.
Furthermore, many fish are injured or
killed passing through hydropower turbines.
The U.S. Department of Energy
has reported that fish kills of 5% to
10% are common for the best existing
hydro turbines, which is obviously a
significant loss (see sidebar).
Although water flows through hydropower
reservoirs, the water in
reservoirs is generally more stagnant
than normal river water. Therefore,
reservoirs often contain high levels of
sediment and nutrients, which provide
fertile conditions for algae and aquatic
weeds. The unwanted flora can crowd
out fish and other animals, as well as
more naturally present plant life. Additionally,
water evaporates from reservoirs
at a much higher rate than in
flowing rivers, and if water is released
from dams at less than normal rates,
downstream areas can dry out more
than they would have with natural
river flows.
Finally, decomposition of organic material
in reservoirs releases carbon monoxide
and methane. The exact amount
depends greatly on site-specific conditions,
but some estimates suggest
the lifecycle global warming emissions
from reservoirs could be as high as
the emissions from a well-run natural
gas-fired plant on a per-kWh-generated
basis. In fact, the Environmental Defense
Fund (an environmental advocacy
organization) conducted a study
on greenhouse gas emissions from
hydropower projects and found that of
the nearly 1,500 facilities it examined
worldwide-which accounted for about
half of global hydropower generation-
more than 100 had greenhouse gas
emissions that caused more warming
than fossil fuels.
www.powermag.com
1. The Aswan High Dam was completed in
1970 on the River Nile in Egypt. The reservoir,
which is 500 kilometers (km, 310 miles) long
and 35 km (22 mi) at its widest, with a surface
area of 5,250 km2 (2,030 mi2), is shown in this
image taken from space. Nearly 100,000 residents
and some archaeological sites had to be
relocated prior to its filling. Source: NASA
Making Hydro More Sustainable
Work is being done to improve the situation.
The IHA recognized the need to
develop sustainability tools for the industry
and established IHA Sustainability,
a not-for-profit subdivision of the
organization. About a decade ago, IHA
Sustainability created three tools to define
and measure sustainability in the
hydropower sector. The tools are the
Hydropower Sustainability Guidelines
on Good International Industry Practice
(HGIIP), the Hydropower Sustainability
Assessment Protocol (HSAP), and the
Hydropower Sustainability ESG [Environmental,
Social, and Governance]
Gap Analysis Tool (HESG).
As part of its management role, IHA
Sustainability offers training and accreditation
courses to practitioners
in the use of the hydropower sustainability
tools. It also assists hydropower
developers and operators in identifying
accredited assessors for independent
project sustainability assessments.
During the Jan. 20 webinar, Joao
Costa, head of sustainability with
IHA Sustainability, explained that the
tools are now being developed into a
standard. The aim of the standard is to
incentivize and recognize hydropower
POWER | March 2021
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POWER March 2021

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