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2 China
gets power sums wrong By Sabine
Johnson-Reiser
China's Jinsha River,
literally the "Golden Sands" River, could soon
live up to its rich name. The approximately
2,300-kilometer long upstream section of the
Yangtze River is the site of up to 25 planned
large-scale (50 megawatt and above) hydropower
projects.
China's state-run hydropower
companies, local governments, and energy-hungry
cities in the more developed, eastern provinces
stand to profit from hydropower construction and
electricity generation. Driven by Beijing's energy
and climate goals, this new dam building rush,
however, will reduce China's climate change
adaptation capacity and hurt relationships with
neighboring countries without providing the
emission-free electricity Beijing is seeking.
China's status as the world's largest
carbon-dioxide (CO2) emitter has put increasing
pressure-both domestic and international-on
Beijing to curb national
emissions. In response, the government has laid
out a set of binding targets in the 12th Five Year
Plan: an 11.4% increase in the use of non-fossil
fuel in primary energy consumption; a 16% decrease
in energy consumption per unit of gross domestic
product (GDP); and a 17% decrease in CO2 emissions
per unit of GDP by 2015 [1].
Now, China is
looking for sources of clean, emission-free and
sustainable electricity to fulfill ever-growing
demand and meet renewable energy and emission
targets. More large scale hydropower is wrongly
thought to be one such source. Consequently,
dozens of projects are planned or already under
construction on a number of rivers, including 26
on the Lancang, headwater of the Mekong, 13 on the
Nu, headwater of the Salween, and 28 on the
Yarlung Tsangpo, the headwater of the Brahmaputra.
Misguided hydropower Addressing
China's power sector - a major contributor to
national greenhouse gas emissions - is critical to
reaching Beijing's emission targets. A terawatt
hour (TWh) of electricity generated in China
produces on average 70% more CO2 emissions than a
TWh generated in the United States, and China's
power sector accounted for almost 50% of the
country's CO2 emissions in 2009. Developments in
the power sector therefore will have a significant
impact on the country's emission trajectory.
The high carbon-intensity of China's
electricity is due to the sector's heavy reliance
on coal, a very carbon-intensive fuel that is used
to generate around 80% of China's electricity.
Hydropower accounts for 16% of the country's
electricity generation with nuclear, wind and
solar making up the remainder. Hydropower
advocates argue that shifting the energy mix from
carbon-intensive coal to more hydropower would
benefit China's emission targets.
This
argument relies on the still widespread "clean,
sustainable and emission-free hydropower"
narrative. Even the United Nations Framework
Convention on Climate Change tacitly supports this
misconception by making reports of greenhouse gas
emissions from dam reservoirs voluntary.
Studies however have shown that hydropower
can be a major source of greenhouse gas. Organic
material from previously forested, but now flooded
land and washed up debris, accumulates and
decomposes in the dam reservoirs, thereby
releasing large amounts of methane, a potent
greenhouse gas.
This problem particularly
affects hydropower projects in tropical areas,
where the vegetation is generally denser and more
organic material is accumulated in reservoirs.
Some hydropower facilities in tropical areas emit
up to twice as much carbon dioxide per unit of
electricity as coal fired power plants [2].
As most of China's planned hydropower
projects are located in densely forested,
subtropical southern and southwestern provinces,
new dam reservoirs are likely to become
significant emission sources.
Making
adaptation harder The 12th Five Year Plan
also addresses climate change adaptation
strategies. Beijing wants to strengthen the
country's "capacity to cope with extreme climate
incidents," thereby enhancing China's climate
change adaptation capacity [3]. Yet, the
construction of more dams will decrease China's
capacity to cope with extreme climate incidents,
which are predicted to include more-frequent and
more-severe record floods and droughts [4].
First, the impacts of large-scale dams on
wetlands and human settlement patterns limit
China's adaptation capacity - the ability to
moderate potential damages or cope with the
consequences of climate change - as they expose
millions of people to climate change related
risks.
To maximize power production, dams
store water during the wet season and release it
during the dry season. This alteration of natural
river flow patterns impacts the health of natural
flood storage systems, such as downstream
wetlands, lakes and marshes, often leading to
their disappearance. Thus, dams reduce the
frequency of smaller floods, but also decrease or
eliminate wetlands' natural capacity to absorb
water and thus mitigate severe floods.
In
addition, dams enable the conversion of wetlands
to agricultural farmland and provide downstream
cities with electricity and water for irrigation,
industrial and household purposes, enabling and
encouraging their development and growth.
Hydropower development therefore
contributes to population growth in downstream
areas, which simultaneously increases the number
of people at risk of dam failure as changing
precipitation patterns could lead to floods that
may exceed the storage capacity of dams upstream.
The controversial Three Gorges Dam is a
case in point. With a capacity of 22.5 GW, the dam
can generate up to 84.7 billion kWh of electricity
for cities in central, southern and eastern China,
including the downstream metropolis of Shanghai.
While its reservoir supplied the population in the
middle and lower Yangtze with a steady source of
water, it also contributed to the drying up of
Dongting and Poyang Lake, two of China's largest
freshwater lakes, during the 2011 drought.
Although the dam withstood its first major
flood test in 2010, whether the Three Gorges Dam
will be able to contain future, possibly worse,
floods is uncertain\. If it fails, downstream
residents will not be able to rely on natural
floodplains to mitigate the impact with possibly
disastrous consequences for life and property.
Second, the operation of large-scale dams
exacerbates droughts in downstream areas. In
theory, reservoirs could provide short-term
drought relief, by releasing stored water for use
downstream. Yet, below a certain water level, the
primary objective of hydropower
operators-maximizing electricity
generation-suffers.
The fact that the
central government had to order the China Three
Gorges Corporation to release water from the
reservoir to alleviate the severe drought
downstream in 2011 suggests that hydropower
operators are likely to put power generation ahead
of drought relief.
Third, dams make it
harder for coastal cities to adapt to rising sea
levels. As freshwater is held back in reservoirs
upstream, natural water outflows at river deltas
are reduced, contributing to a fall in coastal
groundwater tables. Combined with rising sea
levels, this makes coastal delta regions more
susceptible to saltwater intrusion, which
contaminates coastal freshwater aquifers and makes
water unfit for human consumption [5].
More dams could exacerbate future
saltwater intrusion challenges for many coastal
Chinese cities brought on by rising sea levels.
Shanghai, located in the Yangtze River Delta, is
already experiencing saltwater intrusion, which
research has linked to variations in water
discharge from the Three Gorges Dam [6].
Lastly, the expensive and long-lasting
nature of hydropower infrastructure makes it
difficult or impossible to adapt them to future
changes in the environment, agricultural and
economic activities and human settlement patterns.
Large-scale dam construction is very
costly. The record-setting Three Gorges Dam cost
approximately $25 billion. Even smaller projects
like the planned Xiaonanhai Dam on the Upper
Yangtze cost up to $5.6 billion. China Post
Securities analyst Shao Minghui estimates the
hydropower sector will need around $136 billion in
infrastructure investment by 2020.
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