678 5 NOVEMBER 2021 • VOL 374 ISSUE 6568 science.org SCIENCE
dam builders, in contrast, are state-owned
enterprises supported by state-owned banks,
which puts them in a better position to win
financial and political support, Harlan notes.
BRI’s hydropower investments are already
having a disastrous impact on the Mekong
River Basin—the world’s most biodiverse
river system after the Amazon. Rising in
China, the Mekong runs through five coun-
tries before reaching the South China Sea. It
supports the world’s largest inland fishery,
providing a significant source of protein for
the 65 million people living in the
800,000-square-kilometer basin.
The river system already has
more than 400 dams, 126 of them in
China itself, that “reduce the might-
iness of the Mekong’s natural flow,”
says Brian Eyler, a water security ex-
pert at the Stimson Center in Wash-
ington, D.C. The dams suppress the
Mekong’s unique wet season flood-
ing, which is key to fishery produc-
tivity and the riverside agriculture
that tens of millions rely on.
Environmental advocates point
to Cambodia’s Lower Sesan 2 Dam
as an example of the influence a
single hydropower plant can have.
The contract to build the 400-MW
dam, Cambodia’s largest, was signed
in 2012, but was later brought un-
der the BRI umbrella. Completed
in 2018, the dam is located just
downstream from the confluence
of the Sesan and Srepok rivers, two
Mekong tributaries that are key mi-
gratory pathways for hundreds of
fish species, Eyler says. Seventy-five
meters tall, it stretches 6 kilometers
across a wide valley to block the meander-
ing, shallow river. The flooding it caused
displaced 5000 mostly Indigenous peoples
and ethnic minorities from six villages.
A 2 01 2 s t u d y i n t h e P ro c e e d i n g s o f t h e Na -
tional Academy of Sciences by Guy Ziv, now
at the University of Leeds, and colleagues
warned that the dam could cut the entire
Mekong’s fish population by 9.3%—“a huge
reduction caused by a single dam,” Eyler
says. A 2008 impact assessment commis-
sioned by Vietnam Electricity estimatedthe dam would shrink the annual incomes
of 300,000 fishers and farmers living near
the river by millions of dollars.
Peer-reviewed studies of the dam’s im-
pact have yet to appear, but fishers have re-
ported that catches in 2019 and 2020 were
down 80% compared with previous years,
Eyler says. And a 10 August report by Hu-
man Rights Watch says those affected have
not received compensation.
Chinese companies are full or part own-
ers of another big dam already built in
Cambodia and 18 more in neigh-
boring Laos. And more are on the
way: Chinese interests have eight
Mekong dams under construction
and another 34 under study for lo-
cations scattered throughout the
watershed. (Developers and inves-
tors from all of the Mekong basin
countries as well as from the United
States, South Korea, and Japan are
also planning Mekong dams.)
But just as with coal-fired power
plants, the financial calculus is
changing. Eyler says the Mekong
dams were envisioned 20 years
ago when many saw hydroelectric
power as a clean alternative and so-
lar and wind power were still costly.
Now, some dam developers are hav-
ing trouble finding buyers for their
power because other types of renew-
able energy are becoming cheaper.
This makes arranging financing
difficult. “You can’t get money from
the bank if you don’t have a power
purchase agreement,” Eyler says.
In March 2020, poor economic
prospects led Cambodia to delayThe 55-megawatt Garissa Solar Power Station, built northeast of Nairobi, Kenya, exemplifies the Belt and Road Initiative’s shift in focus, from coal to renewable power.
CREDITS: (PHOTO XIE HAN/XINHUA/ALAMY LIVE NEWS; (GRAPHIC N. DESAI/SCIENCE; (DATA C. NEDOPIL WANG,COAL PHASE-OUT IN THE BELT AND ROAD INITIATIVEBRI : AN ANALYSIS OF CHINESE-BACKED COAL POWER FROM 2014-2020, GREEN BRI CENTER, INTERNATIONAL INSTITUTE OF GREEN FINANCE, BEIJING (2021 0510152025303540452013 2014 2015 2016 2017 2018 2019 2020020406080100%2013 2014 2015 2016 2017 2018 2019 2020BRI investment (%)BRI investment ($ billion)Coal Oil Gas Hydro Solar/windRenewables up, coal down
Hydroelectric, solar, and wind power make up a growing share of the
Belt and Road Initiative’s (BRI’s) energy investments. The pandemic
dampened all BRI activity in 2020.