POWER September 2020 - 28

TOP PLANT
Delingha: A Leap for Molten
Salt Tower CSP Technology
Courtesy: Supcon Solar
The 50-MW Delingha concentrated solar power tower plant located on the
high-altitude Tibetan Plateau in China was developed, built, and continues to
be refined by a company dedicated to solar tower technology research.
Sonal Patel
C
hina, a country that has added
more than 200 GW of solar photovoltaic
capacity over the last
decade, in 2016 pushed developers
to jumpstart buildout of concentrated
solar power (CSP) projects by officially
releasing a " short list " of demonstration
projects the government would
help fund. But it came with a caveat:
To qualify for subsidies, the " firstbatch "
projects-which included nine
tower projects, seven parabolic trough
projects, and four Fresnel projects-
would need to be operational before
2019.
Among projects shortlisted was the
Delingha plant, a 50-MW molten salt
storage tower CSP facility proposed
for construction across 800 acres of
land in China's northwestern province
of Qinghai. For its developer Zhejiang
Supcon Solar Technology Co., a company
founded in 2010, the timeframe
posed a formidable challenge.
Though Supcon Solar was one of
China's first enterprises dedicated to
the research and industrialization of
CSP technology, it had previously built
only one other project, a 10-MW tower
project at the proposed Qinghai site,
which it completed in 2013 and outfitted
with a molten salt system in 2016.
The 10-MW Delingha tower project,
it noted, was both China's first commercial
CSP plant and only the third
molten salt tower CSP plant put online
in the world.
28
And while CSP technology has
evolved over 15 years from smallscale
research and development projects
to demonstration pilot plants to
commercialization, its uptake across
the world and in China has been slow,
owing to costs and technology associated
with economies of scale and
efficiency. Also problematic was that
China, determined to cultivate a burgeoning
domestic CSP industry, set
a 10-GW target for CSP capacity by
2020 in its 13th five-year plan, but
stipulated that the majority of components
would need to be sourced
domestically.
As significantly, because the project
was to be built on a sparsely populated
plateau about 3,000 meters (m) above
sea level, the 50-MW Delingha tower
project was likely to pose unique challenges
during construction. The region
is characterized by cold temperatures,
and project developers routinely consider
oxygen-deficiency problems on
the plateau when mapping out implementation
plans.
Finally, Supcon's plans were ambitious.
It planned to install 27,135 sets
of 20-square-meter (m2) heliostats
around a 200-m-tall receiver. The system
would also include a 7-hour molten
salt storage system with 10,093
tons of molten salt. If the project met
its steam parameters of 13.2 megapascals
at temperatures of 540C, the
designed electricity output would
stand at 146 GWh/year.
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Despite Clouds, A Sunny
Performance
The company approached the project
with confidence. " Through years of
technological breakthrough, Supcon
Solar has mastered integrated molten
salt tower CSP technologies and established
[a] whole industrial chain, which
is able to provide domestically sourced
equipment, providing reliable and mature
solutions [for] CSP plant construction, "
it said.
According to Supcon, the plant's construction
kicked off in March 2017, and
the full plant was successfully commissioned
in December 2018. However,
it didn't reach full-load operation until
April 2019, and Supcon officially began
a 182-day (six-month) performance test
period in September 2019. As of April
2020, the plant had run 158 days-the
other 24 days were " too cloudy to
keep running without shutdown due to
equipment failure, " it said.
But on 76 of those 158 days, the
plant " exceeded 100% " of the fulfillment
rate on a daily basis. " The total
[direct normal irradiance levels (DNI)]
of the past half year was 1,055.69
kWh/m2 and the converted electricity
was 74.87 GWh (67.09 GWh has been
delivered to the grid) with an average
fulfillment rate of 97.06%, which
was the top performance among its
peers, " it said. Especially notable was
Supcon's reporting of the plant's performance
for the first three months of
this year, when it consistently exceedPOWER
| September 2020
http://www.powermag.com
POWER September 2020

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