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Z. Lu and G. Zhu
distributed PV capacity surged 41.3% to 12.2 million kW. Cumulative installed PV
capacity reached 204.3 million kW, up 17.3% year-on-year. Cumulative installed
centralized PV capacity grew 14.5% to 141.67 million kW and that of distributed
PV rose 24.2% to 63.63 million kW.
With the massive centralized grid-connection of renewable power, the technical
challenge, first and foremost, is adopting wind and solar power into a weak grid. The
issue is particularly acute in northwest China, where the grid remains vulnerable in
spite of the 750 kV AC and multiple DC transmission lines. The ability of the grid
to absorb the amount of variable power that comes from renewables remains a big
headache. Specifically, the problem can be broken down into two parts. The first
concerns the impact of wind and solar variability on power system stability in weak
grids. Through the coordinated control of renewable generation units, power stations
and clusters of stations, along with grid control, such problems as voltage fluctuations,
power frequency variations and poor power quality can be addressed. The second
concerns the need for peak and frequency modulation of power system stemming
from the volatile, intermittent and uncertain nature of wind and solar power, as well
as wind and solar curtailment. Wind power generators saw its worst curtailment in
China in 2016, which totalled 49.7 billion kWh or 20% of the total amount generated.
The province of Gansu topped the list with a 43% curtailment, followed by Xinjiang’s
38%. In the past few years, with the strengthening of government control over orderly
planning and construction, the implementation of priority scheduling strategy for
wind power and PV in the dispatching operation section, and the improvement of
the technology of power forecasting and optimal operation by the wind farms and
PV stations themselves, the expected goal of controlling the curtailment rate within
5% has been basically achieved.
Given the reality of grid in China, the following measures can be taken to reduce
wind and solar power curtailment: (1) upgrade flexibility in power supply and storage.
For instance, coal-fired power takes up 65% to 90% of the total output in north
China, but the share of flexible resources such as pumped storage stations only
made up somewhere between 0.5% and 1.2%. Flexibility in coal-fired power plants
should be improved and energy storage stations should be developed to cope with
wind and solar power curtailment; (2) encourage local consumption based on local
conditions, including the placement of industries with high energy loads, district
heating and surplus electricity to produce hydrogen and methane; (3) boost grid
interconnectivity and complementarity between hydro, wind and solar power; (4)
promote concentrated solar power (CSP); (5) build power transmission lines.
Apart from the above measures, new possibilities can be explored to address wind
and solar curtailment as grids and power technology continue to evolve.
Z. Lu and G. Zhu
distributed PV capacity surged 41.3% to 12.2 million kW. Cumulative installed PV
capacity reached 204.3 million kW, up 17.3% year-on-year. Cumulative installed
centralized PV capacity grew 14.5% to 141.67 million kW and that of distributed
PV rose 24.2% to 63.63 million kW.
With the massive centralized grid-connection of renewable power, the technical
challenge, first and foremost, is adopting wind and solar power into a weak grid. The
issue is particularly acute in northwest China, where the grid remains vulnerable in
spite of the 750 kV AC and multiple DC transmission lines. The ability of the grid
to absorb the amount of variable power that comes from renewables remains a big
headache. Specifically, the problem can be broken down into two parts. The first
concerns the impact of wind and solar variability on power system stability in weak
grids. Through the coordinated control of renewable generation units, power stations
and clusters of stations, along with grid control, such problems as voltage fluctuations,
power frequency variations and poor power quality can be addressed. The second
concerns the need for peak and frequency modulation of power system stemming
from the volatile, intermittent and uncertain nature of wind and solar power, as well
as wind and solar curtailment. Wind power generators saw its worst curtailment in
China in 2016, which totalled 49.7 billion kWh or 20% of the total amount generated.
The province of Gansu topped the list with a 43% curtailment, followed by Xinjiang’s
38%. In the past few years, with the strengthening of government control over orderly
planning and construction, the implementation of priority scheduling strategy for
wind power and PV in the dispatching operation section, and the improvement of
the technology of power forecasting and optimal operation by the wind farms and
PV stations themselves, the expected goal of controlling the curtailment rate within
5% has been basically achieved.
Given the reality of grid in China, the following measures can be taken to reduce
wind and solar power curtailment: (1) upgrade flexibility in power supply and storage.
For instance, coal-fired power takes up 65% to 90% of the total output in north
China, but the share of flexible resources such as pumped storage stations only
made up somewhere between 0.5% and 1.2%. Flexibility in coal-fired power plants
should be improved and energy storage stations should be developed to cope with
wind and solar power curtailment; (2) encourage local consumption based on local
conditions, including the placement of industries with high energy loads, district
heating and surplus electricity to produce hydrogen and methane; (3) boost grid
interconnectivity and complementarity between hydro, wind and solar power; (4)
promote concentrated solar power (CSP); (5) build power transmission lines.
Apart from the above measures, new possibilities can be explored to address wind
and solar curtailment as grids and power technology continue to evolve.