IEEE Power & Energy Magazine - November/December 2021 - 90

increasing attention on demandside
resources. During the cold
wave in winter 2020, the flexibility
of demand-side resources
in Jiangsu Province made a large
contribution to securing the supply
of energy.
Brazil and Chile have encountered
VRE curtailment, despite
their hydropower generation that
has historically provided good
flexibility. Hydropower accounts
for 65% of Brazil's and 26% of
Chile's installed capacity, with
seasonal and multiyear storage
available. However, hydro
resources are becoming more constrained
due to climate change, an
increasing level of conflicting priorities
for water usage as well as
transmission bottlenecks.
In Brazil, VRE curtailments
have still been small, ranging
from 2 to 6% of capacity, and
are increasing. In Chile, they
increased to 30% during some
days in 2016-2017, mainly due
to network congestion and inflexible
thermal generators with disproportionally
high minimum
generation limits. Once these
limits were reduced, the system's
capability to absorb renewables
increased significantly, reducing
curtailment in 2017-2018 (Figure
5). Investments in transmission,
including a major interconnector
between the main solar
resources in the north and main
load centers in the central part,
reduced congestion significantly
during 2018-2019.
In 2020, there were some
increases in curtailment. Reasons
for this included reduced demand
due to COVID-19 lockdowns,
increased volumes of inflexible
gas purchased through take-orpay
contracts dispatched at zero
marginal cost, high volumes of
hydro resources available, and
network congestion (exacerbated
under network contingencies).
Flexibility from hydropower
generation in Brazil and Chile
90
ieee power & energy magazine
november/december 2021
10,000
12,000
14,000
16,000
18,000
6,000
8,000
4,000
2,000
5
40
December 2016 to Nov. 2017
Historical Peaks due to
Transmission Constraints
Wind (Daily MWh) Solar (Daily MWh) Wind + Solar (Monthly %)
From Jan. 2016
Operating Inflexibility From Thermal
Plants + Transmission Constraints
Nov. 2017
COD of SIC-SING Interconnector
(Transmission Relief)
From August to Sept. 2020
Load Reduction due to COVID-19
Take-or-Pay on Gas Supply Agreements
High Hydro Resources Available/Inflows
Network Congestions
By Jan. 2019
Reductions of Thermal Operating
Inflexibility (Reductions in Minimum
Generation Limits During 2017-2018)
May 2019
COD of Major Transmission Line
(Transmission Relief)
10
20
15
30
35
25
figure 5. The renewable energy curtailments in Chile, in daily megawatthours and as a percentage of the available monthly resource. COD: commercial operation
date; SIC: Sistema Interconectado Central; SING: Sistema Interconectado del Norte Grande.
1 Jan. 2016
1 Mar. 2016
1 May 2016
1 July 2016
1 Sept. 2016
1 Nov. 2016
1 Jan. 2017
1 Mar. 2017
1 May 2017
1 July 2017
1 Sept. 2017
1 Nov. 2017
1 Jan. 2018
1 Mar. 2018
1 May 2018
1 July 2018
1 Sept. 2018
1 Nov. 2018
1 Jan. 2019
1 Mar. 2019
1 May 2019
1 July 2019
1 Sept. 2019
1 Nov. 2019
1 Jan. 2020
1 Mar. 2020
1 May 2020
1 July 2020
1 Sept. 2020
1 Nov. 2020
Generation Curtailment (MWh)
Generation Curtailment (%)

IEEE Power & Energy Magazine - November/December 2021

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