pwr_may-2024 - 5

SPEAKING OF POWER
How the Massive Growth
in Solar Power Is Affecting
Power Grids
Aaron Larson
T
he Solar Energy Industries Association
(SEIA) reported in March
that the U.S. solar industry installed
32.4 GWdc of capacity in 2023,
a remarkable 51% increase compared to
2022. It was the industry's biggest year
by far, exceeding 30 GWdc of capacity
for the first time. Overall, photovoltaic
(PV) solar accounted for 53% of all new
U.S. electricity-generating capacity additions
in 2023, making up more than half
of new generating capacity for the first
time. The utility, commercial and industrial,
and residential sectors all set annual
installation records, while the community
solar sector was within 5 MWdc of an
annual record.
Yet, this is not just a U.S. story, solar
capacity is growing exponentially around
the world. In its Renewables 2023 report,
the International Energy Agency (IEA)
said 2023 saw a step change in renewable
capacity additions, driven by China's
solar PV market. It said global annual
renewable capacity additions increased
by almost 50% to nearly 510 GW last
year-the fastest growth rate in the past
two decades. 2023 was the 22nd year in
a row that renewable capacity additions
set a new record, according to the IEA.
While the increases in renewable capacity
in Europe, the U.S., and Brazil hit
all-time highs, China's acceleration was
extraordinary. In 2023, China commissioned
as much solar PV as the entire
world did in 2022. Solar PV accounted
for three-quarters of renewable capacity
additions worldwide.
Utility-scale projects are what really
drive the industry. In the U.S., utilityscale
installations spiked to 22.5 GWdc
of capacity, according to SEIA, a 77%
increase over 2022. The temporary
moratorium on anticircumvention tariffs
applicable to certain imports from four
Southeast Asian countries brought some
relief to the solar supply chain, helping
projects move forward last year. The
moratorium ends in June 2024, however,
so we'll see how that affects projects in
the second half of this year.
May 2024 | POWER
The Texas Grid Evolves
Texas was the leading state for solar
installations in 2023. Since 2021, more
than 15 GW of new solar capacity has
been added in Texas. Furthermore,
SEIA predicts Texas will lead the nation
with nearly 100 GW of new solar
capacity additions from 2024 to 2034,
outpacing the next closest state by a
two-to-one margin.
According to the Electric Reliability
Coluncil of Texas (ERCOT), the grid operator
for about 90% of the load in Texas,
solar generation supplied 32.4 TWh
to its grid in 2023-7.29% of the annual
total. In the first quarter of 2024, the
percentage increased to 8.16%, which
is notable because the winter season
is not typically a prime period for solar
production. It's also notable in that solar
was not far behind nuclear (9.92%) or
coal (12.10%) in ERCOT's first quarter
energy mix. Natural gas-fired generation
(40.42%) and wind (29.41%) were
the clear leaders in Texas, however.
While solar only accounts for 13.2%
of Texas' installed capacity, according
to ERCOT's December 2023 Capacity,
Demand, and Reserves (CDR) report for
Summer 2024, it can have a significant
impact on the grid during peak times.
An April 2024 ERCOT fact sheet shows
the solar generation record of 18,881
MW was set on March 28 this year. The
solar penetration record was also set
that day at 42.98%. While those numbers
are astounding, it seems likely that
the generation record will be eclipsed
sometime this summer, and on a regular
basis in the not-to-distant future.
The Duck Curve Waddles into
Texas
The increase in solar generation in
Texas is starting to create a duck
curve in the ERCOT grid, similar to
what has long been observed in the
California Independent System Operator's
(CAISO's)
grid. For a little
background, the duck curve was first
brought to light in 2013 when CAISO
published a chart that showed the
www.powermag.com
difference in electricity demand and
the amount of available solar energy
throughout the day. The curve was
a snapshot of a 24-hour period in
California during springtime, which
is when the effect is most extreme
because it's sunny but temperatures
remain cool, so demand for electricity
is low because people don't need to
use much electricity for air conditioning
or heating. CAISO showed how
the pattern created by the midday dip
in the net load curve, followed by a
steep rise in the evening when solar
generation drops off, looks like the
outline of a duck, hence the name.
Since 2013, California's duck curve
has only gotten deeper as more and
more solar power has been added to the
CAISO grid. In fact, on some days, the
net demand curve is going negative in
California.
The situation in Texas is nowhere
near as extreme as that seen in California.
However, the increase in solar
generation is beginning to have a noticeable
effect. The U.S. Energy Information
Administration (EIA) published
an article on April 9 comparing ERCOT's
average hourly electricity generation
in winter 2022-2023 to winter
2023-2024. The solar-caused dip was
distinctively larger this past winter. Furthermore,
it's been observed that the
duck curve is increasingly occurring
in other parts of the world in places
where the share of solar generation is
growing compared to generation from
conventional sources.
Every power grid is different and operators
will end up dealing with increases
in solar capacity in their own unique
ways. In ERCOT's case, it has much
more dispatchable gas-fired generation
to play with than CAISO does and its significant
wind resources tend to complement
solar rather than amplifying the
problem, so it may have an easier time
managing the situation, at least for the
time being. ■
-Aaron Larson is POWER's
executive editor.
5
http://www.powermag.com
pwr_may-2024

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