6 January 2023
Wall Street Journal
interviews
Wind and solar developers are concocting elaborate plans to provide
round-the-clock renewable power, the industry’s holy grail as countries around
the world shift to green energy.
Renewable energy
is notoriously unreliable, generating electricity only when the wind is blowing
and the sun is shining. Project developers, utilities and grid operators are
trying a mix of options to overcome that challenge, including building huge
amounts of renewable capacity, storing excess power on batteries, and using algorithms
to make project economics work.
A few years ago,
ReNew Energy Global PLC RNW -0.87%decrease; red down pointing triangle decided
it could supply India’s grid with a steady stream of electricity by building
wind and solar farms capable of producing as much as three times the amount of
power it had contracted to deliver—all in different parts of the country and
knit together with sophisticated software.
The project,
which is scheduled to come online early this year, is expected to perform more
like coal or gas plants, which utilities count on to deliver a reliable amount
of power when consumers need it, says Sumant Sinha, ReNew’s CEO.
“That is making
it easier for [Indian utilities] to absorb more renewable energy,” he says.
Building the
additional capacity is expensive, with the total project cost at around $1.2
billion. To help pull in more revenue, ReNew plans to sell extra electricity it
generates on India’s spot market, where prices tend to be relatively high,
using computer models to predict the best times to do that.
Even so, the
project can’t guarantee to deliver power on demand 100% of the time—something
developers say is still too tough and costly to do with renewable sources and
batteries alone.
Companies around
the world are wrestling with similar challenges as countries shift away from
climate-warming fossil fuels, raising the amount of solar- and wind-generation
in the power mix.
In the U.S., for
instance, Virginia-based power company AES Corp. is selling 24-hour
renewable-power contracts to big corporations that are trying to slash the
amount of carbon emissions associated with their electricity use, says Leonardo
Moreno, president of the company’s clean-energy business unit.
For the first
such deal, signed in 2021 with Google, AES pledged to build enough new
renewable-energy generation to power the Alphabet Inc. unit’s Virginia data
centers for 90% of the hours contracted. To do that, AES crunched numbers on
thousands of configurations of wind, solar and energy storage, in different
locations, to match the times and amounts of electricity Google wanted, says
Mr. Moreno. Similar to ReNew, AES ultimately built more than three times the
capacity that Google’s data centers would have needed from an energy source
that was generating at full power all the time.
AES later signed
a similar deal with Microsoft Corp. and is now talking to the Defense
Department to discuss whether something like that would be feasible for its
power procurement, Mr. Moreno says.
Building such
large amounts of renewable capacity has its limitations. In addition to the
expense, it takes up vast amounts of land and isn’t possible in some parts of
the world. Getting to 100% renewable energy all the time would require so much
battery storage that it isn’t economically feasible at this time, says Mr.
Moreno.
Many renewables
developers are combining batteries with solar farms to let them store some
energy during the day, when the sun is shining, power production is at its peak
and electricity prices tend to be lower. They discharge that power in the
evening, when solar supply falls but demand for electricity, along with prices,
is high, says Donny Gallagher, vice president of engineering at Solv Energy
LLC, one of the biggest builders of large-scale solar installations in the U.S.
That kind of
strategy is especially important in states such as California, where solar in
2021 comprised around a quarter of the state’s power generation, with wind
contributing 8%, according to the U.S. Energy Information Administration. The
rush of power from all those solar panels around midday means there is often
more electricity than needed, and the state’s grid operator is unable to take
it, says Mr. Gallagher.
“It’s almost
impossible to find a project now in California without batteries,” he says.
Spain-based
Siemens Gamesa Renewable Energy SA, a wind-farm developer and turbine maker, is
similarly working on how best to combine its projects with batteries as well as
systems that can store energy in hydrogen, says Poul Skjærbæk, the company’s
head of innovation and products.
In India, the
country’s electric distribution companies are struggling to handle mismatches
between power demand and supply as the amount of wind and solar has grown to
around 12% of the country’s generation. When the sun and wind are strong, those
projects can produce a lot of electricity, but over the course of the year,
they might generate only 30% or less of their full capacity.
In 2019, the
government took a stab at solving that problem by requesting bids for as much
as 400 megawatts in renewable energy that would produce at least 80% of its
full capacity annually and 70% monthly—the closest India had come to
round-the-clock power from sources such as wind and solar. The government also
included steep penalties for missing those targets.
ReNew, which is
backed by Goldman Sachs Group Inc., calculated it could hit the targets by
“oversizing” the amount of capacity installed, says Manya Ranjan, ReNew’s head
of corporate strategy.
Altogether, ReNew
is building 400 megawatts of solar in the sunny state of Rajasthan in India’s
northwest, along with 900 megawatts of wind in the southwestern states of
Karnataka and Maharashtra. The wind, which can produce power day and night,
helps balance out the peaks and troughs of solar generation.
ReNew is using
batteries to store solar energy during the midday peak and release it when
demand rises in the evening. It is also leaning heavily on computer
modeling—including digital simulations of its turbines and solar arrays,
weather forecasts and projected power demand from the four utilities to which
it is feeding its electricity, says Parul Agrawal, who heads ReNew’s digital
and analytics team.
That modeling
helps ReNew time sales of extra electricity on the spot market for maximum
profit, says Mr. Ranjan.
Those sales “will give you that extra gravy,” he says.
Source
: Wall Street Journal
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