Blue Chips
Going Greenholds the charge), and a maze of wires,
pumps, switches, and PVC piping. They sit
in corrosion-resistant concrete safety pits
that are large enough, in case of a leak, to
hold all 80,000 gallons of electrolyte plus
all the water from the county’s worst day of
rain in the past 100 years.
As grid-scale battery installations go,
the San Diego facility is fairly small. It plays
the role of a shock absorber, charging and
discharging in response to fluctuations in
the local power supply. If there’s a surge of
solar energy one minute, the batteries store
it up; if there’s a sudden spike in demand the
next, the batteries pay it out. Currently, just
over half of San Diego’s electricity comes
from natural gas. As the proportion flips in
favor of renewables, the fluctuations will get
bigger and less predictable. To hit the 2045
goal, utilities across the state will need lon-
ger-term storage solutions—systems that
can stockpile solar by day and disburse it by
night, for instance, or sock away wind power
during blustery weather. Even if California
tripled its share of renewables, the best it
could do without energy storage is a 72 per-
cent reduction in CO 2 emissions, accord-
ing to a study published last year in Nature
Communications. Add in the right mix of
storage methods, including batteries, and
the number rises to 90 percent.
So why did San Diego pick vanadium over
the more familiar lithium-ion? The answer
comes down, in part, to economies of scale.
All batteries work more or less like dams.
There’s a reservoir of electrons on one side,
and as they trickle over to the other side,
they produce a current. With lithium-ion,
the main way of boosting capacity is to string
together lots and lots of small dams—one
or two for your smartphone, perhaps six for
your laptop, thousands for huge facilities like
Tesla’s soon-to-be 150-megawatt installa-
tion in southern Australia. But with vana-
dium flow batteries, rather than building
more dams, you build a bigger reservoir. To
hoard more power, in other words, you just
put more electrolyte in the tank.
Vanadium was something of a no-name
until Henry Ford plucked it out of obscu-
rity and used it to create a durable, light-
weight steel alloy for the Model T. Not until
the 1980s did the element first make its way
into batteries. Researchers at NASA and else-
where had been tinkering with a different
formula, iron-chromium, and kept finding
that the two elements would seep across
the membrane separating them, eroding the
battery’s capacity. Then a group of chem-
ical engineers in Australia, among them a
woman named Maria Skyllas-Kazacos, had
a Ford-like epiphany. “The only way to avoid
cross-mixing is to have the same element on
both halves,” she told me. Skyllas-Kazacos
and her colleagues went through the periodic
table looking for candidates. Vanadium, they
found, is uncommonly good at shuttling elec-
trons back and forth. (The electrolyte fluid
even has a kind of built-in color indicator:
With a full complement of electrons, it’s lilac.
When depleted, it’s pale yellow. In the mid-
dle, it’s blue-green.) By 1986, the University
of New South Wales had filed the first patent.
And then ... time passed. Skyllas-Kazacos
and her colleagues continued to refine their
design. At first, she said, they thought more
about storing energy for remote commu-
nities in the Outback than mitigating thegreenhouse effect. Yet she knew that her
team’s invention, for which she would be
named to the Order of Australia, would
eventually be of interest to governments and
companies looking to adopt more renew-
ables. “We thought that would happen a lot
earlier,” Skyllas-Kazacos said wryly. The
first patent expired in 2006; only in the past
decade or so has large-scale energy storage
gained widespread attention.
Batteries are relative newcomers to the
storage scene. Older, more established
technologies already allow utilities to con-
vert cheap, off-peak electricity into poten-
tial energy. One option: Cram underground
salt caverns with compressed air, then use
it later to stoke generators. Another, by far
the most common: Pump water from lower-
lying reservoirs to higher-lying ones, cre-
ating rechargeable hydroelectric dams. But
different methods work best in different
communities. When you’re confronting a
crisis that touches every square inch of the
planet, from San Diego to New South Wales,
it’s good to have choices.
Grid-scale vanadium batteries have a
couple obvious drawbacks. They must be
big to be useful, which means they’re land
hogs. And because vanadium remains such
an important ingredient in the steel indus-
try, its price can be volatile: When China
builds, costs climb. But as anyone who’s
tried to check a bag at the airport knows,
lithium-ion batteries have a habit of sponta-
neously combusting. They also degrade over
time, particularly if they’re drained to zero
or left unused for long periods. Vanadium
batteries, on the other hand, are nonflam-
mable and highly stable. They have long,
theoretically indefinite life spans. Certain
parts occasionally have to be replaced, but
the electrolyte’s life is never exhausted. You
could, the San Diego engineers tell me with
clear delight, load the solution onto a truck
and drive it cross-country, and it would hold
the same charge on the other end of the
trip. It doesn’t get worn out after hundreds
or thousands of charge-discharge cycles.
“You can run it up and down all day,” said
Jose Cardenas, the project engineer—or, for
that matter, all night.EVA HOLLAND (@evaholland) is the author
of Nerve: Adventures in the Science of Fear.
She wrote about neonatal medicine in
issue 26.04._
BLACKROCK
“Climate risk is investment risk,” CEO
Larry Fink warned in January. From now
on, BlackRock, which manages $7 trillion
in assets, will shun risky companies like
coal producers in favor of more sustain-
able investments._
AMAZON
The world’s biggest retailer aims to be
100 percent renewable by 2030. It has
ordered 100,000 electric delivery vans
(see page 68) and invested in wind and
solar farms to power its servers. CEO Jeff
Bezos has also committed $10 billion of
his own money to fight climate change._
MICROSOFT
In January, Microsoft pledged to become
carbon negative by 2030. It’s borrowing
from many playbooks—planting trees,
opting for greener business travel, and
investing in technology that pulls carbon
directly from the air.