POWER May 2020 - 26

GEOTHERMAL POWER
Is Geothermal Power on the
Brink of a Boom?
After several years of stagnancy, prospects for the geothermal power industry are
heating up. Over the past year, it has seen a flurry of legislative boosts, an uptick of
power purchase agreements, and increased research and development focus and
funding.
Sonal Patel
hen visualized in the context of
all renewable power capacity in
2019, geothermal power's 14
GW contribution is a slim, almost invisible
sliver of the 2,537 GW global total.
Yet, as a renewable power source, geothermal's
technical potential is thought to
be substantially larger. In the U.S., which
leads the world with an installed geothermal
capacity of 2.5 GW-half of it built
in the 1980s-the technical potential is
60 GW, according to the Department of
Energy's (DOE's) comprehensive June
2019-released GeoVision study. Globally
(Figure 1), technical potential is thought
to range between 50 GW and 200 GW.
The slow cumulative growth of the
resource has been a cause of concern
for its advocates because on its face, it
is the perfect renewable. Whereas wind
and solar intermittency require reactive
flexibility measures, geothermal can provide
baseload power and heat. But it can
also complement other renewables, providing
grid reliability, resiliency, and security
both through traditional services,
such as regulation reserve, frequency
response, and contingency reserves,
and nontraditional services, such as flexible
capacity voltage control, inertia, and
GW
GW
2,500
2,000
1,500
1,000
500
100
90
80
70
60
50
40
30
20
10
2015 2016 2017 2018 2019
Capacity added in 2019
■ Hydropower ■ Wind ■ Solar ■ Bioenergy ■ Geothermal
1. In 2019, the world's geothermal power
capacity stood at 13,931 MW-up 40% from
9,992 MW in 2010, according to the International
Renewable Energy Agency (IRENA). In
2019, 682 MW of new capacity came online,
with Turkey leading the expansion (232 MW);
followed by Indonesia (185 MW); Kenya (160
MW); Italy (33 MW); and the U.S. (14 MW).
Courtesy: IRENA
26
W
black-start capabilities.
Asked why geothermal's uptake has
lagged behind other renewables despite
its obvious benefits, Will Pettitt, executive
director of international industry trade
group Geothermal Resources Council
(GRC), pointed to several concerns. The
most glaring is that geothermal has been
typically limited to areas with suitable hydrothermal
reserves. As significantly is
that geothermal power development requires
relatively high upfront capital costs
and carries sizable investment risks because
of long project lead times and payback
periods. Good market conditions are
crucial to help it thrive, Pettitt told POWER
in March. Compared to the 1980s, for example,
when about 100 MW of geothermal
capacity was added in the U.S. each
year, installations have slowed, owing
largely to their short geographical reach,
declining wholesale power prices, and cutthroat
competition with other renewables.
An Extraordinary Year for Geothermal
The past year, however, has been so
remarkable for the industry that some
insiders believe it is " on the brink of a
boom, " Pettitt noted. The DOE's GeoVision
study, which essentially outlined
specific
improvement
scenarios
that
could expand geothermal deployment
nearly 26-fold so that it would make up
57% of U.S. baseload renewable generation
by 2050, was " like a call to action "
to federal lawmakers. Last year a record
three hearings on the resource were
held on Capitol Hill, he said.
Ensuing legislation
retroactively revived
and extended the full production tax
credit (PTC) for geothermal facilities that
expired in 2017 through 2020. Congress
has also crucially furnished the DOE with
more funding to pursue development of
enhanced geothermal systems (EGS) on
top of the agency's Frontier Observatory
for Research in Geothermal Energy
(FORGE) project in Utah. That project is
one of two endeavors that are seeking
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to demonstrate EGS, which promises to
tap into subsurface heat resources, and
essentially remove geothermal's geographical
limitations, and advances it has
made have already been applied in conventional
systems. (The other project is
being spearheaded by Bill Gates' Breakthrough
Energy Ventures.)
A key initiative of federal EGS research
involves improving costs associated
with drilling and well construction. As
the National Renewable Energy Laboratory's
(NREL's) Kate Young explained to
the Senate Committee on Energy and
Natural Resources last year, the cost of
geothermal development is split 50% on
the surface (such as for power plants and
piping) and 50% below ground. " Many of
the below-ground costs are borne at the
front end of the project development,
which can make project financing challenging, "
she said. " And though drilling
and well construction activities are present
in many industries, time and costs
are significantly higher for geothermal. "
Because it typically involves boring
into harder, hotter rocks, with more lost
circulation, geothermal drilling " averages
about 150-200 feet per day, compared to
oil and gas wells that average more than
750 feet per day, and sometimes are as
fast as a mile a day (a.k.a. 'MAD' wells), "
she noted. But breakthroughs are possible
with the right research focus and
funding, such as have been achieved by
the oil and gas industry, Young said.
So far, to boost geothermal drilling
efficiency in the near-term, NREL has
embarked on a number of measures,
including holding its first collaborative
workshop with oil and gas efficiency experts
last year. Research is also underway
to develop sensing electronics for
data collection, and machine learning to
improve geothermal reservoir management.
As critically, NREL is focusing on
materials development for well construction,
which poses another significantly
high cost of geothermal development.
POWER | May 2020
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POWER May 2020

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