POWER September 2020 - 39

ENERGY STORAGE
tegration of energy storage at a fossil
energy plant can improve reliability and
resiliency as cleaner, renewable forms
of energy become stronger components
of the grid. Furthermore, it will provide
a heightened level of energy security so
that electricity can continue to flow to the
grid during unplanned events such as disruptions
in the natural gas supply chain.
A poll taken during the webinar
showed that the strongest level of interest
exists for integrating energy storage
with NGCCs, followed by coal plants.
Attendees were also asked to rate
the most important characteristic of an
energy storage system when deciding
to invest in one. More than 23% of attendees
rated low capital cost as the
top characteristic, followed by duration
of storage (21.10%), and ease of
deployment and integration (16.56%).
Revenue increase was rated as the top
characteristic by less than 10% of the
webinar participants.
Return on investment for utility ownership
cannot be overlooked. Fossil
fuel-fired power plants are designed to
generate power at maximum capacity
all day long. However, with renewables
on the grid, these conventional plants
are required to operate in load-following
mode. Because of the deviation of actual
efficiency from the design value, there is
monetary loss during power plant operation
as fuel consumption increases and
equipment is subjected to increased
wear and tear. Energy storage enables
such plants to run with greater efficiency,
reduce some of their costs, and produce
energy that will be used to generate
electricity for eventual sale.
Reaching Beyond Batteries
The new FE program is seeking partners
from industry, academia, and research organizations
to develop affordable storage
technologies beyond the scope of battery
systems with limited storage capacity.
These areas of research interest include:
■ Thermal Energy Storage. Some work
has begun. NETL is currently supporting
an Electric Power Research Institute
project to design, construct, and
test a pilot-scale concrete thermal
energy storage system. As designed,
high-pressure steam from a power
plant would flow through tubes and
heat concrete modules, which store
the thermal energy until it is returned
to the power plant to generate electricity.
The project will test modules
similar in size to those expected to be
September 2020 | POWER
1. Selected technologies were proposed in response to a Department of Energy (DOE)-issued
request for information and augmented with additional input accumulated through subsequent
stakeholder engagements. The technology readiness level (TRL) scale ranges from 1 (basic principle
observed) to 9 (total system used successfully in project operations). However, TRL is not
an indication of the quality of technology implemented in designs. Source: DOE
used in larger-scale commercial applications.
A team at Lehigh University
in Bethlehem, Pennsylvania, is also
developing a thermal energy storage
prototype with NETL support to improve
plant flexibility and efficiency.
■ Mechanical Energy Storage. Compressed
air energy storage is a prime
example of mechanic energy storage.
It uses off-peak electricity to compress
air and store it in a pressurized storage
reservoir. When electricity is needed
at peak demand, the air is withdrawn
to drive an electric generator. With this
system, air can be preheated by recovering
heat from the compressor train
or by burning fuel such as natural gas
to improve efficiency.
■ Chemical Energy Storage. This energy
storage concept seeks to advance the
use of fossil fuels in an environmentally
responsible manner by generating
hydrogen and other forms of chemical
energy from coal or natural gas, which
can be stored for long durations and
used when needed to produce electricity
and valuable products.
■ Hybrid Energy Storage. HES systems
merge two or more energy storage
technologies to achieve the desired performance
by combining the appropriate
features of different technologies.
Engaging Potential Partners
FE has taken a robust approach to solicit
proposals and a broad range of concepts.
Its FOA sought proposals to advance
near-term, system-integrated, energy
storage
solutions
toward
commercial
deployment with fossil assets; mature
promising mid-technology-readiness-level
(TRL), component-level energy storage
solutions toward eventual system
integration with fossil assets; and develop
innovative, low-TRL concepts and
technologies that offer game-changing
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benefits for fossil assets. Concept papers
were received on June 17, 2020.
As part of this FOA, the formation
of multidisciplinary teams that include
technology developers and asset owners/operators
was highly encouraged. To
support this goal, a team partner list was
included in the FOA, and interested entities
could sign up to publicly share their
interest in participating as team members
on project applications.
Prior to issuing the FOA, FE sought
input from those with experience, expertise,
and interest in energy storage.
These insights were gained by hosting
webinars and workshops, and issuing
an RFI to gather suggestions that could
help utilities operate their plants at high
efficiency while storing power until it is
needed by the grid. Figure 1 summarizes
the results of these efforts.
The insights, recommendations, and
suggestions received were used to develop
the FOA, which will award funding
to proposals designed to mature and integrate
energy storage technologies with
fossil power plants to produce greener
and abundant power for tomorrow.
NETL looks forward to working with
partners who share its passion for energy
storage and the important role it
will play in achieving energy security for
the nation. FE funds R&D projects to reduce
the risk and cost of advanced fossil
energy technologies and to further
the sustainable use of the nation's fossil
resources. To learn more about FE programs,
visit the FE website and sign up
for related news announcements. More
information about NETL is available on
its website. ■
-Briggs White, PhD is technology manager
for High-Performance Materials, Water
Management, and Energy Storage at the
U.S. Department of Energy's National
Energy Technology Laboratory.
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POWER September 2020

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