Page 48 - Energize July 2022

VIEWS AND OPINION

Latest MIT report: The road to decarbonisation:

renewables plus storage

by Fereidoon P. Sioshansi, PhD, Menlo Energy Economics

he Massachusetts Institute of Technology’s (MIT’s) Future of Energy Storage report,
released in mid-May 2022, examines the central role of energy storage in deeply
Tdecarbonised energy systems with high penetrations of variable renewable energy
(VRE). It says the obvious, namely, that energy storage is needed to keep the lights on when
the sun isn’t shining, and the wind isn’t blowing.

Click here to download the full report

The multidisciplinary report from the MIT Energy Initiative (MITEI) urges government
investment in sophisticated analytical tools for planning, operation and regulation of
electricity systems to deploy and use storage efficiently. Because storage technologies will
have the ability to substitute for or complement essentially all other elements of a power
system, including generation, transmission and demand response, these tools will be critical
to electricity system designers, operators and regulators in the future.
The basics are easy to understand. Energy storage enables cost-effective deep
decarbonisation of electric power systems that rely heavily on wind and solar generation, Fereidoon P. Sioshansi
without sacrificing system reliability.
have storage durations of 4 or fewer
Energy storage can be characterised by its: hours; most existing pumped storage
• Maximum instantaneous power, measured in MW; hydro (PSH) facilities have durations of 8 to
• Its energy storage capacity, measured in MWh); and 12 hours or more.
• Its round-trip efficiency (RTE), measured as the fraction of energy used for charging Storage technologies also differ in
storage that is returned upon discharge. energy density, which is the maximum
amount of energy that can be stored per
The ratio of energy storage capacity to maximum power yields a facility’s storage duration, unit volume. Battery technologies with
measured in hours – this is the length of time over which the facility can deliver maximum high energy density are particularly well-
power when starting from a full charge. Most currently deployed battery storage facilities suited for use in electric vehicles (EVs)
and mobile electronics. Technologies with
lower energy density can nonetheless
be used for storage in electricity system
applications where the efficient use
of space is not critical. Energy storage
technologies also differ in a number of
other attributes.
The technologies considered in the
MIT report fall into three main groups,
based on their power and energy
capacity costs (see Figure 4). Generally,
technologies with low energy-capacity
costs and high power-capacity costs are
most suitable for longer duration storage
applications (up to multiple days) and
Figure 1: US PV capacity GW less frequent charge-discharge cycles;

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