Page 50 - Energize July 2022

VIEWS AND OPINION

Some technologies, such as lithium-ion
batteries, pumped storage hydro, and some
thermal storage options, are proven and
available for commercial deployment. The
report recommends that the government
focus research and development (R&D)
efforts on other storage technologies,
which will require further development to
be available by 2050 or sooner — among
them, projects to advance alternative
electrochemical storage technologies that
rely on earth-abundant materials.
The report says many existing power
plants that are being shut down can Figure 4: Shades of storage
be converted to useful energy storage
facilities by replacing their fossil fuel boilers technologies with the lowest capital cost of energy storage capacity are generally best
with thermal storage and new steam suited to provide long-term storage. However optimal storage operation, unlike optimal
generators. This retrofit can be done using generation dispatch, is complicated by the changing shadow value of stored energy. As a
commercially available technologies and result, all storage technologies deployed will operate with charge/discharge cycles of various
may be attractive to plant owners—using durations. Simplified assessments of storage economics based on stylised charge/discharge
assets that would otherwise be abandoned profiles overlook such dynamics and may provide inaccurate assessments of storage value.
as electricity systems decarbonise. In performing energy market arbitrage — that is, buying when prices (and net demand)
The study also looks at hydrogen and are low and selling when prices (and net demand) are high — energy storage can substitute
concludes that its use for storage will likely for other grid resources, both on the demand side and on the supply side.
depend on the extent to which hydrogen The level, range and variation in the marginal value of energy in future low-carbon
is used in the overall economy. That electricity systems will be drastically different than values seen in ISO/RTO- managed
broad use of hydrogen, the report says, wholesale markets today.
will be driven by future costs of hydrogen It is a hard read, as one would expect. The report does not guess which technologies
production, transportation and storage — may prevail or how big the market may be by a certain date, but it provides a guide to what
and by the pace of innovation in hydrogen is technically possible and economically feasible and that will determine how much and what
end-use applications. kind of storage gets built where, when and for what purpose.
The study predicts the distribution
of hourly wholesale prices, or the hourly Acknowledgement
marginal value of energy will change in This article was first published by EEnergy Insider and is republished here with permission.
deeply decarbonised power systems —
with many more hours of very low prices Click here to download the full report
and more hours of high prices compared
to today’s wholesale markets. The report
recommends that systems adopt retail
pricing and retail load management
options that reward consumers for shifting
electricity use away from times when
high wholesale prices indicate scarcity, to
times when low wholesale prices signal
abundance.
The most interesting and relevant
part of this in-depth report is Chapter 6,
modelling storage in high VRE systems.
The detailed analysis reaches a number of
important conclusions.
When it is cost-optimal to deploy
multiple storage technologies, the Figure 5: Growth of pumped storage

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