Hawaii, Scotland present energy storage approaches for Australia

In its new, comprehensive, Energy Storage Study: Funding and Knowledge Sharing Priorities, AECOM Australia Pty Ltd has identified the key storage investment areas for the Australian Renewable Energy Agency (ARENA).

International experience

Drawing on knowledge from the global energy storage market, including analyses of the different projects, policies and support systems in place across 10 international markets, identified as leading, AECOM concluded that while every market is different and, as such, a tailored energy storage strategy is required, Hawaii and Scotland both present interesting case studies for Australia.

Due to its high electricity costs, renewable deployment in Hawaii is competitive, with storage set to boost the market further. "ARENA and interested off-grid electricity operators may obtain significant learnings from the Hawaii experience including sizing, design, technology performance, project delivery and replication," wrote the study’s authors.

Scotland, meanwhile, is interesting in terms of its off-grid electrification approach. Overall, AECOM identified California and Germany have the most "thorough" energy storage programs. "Each of these programs spread the investment focus across all applications, putting the onus on utilities to meet the program objectives, while supporting private users with direct rebates," the authors remark.

According to AECOM, global installed grid-connected electricity storage capacity totals almost 141 GW. The table below provides more details. The U.S. is said to have the highest number of storage projects, at nearly 160, while Japan has commissioned the most capacity, at almost 160 MWh. It also has a "significantly" larger average project size.

Energy storage technology

Global grid-connected capacity (MW)

Pumped hydro storage (PHS)

140,000

Compressed air energy storage (CAES)

440

Sodium sulphur

304

Lithium-ion

100

Lead-acid

70

Nickel-cadmium

27

Flywheel

25

Redox-flow

10

Regarding policies, the study’s authors note, "While many countries discuss the benefits of energy storage and have completed demonstration projects, very few have implemented policies to help create a self-sustaining market."

AECOM says, however, before a market roll-out can be considered, demonstration projects need to be developed, in order to generate knowledge of the different technologies and see where the best investment areas lie.

Technology selection

While pumped hydro storage (PHS) has, to date, been the leading and cheapest form of energy storage – in Australia, there is over 1.5 GW of pumped hydro storage operating in the National Electricity Market – it is not ideal going forward, due to long project development and approval times.

As such, lithium-ion (Li-ion) is seen as the "technology of choice," with its high efficiencies, long lifecycles and cost-competitiveness, among other factors. Flow batteries and advanced lead-acid batteries, are also said to be interesting, as are emerging technologies, including next generation lithium technologies (e.g. lithium sulphur, LiS), sodium ion and liquid metal.