Not enough droughts and hefty network charges: the big barriers to grid storage

Experts have called for a major rethink about how battery storage is supported by the market after two studies identified major roadblocks to a 100 per cent renewable energy grid.

There are some major problems in ensuring enough “long duration” storage is built to allow wind and solar generation to be expanded, and the last coal fired power stations to be closed.

Chief among these concerns is a lack of market signals and policy support to enable enough capacity to be built.

There are also two emerging handicaps: whopping network charges that projects have to pay, and (ironically) the shortage of wind and solar droughts.

Big batteries are often described as the “Swiss Army Knife” of the grid, because of their flexibility and speed and their ability to provide multiple services and perform multiple tasks.

Short-duration batteries are now pretty much able to stand on their own two feet, thanks to the development of frequency and very fast frequency control markets, and the emergence of more volatility in the day to day market. Long duration storage will be the biggest challenge.

Long duration storage is 12 hours or more, and could be provided by pumped hydro, compressed air storage, gravity storage, hydrogen-based storage or solar thermal technologies.

Long duration storage is needed to fill in anticipated “droughts” of wind and solar that could last several days, or longer.

One of the big issues is that these “droughts” will not occur often enough to send a market signal of their own.

More than 50% of current utility-scale battery projects have required government support, indicating the financing challenges, particularly for batteries exceeding two hours duration.

The report recommends a series of solutions, including an orderly coal closure rule to provide market clarity, new markets for battery storage, state funding  for investment in long duration storage, and transparency in the CIS.

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