Storage-on-sea? Whatever floats your batteries

If you follow renewables then you’ll have heard of floating wind. Perhaps you’ve heard of floating solar too. But floating energy storage? Well, you have now!

This is a technology that could shake up the energy world, and enable the development of storage systems that previously wouldn’t have had space for them. Developers and investors should watch this technology with interest.

Last week, we saw a significant development.

Envision Digital, which is part of the Chinese turbine maker Envision Energy, won a grant to building a ‘floating living lab’ in Singapore with enough lithium-ion battery capacity to power 600 apartments.

It picked up the grant as part of a $10m drive by Singapore’s Energy Market Authority and Keppel Offshore & Marine to support development of marine-based energy systems. The grant itself may not be large, but the potential of floating batteries could well be.

If successful, EMA said the technology could be replicated across the Asian state – and we can see how it could be applied globally too.

Floating renewables

The idea of floating renewables isn’t new.

Floating wind has been bobbing around since 2007, but it has only taken off recently. There is still just 66MW of floating wind capacity installed in Europe as of last year, but the market could hit installed capacity of 6.2GW globally by 2030. We expect momentum to increase.

Even newer is floating solar, although its early growth has been rapid.

Partly this is due to the ease of building solar panels on floating foundations compared with wind turbines. With their broad surface areas, solar panels lend themselves to floating structures and don’t have the same complex movements as floating wind turbines.

This has helped floating solar capacity to reach global installed capacity of 2.6GW in August, and a report by Wood Mackenzie says that this could grow 22% annually for the next five years. It can also be paired with pumped hydro, which represents 95% of energy storage capacity globally.

But floating batteries take this further, so what are the benefits?

The main one is that it enables you to build storage systems in areas with little spare land. That's why we're seeing this floating storage pilot in Singapore, the tiny city state at the southern end of Malaysia. The city needs a huge amount of power for its skyscrapers, as well as an abundance of water and a shortage of land. Floating batteries can help Singapore make the most of its power.

The desire to use this marine resource is a key driver behind the EMA and Keppel’s $10m grant drive. The Envision floating lab also includes a seawater-based battery cooling system to improve the battery’s function in Singapore’s hot humid climate. It is due to complete in 2023.

And as with floating renewables, we see that floating batteries could help storage to move into new locations. Specifically, we can see its use in major coastal cities that may find it easier to connect to floating batteries at sea, rather than those on land.

We have also seen a similar project in the Netherlands, where Skoon Energy and the Port of Amsterdam launched a barge-based battery earlier this year.

Further out to sea, floating batteries could help boost energy reliability at structures such as oil rigs, where oil companies such as Equinor are already looking to install floating wind turbines. There will be other applications too.

Finally, we believe floating solar and storage present an opportunity for the smart asset management of pumped hydro projects.

Historically, the reservoirs in these schemes have just sat there. But, in future, we believe these reservoirs could be the site of floating storage and solar, and give owners and investors a chance to make the assets work harder. It could be a very exciting revenue stream. At very least it’s worth floating the idea.