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Energy Storage Ship Could Make Offshore Energy More Efficient

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Jane Marsh's picture

Jane Marsh is the Editor-in-Chief of She covers topics related to climate policy, sustainability, renewable energy and more.

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  • Feb 28, 2022

It’s no secret that it will take time, resources, collaboration and innovations to support the global transition to renewable energy. Many countries have goals to integrate renewable energy into their infrastructure and benefit from all types of renewable energy sources, such as solar energy, wind power, geothermal energy, and hydroelectric power.

Finding viable methods of harnessing and storing renewable energy has been a challenge many industrialized nations are trying to overcome. However, there’s a growing need for feasible energy storage technologies and solutions to help bring renewable energy to the forefront.

In August 2021, one Japanese firm, PowerX, announced its intention to further innovate power storage and transmission. The company plans on building a business alliance with Imabari Shipbuilding Co., a major player in the Japanese shipbuilding, marine engineering and service industries.

Below is more information about PowerX, its plan to build a ship capable of storing and transmitting wind power and how it may make offshore energy more efficient.

PowerX: Plans to Innovate Wind Power Storage and Transmission

PowerX, a Toky0-based firm, recently announced a concept for a ship specifically designed to bring wind power from offshore wind farms back onshore.

The ship is expected to have a capacity of 200 MWh and to be completed by 2025. Additionally, the company revealed plans to build a large-scale battery packing facility in Japan. The facility would bring several benefits to the country, such as electric vehicle (EV) fast-charging, grid and marine batteries.

According to PowerX CEO Masahiro Ito, the overall goal of this ship concept is to resolve growing concerns about the infrastructural challenges Japan faces regarding its offshore wind sector. One main challenge regarding offshore wind farms is that they’re very expensive compared to traditional fossil fuel generators.

Research from McKinsey and Company suggests that Japan’s offshore wind sector has a promising future to help the country achieve energy independence. Japan has an ambitious goal to generate 36-38% of its power from renewable energy sources by 2030.

To achieve this goal, innovations such as PowerX’s power transfer vessel need to be developed and used to help renewable energy sectors operate efficiently.

Additionally, people living in Japan can take various measures, such as energy consultations, to improve the comfort of their homes, lower energy consumption, associated energy costs and reduce their carbon footprint.

Details About PowerX’s Energy Storage Vessel

A core function of PowerX’s energy storage vessel is to eliminate the need for fossil fuel-carrying ships to transport energy to and from their destinations.

Traditionally, undersea cables embedded in the ocean floor would transport energy. Still, there are some disadvantages associated with this. These cables are expensive and could be detrimental to the surrounding environment.

One notable project from PowerX is its Power ARK 100 ship. This ship is a 100TEU container ship that can travel up to 300 km when running only on electricity. It will carry 100 grid batteries, which translates into 200 MWh. 200 MWh is the equivalent of the total energy consumption of 22,000 Japanese households in one day.

The ship is designed to seamlessly navigate Japanese coastal waters, which are fairly rough. The batteries on board would be in containers weighing 50-60 tons, which is much heavier than a standard container ship.

It’s expected that PowerX’s ship will make offshore energy storage, transmission and transportation much more energy efficient. However, the Power ARK 100 will likely be the smallest ship in PowerX’s fleet and will serve as a proof of concept. PowerX plans on creating more innovations at a larger scale and with more battery capacity if all goes according to plan.

PowerX Supporting the Global Transition to Renewables

There’s no denying that PowerX’s innovations will fuel future growth in Japan’s offshore energy sector by making it more efficient and sustainable. The goal would be for other companies to follow suit and work towards building transformational solutions to benefit the industry. It’ll be fascinating to see how the Power ARK 100 will help redefine the maritime and onshore power utilities industry in Japan.

Matt Chester's picture
Matt Chester on Feb 28, 2022

I could see this as being a key economic arbitrage opportunity, but I wonder if that means it would be beneficial to the energy systems. 

Bob Meinetz's picture
Bob Meinetz on Feb 28, 2022

"It’s no secret that it will take time, resources, collaboration and innovations to support the global transition to renewable energy."

Jane, it's no secret renewable energy is incapable of powering a 21st-century world, that a "global transition" to it is but a fantasy embraced by wealthy idealists in developed countries - ones for whom energy poverty has always been someone else's problem.

The last thing we have is more time to indulge that fantasy.

Nathan Wilson's picture
Nathan Wilson on Mar 1, 2022

Transporting energy in batteries for stationary applications is like transporting data by mailing floppy disks (it stops making sense as soon as someone lays enough cable).  If Japanese investors take this idea seriously, that will be a huge vote of no-confidence in Japan's renewable energy industry.

Roger Arnold's picture
Roger Arnold on Mar 4, 2022

That's an interesting analogy Nathan. I remember when the fastest way to transport large volumes of data to backup centers was to load a box truck with racks of mag tapes and ship them to the secure storage site. It wasn't until fiber optic transmission lines were well developed and widely installed that the trucking model for high volume data transport fell out of use.

For energy transmission, I once calculated that a train load of charged batteries moving at 80 mph could have an energy transport capacity an order of magnitude larger than a high voltage transmission line. Battery transport wouldn't be a particularly viable alternative to transmission lines, because the materials and capital cost of the battery storage capacity would be excessive. But it's not an inherently ridiculous idea.

John Simonelli's picture
John Simonelli on Mar 9, 2022

I really struggle with this concept. You can put 200MWh batteries at the point of the on-shore interconnection and get the same bang for your buck as you would using the floating marine option. You would then save the cost of building the ship in terms of cost, raw materials needed, construction labor and, O&M to maintain the ship once built. I just don't see the economic benefit.

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