Hybrid buoyancy-powered energy platform is moving to full-scale pilot stage

Swedish company NoviOcean has tested the third-generation prototype of its wind, solar and wave energy platform, a floating platform with a capacity of up to 1 megawatt that provides constant clean energy around the clock thanks to a fascinating buoyancy-based mechanism. Next step: full-scale pilot.

This renewable energy platform will have a relatively small footprint when built at full size: 38 x 9 m (125 x 30 ft), with the platform itself extending approximately 4 m (13 ft) above the water surface and a further 12 m (39 ft) ) feet) down. Tiny, then, compared to some of the monster offshore wind turbines we’re starting to see, like the colossal 20MW MingYang turbine, which is currently the largest in the world.

However, it is designed to weigh in excess of 140 tons and deliver power more consistently than any single-method generator.

How does it work?

When the sun shines, it powers solar panels with an area of ​​approximately 700 square meters (7,535 square feet), or 50 kW. When the wind blows – and most of the world’s best wind energy resources are located offshore, where this thing will live – it will power a series of six spiral-blade vertical-axis wind turbines (VAWTs). Thanks to an interesting wave power system, it will also collect up to 650 kW of energy from the movement of the ocean.

But first, about these VAWTs. Compared to the horizontal axis wind turbines we are accustomed to, VAWTs have several key advantages, especially in offshore wind applications. For starters, the heavy generator sits at the bottom, rather than the top, of a giant pole, which must also support a huge spinning fan. This will ensure that the platform itself remains vertical, without the need for a counterweight or heavy support structures.

Secondly, they can take wind from any direction because they rotate 360 ​​degrees anyway. This allows the platform to be positioned parallel to the waves to best serve the major energy producer.

The wave energy generator also works interestingly. That big plugged thing sticking out of the top is the turbine/generator system, sitting on top of a big big piston. The top of this piston is attached to the floating platform and the bottom is attached to the ocean floor.

Between waves, the platform descends, and at the end of its journey, a valve closes to keep the platform down as the next wave begins to rise. As a result, up to 3 meters (10 feet) of this giant float is held underwater, trapping approximately 600 cubic meters (21,200 cubic feet) of air that desperately wants to rise up.

At the optimal moment, the valve opens and buoyancy is released, creating a huge lifting force on the float of up to 600 tons. This force pulls water up through the pipeline as the float rises and shoots it through the turbine of the Pelton generator at the top at high speed to produce up to 650 kW of clean energy instantly. According to NoviOcean, waves as low as 4 m (13 ft) will be needed to achieve maximum power.

Once the float is built, solar and wind systems will more or less get a free ride. “Typically with floating solar you have to build a structure, have the systems on board and the cable,” NoviOcean CO and founder Jan Skoldhammer told listeners during the Marine Energy Alliance Talks at OEEC 2022. “Well, we have the structure and we have the cable and the systems on board, so why not take advantage of it?”

What is the promise here?

NoviOcean says a full-scale platform should operate 24/7 at a capacity factor of 40-70%, with each unit generating an average of about 3.5 gigawatt-hours per year. For comparison: According to the U.S. Energy Information Administration, the average U.S. home used 10,791 kWh of electricity in 2022, so each platform should generate enough energy to power about 324 homes.

Building, installing and maintaining these components should be a trivial task compared to the magic associated with huge offshore turbines, and they are designed to be arranged in networks that will be visually unobtrusive and can be collected closer together than larger turbines because they will leave fewer traces in the air currents flowing through their VAWT.

How advanced is this project?

NoviOcean has built three prototypes so far, in 1/7, 1/6 and 1/5 scale respectively. The latter spent 24 months on a test platform, 6 weeks in a wave tank and 14 months at sea, where the company says it performs exactly as the simulations predicted.

The next step will be a full-scale pilot platform, which the company hopes to build and put on the water by 2026-27, followed by a “pre-commercial kit” in 2028-2030 and full commercial deployment by 2031-32.

What is the “but?”

All renewable energy inventions must ultimately be assessed against the all-important levelized cost of energy (LCoE) – that is, how much they will be able to sell clean energy to the grid, taking into account everything from upfront construction and installation costs to ongoing maintenance costs, personnel, depreciation and finances taken into account throughout the life of the project.

NoviOcean says it expects the first full-scale 1MW hybrid platform to cost €3.6 million ($4 million) to build, and the 100th platform, which will bring economies of scale of about €2 million ($2.2 million). ).

This contributes to an initial LCoE of $275/MWh at launch, which, as NoviOcean notes, is about one-third of what wind and solar used to start at. But that’s certainly not where wind or solar power is today; according to IRENA data for 2022, onshore wind was priced at $33/MWh, utility-scale solar was around $49/MWh, and even offshore wind was able to transmit energy back to land at a price of $81/MWh.

By the time 100 units are deployed, NoviOcean plans to achieve an LCoE around $110, and the company says it sees a path to $77 much further.

Please note that LCoE may not tell the whole story here, as the platform’s multiple power generation modes may well enable it to sell power during costly peak periods when one or another renewable source is not using up its weight to the grid.

Still, it will initially struggle to compete without major government support, and NoviOcean is currently tipping its hat to private investors in hopes of reaching the €9 million ($9.9 million) funding level it needs to get its first full-scale platform built.

Finances are not the only “but” here – it is worth noting that the design is based on a hydraulic piston working for decades in salt water, which has an annoying habit of eating metal.

However, the “but” to answer these “buts” is this: the world must significantly increase renewable energy production in the coming decades – not only to replace our current impressive levels of energy consumption, but to handle the coming electrification of land, maritime transport and aviation, as well as a nationwide appetite for cryptocurrency mining and the development of artificial intelligence, which appears to have a virtually bottomless appetite for electricity.

Moving away from fossil fuels, which can be easily ramped up and down to meet the grid’s demand curve, fully clean energy networks will need to diversify generation sources so they don’t get caught shorting their pants when the sun isn’t shining and the wind isn’t blowing.

Sources such as wave energy can be of great value in this context. We wish NoviOcean the best of luck in its efforts and hope that this project will proceed much faster than others in the wave energy industry, which appears to be gaining in popularity due to its long and increasing time frames.

Source: NoviOcean