SEABASED 10 big advantages of smaller wave energy converters

  • Sep 27, 2021
  • Electric Energy

In the world of power generation, it is often assumed that bigger is better. But building a wave energy power park, it turns out, can be an exception. Seabased has refined its Wave Energy Converters (WECs) over many years, experimenting in different ocean environments with different designs. The aim has been to create a WEC and wave park design that meets several goals:

Get the most energy possible from a moderate ocean wave climate.

Make wave energy cost-competitive with more mature renewable technologies.

The result is a modular, scaleable wave energy power park with relatively small WECs, buoys, and a marine substation electrical conversion system that can all be efficiently transported and installed with minimal impact on the environment. In the case of Wave Energy Converters, Seabased has discovered, smaller is better. Here are some reasons why:

1. Smaller WECs extract more power from moderate waves

One of the reasons bigger seems better is that, with other technologies, it is better. With wind turbines, for example, the larger the diameter of the area swept by the blades, the more power the turbine can generate. With solar, the more panel surface you have, the more power you can collect on a sunny day. Waves, however, work differently. We're trying to collect as much energy as possible from each individual wave - in our case, medium-sized waves of 1-3 meters height. The right size buoy will be lifted to the peak and lowered to the trough of every single wave, maximizing access to the power it packs. If it's too large for the wave climate, the buoy could straddle the waves, and the rising action of one wave would partially cancel out the falling action of another. Consider the relative stability - and comfort - of a large ship versus a smaller boat in rough water. But we're not looking for comfort; we want to pull the most power out of each wave. So we want the wave energy converters to be smaller.

More people live where the waves are moderate, rather than huge. The buoys of Seabased's point absorber linear generators are designed to work best where most people live.

Grids need power that is delivered in a steady stream. Having many smaller wave energy converters working at different times, moved by different waves, achieves a more consistent stream of power. After studying the way that waves move in a particular location, we configure our smaller WECs in an array designed to maximize the power we can extract from that wave climate. Each of the WECs' buoys will be doing different things at any given moment. One will be on its way up, another on its way down, another just rounding off the peak of a wave. They will be moving at different speeds, with different levels of resistance, and changing instant by instant. This asynchronous movement of many smaller buoys collectively produces a more stable stream of power than if you had a few larger buoys. It is easier to make this power ready for the grid, which requires a high degree of stability.

3. Smaller WECS offer a fast track to a lower LCOE

It's a time-tested principle of economics: Every time you double production of a thing, the cost of production drops, because you grow more efficient with repetition. This learning curve is often in the area of 80%. So if the first 20 units of a product takes 100 hours to make, the next 20 should only take 80 hours; the following 20, 64 hours; the next batch 51 hours until you've reached maximum efficiency. The costs drop as efficiency rises. This accounts in part, for the low Levelized Cost of Energy (LCOE) achieved by many mature renewables today. With small WECs, more must be produced to create a power park, leading to a rapid learning curve and dropping costs.

Our modular, plug-and-play wave energy parks are designed so that wave park customers can start small, if they like, and scale up as needed.

5. Smaller WECs can be shipped with a smaller environmental impact

Seabased has designed its components so that they can be shipped in containers, which means that standard cargo vessels can move them along with other goods. This greatly reduces the carbon footprint of transportation for installation, relative to a large device that requires special transport.

6. Smaller WECs can be installed and maintained with smaller vessels

Because of their size, Seabased can use smaller work boats to install a wave energy park. Wind power parks tend to need much larger vessels because their power depends on long blades that create a larger diameter.

7. Smaller WECs can be installed quickly and sustainably

An entire wave park can be installed in only a few days, from wave to grid. And, because the WECs are small, no drilling, mooring, or other seabed preparation that could harm the environment is required. Their concrete bases are enough to anchor them to the sea floor. This means less cost and better outcomes for the ocean environment and ecosystem.

With smaller WECs, it becomes easier to find facilities that are capable of building or assembling components locally. This means wave energy parks create local jobs. Very large components require facilities and transports that are unavailable in many places.

Coastal areas are prime real estate. Fishing, shipping, tourism, all compete for space in coastal areas. A wave power park needs utilize an area with optimal waves that will have the least impact on other local ocean stakeholders. Seabased's smaller WECs are virtually invisible from the shore. This makes them good neighbors in area where ocean views are an essential part of a coastline.

10. An array of Smaller WECs can make the most of the waves

Before installing a wave energy park, we conduct extensive feasibility studies to understand, among other things, how waves move in that particular location. Because of latitude, climate, topography of the sea floor (bathymetry), and other factors, the length and shape and regularity of the waves will be a little different in each place. With smaller WECs, we have more flexibility to fine tune the arrangement of the wave park array to make the most of each wave climate.

Seabased arrived at its conclusions about size with a lot of testing and experimentation. But now, as we work toward the certification of our technology, we're increasingly appreciative that size does matter in our case, smaller is better.