28-ton, 1.2-megawatt tidal kite is now exporting power to the grid
A 28‑ton “tidal kite” now generating 1.2 MW to the grid has renewed interest in tidal power as a predictable complement to solar and wind. Commenters weigh its potential benefits — high energy density, no visual impact on landscapes, and suitability for remote or northern regions — against serious concerns over maintenance in harsh saltwater, biofouling, undersea cabling costs, and local ecosystem effects. Many see it as a promising but geographically limited niche that must prove long‑term reliability and cost competitiveness against ever‑cheaper solar, wind, batteries, and nuclear.
Technology & Operation
- Device is a 28-ton “tidal kite” with a 1.2 MW generator, flying figure‑8 paths on a seabed tether in strong tidal currents.
- Moving at an angle to the current increases relative water speed over the turbine vs a fixed seabed turbine.
- Power is transferred via a cable in the tether and a seabed umbilical to shore.
- Compared to fixed turbines or dams, this is seen as more modular, transportable (fits in a container), and potentially easier to service (kite can surface).
Economics & Comparisons
- Some see it as more practical than airborne wind systems and less visually intrusive than wind turbines.
- Comparisons: modern onshore wind ~2–4 MW, offshore 8–12 MW; coal plants ~GW scale; nuclear plants up to several GW.
- Projected levelized cost of energy (LCOE) around $50–54/MWh is compared to ~$30/MWh for solar, <$50/MWh for offshore wind, and ~$48/MWh average US grid power; skeptics doubt competitiveness.
- Others argue tidal doesn’t need to be cheapest if it reduces storage needs for wind/solar.
Maintenance & Engineering Challenges
- Strong concerns about saltwater corrosion, barnacle/marine growth, moving parts in seawater, and tether wear.
- Counterpoint: marine industries (ships, offshore oil, subsea cables) already manage long‑lived hardware in similar conditions.
- Advantage noted: no giant offshore cranes or divers are needed if kites can be surfaced for service.
- Unclear how long units will last and what annual maintenance/replacement costs will be.
Environmental & Planetary Impacts
- Local wildlife: questions about fish, whales, and navigation hazards; expectation of some impact but unclear magnitude.
- Some speculate moorings could act like artificial reefs, attracting marine life.
- Larger philosophical debate: tidal energy ultimately taps Earth–Moon rotational energy; technically non‑renewable but reservoir is vast and current extraction negligible compared to natural tidal dissipation.
- Concerns about cumulative ecosystem effects of large‑scale tide dampening are raised but seen as highly theoretical at present.
Grid Role, Predictability & Scale
- Tides are highly predictable but not continuous; kites park at slack tide.
- Seen as valuable for firm, forecastable generation to complement intermittent solar and wind, especially in high‑latitude or remote coastal regions.
- Power scale: 1 MW can support hundreds of average households; arrays of 20–40 MW are planned in some locations, but replacing large fossil or nuclear plants would require thousands of units.