After delivering the world’s first subsea grid connected tidal array in 2016, clean tech company Nova Innovation has followed up with another world first — a tidal array and Tesla battery providing baseload tidal power to the grid.
The system provides some of the electricity for the 23,000 inhabitants of the Shetland Islands, a Scottish archipelago with a standalone electricity system, not connected to mainland UK.
Fully utilizing the tidal turbines
The islands rely mainly on diesel generation, with intermittent wind power connected to the system. Finding their output was constrained, Nova Innovation sought a way to utilize the full capability from the three 100 kW tidal turbines. One solution was to integrate storage.
“We worked together with Tesla to produce a 500 kWh/300 kW capacity storage system. Therefore the 300 kW of tidal power can have full export capacity into the battery,” said Gary Connor, engineering director for Nova Innovation, which is based in Scotland.
The project was partly funded by the Scottish Government’s Low Carbon Infrastructure Transition Program, which aims to accelerate the development and delivery of low carbon infrastructure projects across Scotland. Costs were also covered by some private investments.
Predictable generation
You begin to look like a nuclear power station on baseload…
Unlike wind and solar, tidal power is predictable. The six hourly tidal cycles are based on the gravitational forces of the moon and the sun, and the rotation of Earth. This leads to precise power generation volume predictions, so the systems and battery can be sized efficiently. As such, baseload generation becomes a suitable application.
“We can take the variances between the tides, and via battery, turn that into a completely flat line of generation to the grid. You begin to look like a nuclear power station on baseload,” Connor told Microgrid Knowledge.
Active network management
According to Connor, the system is not limited to providing baseload power, it can also be dispatched as needed to balance the grid system. This is advantageous when developing commercial cases, as it opens the door to other revenue streams.
The controls system and software installed along with the battery allows the Shetland Islands’ electricity system operator to actively manage their network. The asset can be dispatched to balance the network, in a similar way to how a large grid generator would be dispatched.
International market
In addition to tidal systems, Nova Innovation intends to use the expertise gained in active network management and grid integration to develop similar systems for other constrained technologies like wind and solar PV.
“We see a good international market for small tidal turbines alongside battery storage. And possibly bringing in other microgrid necessities…Our system is agnostic. We can add generation or demand to make the best commercial case,” Connor explained.
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