Is tidal energy expensive?

Yes. Today tidal energy costs more per unit than offshore wind or solar. That is the
short answer and it is not close.

The longer answer is more useful, because the costs that make it expensive are not the ones
most people assume.

It is not the turbine

The machine is a minority of the bill. Most of the money goes on foundations or moorings,
installation vessels, subsea cable and grid connection. Halving the cost of the turbine would
barely move the total.

It is the access

Work at a tidal site often has to happen around slack water, which can be a window under an
hour, twice a day, at times set by the moon rather than the schedule. Vessels are charged by the
day and wait for weather. That is the real cost driver.

It is also the volume

There is no mass production. Each project has been close to bespoke, which means no learning
curve, no standard parts and no competitive supply chain. Offshore wind was in exactly this
position and is now among the cheapest generation available.

So will it get cheaper

The dominant costs are the ones that historically fall with deployment. The one that does not
is the number of suitable sites, which is fixed by geography. The industry’s question is whether
enough volume can be built at the good sites to bring costs down before the good sites run out.

Full detail in what tidal energy costs and
the per kWh comparison.