Renewable power generation is behind schedule. Wind farm proposals are resisted by residents in rural areas, planning permission is hard to obtain and Government 2030 targets for low-carbon power, solar as well as wind, look unrealistic.

This feeds the pressure for tougher targets in agriculture as power generation cannot deliver. Emissions from the electricity industry, boosted by the rapid expansion of data centres, are rising again despite the retirement of turf and coal plants.

The popular political response is to urge wind farms to locate offshore, where there is less opposition. But the offshore wind industry in Ireland is theoretical and too little attention has been paid to the potential cost of a major expansion.

Tall turbines visible from the shore are controversial anyway, and developers are contemplating locations further out to sea. If distant offshore wind farms cost extra for both construction and transmission, who pays?

The extra costs are difficult to judge but if the targets are serious, it is time to enumerate them in detail. The current presumption is that Ireland’s territorial waters include a vast expanse of the Atlantic Ocean, and thus a huge opportunity is on offer.

There could be a big enough power surplus to permit enormous exports of electricity or of hydrogen, into which cheap surplus power can be converted, according to offshore wind lobbyists.

If a substantial offshore wind industry comes to be developed, mainly off the west coast, wind speeds may be high but water depths are a problem, so floating platforms would be required.

This is a developing technology but the experts are agreed that inshore platforms are cheaper since they can be fixed to the ocean floor, and onshore turbines are cheaper again.

Bigger bills

Since power generation is a cost-recovery business, extra costs of floating platforms will show up in customer bills. Longer transmission lines to shore will cost more as well.

A document released last week by the regulator, the Commission for the Regulation of Utilities (CRU), estimates that Eirgrid will have to add €5 billion to its asset base by 2030 for offshore transmission under current targets, to be passed on to customers.

To this must be added the costs for Eirgrid onshore – the extra electricity needs to be transmitted onwards to the east coast where supply is inadequate, or over greater distances to export markets.

That means new high-voltage transmission lines across Ireland and more cost for Eirgrid, which faces local opposition to every planning application for pylons.

Costs for floating platforms, along with offshore and onshore transmission bills are passed on to consumers, but that is not the end of the extra cost.

Platforms have to be assembled and towed out for installation, and ports serving the offshore industry need space and facilities.

If offshore capacity is to exceed domestic demand by large multiples as is intended, the industry will have to cover the cost of exporting the surplus or of converting spare power into hydrogen at further cost.

Intermittent power on this scale also implies further hidden costs for balancing the system with expensive ‘always on’ generation or batteries.

Ireland already has expensive electricity by European standards – has the Department of Energy, the CRU or anyone else established that Ireland will be competitive in the electricity export business?

The United Kingdom enjoys shallower water in the North Sea, is able to economise on costs since there is less need for floating platforms, and there are substantial developments in train.

Capital works for a port wishing to get into this business have been estimated in the hundreds of millions to fund onshore facilities for vessels, storage and assembly.

Numerous ports in the UK have been investing, including several in the east of Scotland and down the North Sea coast in England, building on spare capacity left over from the offshore oil boom.

Belfast is the only port on the island with capacity to service new offshore developments, and Barrow-in-Furness on the coast of Cumbria is also adjacent for any new east coast projects.

A long list of Irish ports have announced ambitions to service offshore business, including a proposed new port at Bremore in Co Meath and Rosslare, both on the Irish Sea as is Belfast. Waterford, Cork, Shannon/Foynes, Moneypoint, Galway, Rossaveal and Killybegs, which are oriented south and west, also have plans, without identifying firm customers.

None have access to private capital for their proposals, and the presumption is that the State, owner of all main Irish ports, will volunteer capital money, exposing the public to double jeopardy, as electricity customers and as taxpayers.

Before any capital exposure is undertaken, the Government should publish an assessment of the commercial viability of offshore wind for export, including market analysis and a detailed cost estimate for every step in the process.