Energy Institute

Why is wind so central to Irish energy policy?

With careful integration into the electricity system wind can be a competitive low-carbon energy for electricity generation. In 2014 we generated seven times more electricity from wind than from hydro for example 1. It is one of the largest and lowest cost sources of renewable energy for electricity currently available in Ireland. As an abundant, free, readily available and indigenous source of renewable energy it is important in an Irish context. It already has reduced CO2 emissions and further decarbonisation of the electricity system is possible while making us less dependent on imports.

Despite its advantages, the intermittent nature of the resource creates issues for the management of the grid, the reliability of electricity supply and the apportionment of the costs entailed in offsetting these issues. The electricity system has to be adapted to accept and compensate for the special characteristics of wind power. An optimisation is required between the cost of grid upgrade, the cost of wind turbines and the energy yield. Adaption means extending the grid to where wind turbines can produce the highest energy yield at the minimum social cost, making provision for connecting some wind at the low voltage distribution level, and providing alternative energy sources for occasions when the wind is not blowing 2.

The challenge for policy makers is to balance the costs and benefits of wind deployment and with that make sure that other technology options to achieve similar results are not inadvertently closed off now or in the foreseeable future.

One key barrier to having more than 40% of renewable electricity on our grid is the over-production of electricity that occurs when the wind is strong and electricity demand is low. This could be partially resolved by finding new uses for the excess electricity such as charging electric vehicles (EV), heating water in homes or powering storage heaters. For example, there is a potentially strong synergy between the deployment of EVs and wind-power in Ireland 3. The infrastructure to support EVs is already being rolled out by ESB Networks under a public service mandate funded through the Commission for Energy Regulation. EVs are the subject of a global research effort by car companies, battery manufacturers and research organisations that see the benefits of reducing harmful emissions and the oil dependence of our transport systems.

Alternatively, markets could be found for the temporary excess of wind power. The East-West interconnector is already enabling the export of surplus wind power to Britain. Ireland exports excess electricity at low prices at night and imports, for the moment, cheaper electricity from Britain during the day. On a larger scale, the options are to store the extra wind power (e.g., by pumping water up into reservoirs from where it can flow back down to power turbines when there is demand for electricity) or by exporting the surplus to another country.

Such temporary storage happens on a daily basis when the pumped storage facility at Turlough Hill is charged at night using low cost electricity and the release of the water is used to regenerate electricity to meet peak demands for electricity the following day. However, the economic potential for further pumped storage in Ireland is affected by other developments such as interconnection and the prospects for other forms of storage.

Studies have shown that the presence of generators such as wind with “priority dispatch” or must-run status has effects on other generating plant, some of which is either economically and/or technically challenged to cope because they have to ramp up and down more and at short notice (when the wind drops or picks up), or are not operating enough of the time to make a profit . More wind farms mean wind power replaces the generation output of conventional plants due to their priority status. Much of the mid-merit combined cycle gas fired plant on the Irish system was expected to run under steadier conditions and it is not clear what the effects will be of more rapid cycling up and down.

Thus wind can create the need for investment and innovation in new types of plant. This might occur either through technological developments allowing conventional plants to respond quickly, increasing the flexibility with the development of variable speed pump turbines, reducing plants minimum operating levels from the usual values and developing energy storage facilities or smart grids along with demand side management.  These issues are addressed by EirGrid’s DS3 programme.