Studies supporting the deployment of wind to meet this target put forward the arguments firstly, that wind deployment in Ireland has at little or no extra cost,
- reduced emissions,
- increased security of supply and
- reduced imports and crucially,
- there are no better alternatives at this time ,.
However, the system challenges will be greater and potentially more costly as we break new ground. The costs and issues entailed will have be monitored and evaluated. Issues will be raised regarding the stress on the system and its management arising from the intermittency of wind and its priority dispatch status. Greater levels of interconnection and possibly other means such as large-scale storage will be required if wind is to supply above 40% of our electricity needs. The option of a 700MW connection to France to meet this need is being evaluated by EirGrid as well as other linkages to Great Britain .
New plant and system adaptation will be required to accommodate the intermittency of wind. This might occur either through technological developments and investments to allow conventional plants to respond quickly, increasing the flexibility with the development of pumped storage and 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 .
Battery storage enhances grid reliability by providing fast response ancillary services. The 10 MW of interconnected energy storage being built at Kilroot in Northern Ireland is the first step to a planned 100MW energy storage array. The 10MW is estimated to be able to provide £8.5 million in savings per annum and eliminate an equivalent of 123,000 tons of CO2 per annum . Local electricity storage capacity is also being considered - potentially in the form of the batteries in electric vehicles to decarbonise the electricity system and make a contribution to renewable energy in transport targets as well Available Online '>10.
Compressed air energy storage (CAES) is another option under consideration. This converts excess energy to compressed air to be stored underground in geological caverns and later released through an electricity generator. A CAES project has been submitted to the planning division in December 2015, at Larne in Northern Ireland. The facility is said to be able to generate up to 330MW of power for up to 6 hours .
Evidence-based decisions on what renewable technologies are the most cost-effective at reducing our emissions will help to ensure that we have a competitively priced and secure supply of sustainable electricity.