WIND ENERGY:In just 11 years, the Government would like us to be sourcing 40 per cent of our electricity from renewable sources – a target inconceivable a decade ago. This may be a huge target, but our wind energy resource is such that we can provide renewable energy on this scale and, most crucially, at a profit.

Last year the All-Island Grid Studywas released, a comprehensive attempt to determine how much of our renewable energy resource we could – and should – exploit. Most surprising was the sheer quantity of renewable generation that was both technically and economically feasible.

An electricity system with vast quantities of wind generation and other renewables could be built and operated at a similar cost to alternative systems, with a greater proportion of fossil fuel generation. Furthermore, a high wind system would shield us from a great deal of fuel price risk – which tends to be an issue when you rely on everyone else for your coal, oil and gas. So wind energy could not only slash our emissions, create jobs and rejuvenate isolated communities, it could also help keep costs low and stable throughout the economy.

Why the emphasis on wind power? What about wave? Our wave resource is, after all, world-leading. Also, ocean waves tend to have more momentum than winds, meaning more energy. Unfortunately, these devices also need to be rugged enough to survive under these conditions. In the end it remains to be seen whether reliable, cost-effective designs can be developed.

And tidal? Well, our tidal resource isn’t that large in the first place and secondly, while tidal outputs are perfectly predictable, the coincidence between electricity demand and tidal output is not strong enough for the devices to replace much conventional fossil fuel plant.

But wind has its problems. In truth, every electricity generation option has its problems. The challenge is to fit all these less-than-ideal elements into a system that delivers clean, cost-effective and reliable energy.

To understand this challenge a little better we need to discuss the electricity system for a moment. To “keep the lights on”, the system operator has to ensure the amount of electricity generated is almost exactly equal to demand. Insufficient generation means switching out parts of the network until full demand can be met. In situations where the operator cannot respond in time, a total blackout may occur, a situation we have thus far avoided.

As our power system is relatively electrically isolated – we have only one electrical connection to another country – system reliability is a major concern. The upshot is that, to maintain a reliable system, we need to be able to cope with rapid unexpected changes in generation or demand. If a power station goes offline suddenly, we need power from somewhere else in an instant; if wind speeds are slacker than forecast we must switch generation. In summary, we need a flexible system. It’s useful then to characterise electricity generation options in terms of cost and flexibility. This allows us to compare different technologies in an equitable manner.

Variable sources, such as wind or wave power, increase the need for flexibility as their output is non-controllable and cannot be perfectly forecast. Nuclear installations are not amenable to variable output and, since they provide a lot of power, a sudden loss of a nuclear unit would require a great deal of backup power. Nuclear power on the Irish system would therefore require more flexibility and/or reduce the maximum potential for wind and wave.

So what are the options for increasing system flexibility? Right now, flexibility is provided by a combination of open cycle gas turbines – a nimble form of generation that can vary its output rapidly – and hydroelectric pumped storage, where water is pumped uphill into large reservoirs when the system has more power than needed. The water can then be released through turbines to provide power when we’re short on generation.

An undersea cable to Scotland – soon to be supplemented by another to Wales – also gives some flexibility by allowing electrical flows in either direction in response to requirements. Another, as yet largely hypothetical, flexibility tool is demand side management, an attempt to influence demand in response to system needs.

Several ways of achieving this have been proposed. In the future, the charging of electric vehicles could be controlled to take advantage of hours when electricity demand might be slack or renewables output might be high. Certain household appliances such as immersion heaters could be switched off for a short period in response to an unexpected system event, allowing just enough time for other flexibility tools to kick in—similar schemes are already offered to industrial and business customers in exchange for lower tariffs.

Smart metering could also play a role, whereby a real-time electricity price could be calculated by the system and presented to us in the home. A high peak-time price might persuade us to do our washing at a different time for example.

The most effective means of delivering flexibility in the power system, the quantity required and even simply how to quantify it are all highly contentious questions in the industry at this time. One thing is for sure, if we pursue a “high wind” strategy, we’ll need a lot of system flexibility.

So where are we at now? There are 1,000 megawatts (MW) of wind power on the system right now. The latest stage of wind farm development in Ireland, next year’s Gate 3 process, should see the commencement of another 3,500MW of wind power projects over the coming decade. Add that to the 1,500MW of already contracted projects, giving a total of 5,000MW of new wind, or about 2,500 new turbines. This is the sort of capacity required to get us to our 40 per cent target.

But levels of investment and economic feasibility are not enough. There are several potential pitfalls to progress. A wind farm developer must successfully pass the grid-connection process as well as the regular planning permission process. In some cases, synchronising these two steps is proving difficult. But, even if the turbines can be built and connected, there is still the sticky issue of transmission. Much of the new wind connection will be in areas where the network has been specified to meet very limited needs.

Therefore, in order to transfer the power to where it’s needed, a massive programme of grid development – recently priced at €4 billion – will have to take place. And while €4 billion may be minor, relative to the value of electricity the transmission will cater for over its lifetime, the challenge of actually getting it there will be enormous. Obtaining public acceptance for 2,500 new wind turbines is one thing, but persuading the nation to accept the accompanying high-voltage transmission lines will be quite another.

But there’s cause for optimism. We’ve come a long way in a short time and, with Eamon Ryan as Minister for Communications, Energy and Natural Resources, we have a genuine and effective advocate for renewable energy in the driving seat. If we analyse our future options with rigour and honesty and maintain the momentum that has got us this far, we can meet these targets and find innovative ways to go even further.

• Aonghus Shortt is a PhD student from the Electricity Research Centre at UCD