Think of Ireland’s electricity grid as a restaurant kitchen. Wind and solar are like ingredients that arrive fresh each morning – brilliant when they show up, but unpredictable in quantity. Dispatchable generation is the head chef who can cook to order, firing up the stove whenever a dish is needed and turning it off when the rush dies down.
Dispatchable generation refers to any power source that grid operators can switch on, ramp up, ramp down or switch off on demand. It is the opposite of variable or intermittent generation, where output depends on weather conditions that nobody controls. In Ireland, dispatchable sources include gas-fired power stations, oil-fired backup plants, battery storage, pumped hydro storage and interconnectors. EirGrid’s Resource Adequacy Assessment 2025-2034 recorded 6,920 MW of fully dispatchable plant capacity in Ireland in 2025 – compared to 5,400 MW of onshore wind capacity that cannot be summoned at will.
🌿 How Dispatchable Generation Works
The key feature of dispatchable generation is controllability. A gas turbine can receive an instruction from EirGrid’s National Control Centre and begin producing power within minutes. An open-cycle gas turbine (OCGT) can start from cold in 10-15 minutes, making it ideal for sudden spikes in demand or unexpected drops in wind output. A combined-cycle gas turbine (CCGT) takes longer to start but runs more efficiently, converting more of the fuel’s energy into electricity by capturing waste heat through a steam cycle.
Variable renewables like wind turbines and solar panels produce electricity only when conditions allow. On a calm, overcast January evening when demand peaks, these sources might contribute very little. Dispatchable generation fills the gap, ensuring the lights stay on regardless of the weather.
🌿 The merit order in the Single Electricity Market
Ireland operates the Single Electricity Market (SEM) across the whole island. Generators bid into the market for each half-hour trading period, and the system operator stacks them in order of cost – cheapest first. This is the merit order. Renewables sit at the bottom because their marginal cost is essentially zero. Interconnector imports come next, followed by efficient CCGTs, then OCGTs and oil-fired peaking plants at the top. The last generator needed to meet demand sets the price for everyone, and in practice that is almost always a gas-fired plant – which is why wholesale electricity prices in Ireland track the international gas market so closely.
🌿 Why Dispatchable Generation Matters in Ireland
Ireland’s grid is unusually dependent on dispatchable gas. Natural gas generated 40% of the country’s electricity in 2025, down slightly from 41% in 2024, according to Gas Networks Ireland. During low-wind summer months, gas’s contribution peaked at 92% in 2025 – meaning the grid relied almost entirely on dispatchable plant to keep running. Wind generated 33% across the full year, but that average hides enormous variation from hour to hour and season to season.
The challenge is that dispatchable capacity is declining. Several older plants have been decommissioned or face retirement under the EU Industrial Emissions Directive. At the same time, electricity demand is rising sharply. Data centres accounted for 27% of demand in 2025 and are forecast to reach 31% by 2034. Heat pumps and electric vehicles are adding further load. The government’s Climate Action Plan targets at least 2 GW of new flexible gas-fired generation by 2030, procured through capacity market auctions, to replace retired coal, oil and peat plant and keep the system secure as renewable energy scales up.
🌿 Capacity versus energy – a critical distinction
This is where many people get confused. A wind farm with 100 MW of capacity might produce the equivalent of 28-30 MW on average over a year because of its capacity factor. A gas-fired CCGT with the same 100 MW might run at a 50-70% capacity factor. But the real value of dispatchable generation is not how much energy it produces over the year – it is the guarantee that it can produce when called upon. Planning a secure grid requires enough capacity to meet peak demand even in worst-case conditions (cold, dark, still evenings in winter). That is why EirGrid measures dispatchable capacity in megawatts of firm, controllable output, not in annual energy terms.
🌿 Moneypoint, Emergency Generation and the Transition
Ireland’s most symbolic dispatchable plant is Moneypoint in Co Clare. The 915 MW station burned coal for nearly 40 years before ceasing coal generation on 20 June 2025, making Ireland the 15th coal-free country in Europe. Moneypoint has not closed – under an ESB-EirGrid agreement, it was converted to heavy fuel oil and remains available as a backup generator of last resort until 2029, sitting outside the wholesale market.
Alongside Moneypoint, 650 MW of Temporary Emergency Generation (TEG) has been installed at four sites – North Wall, Huntstown, Shannonbridge and Tarbert – as a short-term insurance policy while new permanent plant is built. The TEG units are gas-fired and also sit outside the market. EirGrid’s Winter Outlook for 2025/26 showed a Loss of Load Expectation (LOLE) of just 1.1 hours with these measures in place. Without TEG and Moneypoint, the figure would have been 43.4 hours – more than 14 times the acceptable standard of 3 hours per year.
These are stopgap measures. The real solution is new permanent dispatchable capacity. Bord Gais Energy secured a 10-year capacity market contract in early 2025 for a new 334 MW OCGT in Galway, with commercial operation expected in 2029. The Greenlink interconnector (500 MW between Ireland and Wales) became commercially operational in January 2025, joining the existing Moyle and East-West links to give Ireland approximately 1,400 MW of interconnection with Great Britain. The Celtic Interconnector between Ireland and France will add a further 700 MW when commissioned in spring 2028, creating Ireland’s first direct link to continental Europe.
🌿 The IEA’s Warning – 16 GW by 2035
In December 2025, the International Energy Agency published Powering Ireland’s Energy Future, developed with EirGrid. Its central finding: under the Adapted Transition Pathway, Ireland’s peak residual demand (total demand minus wind and solar output) could reach 10 GW by 2035. To cover this securely, the country would need a portfolio reaching 16 GW of dispatchable capacity, including thermal generation, energy storage and interconnectors.
That is more than double the 6,920 MW of dispatchable plant available today. The IEA projects that the role of gas-fired generation will shift from providing the bulk of electricity to acting mainly as security backup, with utilisation rates dropping from around 46% in 2023 to approximately 12% by 2035. This creates a commercial problem: operators need to cover fixed costs despite running far fewer hours. Ireland’s capacity market – which pays generators to be available, not just for the energy they produce – will be critical to keeping enough dispatchable plant on the system.
The transition does not mean gas disappears. It means gas shifts from workhorse to safety net, ready to step in during cold, still weeks when wind and solar cannot deliver. Battery storage, demand response and interconnectors will shoulder more of the balancing role, but thermal plant remains essential as the ultimate backstop for an island grid with limited connections to its neighbours.
🌿 Frequently Asked Questions
🌿 What is the difference between dispatchable and non-dispatchable generation?
Dispatchable generation can be turned on or off by the grid operator whenever needed. Gas turbines, oil plants, pumped hydro and battery storage all qualify. Non-dispatchable (or variable) generation depends on weather – wind turbines only produce when the wind blows, and solar panels only generate in daylight. The grid needs both, but dispatchable sources provide the reliability guarantee that keeps the system secure.
🌿 Why does Ireland need gas plants if it has so much wind energy?
Wind generated 33% of Ireland’s electricity in 2025, but output varies enormously. During calm periods, wind can drop below 5% of demand. Gas-fired plant fills those gaps. Until long-duration energy storage and stronger interconnection are built at scale, gas remains essential. The government targets 2 GW of new flexible gas capacity by 2030.
🌿 Is dispatchable generation always fossil fuel based?
No. Battery storage, pumped hydro (such as Turlough Hill in Wicklow), interconnectors importing power from other countries and biomass generators are all dispatchable sources that do not rely on fossil fuels. Ireland’s green hydrogen strategy also envisions hydrogen-capable gas turbines as a long-term zero-carbon dispatchable option. The IEA’s 16 GW target for 2035 explicitly includes storage and interconnectors alongside thermal plant.
🌿 What happens to electricity prices as dispatchable gas runs less often?
Under the current market design, the wholesale price is set by the most expensive generator needed in each half-hour. As renewables supply a larger share, gas plant runs less often but still sets the price during low-wind periods. The IEA noted that gas set wholesale electricity prices 80% of the time in 2022. Greater renewable penetration should reduce average prices, but volatility is likely to increase – very cheap during windy hours and expensive during calm spells. Ireland’s curtailment and demand response strategies aim to smooth out these swings.