Marshall on Policy : Energy Briefing Series

Ireland's Spilled Energy Problem

About the Energy Briefing Series

The Energy Briefing Series examines how Ireland’s energy system is changing and the choices that will shape its future. Each briefing explores a specific component of the system while contributing to a broader understanding of energy, infrastructure, demand, storage and public policy.

Ireland’s Spilled Energy Problem

1: Why this briefing exists

Ireland’s public policy challenges are becoming more complex. They cross domains. Housing affects transport. Transport affects energy. Energy affects climate and the cost of living. These systems cannot be understood in isolation. They need clear explanation and structured thinking.

Marshall on Policy will run a series of briefings to make these systems understandable. A briefing is not an opinion piece. It is not advocacy. It is a way to explain how a public policy system works, why it matters, and what choices lie ahead. This series begins with energy because energy shapes every other domain. It shapes our homes, our transport, our economy, and our climate future.

The aim is simple. To explain the system clearly. To show where the opportunities lie. To outline the choices Ireland will face in the years ahead.

2. Ireland’s changing energy needs

Ireland’s energy needs are changing because Ireland is changing. More homes are electrifying their heating. More vehicles are shifting to electric power. Industry is moving toward lower‑carbon processes. Data centres are expanding. Agriculture is under pressure to reduce emissions. Every sector is being reshaped by electrification.

At the same time, fossil fuels are becoming more expensive and more unstable. Ireland imports most of its energy. This drains billions from the economy every year. It exposes us to geopolitical shocks. It leaves us vulnerable to price spikes. Climate change adds further pressure. The global energy system is being forced to change whether we are ready or not.

Ireland has built strong renewable generation, especially wind. But the rest of the system has not kept pace. Storage is limited. Transmission is uneven. Tariffs are outdated. Flexible demand is underdeveloped. As a result, Ireland spills large volumes of clean electricity. This is called curtailment. It happens when wind farms produce more energy than the system can absorb.

Curtailment is not a failure of renewables. It is a sign that the system around them has not yet been modernised.

3. The cost of spilled energy

Ireland is estimated to spill between five and seven and a half terawatt hours of clean electricity each year. That is hundreds of millions of euro worth of energy. It is also millions of tonnes of avoidable carbon emissions. When clean electricity is spilled, it is replaced by fossil generation. The cost is economic. The cost is environmental. The cost is strategic.

Spilled energy is wasted climate progress. It is wasted economic value. It is wasted national capability.

But it is also an opportunity. Few countries reach the point where they spill renewable energy. Fewer still act on it. Ireland can turn this waste into value. We can use spilled energy to heat homes, charge vehicles, support industry, and reduce fossil reliance. We can build storage. We can reform tariffs. We can activate flexible demand. We can modernise the system around the wind we already have.

4. The uneven development of our infrastructure

Ireland’s energy infrastructure has grown unevenly. Some parts are modern. Some parts are a century old. Ardnacrusha is still part of our system. It was built for a different era. It shows how infrastructure shapes national capability long after the moment of construction. The proposed LNG terminal at Shannon shows how Ireland is still deciding between fossil pathways and renewable pathways. These choices will shape the next fifty years.

It is sobering to recognise that one year of spilled wind generation is roughly equivalent to five years of electricity generation at Ardnacrusha. A century ago, Ardnacrusha represented one of the most ambitious infrastructure projects in the history of the State. Today, surplus wind generation points to a different challenge: not how to generate electricity, but how to use, store and manage the clean energy we already produce. This alone illustrates the magnitude of the transition Ireland is being asked to manage.

Our transmission network is strong in some regions and constrained in others. Our storage capacity is limited. Our tariff system was designed for fossil baseload. Our demand patterns are shifting faster than our policy frameworks. These mismatches create inefficiency. They create waste. They create uncertainty.

The Energy Briefing series will explore each of these elements. Generation. Storage. Consumption. Management. Tariffs. Flexible demand. Surplus energy. CO₂ reduction. The possibility of exporting energy in the future, whether as electricity, hydrogen, or ammonia.

5. The nature of demand

Ireland’s future energy system will be shaped by demand. Not just supply. Demand is changing. Heat pumps shift heating load to electricity. EVs shift transport load to electricity. Industry is shifting process heat to electricity. Data centres create constant load. Agriculture will need new forms of energy for lower‑carbon processes.

Demand is becoming more flexible. It can move. It can respond. It can support renewable generation. But only if the system is designed to allow it. Tariffs must change. Storage must expand. Infrastructure must modernise. Policy must recognise that demand is now a tool, not just a requirement. Flexible demand is the missing half of Ireland’s energy system. It is how we use the energy we already produce. It is how we reduce fossil reliance. It is how we cut emissions. It is how we lower costs. It is how we build resilience.

6. The opportunity, the waste, the challenge

Ireland has built enough renewable generation to create surplus. This is momentum. It is a sign of progress. It is a good problem. But it is also a challenge. The system around renewables must be modernised. Storage must grow. Tariffs must change. Demand must become flexible. Infrastructure must be strengthened. Policy must shift from fossil assumptions to renewable realities.

The opportunity is clear. Ireland can use the energy we already produce. We can reduce emissions. We can lower costs. We can support households. We can strengthen industry. We can build resilience. We can export energy in the future. But only if we act. This briefing series will explore how.

7. What comes next

The purpose of the Energy Briefing Series is not simply to examine energy policy. It is to explain how a major public policy system works. Each briefing will focus on a specific component while contributing to a broader understanding of how Ireland can make better use of the resources it already possesses.

The next briefing will examine flexible demand. It will explain how Ireland can use surplus wind to heat homes, charge vehicles, support industry, and reduce fossil reliance. It will outline the tools, the technologies, and the policy choices that make flexible demand possible. Energy Insights will accompany each briefing. They will provide definitions, data, and detailed explanations. They will live quietly at insights.marshall.ie and support the series without cluttering the main articles.

This is the beginning of the Energy Briefing series. It will unfold slowly, clearly, and constructively. It will build a coherent picture of Ireland’s energy future. It will show how we can use the energy we already produce.

David Marshall
Dublin

Marshall on Policy : Policy Briefings
policy.marshall.ie

Inadequate policy and indifferent governance leave people in want.