Renewables series: Ireland's wind energy milestone and other temporary 100% achievements

A significant milestone for wind power was achieved in Ireland when wind turbines provided more than 100% of the country's electricity for three hours.

This milestone reflects the expanding role of renewables in the power grid and demonstrates how the electricity grid is getting cleaner, leading to better Energy Performance ratings for buildings.

Whilst significant, issues with stability and reliability of relying on power generated from wind renewables need to be solved.

Ireland's wind energy achievement

On 12th of December 2023, Ireland's wind farms continuously produced more electricity than the country's total demand for three hours; the first time Ireland was powered entirely by wind energy. EirGrid, the national grid operator, reported that wind power accounted for more than 100% of Ireland's electricity consumption.

This event was partly made possible by Ireland's geographical advantage, being on the edge of the Atlantic and one of the windiest locations in Europe. Over the past two decades, Ireland has gradually  developed its wind energy sector, with wind now providing about 35% of the country's annual electricity demand. The government aims to increase this to 80% by 2030 as part of its commitment to achieving net-zero carbon emissions.

Other 100% wind energy achievements

Ireland is not the only country that has temporarily run entirely on renewable energy. Some interesting wind milestones:

• Portugal: In March 2018, Portugal ran entirely on renewable energy (wind, solar, and hydropower) for more than four days. The country continues to expand its renewable infrastructure and regularly achieves high levels of clean energy production.
• Denmark: Denmark has on multiple occasions generated more wind power than it needed, exporting excess electricity to neighbouring countries like Germany and Sweden. Denmark first ran 100% on wind power in 2013 on the 3rd of November. Increasingly Denmark is achieving 100% of electricity from wind power.
• Germany: In May 2022, Germany experienced a day when renewable energy (primarily wind and solar) accounted for nearly all electricity consumption. The country continues integrating large-scale battery storage and grid-balancing technologies to manage intermittent renewables effectively.
• Scotland
  August 7, 2016: Wind power generation reached 106% of Scotland's electricity demand over 24 hours, marking the first time wind energy output exceeded national consumption.
• Sweden
  July 9, 2015: Wind turbines generated 116% of Denmark's electricity demand during the day, peaking at 140% overnight. Surplus power was exported to neighbouring countries, including Germany, Norway, and Sweden.
  September 15, 2019: Strong winds enabled wind turbines to produce 130% of the country's electricity consumption over 24 hours, with excess power sold abroad.
• El Hierro, Spain
  2019: El Hierro, the smallest of the Canary Islands, achieved 100% self-sufficiency in electricity for nearly 25 consecutive days through its combined wind and hydro project - this seems incredible and is interesting, so let's look a little further at it. 

El Hierro hydro/wind plant

The hydro-wind power plant combines 11.5 MW of wind turbines with 11.3 MW of pumped hydro storage. Wind turbines generate energy, which when demand exceeds supply is used to pump water to an upper reservoir for storage and later releases it to produce electricity.

The electricty plant previously relied on diesel oil generators for electricity, and the diesel oil had to be shipped to the island, further increasing carbon emissions. The hybrid wind/hydro plant has reduced diesel consumption by approximately 6,000 tons of diesel oil and lowered CO₂ emissions by 19,000 tons annually.

Plans include adding 5 MW of solar power and battery storage to increase renewable energy use and reduce reliance on fossil fuels.

Challenges of Excessive Wind Power

Although wind power provides numerous environmental and economic benefits, it also presents challenges when its generation exceeds demand.

1. Grid Stability and Curtailment
Electricity grids are required to maintain a constant balance between supply and demand. When wind energy generation surpasses what is required, grid operators often need to reduce production or store the power. Current storage limitations mean that operators must shut down turbines or reduce output. In Ireland's 3-hour wind energy event, EirGrid exported the surplus to neighbouring grids, but in situations where transmission capacity is limited, reducing turbine production is needed.

2. Storage limitations
The current lack of energy storage is one of the biggest hurdles to harnessing wind energy fully. While battery technology has improved, large-scale storage remains expensive. Countries investing in pumped hydro storage, hydrogen production, and grid-scale batteries can handle surplus wind power by operating hydro pumps when electricity demand is low.

3. Turbine shutdowns in high winds
With the current infrastructure, too much wind can also be a problem. Current wind turbine technology means turbines must shut down when wind speeds exceed 50 mph to avoid damage. When approaching this wind limit, turbines are angled inefficiently to reduce exposure to the wind, which results in sudden power drops, making power demands difficult to balance.

4. Policy challenges
Surplus wind energy can lead to negative electricity prices, as producers must pay to offload excess electricity.

Paying to offload electricity reduces wind farm profitability and makes future investments less attractive without proper market reforms. Policies are developing to incentivise energy storage. Dynamic pricing in the UK has increased, with some utility companies selling electricity for 7 pence per kWh. Governments and industries are electrifying heating and transport to reduce carbon emissions, and they expect this trend to continue.

The future of wind power

On March 6, 2025, the UK and Ireland announced a collaborative effort to connect offshore wind farms in the Irish Sea to their national energy networks. The countries intend to do this by joint consent, data sharing, sea basin mapping, and interconnecting offshore projects.

Ireland is continuing to develop offshore wind farms as these have the potential to generate even more consistent wind power energy than onshore installations.

AI and predictive analytics advancements are helping grid operators manage renewable energy fluctuations more effectively.

Conclusion

Wind power continues to develop, and the example of the dual wind/hydro power plant in El Hierro, Spain, achieving 25 days of their 100% electricity needs, blew me away!