Transitioning Ascension Island Towards a Renewable Future

Challenge

Ascension Island, one of the most remote territories in the world, has historically relied on diesel generation to meet its electricity needs. This dependency poses significant challenges: high fuel import costs, exposure to supply chain risks, and substantial carbon emissions. The island’s ambition to achieve net zero required a robust, future-proof energy strategy that could deliver sustainability, security and resilience while remaining cost-effective. Additionally, the solution needed to accommodate critical loads, including an international broadcaster and the Defence Management System (DMS) base, ensuring uninterrupted power supply.

Solution

Ricardo was enlisted by the Ascension Island Government to design a comprehensive renewable energy transition strategy. Renewable energy experts developed detailed load forecasts, incorporating projected demand growth and operational requirements for essential services for domestic, broadcasting, military and transportation (electric vehicles) sectors. Using techno-economic demand-supply simulation modelling, the optimal mix of wind, solar, and battery storage to achieve over 85% renewable penetration was identified.

The modelling process identified various energy system configurations and evaluated the least-cost supply option. Given the island’s isolation, redundancy and security were integral to the design, guaranteeing resilience against equipment failure and supply disruptions. This strategic approach enabled the Government to finalise its net zero roadmap and prepare compelling grant applications to the UK Government.

Benefits

By partnering with Ricardo, the Ascension Island Government gained a clear, actionable roadmap to transform its energy system. The strategy not only positions the island to achieve net zero emissions, but also delivers tangible advantages:

• Confidence in carbon reduction: The modelling demonstrated how an 85%+ renewable mix could dramatically cut diesel consumption, enabling the Government to meet its climate commitments and strengthen its environmental leadership.
• Future-proof energy planning: With detailed forecasts, the Government now has a long-term plan that adapts to evolving technologies and demand, ensuring sustainability for decades.
• Security and resilience built in: The solution addresses the unique challenges of operating in one of the world’s most remote locations. By incorporating redundancy and storage, the island can maintain reliable power for critical services, even in adverse conditions.
• Financial clarity and cost control: Through rigorous analysis of CAPEX, OPEX and levelised cost of electricity, the Government can make informed investment decisions, reduce reliance on imported fuel, and stabilise energy costs.
• Unlocking funding opportunities: The strategy provided the evidence base needed to support grant applications to the UK Government, accelerating progress towards implementation.

This project demonstrates how remote energy systems can move decisively away from fossil fuel dependency while strengthening, rather than compromising, security of supply. By integrating high‑penetration renewables with storage, redundancy and robust system design, Ascension Island is reducing exposure to volatile fuel supply chains, significantly lowering carbon emissions and improving long‑term cost stability. Crucially, the strategy safeguards resilient power for critical national infrastructure, including defence and broadcast operations, even in the face of extreme isolation, logistical disruption or equipment failure. The outcome is an energy system that not only supports the island’s net zero ambitions, but also delivers a secure, reliable and future‑ready foundation for economic, environmental and operational resilience for decades to come.

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