The project entails the revamping of the Ribeira Grande geothermal plant, which has been in operation since 1994. Two of the four existing ORC units, each rated at 2.5 MWe, will be replaced with a new 5 MWe unit. Exergy’s ORC system, based on a single-pressure-level cycle, will harness a geothermal resource at approximately 150°C in both brine and steam phases, to produce clean electricity using Exergy’s Radial Outflow turbine technology.

The cycle is designed to utilise all available heat content of the steam, minimising geothermal fluid loss. Additionally, the high isentropic efficiency of the Exergy radial outflow turbine will enable the generation of approximately 5.3 MWe of net power, exceeding the 5 MWe requested by the customer, thus enhancing the overall competitiveness of the systems. An air-cooled condensing system will be used to avoid water consumption, and the geothermal steam and brine will be reinjected into the well at the ORC outlet.

Exergy’s scope of work includes the full engineering, procurement, and construction (EPC) of the ORC plant and associated gathering systems. The plant is planned to be fully operational before the end of 2026 with the first provisional take-over (partial) scheduled for the end of June 2026. By means of the Ribeira Grande repowering project, EDAR will ensure a sustainable and reliable electricity supply for the local population, marking another step towards the Azores’ goal of carbon neutrality.

This is the second contract awarded to Exergy by EDA Renováveis, the renewable energy division of Azorean utility company EDA, following the supply of the 4 MWe Pico Alto plant on Terceira Island, which has been in operation since 2017.

Exergy’s Deputy CEO, Luca Pozzoni, commented: “We are honoured by the renewed trust placed in us by EDAR, a long-standing partner with whom we have maintained a strong and continuous collaboration. We are pleased to engage once again in a project that will ensure a stable and reliable source of renewable energy for the local community on the island of São Miguel for many years to come. This initiative further consolidates our expertise in the development of geothermal energy solutions in complex and distinctive environments. Exergy will oversee the entire execution process – from engineering and design to construction and commissioning – within a highly demanding timeframe. Once again, Exergy reaffirms its commitment to being a reliable and comprehensive partner, capable of delivering high-performance products and services that meet the evolving needs of our clients.”

António Félix Rodrigues, Managing Director of EDA Renováveis, added: “In the Azores, in the year 2024, around 89% of the electricity fed into the grid from renewable or endogenous resources was the responsibility of EDA Renováveis. The revamping of the Ribeira Grande geothermal power plant, along with the expansion of the Pico Vermelho geothermal plant – both located on the island of São Miguel – will contribute to increasing the share of renewable energy on that island to around 60% by the end of 2026. The revamping project of the Ribeira Grande geothermal power plant is particularly challenging, as it involves the simultaneous development of various construction works co-ordinated by EDA Renováveis. These range from the dismantling of generator units to civil engineering work on the ORC platform, always in close collaboration with Exergy International.”

Today, the Azores boast significant achievements in renewable energy, with the share of RES in electricity production exceeding 35% in 2021 and 2022. The region aims to go further, targeting above 70% in the near future and full carbon neutrality by 2050. Geothermal is the most important renewable resource in the Azores, accounting for around 21% of the total regional electricity demand in 2024, despite current exploration being limited to the islands of São Miguel and Terceira. The Azores hosts three geothermal plants: two in São Miguel (10 and 12 MWe), and one 4 MWe plant by Exergy in Terceira.

For more news and technical articles from the global renewable industry, read the latest issue of Energy Global magazine.

Energy Global’s Summer 2025 issue

Dive into the latest renewable energy insights in the Summer issue of Energy Global, out now! This edition features a guest comment from Change Rebellion on the role real change management can play in the global energy sector before a regional report, which looks at energy trends and transformations across the Americas. Other key topics are also explored, including offshore support vessels, floating wind, weather analysis, and battery storage. Contributors include Ørsted, CRC Evans, Miros, Solcast, and more, so don’t miss out!

Read the article online at: https://www.energyglobal.com/other-renewables/18072025/exergy-awarded-new-contract-to-power-so-miguel-azores-island-with-geothermal-energy/