Work

Optimizing pumped hydro and hydrogen storage for water-dependent renewable systems

Year: 2026

Type: article

Abstract: Brazil’s electricity sector is undergoing a profound transformation as the share of intermittent renewables, such as wind and solar, continues to grow. While the country benefits from abundant renewable resources and a historically hydro-dominated grid, this configuration is increasingly challenged by seasonal water variability, rising curtailments, and the need to phase out fossil-based backup generation. Addressing these challenges requires the deployment of long-duration energy storage technologies that can provide reliability, flexibility, and resilience at the system level.For the first time in the Brazilian context, this study proposes a long-term optimization framework to assess the role of Pumped Hydro Storage (PHS) and Hydrogen (H₂) in enabling a cost-effective and sustainable expansion of Brazil’s power system. The model spans a 25-year planning horizon (2026–2050) with monthly resolution, capturing hydrological cycles, renewable expansion, storage deployment, hydrogen exports, and fossil imports. Decision variables include renewable capacity additions, the siting and adoption of PHS plants, and modular deployment of H₂ electrolysis and re-electrification units. The formulation incorporates round-trip efficiencies, investment and operating costs, CO₂ emissions with a carbon price, and penalties for curtailment, thereby ensuring an integrated assessment of technical, economic, and environmental trade-offs.The results highlight distinct but complementary contributions of PHS and H₂. PHS consistently delivers higher round-trip efficiency and cost-effectiveness, confirming its role as a mature and reliable backbone for renewable integration. Hydrogen, in turn, offers strategic systemic flexibility, particularly under high-renewable penetration, enabling surplus absorption and export opportunities. The combined adoption of PHS, H₂, renewable expansion, and hydrogen exports (Scenario 7) produced the lowest overall system cost, reducing expenditures by almost 30% relative to the baseline. Importantly, the Fossil-Free scenario demonstrated the feasibility of eliminating fossil imports during the final five years of the horizon, ensuring supply autonomy and reinforcing a credible decarbonization pathway, albeit at a higher cost.Overall, this research shows that Brazil’s unique renewable potential, when strategically combined with PHS and H₂, can support a resilient, low-carbon, and economically viable power system. The framework and findings provide actionable insights for policymakers and system operators, highlighting the necessity of integrated planning that balances economic competitiveness, energy security, and climate credibility in the transition toward a fossil-free future.

Source: Energy Nexus

DOI: 10.1016/j.nexus.2026.100634

Authors: Claudinei de Moura Altea, Jurandir Itizo Yanagihara

Institution: Universidade de São Paulo

Language: English

Topic: Integrated Energy Systems Optimization

Subfield: Electrical and Electronic Engineering

Field: Engineering

Domain: Physical Sciences

SDGs: Affordable and clean energy, Industry, innovation and infrastructure, Climate action

Open Access status: gold

Estimated APC paid: $2,200