The benefits of hydropower

What is hydropower?

Hydropower converts the kinetic and potential energy of moving water into electricity. Three common types are:

Run-of-river

Uses natural river flow with limited storage; delivers low-carbon, near-baseload renewable electricity.

Reservoir hydropower

Stores water behind a dam, enabling dispatchable renewable energy and seasonal shifting.

Pumped storage hydropower (PSH)

Moves water between two reservoirs to store energy, acting like a giant, long-duration battery.

Across these forms, hydropower benefits include high round-trip efficiency (especially for PSH), rapid ramping, and grid services few other resources can match.

Key benefits of hydropower for clean power systems

• Low lifecycle emissions: hydropower produces very low greenhouse gases per kilowatt-hour compared with fossil fuels, supporting net-zero targets.

• Baseload and peaking in one asset: reservoir plants can run steadily or ramp on demand, providing both energy and capacity.

• High efficiency and long life: modern turbines and well-maintained civil works can operate efficiently for 50–100 years, spreading capex over decades and delivering low levelised cost of electricity (LCOE).

• System services: inertia, frequency regulation, spinning reserve, voltage support, and black-start capability help stabilise the grid, especially during disturbances.

• Scalable storage: PSH provides multi-hour to multi-day storage at large scale, reducing reliance on gas peakers and lowering overall system costs.

These advantages of hydropower position it as a backbone technology in high-renewables portfolios.

Grid reliability and energy storage

As variable renewables grow, grids need flexible, dispatchable resources. Hydropower shines in three ways:

1. Fast ramping and regulation: Turbines adjust output in seconds to follow demand and renewable swings, improving grid stability.

2. Curtailment reduction: PSH absorbs excess wind and solar generation that would otherwise be curtailed, then releases it during peaks—boosting renewable integration and capture prices.

3. Resource adequacy: Reservoir hydropower contributes dependable capacity for stressful hours and seasons, supporting energy security during cold snaps, heat waves, or droughts (with prudent water management).

In plain terms, hydropower is both the seatbelt and the shock absorber of a clean power system.

Economic and community benefits

Beyond electrons, the benefits of hydropower extend across local and national economies:

• Jobs and supply chains: construction, operations, maintenance, and refurbishment create sustained, skilled employment in engineering, civil works, and environmental services.

• Long asset lifespans: dams, penstocks, and powerhouse structures last generations; turbine upgrades and digital controls can lift output without new civil footprints.

• Lower system costs: flexible hydropower reduces the need for expensive peakers and grid reinforcements, helping moderate retail prices over time.

• Regional development: access roads, communications, and power lines often improve local infrastructure and investment prospects.

Because hydropower can be refurbished instead of rebuilt from scratch, it offers a pragmatic path to durable value.

Environmental benefits and considerations

Hydropower’s environmental benefits include low operational emissions, avoided air pollution, and potential support for river basin management. Yet it must be developed responsibly:

• Fish and aquatic ecosystems: migration barriers and altered flow regimes require mitigation (fish passes, nature-like bypass channels, environmental flows, and turbine design improvements).

• Sediment transport: trapping sediment can affect downstream habitats and reservoir capacity; controlled flushing and adaptive sediment management help.

• Water quality and temperature: selective withdrawal structures and environmental releases can protect aquatic life.

• Land and cultural impacts: careful siting, community consultation, and benefit-sharing programs are essential.

With modern planning standards and continuous monitoring, many impacts can be minimized while preserving the advantages of hydropower for climate and reliability.

Co-benefits: water, agriculture and resilience

Reservoir hydropower can deliver critical non-energy benefits:

• Flood control: managed storage reduces downstream flood risk and improves climate resilience.

• Irrigation and drinking water: multi-purpose reservoirs support agriculture and potable supply, especially in water-stressed regions.

• Recreation and tourism: reservoirs may create local amenities that bolster rural economies.

When coordinated through integrated water resources management (IWRM), these co-benefits compound the overall benefits of hydropower.

Use cases across regions and sectors

Hydropower adds value in diverse contexts:

• Mountain and Nordic systems: reservoir and PSH smooth seasonal swings, support interconnectors, and anchor ancillary services.

• Islanded and remote grids: small hydro and run-of-river reduce diesel dependence and fuel imports, improving energy security and air quality.

• Interconnected continents: large hydro fleets act as balancing hubs for cross-border wind and solar flows, cutting curtailment and volatility.

• Industrial zones and data centres: firm, low-carbon electricity from hydropower supports 24/7 clean energy matching and on-site backup strategies.

Wherever variability and reliability collide, hydropower is a proven stabiliser.

How to maximise the benefits of hydropower

To fully realise hydropower benefits while protecting ecosystems and communities, focus on five actions:

1. Prioritise refurbishment and uprates: modernise existing plants (digital monitoring, turbine upgrades, efficiency gains) before building new dams.

2. Expand pumped storage hydropower: site PSH strategically to soak up surplus renewables and relieve congested corridors, with environmental safeguards.

3. Adopt nature-positive design: bake in fish passage, environmental flows, habitat restoration, and sediment management from the concept stage.

4. Digitise operations: use advanced forecasting (hydrology, inflows, markets) and AI-assisted dispatch to optimise revenues and reduce spill/cycling.

5. Strengthen governance and community benefits: transparent stakeholder engagement, fair resettlement (when required), and long-term local investment build durable social license.

These steps preserve hydropower’s advantages while aligning projects with modern sustainability expectations.

Hydropower can be the backbone of clean, reliable, affordable high renewables grids. With low lifecycle emissions, century scale lives, and the ability to run steady or ramp fast, it bridges variability and demand. Pumped storage adds multi hour to multi day flexibility, cutting curtailment, easing peak prices, and reducing fossil peakers.

To unlock full value, apply modern standards: nature positive design, sediment and flow management, and transparent community benefits. Priorities are to refurbish and uprate existing plants, strategically add pumped storage, digitise operations, and strengthen governance, so hydropower remains the seatbelt and shock absorber of the transition, stabilising grids, enabling 24/7 decarbonisation, and delivering durable benefits for people and ecosystems.