The use scenarios of run-of-river units in hydropower stations (without regulating reservoirs, directly using natural flow in rivers to generate electricity) mainly depend on their technical characteristics and natural conditions. The following are typical application scenarios and advantages and disadvantages analysis:
I. Applicable scenarios
1. Areas with stable river flow and small seasonal fluctuations
Scenario examples:
Small and medium-sized rivers in mountainous areas: such as small tributaries in southwest my country, with relatively stable flow throughout the year.
Tropical/subtropical basins with uniform rainfall: such as some rivers in Southeast Asia with abundant rainfall all year round.
Advantages: No reservoir regulation is required, direct use of natural runoff for power generation, low construction cost.
2. River sections with steep terrain and concentrated drop
Scenario examples:
Canyon or waterfall areas: Concentrate water head through short diversion channels or pressure pipes (such as some tributaries of the Nujiang River in Yunnan).
Advantages: Use natural terrain to achieve high water head (>50 meters) and improve power generation efficiency.
3. Distributed energy supplement or power supply in remote areas
Scenario examples:
Microgrids in remote mountainous areas: such as the small runoff power station in Medog County, Tibet, which supplies power to isolated villages.
Industrial self-provided power supply: Provide low-cost electricity for mines, forest farms, etc.
Advantages: Small installed capacity (usually <10MW), suitable for decentralized development.
4. Ecologically sensitive areas or areas where reservoir construction is restricted
Scenario examples:
National parks or protected areas: such as the small runoff power station in Yellowstone Park in the United States, to avoid damaging the landscape.
Suburban rivers: such as the micro runoff power station in Tama River, Tokyo, Japan, to reduce land flooding.
Advantages: Little interference with the ecological environment, no need for resettlement.
II. Inapplicable scenarios
1. Rivers with drastic seasonal fluctuations in flow
Problems:
Power generation drops sharply in the dry season (such as some sections of the middle reaches of the Yellow River, where the annual flow fluctuation exceeds 80%).
In the rainy season, the equipment may be shut down due to floods, and it is easy to be damaged.
2. Power grids that require peak load regulation or stable power supply
Problem:
The output of run-of-river power stations fluctuates with flow and cannot participate in grid peak load regulation (e.g., the southern German power grid has a high proportion of run-of-river power and needs to rely on thermal power/energy storage balance).
3. Plain rivers with low head and large flow
Problem:
When the head is insufficient (<10 meters), the efficiency of the unit decreases significantly (e.g., some sections of the middle and lower reaches of the Yangtze River are more suitable for building cross-flow units).
III. Comparison of typical cases
Project Installed capacity Head (meters) Applicability analysis
A run-of-river power station in the Red River, Yunnan 2×5MW 120 Canyon terrain, stable flow, and annual utilization hours of 4,500.
Zhejiang Tianmu Mountain Micro Hydropower 0.3MW 25 Uniform rainfall, power supply for scenic spots, and little ecological impact.
Indian Ganges tributary power station 10MW 50 The power generation in the dry season is only 30% of that in the rainy season, which is poor in economic efficiency.
4. Technical optimization direction
Intelligent prediction and dispatch
Predict flow through hydrological big data and dynamically adjust unit operation (such as the Norwegian runoff power station connected to the Nordic power grid real-time trading system).
Unit adaptability improvement
Develop a propeller turbine with a wide head/flow adaptability range (such as the Matrix™ technology of Andritz, Austria).
Hybrid energy complementarity
Combined with photovoltaic/energy storage to make up for the gap in the dry season (such as the "hydro-photovoltaic complementarity" project in the Andes Mountains of Peru).
5. Summary
The core value of runoff hydropower stations lies in low-cost development and eco-friendliness, but they need to strictly match natural conditions. Its ideal scenario is:
✅ Small and medium rivers + stable flow + concentrated drop + decentralized power supply demand
If large-scale stable power supply or participation in grid peak regulation is required, a water storage power station or pumped storage power station with a regulating reservoir should be selected.
