NMHDA

Nepal Micro Hydropower Development Association (NMHDA) is a non-profit organisation established on December 11, 1992 (B.S. 2049/08/26), representing privately run companies and firms engaged in micro hydropower development across Nepal. It is the sole association of private sector stakeholders in Nepal's micro hydropower landscape and has been representing the industry for over three decades. NMHDA member companies have collectively installed over 2,500 micro hydro plants, providing electricity to tens of thousands of rural households — significantly reducing the burden on women and girls who previously spent hours collecting firewood and kerosene.

Field of Work
NMHDA promotes innovative and sustainable micro hydropower projects for rural and remote electrification. Its work spans project identification and feasibility assessment, technical design, installation, research, equipment manufacturing, and long-term maintenance. NMHDA conducts training seminars and workshops, publishes technical manuals and guidance documents, partners with AEPC and academic institutions, and organises symposiums and exhibitions to advance the sector. It advocates for private sector interests in policy dialogue and collaborates with solar and wind energy sectors on hybrid solutions.

Technologies Used by NMHDA

Micro Hydropower Plants (Up to 100 kW) — Run-of-River Schemes

Micro hydropower plants generate electricity from the flow of water in rivers and streams without the need for large dams or reservoirs. The fundamental principle is simple: water diverted from a river flows through a pipe (penstock), gaining pressure as it descends in elevation, and then strikes the blades of a turbine at the powerhouse at the bottom. The spinning turbine drives a generator that produces electricity. The water is then returned to the river downstream.

Civil components include a diversion weir (a small structure across the river that raises the water level enough to divert flow into the intake), a settling basin (where suspended sediment drops out to protect the turbine), a headrace canal or pipe conveying water to a forebay tank, the penstock (a high-pressure pipe descending to the powerhouse), and the powerhouse building itself. Electro-mechanical components include the turbine, generator, electronic load controller (ELC), and the local distribution network. For micro hydro in Nepal, Pelton turbines are used for high-head, low-flow sites (common in steep mountain streams), while crossflow (Banki-Michell) turbines are widely used for medium-head applications due to their simplicity and local manufacturability.

A key advantage of micro hydro over solar is that it generates power 24 hours a day, year-round (subject to seasonal flow variation), making it ideal for powering not just lights but also productive uses — grain mills, battery charging stations, small workshops, and water pumps. Nepal has developed a strong local manufacturing base for micro hydro electro-mechanical equipment, particularly in the Kathmandu Valley, reducing costs and enabling rapid sector growth.

Mini and Small Hydropower (100 kW – 10 MW)

NMHDA member companies also work in the mini (100 kW–1 MW) and small (1–10 MW) hydropower segments. These plants follow the same run-of-river principles as micro hydro but require larger civil structures, more sophisticated electro-mechanical equipment (synchronous generators, power transformers, automatic voltage regulators), and formal grid interconnection. They generate enough power for large towns or to export to the national grid, and are typically developed by private Independent Power Producers (IPPs) under Power Purchase Agreements (PPAs) with Nepal Electricity Authority (NEA).

Electro-Mechanical Equipment Manufacturing

Nepal has developed a notable domestic industry for micro and mini hydro electro-mechanical components, with manufacturers concentrated in Kathmandu and Butwal. NMHDA member companies produce and supply crossflow turbines, Pelton turbines, induction generators, electronic load controllers (ELCs), and balance-of-plant components. Domestic manufacturing significantly reduces costs compared to importing from India or China, and ensures that spare parts and technical expertise are available locally for long-term maintenance. NMHDA promotes and supports this manufacturing ecosystem as a critical element of Nepal's energy sovereignty.

Electronic Load Controllers (ELC)

A unique challenge in isolated micro hydro systems is frequency and voltage regulation. Unlike grid-connected systems that have a large stabilising grid to absorb fluctuations, an isolated micro hydro plant must maintain constant frequency (50 Hz) regardless of how much or how little load the village is drawing. The Electronic Load Controller solves this by automatically diverting surplus power to a "dump load" (typically an electric water heater or resistor bank) whenever village consumption drops below the plant's output, keeping the turbine spinning at a constant speed. ELCs are a Nepali innovation that has been refined and cost-optimised by local manufacturers over decades, and are now exported to micro hydro projects in other countries.

Hybrid Solar-Hydro Systems

Because micro hydro output can drop significantly during dry season (when river flows are lowest), and solar PV output is highest during the dry season's clear, sunny days, hybrid solar-hydro systems are an increasingly important configuration. The solar array supplements hydro generation during low-flow months, while the hydro plant provides reliable 24-hour baseload during the wet season when solar output is limited by cloud cover. NMHDA members design and implement these hybrid systems with shared battery banks, combined charge controllers, and integrated management systems that optimise dispatch from both sources.

🌐 microhydro.org.np | 📧 nmhdanmhda@gmail.com | 📞 +977-1-5375507
📍 Gyanodaya Marg, Kalanki, Kathmandu