Hydropower is recognized as a key contributor to America's clean energy infrastructure. It plays a critical role in advancing our energy future as a renewable energy source. NID is dedicated to protecting and improving the environment, and hydro energy is one of the ways we do it.

Our district has been generating hydroelectric power for more than 50 years, starting with the completion of the Yuba-Bear Power Project in 1966. Today, we have a generation capacity of 82.2 megawatts, producing an average of 375 million kilowatt-hours of energy each year. There are 7 NID Hydropower plants in operation. Our hydropower facilities include 15 dams, 13 reservoirs and 20.75 miles of pipes, flumes, tunnels, and open ditch canals.

What is Hydropower?

Essentially, hydropower is energy in moving water. It is electricity produced from generators driven by turbines that convert the potential power of moving water into mechanical energy.

In terms of renewable energy sources, hydropower, or otherwise known as hydroelectric power, is one of the oldest and most extensively utilized. It currently accounts for 37% of total U.S. renewable electricity generation and about 7% of entire electricity production.

Hydropower facilities come in all sizes, like the enormous and, probably the most famous, Hoover Dam. It generates 2,000 megawatts per year! Then there are the smaller ones like NID's own Combie North plant, which produces 0.50 megawatts annually.

The History of Hydropower

The history of producing energy through moving water is thousands of years old. For example, the Egyptians used Archimedes water screws for irrigation in the third century B.C. The Greeks also utilized primitive hydropower by using water wheels for grinding wheat into flour more than 2,000 years ago. 

Modern hydropower began in the mid-1700s with the groundbreaking Architecture Hydraulique written by French hydraulic and military engineer Bernard Forest de Belidor. The four-volume text, which covered engineering mechanics, mills and waterwheels, pumps, harbors, and sea works, ushered in the hydropower turbine.

In the United States, Hydropower was used as early as the 1880s. For instance, a dynamo connected to a turbine in a flour mill provided street lighting at Niagara Falls, New York, in 1881.

How Does Hydropower Work?

The source of hydropower is water. Energy is generated by using a dam or diversion structure that alters the natural flow of a river or other body of water. Hydropower utilizes the endless, constantly recharging system of cycling water to produce electricity.

The amount of power generated depends on the volume of the water flow and the elevation change. In other words, the greater the flow of water and the higher the starting point of the fall, the more electricity a hydropower plant can produce. This amount varies each year and mainly depends on snowmelt runoff and rainfall.

In simple terms, power is generated as water flows through a pipe spinning the blades in a turbine. In turn, the turbine spins a generator, producing electricity. Most conventional hydropower plants operate this way, including the two most common - run-of-the-river systems and pumped storage systems.

Run-of-the-river systems utilize the force of the river's current to apply pressure on the turbine. The facilities often have a dam in the waterway. The dam serves to raise the water level or direct or regulate the flow.

In a pumped-storage facility, water is pumped from a water source up to a storage reservoir at a higher elevation. The water is then released from the upper reservoir to power turbines located below. This type of plant typically pumps water to storage when electricity demand, generation costs, and wholesale electricity prices are relatively low. Then the stored water is released during peak electricity demand periods to generate electricity.

Hydropower Plants are a Huge Win for NID Customers

In addition to producing clean and renewable hydropower, NID's seven plants provide significant benefits to our customers. We sell our electricity to the Pacific Gas & Electric Company (PG&E) and the Northern California Power Agency. These power sales contribute millions in revenue to offset water rates for our customers. The proceeds also cover all of the costs of upper-division water storage, conveyance, delivery, maintenance, and operations from the headwaters of the Middle and South Yuba Rivers, Bear River, Canyon Creek, and Deer Creek watersheds through NID's mid-elevation storage reservoirs of Scotts Flat, Rollins and Combie.

NID is a clean, renewable hydropower leader among northern California water agencies. Our focus is on maximizing the benefits of hydroelectric power while minimizing the impact on the environment. Please participate in the Plan for Water as we work together with the public to develop strategic options to guide our water management into the future.