Alameda Municipal Power Hydroelectric Power Tour


I live in Alameda, California, and through a series of blog posts, I chronicled some energy improvements that I made to my home:

One of the other things that I did was that I signed up for Alameda Green. Though I pay a few dollars more for the electricity that I consume, the energy is obtained from renewable sources.

Alameda Municipal Power (AMP), our community-owned utility, turned 130 years old this year. To celebrate Public Power Week, which is held during the first week of October, as an Alameda Green customer, I was invited to take a behind-the-scenes tour of Alameda Municipal Power's hydropower plant on Tuesday, October 3, 2017. The tour provided me with an inside look at the Collierville Power Plant and McKays Dam, near Murphys, California.


When you flip a switch, and a light goes on, do you ever wonder how that happens? Well, this tour helped me find out that and more. I am was among 60 Alamedans on the tour. We had 2 busses with about 30 people on each one. I was on the bus with Rebecca Irwin, Assistant General Manager — Customer Resources at AMP. As we traveled, Rebecca shared some facts about AMP:

  • As a city-owned power company serving 78,000 customers, AMP is too small to have its own power producing facilities. There are 22 public power companies in Northern California. Some of these companies have pooled their resources to form a non-profit, the Northern California Power Agency (NCPA), that owns and operates power producing resources (like dams and power plants) where the costs and energy produced are shared among the members. The costs and resulting power are shared based on the percentage that each NCPA member company elects to contribute to a particular project.

  • AMP gets its power from:

    • Geothermal (geysers)
    • Landfill (methane gas emanated from decomposing trash)
    • Large hydro and small hydro
    • Wind
    • Purchased from the energy market (often coming from natural gas)

    There is currently no solar, but AMP is currently working with the Alameda Unified School District to place solar panels on the tops of their school buildings. Today, the vast majority of AMP's energy is carbon-neutral. In addition, AMP's Alameda Green Program has earned two "Top 10" national rankings.

Here's how the McKays Dam and the Collierville Power Plant work together to produce electricity:

  • The McKays Dam is located at an elevation of 3,370 feet above sea level. It forms a small water reservoir from the north fork of the Stanislaus River.
  • The Collierville Power Plant is located at an elevation of 1,086 feet above sea level. It has two generators that are powered by spinning turbines.
  • The dam's reservoir is connected to the power plant by an underground tunnel. Since the dam is at a higher elevation (a 2,300-foot difference), gravity performs its magic, and water flows down the tunnel, hits the turbine blades that turn a shaft that is connected to a generator, and the spinning magnets of the generator produce electricity.

Water and gravity are resources that don't pollute the environment.

McKays Dam:

  • Dam


    The curved, double-shelled dam forms a small reservoir of 2,065-acre-feet. Water is allowed to pass through the dam (flow pictured at the bottom) to nourish vegetation and wildlife that still depend on the river.

  • Tunnel Entrance (supplies water to the power plant)

    Tunnel entrance 2

    The tunnel entrance goes down 100 feet. The tunnel is 38,544 feet long and 18 feet in diameter.

Collierville Power Plant:

  • Crane


    The power plant includes a 172-ton crane (max lifting capacity) that is necessary to move heavy machinery. Other power plants have to bring in cranes as needed.

  • Generator Top

    Generator top

    This is the cap atop the shaft of the generator.

  • Generator Shaft (what's below that gray structure in the previous picture)


    The shaft of the generator spins at 450 rpms. The speed remains constant, and the torque is varied to produce more or less power based on consumer demand, pricing, and safety factors.

  • Turbine (spare pictured below)


    Water flows at 600 ft3/second to turn each turbine. Weighing 4,000 pounds, and created as a single cast, each blade must be perfect, or the turbine would be off balance. Each generator shaft (previous picture) has one turbine attached at its base.

  • Transformer


    The plant has two active transformers, one per generator, that connect the generated power (carried in those gray tubes) to the grid. There is also a backup transformer.

  • Control Room

    Control room

    Though the control room looks very retro, as a plant built in the 1980's, it is one of the more modern facilities. The system outputs 565,500,000 kWh of power annually — enough power for 52,000 homes.

  • Color-coded Pipes


    Yellow pipes carry oil to lubricate the machinery, and blue pipes carry water to keep everything cool.

  • Machine Shop


    The plant has its own machine shop so parts can be repaired on site. Many employees are part problem-solver, mechanic, and electrician all in one.

  • Microwave Transmission Towers


    The power plant has a staff of only 15. Employees are on site during the week and take turns being on-call 24/7. Even without employees present, system status is continuously transmitted via microwaves to monitoring staff at other locations.

  • Connecting Canal


    The water is not treated or affected by the process. After turning the turbine, it is released by the plant and flows downstream to connect back to the river.

This walking tour was a great way to see first-hand how clean and renewable hydroelectric power is transformed into our electricity. Thanks, AMP.

Electricity is alive in the lab.