A Brief History of the Morro Bay Power Plant


California’s population increase, both during and after World War II, combined with a growing economy and changes in technology, necessitated additional electrical power generation. In the San Joaquin Valley, for example, the advent of electric water pumps increased by 150% between 1946 and 1954, compared with a power system growth of 105% during the same time period. New power plants were needed to meet the demand for agriculture as well as industry. Morro Bay was chosen as the location for a new power plant, given its proximity to ocean going fuel oil tankers and an unlimited source of cooling water for the power plant’s turbine generators.

Most of the power generated at the Morro Bay plant was transmitted to the San Joaquin Valley, while a much smaller amount of power was made available for local distribution via the San Luis Obispo substation.

Plant Construction

Excavation of Morro Bay Power Plant

Excavation of Morro Bay Power Plant

Excavation for the Morro Bay steam electric plant began in October 1953 on a 140-acre site that was formerly a U.S. Navy Base during World War II. Bechtel Corporation of San Francisco was chosen as the design and construction firm for the job, and Dames and Moore were the soil scientists charged with designing the plant foundations. The plant consisted of the power building housing two 150,000 KW generators, seawater intake building, a single 450 tall stack, fuel tanks, cooling water discharge pipe, marine fuel line, and 230 KV switchyard. For each of the generating units, there was one boiler furnace 139 feet high, or the equivalent of a 14 story building. There were 43.5 miles of wire and cable in the plant and 60 miles of tubing in each boiler. The $44.3 million project was completed in July 1955; other generators and stacks were added later.

How The Plant Works

The power plant employed the first seawater evaporators used for industrial production of fresh water in the United States. The plant was powered by fuel oil, delivered via oil tanker to a 24 fuel oil supply line that extended 4, 400 feet into the ocean. The fuel oil was stored in four seven-million gallon tanks, and the plant consumed 500,000 gallons of fuel oil a day. According to the engineers, The cycle is simple: fuel to the boiler where steam is created, steam to the turbine where motion is created, and motion to the generator where electricity is created.


Morro Bay Power Plant - West

Morro Bay Power Plant – West

The scenic location and design of the new industrial facility were not lost on the engineers planning and building the plant. A 1956 article authored by Thon and Coltrin stated, “The location of the plant near the city of Morro Bay and just off Californias scenic Highway No. 1 prompted an architectural treatment which, while not obscuring the function of the structure, would be at the same time aesthetically pleasing.”

Morro Bay Power Plant - East

Morro Bay Power Plant – East

Although the climate is mild and suitable for outdoor operation, the close proximity of the plant to the ocean combined with a humid atmosphere dictated the necessity of a totally enclosed plant. A fluted aluminum siding was chosen for the walls of the power building. At the power plant dedication on July 8, 1955, one speaker said, It’s a great thing for the County to have this giant industrial plant, which is as modern as tomorrow.

The Stacks

Morro Bay Power Plant - Foundation

Morro Bay Power Plant – Foundation

One of the most prominent features of the Morro Bay power plant is the 450-foot tall smokestacks. These cylindrical structures are founded on a reinforced concrete, octagonal mat 90 feet wide and six to ten feet thick. This concrete pad is supported by 289 concrete piles of about 68 feet in length, driven into the sand and gravel soils. The inside of the first tower was lined with acid resistant brick in December 1954. The outside diameter of the tower’s base is 428 and covers 1452 square feet. The tower measures 176 at the top. The other two stacks were added in subsequent plant expansions. In a July 7, 1955 issue of the San Luis Obispo Telegram-Tribune, a special insert titled PG&E Morro Bay Steam Plan Section included the following: The Rock at Morro Bay has competition today from The Stack, a 450-foot structure that stands as a man-made California landmark atop the Pacific Gas and Electric Companys steam plant.The tower is an impressive sight to tourists traveling Highway 1.

The Generator


Morro Bay Power Plant – Brickwork

The turbine generators were made by General Electric Corporation in New York and shipped to San Luis Obispo, California via rail. At 156,250 KW they were among the largest machines installed and in operation in the U.S. in 1954. When they arrived at a special railroad siding at Camp San Luis Obispo in December 1954 they were loaded onto special tractor trailers for transport to Morro Bay. Highway 1 was closed to traffic, and the concrete roadway covered in wooden planks for the entire nine-mile distance, in order to prevent road damage from the tremendous weight of the generators and the trucks. A crew of 59 men working with crane trucks and a lumber carrier picked up and laid down the large wooden planks (measuring 20 feet long by 12 wide and 3 thick), laying them edge to edge. Each plank was moved 86 times in traversing the nine-mile stretch. The move required eight days, working around the clock. By the end of the move, the planks were reduced to kindling.

Postcard of Morro Bay Plant


    • J. George Thon, M. ASCE was the Bechtel Corporation Project Manager and Gordon L. Coltrin, A.M. ASCE was Senior Civil Engineer for PG&E. The first plant manager was B.H. Mudgett.
    • San Luis Obispo Telegram-Tribune, July 7, 1955, PG&E Morro Bay Steam, Plant Section
    • Thon, J. George and Gordon L. Coltrin, Morro Bay Steam Electric Plant, American Society of Civil Engineers Transactions Paper no. 2919 (June 1956), 207-238.
    • James C. Williams, Energy and the Making of Modern California (Akron, Ohio: University of Akron, 1997)

Historical photographs courtesy Duke Energy, Morro Bay.