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Lawrence Hydroelectric Project


Project Name: Lawrence Hydroelectric
Project Companies
: Lawrence Hydroelectric Associates, Inc. and Essex Company
Project Location: Lawrence, Massachusetts
Project Region
: Northeast
River Name
: Merrimack River
Project Capacity: 14.3 MW
Start of Operations
: July 1981
Number of Units
: 2 total

The Lawrence Project is a 16.8 megawatt hydropower facility that produces enough electricity to power roughly 7,000 average New England homes each year. The Lawrence Project, on Massachusetts' Merrimack River, was developed in 1981 and acquired in 1986 by Enel subsidiaries. Subsidiaries of Enel Green Power North America operate and maintain the project in connection with the 24-MW Boott Hydropower Project in Lowell, Massachusetts, also on the Merrimack River. After acquiring the project, Enel improved the project through such measures as replacement and upgrading of trashracks, automation, automatic pond level control, and redesign of the intake. A hallmark of the Lawrence Project is the management of a complex fish passage system which is part of a regional salmon restoration program.


Power from water has a long and distinguished history in Lawrence. It was in the mid 1800's when, influenced by the success enjoyed by Lowell some 11 miles upstream, a group of local entrepreneurs set out to once again harness the power of the Merrimack River. The project attracted a group of Boston investors who visited Bodwells Falls on the Merrimack in 1845 to find the site surrounded by farmland and woodlots. With a drop of only five feet, it became clear that a dam of impressive, perhaps even unprecedented, size would be required to raise the fall of the river to a usable height of 30 feet. Undeterred, Abbott and Samuel Lawrence, Nathan Appleton, Charles Storrow, and the other founders of the Essex Company, set out to create a "New City on the Merrimack."

The heart of the venture was the construction of the Great Stone Dam. After much study, Storrow settled on a slightly arched, masonry gravity dam. The first stone was laid on September 19, 1845 and the final crest stone was set exactly three years later in 1848. Though many speculated about the dam's strength, nerves were calmed and Storrow's solid design and workmanship were confirmed when it withstood the fury of the great flood of 1936.

If the dam was the heart of the operation, the canals were the veins, delivering water to power the industry that eventually defined Lawrence. The North Canal was completed a few months prior to the dam and the smaller South Canal was built in 1896. The Essex Company sold water rights, known as "mill powers" to mills, used to turn turbines. The largest mills were located on the North Canal, which at its peak had a capacity from 10,000 to 13,000 horsepower. The South Canal was home to smaller mills able to use its 2,000 horsepower.

By the mid-20th century the textile industry's migration out of New England and lower-priced alternatives to mechanical water power combined to threaten the firm's well-being. A radical increase in oil prices during the 1970's made water power, this time in the form of hydroelectric power, economically attractive once again. In the mid-1970's, the Lawrence Hydroelectric Associates, a partnership intent on a major redevelopment of the Merrimack's power potential purchased controlling interest in the Essex Company. By 1979, the firm had secured private financing, reaquired water rights from mill owners and received the necessary state and federal permits to begin construction on a new $28-million power plant at the south end of the Great Stone Dam.

Without disturbing the historical Great Stone Dam, the Essex Company placed the 16.8 MW project into operation in 1981 with enough generating capacity to meet one third of the electricity needs of a city the size of Lawrence at the time.

CO2 Neutral