Northfield Mountain (hydroelectricity facility) facts for kids
Northfield Mountain is a special kind of power plant that uses water to make electricity. It's called a pumped-storage hydroelectric plant. This plant and its big water storage area (reservoir) are found on and under Northfield Mountain itself, in the towns of Erving and Northfield, Massachusetts. Today, a company called FirstLight Power Resources owns and runs this important facility.
Contents
Building Northfield Mountain
Engineers started planning the Northfield Mountain plant in October 1964. Work to prepare the site began three years later. By 1972, the plant was ready to go. It could make 1,168 megawatts (1,566,000 hp) of hydroelectric power. At that time, it was the biggest plant of its kind in the whole world! The plant was built to help balance the electricity supply. It worked with the nearby Vermont Yankee Nuclear Power Plant to make sure there was always enough power.
How Northfield Mountain Works
The Northfield Mountain power plant is built completely underground. It is located about 5.5 miles (8.9 km) (about 9 kilometers) up the Connecticut River from the Turners Falls Dam. A long part of the Connecticut River, stretching about 20 miles (32 km) (32 kilometers) north to the Vernon Dam in Vermont, acts as the plant's lower water storage area, or "reservoir."
Storing Energy with Water
The plant uses two main water storage areas:
- A lower reservoir (the Connecticut River itself).
- A man-made upper reservoir on top of the mountain.
When people don't need a lot of electricity, the plant pumps water from the lower reservoir up to the upper reservoir. It uses a special path called the Northfield Mountain Tailrace Tunnel to move the water. This is like storing energy for later.
Making Electricity with Water
When people need a lot of electricity, the plant lets the water flow downhill from the upper reservoir. This rushing water spins a machine called a turbine. The turbine then turns a generator, which makes electricity. After making power, the water collects in the lower reservoir. It waits there until it's pumped back up again. This way, the water is used over and over to create power.
Inside the Plant
Northfield Mountain's upper reservoir is very large. It covers about 300 acres (120 ha) (1.2 square kilometers). It sits 800 feet (240 m) (244 meters) above the river. This reservoir can hold a huge amount of water: 5.6 billion US gallons (21 Gl) (over 21 billion liters)!
The main power-making part of the plant is deep underground. It is 700 feet (210 m) (213 meters) below the surface. You can reach it through a 2,500-foot (760 m)-long (762-meter) tunnel. Inside, there are four huge turbines. These turbines can do two jobs:
- They can pump 15,200 cubic feet (430 m3) (430 cubic meters) of water per second up to the upper reservoir.
- They can release 20,000 cubic feet (570 m3) (566 cubic meters) of water per second to make electricity.
Together, these turbines can generate 1,143 megawatts (1,533,000 hp) of electricity. They can start making full power in just 10 minutes. They can then deliver this full power for 8 hours straight!
