Overview

The Spencer Mountain Hydropower Project was originally developed in 1905 to provide power to a nearby textile mill. Later, the project was sold to Southern Electric, which subsequently merged with Duke Power, who operated the project until 1996.

The current owners have operated the Spencer Mountain Project as a licensed hydropower plant since 2016, exporting power to Duke Energy Carolinas. At the time, Unit 1 was non-operational, and Unit 2 needed extensive restoration. Since taking ownership, SMH has completed significant capital improvements. A PLC-based control system was added in 2016, and all of the water control gates have been replaced. After receiving a license amendment in 2020, Unit 1 was replaced with a vertical shaft turbine and generator, which was commissioned for operation in January 2024.  The Unit 2 turbine was completely rebuilt and recommissioned for operation in 2026.

Project Works

Project works consist of: (a) a 12-foot-high, 636-foot-long masonry low head dam with a crest elevation of 634.7 feet msl; (b) an 8-acre reservoir with a storage capacity of 46 acre-feet (c) a 58.9-foot-long canal headwork, consisting of four 6-foot-wide gates (d) a 53.8-foot-long canal spillway connected to the downstream side of the canal headwork, (e) a 30-foot-wide, 10-foot-deep, 3,644-foot-long open earthen canal; (f) a 32-foot-wide trashrack at the powerhouse forebay; (g) a 36-inch-diameter bypass pipe; (h) a 22.5-foot-high, 49.5 -foot-long powerhouse containing two Francis-type turbines and generators; (i) a concrete lined tailrace discharging flows back into the South Fork Catawba River; (j) substation containing a 2.3/44-kV transformer and interconnection to Duke Energy’s 44kV transmission line; and related facilities.

Contact

Kevin Edwards
SMHydro@pht1.com
(336) 589-6138 (no text)

Capacity & Generation

Capacity: 640 kW total

Generating Units:
· Unit 1 – single runner Francis turbine (vertical shaft)
· Unit 2 – double-runner Francis (horizontal)

Both turbines are driving a direct connect synchronous generator

Gross Head:
26 feet at powerhouse

Average Annual Generation:
4.0 GWh (Projected, now that both units are operational)

Power Purchase Agreement:
Duke Energy Carolinas

Real Estate: 4.2 acres

FERC Project Boundary: 55.31 acres

Notes:
The Avalon and Mayo projects are located 1 mile apart in Rockingham County NC, and 15 miles from the Spray Hydropower Plant. The Spencer Mountain plant is located in Gaston County, NC.