Overview

The Mayo Hydropower Project was originally developed in 1896, when the dam was built to provide shaft power to the Mayo Mills textile mill located on site. The project was later modified to produce electricity, and operated until the 1960s. Redevelopment of the Mayo Hydropower Project began in the early 1990s. The Project received an FERC license in 1993, and started producing power in 2001 with Unit 1.

The current owners have owned and operated the Mayo Project as a licensed hydropower plant, exporting power to Duke Energy Carolinas, since 2002. Unit 3 was added at the dam in 2002, and Unit 2 was commissioned in the main powerhouse in 2004, completing redevelopment to the licensed capacity. The project has received ongoing capital investment and maintenance, including a modern control system installed at the main powerhouse in 2017, and a replacement turbine and generator, and updated control system at the bypass powerhouse in 2024.

Project Works

Project works consist of: 1) a concrete and stone masonry dam with a height of 13.5 feet and about 590.5 feet long (2) a 160-foot-long stone masonry headworks section equipped with intake gates and 406-foot-long uncontrolled overflow spillway (3) a reservoir with a surface area of about 11 acres, a volume of about 96 acre-feet, and a normal water surface elevation of 586.4 feet mean sea level (msl); (4) an upper powerhouse located at the dam with one generating unit (5) an earth bank power canal about 1,600 feet long, 30 to 40 feet wide, and 10 to 15 feet deep (6) a stone masonry intake structure about 20 feet high located at the lower end of the power canal; (7) two steel penstocks extending from the intake structure at the end of the power canal to the lower (main) powerhouse; (8) a lower (main) masonry powerhouse with two generating units (9) a 12.4-kilovolt (kV) transmission line extending from the lower powerhouse to a Duke Power Company transmission line; and (1) appurtenant facilities and equipment.

Contact

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

Capacity & Generation

Capacity: 950 kW total

Generating Units:
Main Powerhouse
· Unit 1 – Francis
· Unit 2 – Francis
Bypass Powerhouse
· Unit 3 – Propeller

All generating units are vertical shaft turbines driving a direct connect synchronous generator

Gross Head:
29 feet at main powerhouse

Average Annual Generation:
4.00 GWh (2016-2024)

Power Purchase Agreement:
Duke Energy Carolinas

Real Estate: 29.1 acres

Notes:
Sale of the Avalon and Mayo projects is contingent on both being sold.