LIHI Certificate #88 - Collins Hydroelectric Project, Massachusetts
The 1,480 KW Collins project located on the Chicopee River between Ludlow and Wilbraham, MA is an example of constructive reuse of a low-head, breached mill dam. The facility uses two ESAC bulb turbines designed and built in France. The advantage of the bulb for the Collins site is that bulb require no powerhouse; controls and switchgear are located in a small building well above the river flood levels and therefore the full crest length of the dam is available to spill water in case of flood flows.
The two 750 KW full Kaplan turbines operate at a net head of 15.4 feet and are installed in bulbs which operate under computer control as a run-of-the-river hydro project. The average annual production is 5,570,000 kWh. The project was FERC exempted (p-6544) and built in 1983-1984 on an existing, abandoned dam. The installation of the new hydroelectric station enabled the site to resume energy generation that ended in the mid part of the 1900’s. The station is located on the Chicopee River, in Wilbraham and Ludlow, Massachusetts, approximately 13 miles upstream of the Chicopee River’s confluence with the Connecticut River. The project utilizes a drainage area of 682 square mile and each unit has an installed hydraulic capacity range of 100 to 598 cfs or a station hydraulic capacity range of 100 to 1196 cfs. The two hydraulic turbine generation units are located at the dam and turbine flow discharges into the plunge pool located directly downstream of the dam. The project does not bypass any portion of the Chicopee River and is required to release 332 cfs or inflow to the plunge pool located directly below the project dam. The site was hard to permit because houses were built in the flood plain upstream after the dam was breached. However, by using the existing forebay as an additional spillway on the right side of the river and also designing three 4 foot high sections of hinged flashboards that are lowered during floods, the site was approved by the local conservation commission, the state dam safety agency and by federal fish environmental agencies. For 35 years Collins has operated above its design output level and few unplanned outages. Key Benefits of Bulb Turbines Bulb turbines where both the turbine and generator are housed under the water behind the dam are ideal for this application because:
- The ESAC equipment was delivered pre-assembled and aligned in the bulb so no powerhouse is required and installation time is 20% of the conventional powerhouse,
- The bulb can be lifted in with a crane and anchored inexpensively into the dam structure without reducing the dam's crest length required to pass floods,
- The ESAC full Kaplan turbine is very efficient over the full range of flows found in the Chicopee River, operating on a float control following the discharge rates of the Red Bridge powerplant located a mile upstream.
- The 750 kW Ideal generators are American made, are compact to fit easily inside a bulb; are air cooled generators and have operated for 35 years with no special maintenance other than checking alignment.
- ESAC turbines have a gearbox so generators are 900 rpm. In 2011 Collins rigged a gearbox and generator out to install new gears and bearings.
- The hydraulically operated flashboards were replaced after 30 years with new pressure treated wood and geo-textile liners on the upstream side.
- The dam has an extension with static flashboards that bend over in case of flooding, while the hydraulic boards are lowered during a flood. Collins would like to move the hinged boards to the side dam and install flap gates on the crest of the gravity dam.
|LIHI Certificate No.||88|
|LIHI Certificate Term||March 3, 2017 - March 3, 2025|
|Owner||Dichotomy Collins Hydro LLC|
|Location||Located on river mile 12.8 from the confluence of the Chicopee River and the Connecticut River in Wilbraham and Ludlow, Massachusetts.|
|Installed Capacity||1.3 MW|
|Average Annual Generation||5,265 MWh|
|FERC No.||P-6544 exempt 1984|