muddy run pumped storage project (ferc no. 2355) - Exelon ...

MUDDY RUN PUMPED STORAGE PROJECT (FERC NO. 2355)
EXHIBIT B-PROJECT OPERATION AND RESOURCE UTILIZATION
During mean flow years, flow issues do not typically arise at the Project, as there are sufficient flows to
maintain the total usable volume of water for Project operations and to provide flows downstream of
Conowingo Dam. During a high-flow year, the Project will also have sufficient water available to
maintain the total usable volume in the system, while also passing higher levels of flow downstream.
However, during extreme high-flow events, Project operations could be impacted by having excess water
in the system. Exelon typically adjusts operations to reduce the levels in the upper reservoir prior to high
Susquehanna River flow conditions. This allows the upper reservoir to be re-filled during high flow
periods and possibly reduce spill conditions at Conowingo Dam. Extended periods of high flow
conditions (potential spill situation at Conowingo Dam) could reduce the generation at the Muddy Run
Project when Conowingo Pond is at or near full pond conditions, in order to reduce spill over the
Conowingo Dam.
During adverse water years, with limited inflow, the water management for the Project will require
adjustments in the generation cycle. The most typical occurrence is a reduction in the total usable volume
of water available for Project operations. The extent of the adjustments in flow and the volume of water
retained in the Muddy Run Power Reservoir and Conowingo Pond will depend upon the level of low flow
experienced, as well as the length of time of the adverse low-flow conditions. Maintaining the licensed
Conowingo Pond levels and minimum flow requirements below Conowingo Dam are the primary factors
affecting the total usable volume of water.
1.5 Lower Susquehanna River Operations Model
Exelon developed an operations model to better understand how operational changes at the lower
Susquehanna River’s four hydroelectric facilities (Safe Harbor, Holtwood, Muddy Run, and Conowingo)
affect the timing of river flows and energy generation. The model takes into account each Project’s
engineering data and operational constraints, such as Conowingo’s minimum flow requirements. The
model outputs include hourly flow, pond elevations, and generation from the lower Susquehanna River’s
four hydroelectric projects.
The model calibration procedure involved adjusting several model parameters and constraints to match
historic (2004-2007) Project data (flow, stage, generation), and then using the parameters and constraints
from the final calibrated model to predict Project operations over a longer-term period (1930-2007) to
establish a “Baseline” model.
B-3