Ppl Corporation · NYSE:PPL
Ppl — Technical Presentation (September 2006)
36 slides from Ppl's technical presentation, September 2006
Slide 1: Downstream Passage for American Eel
Downstream Passage for American Eel • Quick Overview of Existing Knowledge • Potential approaches at Holtwood
Slide 2: Existing Technologies for Downstream Passage
Existing Technologies for Downstream Passage • Physical • Behavioral • Operational
Slide 3: Physical Devices
Physical Devices • Close spaced trash racks and trash rack overlays at turbine intakes (punch plates, screens, wire mesh) – Usually in association with a bypass spill or a deep gate release in close proximity to the intake • Louvers or angled bar racks with a bypass at the downstream end • Laborator
Slide 4: Behavioral Devices
Behavioral Devices • Provide a stimulus – elicit a response (usually negative) • Utilize negative response to preclude eels from an area and/or to guide/direct them to a bypass • Potential deterrents – Light – Infrasound – Electrical – Water jets and air bubbles
Slide 5: Behavioral Devices cont.
Behavioral Devices cont. • Light – Variable results to date – Many years of anecdotal evidence that outmigrating eels avoid light – Some recent research provided promising results but there are no field applications at hydros • MIGROMAT – Monitors activity of captive eels, shut down powerhouse and b
Slide 6: Operational Alternatives
Operational Alternatives • Turbine passage – Survival rates in studies to date has been highly variable – Survival generally related to speed of turbine and flow • high speed low flow turbines have lower survival than low speed high flow turbines • 60% to 80% is a fairly common survival range – Surv
Slide 7: Behavior of Outmigrating Eels
Behavior of Outmigrating Eels • Seasonality – No data for Susquehanna River, Delaware might act as a segregate • No movement data near the dam but data from other studies
Slide 8: Tagged (sonic) mature outmigrating American eels
X Tagged (sonic) 162 mature outmigrating American eels X 0.8 to 1.1 m in length X Released tagged eels 20 km upstream of dam X Monitored movements remotely
Slide 9: Speed of Movement
Speed of Movement • Actively migrating eels were moving between 0.6 and 1.1 m/s (“instantaneous” velocity) while water velocities were approximately 0.2 to 0.4 m/s
Slide 10: Dive time chart
34 minutes 7 Dives EACH UNIT IS 1.7 MINUTES
Slide 11: Movement By Time of Day
Movement By Time of Day 7 75% migrated 6 through the Dam 5 area at Night DAY Number of Eels 4 3 2 1 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 Hour
Slide 12: Approach and Time at the Dam
Approach and Time at the Dam (within 100 m) • For the most part eels approached the Dam directly then passed relatively quickly • 35% passed in less than 2 minutes • 92% passed in less than 21 minutes
Slide 13: Movement Patterns
Movement Patterns • Eels don’t seem to be entrained in the classic sense, eel paths demonstrate that they swim and alter their paths in front of intakes • Most vertical and lateral movement was very near the Dam--primarily within 100 m • Flow velocities in this region are approximately 0.5 m/s (1.6
Slide 14: 300 m Upstream of Dam
300 m Upstream of Dam Current Speed m/s Moored Receiver Dam Mounted Receiver Point where eel track crosses plane 300 m upstream of Power Dam Power Dam P1 P10 Canada USA Plane 300 m Upstream of Power Dam Water Flow
Slide 15: 100 m Upstream of Dam
100 m Upstream of Dam Current Speed m/s Moored Receiver Dam Mounted Receiver Point where eel track crosses plane 100 m upstream of Power Dam Power P1 P10 USA Canada Dam Plane 100 m Upstream of Power Dam Water Flow
Slide 16: 50 m Upstream of Dam
50 m Upstream of Dam Current Speed m/s Moored Receiver Dam Mounted Receiver Point where eel track crosses plane 50 m upstream of Power Dam P1 Power Open Gates P10 Dam Canada USA Plane 50 m Upstream of Power Dam Water Flow
Slide 17: Eel Behavior at the Power Dam - Side View
Eel 87 Behavior at the Power Dam - Side View Looking Northeast
Slide 18: Avoidance of Light by Outmigrating American Eels
Avoidance of Light by Outmigrating American Eels
Slide 19: Platform Design
Platform Design Underwater Cable Approximately 600 meters in length 4,800 volts
Slide 20: Complete Platform 80 m Long
Complete Platform 80 m Long NOTE DIRECTION OF FLOW
Slide 21: Area illuminated was approximately 52 m wide x 90 m long
Area illuminated was approximately 52 m wide x 90 m long, surface to bottom
Slide 22: Experimental Design for Determining Effect
Experimental Design for Determining Effect Control Conditions (Lights Off) Treatment Conditions (Lights On) 28 nights of sampling 25 nights of sampling Blocking Blocking Net Net Treatment Deflection Treatment Deflection Net Net Net Net 1 1
Slide 23: Estimating Light Avoidance Results from Net Collections
Estimating Light Avoidance Results from Net Collections Probability an eel avoids the Treatment = Net with LIGHTS ON 77.6% with a 90% confidence interval between 65.6% and 91.7%
Slide 24: Movement Pattern of Eels – Observation Results
Movement Pattern of Eels – Observation Results Through 17 111 = 15.3% Deflected - Away 26 111 = 23.4% Deflected - Parallel 68 111 = 61.3%
Slide 25: What Is Known
WHAT IS KNOWN • Migrating eels avoid a 90 m long underwater “wall of light” set 30° to the flow in a current of approximately 0.6 m/s • Based upon netting results 77% of the eels avoided the light field • Based upon observational results 85% were able to modify their trajectory, avoiding the light f
Slide 26: What Is Not Known
WHAT IS NOT KNOWN • How changes in light intensity affect avoidance • How changes in light frequency affect avoidance • How increases in angle of the array affect avoidance • How increases or decreases in current velocity affect avoidance • Will eels become habituated as distance increases
Slide 27: What Is Not Known cont.
WHAT IS NOT KNOWN cont. NYPA study demonstrated that eels readily avoid light but it did not demonstrate that eels could be effectively guided in a large scale system
Slide 28: Potential Options for Downstream Passage at Holtwood
Potential Options for Downstream Passage at Holtwood • Turbine Passage – preferential operation of new units • Large runner – approx. 25 ft diameter • Slow rotation - 88 rpm • Four blades • Minimum gap at the hub • Large flow – approx. 15,000 cfs • Survival will likely be high – best guess 85% • Wha
Slide 29: Potential Options at Holtwood cont.
Potential Options at Holtwood cont. • Skimmer wall with behavioral deterrent (light) and a bypass
Slide 30: Plan View: New Skimmer Wall
Flow Flow 150 0 15 Plan Plan View View New New Skimmer Skimmer Wall Wall
Slide 31: Skimmer wall diversion with bypass: Pros
Potential Options at Holtwood cont. • Skimmer wall diversion with bypass • Pros • Skimmer wall is oriented approximately 15 degrees to the main river flow • All flow that goes to the turbines must pass through the skimmer wall • The top 12 ft of the water column is protected by the solid portion of
Slide 32: Skimmer wall diversion with bypass: Cons
Potential Options at Holtwood cont. • Skimmer wall diversion with bypass • Cons • Based on data from other river systems – it is likely that the entire water column will need to be protected • (800 ft long x 55 ft deep – approx. 43 ft unprotected at normal pond) • Water clarity might preclude the us
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Slide 36: What Is Not Known (Continued)
WHAT IS NOT KNOWN (Continued) •Is there a linear distance along the array where eels no longer avoid but instead pass through 90 m 200 m