September 28, 2010 Anna Zaklikowski, PE Brian Hemphill, PE HDR Engineering, Portland, OR
1. Micro Hydro- Turbine Tutorial 2. Evaluation Approach for Estimating Annual Energy Recovery 3. Impacts from Variabilities and D/S Flow Control
Basic Concept Energy Recovery in Water Distribution Systems Pressure from sources is too high and must be reduced Typically done with pressure reducing valves (PRVs) By using a turbine, part of energy is converted to power Power Output (kw) = (Flow, gpm)(tdh, ft)(0.746 kw/hp)(100)(eff) 3,960
Case Study: TVWD Center St. Generator Station Identify energy recovery opportunities Evaluate alternatives for retrofit or replacement of existing turbine Determine annual energy recovery and project payback periods Sustainability evaluation (CO 2 emission offset)
Center St. Generator Station
TVWD Distribution System Center St. Generator Station
Center St. Generator Station Worthington Turbine (112 kw) Generator 14 BFV
Evaluation Approach Identify evaluation period and future system changes Develop hourly flow & pressure projections for evaluation period Capture diurnal and seasonal variabilities Future system growth and changes Calculate generator kw for each hour during evaluation period Determine project cost and construction/retrofit feasibility for alternatives Compare alternatives: Determine project payback period (assume $0.05/kWh) Calculate carbon offset for each alternative (1 kwh = 1 lb CO2)
Center St. Generator Station - Pressure vs. Flow 50 Generator Station Pressure Drop, psi 45 40 35 30 25 Existing turbine H/Q (Estimated) Pressure too low to run turbine Center St Data Turbine curve 20 0 2,000 4,000 6,000 8,000 10,000 12,000 14,000 16,000 18,000 Net Generator Station Flow & Turbine Flow, gpm
Center St. Generator Station - Pressure vs. Flow 50 45 Generator Station Pressure Drop, psi 40 35 30 25 Available pressure converted to energy Pressure too low to run turbine Bypass needed in this area Center St Data Turbine curve 20 0 2,000 4,000 6,000 8,000 10,000 12,000 14,000 16,000 18,000 Net Generator Station Flow & Turbine Flow, gpm
Center St. Generator Station - Pressure vs. Flow 50 45 Flow too low; need PRV to use turbine Generator Station Pressure Drop, psi 40 35 30 25 Available pressure converted to energy Center St Data Turbine curve Pressure too low to run turbine Bypass needed in this area 20 0 2,000 4,000 6,000 8,000 10,000 12,000 14,000 16,000 18,000 Net Generator Station Flow & Turbine Flow, gpm
Center St. Generator Station - Pressure vs. Flow Generator Station Pressure Drop, psi 60 55 50 45 40 35 30 25 15 68 112 Center St Data Turbine curve Turbine kw 120 100 80 60 40 20 Turbine Power (kw) 20 0 2,000 4,000 6,000 8,000 10,000 12,000 14,000 16,000 18,000 0 Net Generator Station Flow & Turbine Flow, gpm
Analysis Approach: Center St Generator Station Calculate hourly kw through 2016 Identify and evaluate alternatives: Existing 112 kw turbine (baseline scenario) Existing turbine with D/S PRV Replacement of existing turbine with Cornell 44, 50, 83, and 96 kw turbines (w/ and w/o D/S PRV)
Center St. PRV Station Flow and Pressure 25,000 100 Generator Station Flow (gpm) Generator Station Pressure Drop (psi) Generator Station kw Summer: High flows; lower pressure 90 20,000 80 Generator Station Flow (gpm) 15,000 10,000 70 60 50 40 30 dpressure (psi) Power (kw) 5,000 20 10 0 J F M A M J J A S O N D Month -
Center St. Flow and Pressure Projections 8 7.9 Average Pressure Drop 42 41.8 7.8 41.6 7.7 41.4 Flow (mgd) 7.6 7.5 7.4 7.3 Average Flow 41.2 41 40.8 40.6 Pressure Drop (psi) 7.2 40.4 7.1 40.2 7 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 40
Alternative 3: 6TR2 (50kW) Alternative 5: 10TR2 (83kW) Alternative 2: 6TR1 (96kW) Alternative 4: 5TR1A (44kW)
Station Pressure Drop (psi) 80 70 60 50 40 30 20 10 0 Center St. Turbine Alternatives 0 5,000 10,000 15,000 20,000 25,000 Flow (gpm) Existing Turbine Cornell Turbine 6TR1 Cornell Turbine 6TR2 Cornell Turbine 5TR1A Cornell Turbine 10TR2 2007 Data 2016 Data
Center St. Evaluation Results 2,500 no D/S PRV w/ D/S PRV Energy Recovery (MWh) 2009-2016 2,000 1,500 1,000 500 810 1,680 1,390 1,800 1,320 1,760 1,390 1,590 1,290 1,720 0 1) Existing Turbine 2) Cornell Turbine 6 TR1 3) Cornell Turbine 6 TR2 4) Cornell Turbine 5 TR1A 5) Cornell Turbine 10 TR2 Flow control D/S of turbine was found have major impact on energy recovery results
120 100 Center St Generator Station Modeled Generator kw: Existing Turbine (no PRV) Theoretical (Modeled) kw Actual kw Generator Station Flow (gpm) 2007 Energy Recovery: 28,500 kwh (~$1,430) 25,000 20,000 Power (kw) 80 60 40 20 15,000 10,000 5,000 Flow (gpm) 0 J F M A M J J A S O N D Estimated 2009-16 Energy Recovery: 810 MWh (~$40,000 or ~$5,700/yr) 0
120 100 Center St Generator Station Modeled Generator kw: Existing Turbine (w/prv) Theoretical (Modeled) kw Actual kw Generator Station Flow (gpm) 25,000 20,000 Power (kw) 80 60 40 20 15,000 10,000 5,000 Flow (gpm) 0 J F M A M J J A S O N D Estimated 2009-16 Energy Recovery: 1680 MWh (~$84,000 or ~$12,000/yr) 0
Recommendations for Center St Worthington Turbine (112 kw) Generator Flow control is more beneficial than replacement of the existing turbine Modify existing D/S 14 BFV and integrate with SCADA for automatic remote modulation/throttling of flow 14 BFV
Turbine Evaluation Sensitivity 2007 Estimated Energy Recovery (MWh) 600 500 400 300 200 100 Hourly Calculation Approach Average Flow and Pressure Approach 0 Existing 112 kw Turbine w/prv Cornell Turbine 6TR1 w/prv Cornell Turbine 6TR2 w/prv Cornell Turbine 5TR1A w/prv Cornell Turbine 10TR2 w/prv Considering diurnal and seasonal variabilities significantly impacts outcome of energy recovery estimates
Acknowledgments TVWD: Ryan Smith, Troy Van Roekel, Cheryl Welch, Mark Knudson Energy Trust of Oregon Contact Information: Anna.Zaklikowski@hdrinc.com 503-423-3822