1. Municipal Wastewater Treatment Preliminary Seventh Power Plan Energy Efficiency Estimates November 18, 2014 West Point Wastewater Treatment Plant, Seattle Washington

2. Municipal Wastewater Industry in the PNW  Over 1100 Plants use 140 aMW of Energy  Sixth Plan: 893 plants, 137 aMW  Processes Include  Collection  Treatment  Sludge Processing & Disposal  Discharge Picture from: Arkansas Watershed Advisory Group 2

3. The Many Factors that Affect Plant Energy Consumption  Influent Biological Oxygen Demand (BOD)  Effluent BOD  Weather/Location  MGD design capacity  MGD flow  Primary Clarifier Effectiveness  Secondary Treatment Process Type  Activated Sludge  Coarse or fine bubble aeration  Dissolved Oxygen control method  Aerated Lagoon  Dispersed Aeration or Mechanical Aeration  Varying amounts of aeration  Trickle Filter  Disinfection method (Chlorine or UV)  Tertiary Treatment Process Type  Sludge Treatment Processes  Dewatering method  Digestion  Onsite Generation (IC Engine or Micro-Turbine Using Digester Gas, Micro-Hydro at discharge, etc.) Lebanon, OR 3

4. Energy Savings Measures  Energy Savings Measures  VFDs  Upgrade to premium efficiency motors  Aeration blower control via automated dissolved oxygen monitoring  Fine bubble diffusers  Optimize pumping and blower configurations and operation/controls  Upgrade to more efficient pumps and blowers  Use hydraulic digester mixing & optimize mixing time DO Control from wateronline.com Blower from spenserturbine.com Fine Bubble Diffusters from sequencertech.com 4

5. Sixth Plan Summary  Technical Potential: 36.0 aMW (for reference, the Fifth Plan technical potential was 65 aMW)  Achievable potential at a levelized cost of $16/MWh. Achievements since Sixth Plan  From the BPA Six Going on Seven Project:  Savings = 6.07 aMW (2010 – 2012, approximately 2 aMW per year)  Well aligned with 6P ramp rates  Assume 10 aMW for 2010 - 2014 5 Achievements Since Sixth Plan

6. Energy Variables  Baseline  Number of WT facilities – EPA 2008 data (6P was 2004 data)  Treatment flow (Million Gallons per Day, MGD) – EPA 2008  Energy Consumption(Million kWh/MGD) – same as Sixth Plan  Growth – Council population forecast  Assume a 0.5% annual increase in efficiency – from Sixth Plan  EE potential (kWh/MGD) – Sixth Plan values, but adjusted for achievements:  Saturation – From BPA “Six Going on Seven” project (6 aMW 2010-2012, assume 10 aMW through 2014 6

7. Proposed Changes To Savings Sixth Plan Assumptions Sub CategoryCount Sum Capacity (MGD) Sum Flow (MGD) Avg Flow (MGD) Annual energy use/Volume (mmkWh/ MGD flow) Total Wastewater Consumption (aMW) Estimated Savings (million kWh/MGD flow) Estimated Total Savings Potential (aMW) Estimated Average Savings Rate (%) Average Facility use (kWh) Average Facility Savings (kWh) <1 MGD6781511060.162.1126 1.29 15.6 61% 330,143 201,836 1-10 MGD1765783852.20.8738 0.29 12.7 33% 1,896,714 634,355 >10 MGD401,4791,088270.5973 0.06 8.0 11% 16,172,843 1,768,800 All 8932,2081,5791.77 137 36 Proposed Seventh Plan Assumptions – Net of Accomplishments <1 MGD905205119 0.132.1129 0.96 13.1 45% 278,336 126,520 1-10 MGD210701430 2.050.8742 0.21 10.6 25% 1,770,805 440,345 >10 MGD351,3101,015 29.270.5968 0.05 5.6 8% 17,273,572 1,404,645 All1,1502,2161,565 1.36 140 29 Savings values adjusted for achievements 7

8. Cost Variables  Measure cost  Sixth Plan, adjusted for 2012$  Recent project experience and data for first-year cost - $0.41/kWh (Cascade data), $0.71/kWh (Energy Trust)  Not enough variation by size  New cost data align with the adjusted 6P costs  O&M Cost/Benefit  Used Sixth Plan values, adjusted to 2012$  Source was NYSERDA study 2006 (Detailed O&M benefits and costs for 11 sites) 8

9. Proposed Changes To Costs Sub Category Measure Cost ($/kWh) O&M and NEB's ($/kWh) Average Facility Measure Cost Average Facility Annual O&M and NEB's Measure Cost per MGD Flow O&M and NEB per MGD Flow <1 MGD $ 0.49 $ 0.03 $ 99,558 $ 5,594 $ 637,762 $ 35,837 1-10 MGD $ 0.57 $ 0.03 $ 360,276 $ 17,583 $ 164,322 $ 8,019 >10 MGD $ 0.20 $ 0.03 $ 360,838 $ 49,027 $ 13,167 $ 1,789 Sub Category Measure Cost ($/kWh) O&M and NEB's ($/kWh) Average Facility Measure Cost Average Facility Annual O&M and NEB's Measure Cost per MGD Flow O&M and NEB per MGD Flow <1 MGD $ 0.55 $ 0.031 $ 69,107 $ 3,883 $ 525,094 $ 29,506 1-10 MGD $ 0.63 $ 0.031 $ 276,938 $ 13,515 $ 135,293 $ 6,603 >10 MGD $ 0.23 $ 0.031 $ 317,311 $ 43,113 $ 10,841 $ 1,473 First Year Cost Notes: - Cascade database: $0.41/kWh (N=105) - Energy Trust: $0.71/kWh (N=21) Adjusted measure and O&M cost for 2012 dollars, from 6P 2006 dollars 9

10. Load Shape  Don’t have a good load shape for Wastewater Treatment  6P used “Flat”, but that’s not right  Currently using a refrigerated warehouse ventilation shape  Matches pretty well with monthly data from one PNW major water supply facility  No daily data available 10

11. Summary and Next Steps  Summary  Achievable potential approximately 28 aMW  Preliminary levelized costs approximately $12/MWh  We still have some data coming in; will adjust  2014 EPA data  New utility data  One more year of results from 6 Going on 7  RTF Input  Finalize with existing data or is more research needed?  Anybody have an 8760 load shape? 11