Insight into Energy Savings at Your WWTP: The Good, the Bad, and the Ugly

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1 Fishbeck, Thompson, Carr & Huber, Inc. Insight into Energy Savings at Your WWTP: The Good, the Bad, and the Ugly John Eberly, P.E. and Erin Szczegielniak, P.E. Fishbeck, Thompson, Carr and Huber, Inc.

2 Overview: Introduction Resources for beginners Case studies Energy audits Cost/benefit analysis Impact of electric rates

3 Introduction: Why are we here? Energy and sustainability drivers WWTP: cost drivers ($$$)

4 Introduction: Why does it matter? Utility vs. general fund Enterprise fund users pay fees General fund taxes are levied Why not just pass the costs on?

5 Introduction: Where it makes a difference Michigan populations are shrinking. Water and sewer Aging plants will require capital. Energy costs rising. City initiatives: cut costs 10 to 20% Energy savings interest us all.

6 Resources for Beginners WE&T articles: July 2011 Energy sense What you know can save you Powerful predictions December 2011 Small changes add up to big savings

7 Resources for Beginners Energy Star Portfolio Manager Department of Energy Best practices, recognition, free tools Benchmarking and comparison Water/wastewater utilities NEW

8 Resources for Beginners

9 Improvement - What s the Process? Benchmarking Facility audit Process audit Retro-commissioning O&M (operations and maintenance) ECM (energy conservation measures)

10 So You re Serious About Saving Energy: Energy audits Generate ideas Cost/benefit analysis What s right for your WWTP? Electric rates How it makes a difference

11 Energy Audits: What is Your Focus? Energy audit: broad look at the whole system Reasons: Electricity or fossil fuel reduction Grant conditions Operations costs Long-term planning efficiency

12 Audit Levels ASHRAE Level I Benchmarking, walkthrough, observations ASHRAE Level II Adds deeper analysis Process audit Delves into treatment

13 ASHRAE Audits The Usual Suspects Lighting Retrofits Controls HVAC Upgrades Controls Envelope Insulation Sealing

14 Energy Audit: Example Community-wide system Equipment locations: Water lift stations Retention treatment basins Occupied/equipment locations: Wastewater pump stations WWTP Occupied locations: Water system office Maintenance building

15 Energy Audit: Example Equipment locations: Operations: Adding elevated storage tank DO (dissolved oxygen) control of aeration tanks Large equipment, high run times: Premium efficiency motors VFDs (variable frequency drives) Pump efficiency design curve vs. operation

16 Energy Audit: Example Occupied locations: Light bulbs Incandescent to CFLs, fluorescent T-12 to T-8 Occupancy sensors Repairing exterior doors Heating: High-efficiency furnaces Replace gas-fired hot water boiler

17 Energy Audits: Lessons: There are always opportunities. An estimate, not a guarantee. Starting place sometimes need more information.

18 Cost/Benefit Analysis: Good Idea, Bad Idea? Closer consideration How to tell what s right for: Your plant Your staff Your community Further investigation

19 Cost/Benefit Analysis: Example Equipment replacement = opportunity for new technology Ex. Aeration: coarse bubble diffusers Considering: fine bubble diffusers (+) More efficient air transfer (+) Lower blower horsepower (-) More maintenance

20 Capital costs: Cost/Benefit Analysis: What You Need to Know Make a fair assessment. Would these need to be replaced soon anyway? Look at ancillary costs. Do existing systems work with the new technology?

21 Cost/Benefit Analysis: What You Need to Know Maintenance costs: Hidden costs? Staff availability? Funding Return on investment: what s the acceptable risk?

22 Cost/Benefit Analysis: Example Result: Kept existing coarse bubble diffusers Return on investment too high. High capital investment and maintenance. Still an estimate.

23 Cost/Benefit Analysis: Lessons: Each plant has site-specific needs and considerations. Energy is one of many cost factors. What s wrong for Plant A, may be right for Plant B.

24 Electric Rates: Look at Your Assumptions Equipment replacement may look good on paper. Preliminary estimates use a flat rate: $ /kWh Reality: most WWTPs have a tiered rate structure that can change the results.

25 Electric Rates: Example Plant A pays $22,500/month for 230,000 kwh Average cost: $0.096/kWh Equipment Change: Estimating 20% Energy savings (46,000 kwh/month) HOW MUCH $$ WILL THEY SAVE?

26 Electric Rates: Example Electric Bill (simplified) break down Charges Rate ($/kwh) Cost Access Fees $6,700 First 50,000 kwh $0.10 $5,000 Next 180,000 kwh $0.06 $10,800 TOTAL $22,500

27 Electric Rates: Example 20% savings (46,000 kwh): All at $0.06/kWh Charges Rate ($/kwh) Cost Access Fees $6,700 First 50,000 kwh $0.10 $5,000 Next 180,000 kwh $0.06 $10,800 TOTAL $22,500

28 Electric Rates: Example Plant A reduces energy use by 20%: Only 7.3% Cost Savings 550,000 kwh /year Rate ($/kwh) Annual Savings Estimated $0.096 $52,800 Actual $0.060 $33,000 DIFFERENCE $19,800

29 Electric Rates: Know Your Assumptions Not all bad: Still saving $33,000 per year. Lesson: If you need precise estimates, use precise assumptions.

30 Electric Rates: Know Your Assumptions Communication is key. Talk to your engineer or other energy assessor. Make sure they understand the realities of your facility.

31 Energy Savings: What Did We Learn? What s best for YOUR PLANT isn t always obvious. There are different tools available to help. Energy audits Cost/benefit analysis Risk-appropriate assumptions Good communication

32 Questions? Erin Szczegielniak John Eberly Happy Savings!

Establishing a Baseline, Energy Audits and Energy Star s Portfolio Manager

Establishing a Baseline, Energy Audits and Energy Star s Portfolio Manager Glenn Barnes Environmental Finance Center University of North Carolina at Chapel Hill 919-962-2789 glennbarnes@sog.unc.edu Energy