Real-time energy and water quality management system designed for success!

Transcription

1 Real-time energy and water quality management system designed for success! Texas Water 2012 San Antonio, TX April 13, 2012 Manuel Perez Energy Manager Peter Martin Vice President Brian Skeens Global Technology Leader

2 Agenda 1. About El Paso Water Utilities 2. Project drivers & background 3. Feasibility study/cost benefit analysis 4. Design 5. Challenges & opportunities 6. Applicability to other utilities

3 El Paso Water Utilities Supplies water to 750,000 population 202,000 service connections Supply 4 WTP 119 wells (active) 101 MGD avg production 160 MGD max production 3

4 El Paso Water Utilities 2 conventional surface water plants 1 desalination (brackish groundwater) 1 arsenic removal plant Blended ground & surface supplies 50% supply from surface 50% from groundwater (potable & brackish) Seasonal variations Increased groundwater pumping in times of surface water shortages 4

5 El Paso Water Utilities Storage 71 storage reservoirs 190 MG 1.88 times average day 20 zones 46 booster pump stations Mix of electric and gas powered pumps Water is pumped up to 6 times from river elevation to upper system reservoirs (1,280 ft) 5

6 Project drivers & background Cost of energy $7 million annual pumping cost Second largest cost Was increasing each year Need sustainable way to maximize efficiency for water production & delivery Complex tariffs El Paso Electric (EPE) Negotiated switch from flat to TOU rates Increased importance of understanding rates Need to coordinate electric rates with complex water operations 6

7 Project drivers & background, cont. Base realignment (BRAC) Troop Fort Bliss 20,000 troops + family + support Need to do more with less Water quality Water age concerns Complex new EPA requirements & constraints Need method to enforce water turnover Consistent operations Operators busy keeping growing, complex system running Manage aging facilities to meet myriad constraints Reduced budgets Managing line breaks, maintenance scheduling Need a tool to provide info and feedback about how the system responds to support decision making 7

8 Requirements Must optimize usage of wells & WTPs to reduce energy cost Must work in real time to adapt to changing TOU tariffs Must provide decision support for operators Must be accessible to multiple depts Must utilize hydraulic model for verification Do all this without compromising reliability or WQ 2008 test pilot: SCADA-based logic controls Poor results at EPWU and others Not holistic approach Not scalable Abandoned & project cost refunded 8

9 EMS Feasibility study Energy management system (EMS) identified as potential solution EMS a system of computer-aided tools used by operators to monitor, control, and optimize performance Derceto & CH2M Hill team Energy tariffs analyzed (1-year) SCADA data analyzed (1-year) Optimized operations comparisons Significant storage to average demand ratio Ability to shift load can result in significant cost savings 9

10 Feasibility study results An EMS could meet all of EPWU s operations optimization requirements Feasible to dynamically choose most efficient pump combinations, VFD speed, and valve settings Real time optimizer would use 8.9% less energy on average per year Load shift savings: $280k to $440k per year Efficiency gains: $220k to $350k per year Total savings: $500k to $790k per year 10

11 TOU tariff analysis Proposed TOU tariff structure Period Start time End time Cost / kwh Summer weekdays Critical 13:00 17:00 $ Summer weekdays Mid peak 10:00 13:00 17:00 20:00 $ All other times Off peak $

12 TOU tariff analysis & EMS schedule 32% savings during the four summer months (June Sept) 12

13 Feasibility study results Recommend all sites be moved to TOU tariff WTPs & finished water pumps excluded Wells included in optimization for increased load shifting savings Other EMS benefits Mitigates risk of inadvertent energy use during peak pricing periods Optimizes delivery sources and paths Reduces greenhouse gas (GHG) emissions ~1,700 metric tons of CO2 per year equals: 188,000 gallons of gasoline consumed 329 passenger vehicles for one year 69,917 propane cylinders used for home barbeques 13

14 EMS design Hazard & operability study (HAZOP) Priorities: Deliver water at appropriate pressure Minimize cost of energy Maximize energy efficiency of pumps (BEP) EMS will read SCADA every 10 minutes Passes through data cleaner Tank cycler will force tank turnover Recalculates schedules every 1/2-hour for next rolling hour period Adapt to changing conditions of the day 14

15 Included facilities Majority of the system as follows: 181 pumps (43 out of 46 pump stations) 69 out of 71 reservoirs 123 out of 162 wells 9 out of 24 MOV valves 0 out of 4 WTPs Booster stations with negligible savings or dedicated use excluded Desalination plant, surface water plants produce continuous flows Only key valves in EMS control 15

16 Pumps Pump priority & order sequencing optimized Same size pumps grouped as combinations 1 pump priority 1 pump 2 pumps priority 1 and priority 2 pumps 3 pumps priority 1, priority 2 and priority 3 pumps Pump constraints Number of pumps per pump station Pressure constraints Speed constraint for VSD pumps Pump run-time 16

17 Pump curve & efficiency curve calibration 17

18 Pump efficiency in combination (ft) Head ( Flowrate (MGD) Telemetry Points Paper Curve (1 pump) Paper Curve (2 pumps) Scaled Curve (1 pump) Scaled Curve (2 pumps) Scaled Efficiency Curve (1 pump) Scaled Efficiency Curve (2 pumps) 18 Series8 Efficiency (%)

19 Wells Wells grouped into combinations by Capacity Treatment cost Water quality ranking Seasonal operation Within a group priority determined by Efficiency (runs more efficient wells first) Water quality ranking (treatment cost) Well constraints Well blow off: no flow for the first 15 minutes Time between starting another well in a well field (30 minutes) 19

20 Tanks / reservoirs EMS will maintain reservoirs in bounds by: Predicting demand Scheduling pumping into and out of reservoirs Safety protection interlocks Local / mechanical means SCADA signals High Alarm Operational High SP Operational Low SP Low Alarm 20

21 Tanks / reservoirs Turnover challenges 21

22 Reservoir turnover: EMS cycler 22

23 Hydraulic model EPANET Embedded EPANET hydraulic modeling software used to verify schedule Current model - H 2 OMAP Water (Innovyze) High level of detail (~20,000 pipes) Suitable for EMS use H2OMAP converted to EPANET format Skeletonized to improve run time (~5 seconds) Retained main facilities and transmission mains (~5,000 pipes) 23

24 System architecture Water Utility SCADA Operator Panel Application Manager Strategic Simulator Dashboard Read / Write Online Server Replication Offline Server Online Database Historian Database 24

25 EMS operator panel (pump station view) 25

26 EMS dashboard Asset performance data 26

27 Challenges & opportunities (I) Well grouping EPWU has 119 active well sites Grouping determined by optimum treatment cost & path GUI toggle between pump combination view and individual view Assists operators in understanding pump and well groupings and priority rankings 27

28 Challenges & opportunities (II) Pump alerts. EMS alerts the operator to: Pumps that do not operate on normal basis over a specified duration Pumps/wells not delivering an appropriate amount of water Determined by the pump curve, pump test data & real-time data Improves service life of pumps The least efficient pumps that are not be chosen by EMS can be run manually 28

29 Challenges & opportunities (II) Pump alerts 29

30 Challenges & opportunities (III) Seasonal operation During surface water season surface WTPs maximized / wells used to supplement During ground water season surface WTPs are off / wells supply the system Triggered by surface WTPs coming online (manually) Moving water different directions Tank operating levels change seasonally for some tanks EMS operation will follow seasonal modes EMS adapts to zone configuration changes 30

31 Applicability to others Who should consider real time EMS? Large population centers Energy expenditures over ~$1.5 million per year Utilities moving to TOU or real time electric rates Elevated storage allows load shifting, taking advantage of TOU rates Real time pricing advantages EMS improves system-wide pump efficiency, so even with minimal storage, benefits are still there Electric utilities offer incentives for energy efficiency and demand response 31

32 Questions Real-time energy and water quality management system designed for success! Contact: Peter Martin, Derceto (916) Manuel Perez, EPWU (915) Brian Skeens, CH2M Hill (678)