Strategic Energy Management (SEM) Summary
Background
In order to serve the community, SAWS’ operations consume significant amounts of electricity as water distribution and wastewater treatment are inherently energy intensive. Reducing energy consumption would result in significant cost savings and a reduction in SAWS’ carbon footprint.
| Location | 2024 Energy Savings (kWh) | 2024 Cost Savings ($) |
| Medio Creek WRC | 1,745,338 | $157,080 |
| Clouse WRC | 1,379,959 | $124,196 |
| Leon Creek WRC | -271,727 | -$24,455 |
| 2024 TOTALS | 2,853,570 | $256,821 |
| LIFETIME SAVINGS (June 2022-Dec 2024) | 8,765,697 | $788,102 |
kWh– Kilowatt-hour: measured as 1 kilowatt (1,000 watts) of power expended for 1 hour.
Project Description
Traditionally, there are two types of energy conservation measures: Retrofit type projects (replacing existing equipment with new equipment) and behavioral/operational modifications. Due to the magnitude and complexity of SAWS operations, behavioral type projects present a more attractive opportunity because they require far less capital and yield more immediate savings resulting and a better return on investment.
In 2021, SAWS partnered with Cascade Energy to begin a Strategic Energy Management project that focused on optimizing existing equipment by making behavioral and operational modifications. This project began by establishing energy teams comprised of key water/wastewater staff and operators. These energy teams attended training sessions focused on energy education and ways to save energy within their specific operations. In 2024, wastewater continued to see savings but at a less accelerated pace compared to 2023. Overall, strategic energy conservation measures resulted in more than $250,000 in cost savings (highlighted above).
Notes
Energy consumption and cost savings are verified by a software platform called Gazebo. Gazebo models take water/wastewater data and combine it with weather information and energy data. These models highlight assumed energy consumption based on specific variables vs. actual energy consumption, and the delta between the two is energy savings.
2024 District Cooling Upgrades and Optimization
Background
SAWS operates four chilled water plants across two separate district chilled water systems, downtown and Port San Antonio. The downtown chilled water system supplies about 22,000 tons of cooling capacity to critical facilities including the Convention Center, Alamodome, and Grand Hyatt Hotel to name a few. The Port San Antonio chilled water system supplies about 7,000 tons of cooling capacity to Boeing, Standard Aero, Chromalloy, Port San Antonio, and the U.S. Air Force.
Project Description
In 2024, district cooling continued its implementation of energy efficiency projects, including adding high-efficiency chillers, variable frequency drives (VFD), and Delta T correction. The high-efficiency chillers replaced 20+ year old single-speed chillers, and the variable frequency drives were added to chilled water and condenser pump motors. The Delta T correction was made by focusing on the efficient use of chilled water by SAWS customers.
These projects resulted in an operational efficiency of 0.96kWh/ton-hr in 2024 vs the pre-projects baseline of 1.09kWh/ton-hr (2021). At the 45million ton-hrs of chilled water a year produced by SAWS, this equates to annual savings of roughly $450,000.
Notes
Since utilities costs are a direct pass through to chilled water customers, SAWS passes these energy savings on to customers through their monthly bills.
2024 Utility Tariff Analysis and Adjustment Project
Background
San Antonio Water System utilizes four different CPS Energy utility tariff structures: General Service (PL), Large Lighting and Power Service (LLP), Extra Large Power Service (ELP) and Super Large Power Service (SLP) rate. Each tariff has its own unique billing structure and minimum term of service. The SLP rate has a five-year minimum term, the ELP and LLP rates have a one-year minimum term, and the PL rate has no minimum term. SAWS has several utility accounts in each of the four tariff categories and can request a change in tariff if potential cost savings can be verified.
Project Cost and Savings Summary
| Account/Location | Description | Annual Cost Savings |
| ASR Plant/East Pumps | PL to ELP | $67,759 |
| West Tops Pumps | LLP to PL | $17,883 |
| H&C Downtown-Chill H2O | ELP to SLP | $17,563 |
| Artesia – ASR | LLP to PL | $12,934 |
| Sunset Tank | PL TO LLP | $9,239 |
| East Side Service Center | PL to LLP | $4,405 |
| Basin Pump Station | ELP to LLP | $3,986 |
| Cagnon Pump Station | LLP to PL | $3,231 |
| Stevens Pkwy Pump Station | LLP to PL | $637 |
| SE Booster Station | PL to LLP | $617 |
| Seale Pump Station | LLP to ELP | -$3,524 |
| Sutton Pump Station | PL to LLP | -$6,999 |
| 2024 TOTALS | $127,731 | |
| LIFETIME SAVINGS | $1,906,726 |
Project Description
Due to the nature of SAWS operations, utility accounts and energy consumption do not always remain consistent for long periods of time. Therefore, what may have been the most cost-effective utility tariff for an account one year, may not be the most cost-effective tariff the next. Being aware of these changes in energy consumption, and the ability to request a new tariff, presents SAWS with a significant opportunity for utility cost savings.
To identify cost savings opportunities, the Office of Energy Strategy performs a monthly analysis to calculate the “would be” utility costs of each of the four tariff structures for all of SAWS’ nearly 600 CPS Energy utility accounts. This analysis highlights specific accounts where SAWS would be saving money by being in a different tariff than the one currently utilized. Once accounts are identified, OES meets with applicable SAWS staff to understand the account’s operational consumption, peak demand, seasonality, outliers, and maintenance/construction schedules. These meetings help provide the needed assurance that the existing operations will remain consistent and warrant a tariff change. This is a critical step because it helps avoid a scenario where SAWS requests a rate change based on a previous month’s utility data and ends up losing revenues due to significant operational changes down the line. Ultimately this step verifies the proposed tariff change is appropriate and cost effective.
Notes
Cost savings opportunities are identified by taking several months of previous energy consumption data for each account and calculating what the bill would look like in each of the four tariff categories. If the calculated bill with the lowest total is from a different tariff than is currently utilized, then a cost savings opportunity is present.
Making a rate change request only makes sense when a pattern has been established, so only accounts with cost savings over several months are considered. Cost savings are quantified by subtracting the new tariff costs (i.e. the new request) from the costs under the previous tariff.
Per CPS Energy’s request, SAWS provides several months of cost savings to verify why a tariff change request is being presented. The timeframes provided to CPS range from 10 to 16 months of identified cost savings. The figures in the 2024 cost savings column of the summary table are real dollars saved by SAWS in 2024.
CPS Energy 2024 Demand Response Program Summary
Background
CPS Energy’s Demand Response program is a voluntary load curtailment program for its commercial and industrial customers. The program is designed to reduce CPS Energy’s peak load growth by incentivizing customers to shed electrical loads on peak summer days.
| Location | Winter | Summer | Bonus | Total DR |
| Chilled Water Plant | $14,922 | $222,801 | $22,500 | $260,233 |
| Micron PS | $11,332 | $113,229 | $5,888 | $130,449 |
| 34th St PS | $15,810 | $38,669 | $3,375 | $57,854 |
| Basin PS | $11,347 | $23,122 | $15,000 | $49,469 |
| Marbach PS | $19,843 | $31,979 | $1,875 | $53,697 |
| Clouse WRC | $10,584 | $29,943 | $3,375 | $42,902 |
| Seale PS | $11,664 | $24,338 | $3,938 | $39,940 |
| Pinn Recycle | $2,457 | $21,972 | $3,375 | $27,805 |
| Golden PS | $6,903 | $17,990 | $1,388 | $26,281 |
| Leon Creek WRC | $3,833 | $16,342 | $2,625 | $22,800 |
| Pearsall Recycle | $1,853 | $14,968 | $1,875 | $18,696 |
| TRP PS | $3,567 | $5,970 | $375 | $9,912 |
| Medio Creek WRC | $0 | $1,600 | $1,688 | $3,288 |
| Leon Creek WRC | $659 | $1,566 | $938 | $3,163 |
| $114,776 | $564,489 | $68,213 | $747,478 |
Project Description
CPS Energy’s Demand Response program now provides both a winter and summer option which run January through March and from June through September respectively. During this time, CPS Energy can call a demand response event any weekday.
In 2024, SAWS enrolled in the winter demand option, the summer demand option and a bonus hours option. SAWS’ average demand reduction for the summer option was 7.8 MW which is enough electricity to power roughly 2,000 Texas homes on a hot summer day.
Electrical demand at Production, Treatment and Recycle locations was reduced by strategically shutting off pumps and motors when possible. At the Central chilled water plant, demand was reduced by utilizing thermal energy storage.
Notes
Special thank you to all Production, Treatment, Recycle and DCS staff who made this possible.
Pump Station Optimization Project
Background
In August of 2024, the Energy Strategy team worked with Production and Cascade Energy, our SEM contractor to perform an audit of the eight highest energy consuming primary and secondary pump stations. In spring of 2023, SAWS piloted an energy efficiency mode at the Mission Primary Pump Station which resulted in a 10% energy reduction, saving approximately $75,000 in annual electricity bills.
Project Description
Most SAWS pump stations have an array of well and high-service pumps and there are several different pumping combinations. Rather than giving all pumps equal run times, the proposed “energy efficiency mode” prioritizes use of the most energy efficient pumps.
Signature Automation was contracted to provide updated SCADA screens, programming, testing, and commissioning for the SAWS Energy Optimization project. This task includes modifying the screens for the Southeast Booster, Pinn Recycle Booster, Maltsberger Pump Station, Naco Pump Station and incorporating efficiency controls at each location. Signature Automation will utilize the existing control system as the basis for modifying the control system. This task includes database development, HMI configuration, programming, and alarm configuration as necessary to implement efficiency modes at each location.
Notes
Project completion date is mid-2025 with energy saving measured and verified by the end of 2025.
CPSE Incentive Rebates Summary 2018 – 2023
| Project | Program Year | Rebate Amount ($) |
| Central CHW Plant VFDs | 2024 | $229,678.30 |
| GRAND TOTALS 2018-2024 | $969,521.77 | |
Background
In 2009, CPS Energy launched its first energy efficiency and conservation plan known as the “Save for Tomorrow Energy Plan,” or STEP. The plan established a goal of saving 771 MW of energy by 2020. Through community participation and shared commitment, this goal was met ahead of time. In June 2022, the City of San Antonio authorized a new initiative titled the “Sustainable Tomorrow Energy Plan,” which established a goal of reducing community demand by 410 MW by 2027.
Project Description
One of CPS Energy’s programs under the umbrella of STEP includes the Commercial Solutions Program. This program incentivizes commercial customers who implement projects aimed at reducing energy consumption. CPS Energy helps customers identify energy conservation measures and then pays the customers up to $0.05/kWh and $325/kW, depending on the project type. Some common projects include lighting, variable frequency drives, chillers, refrigeration and more.
Many of SAWS’ construction projects inherently save energy because outdated infrastructure is being replaced with newer and more efficient equipment. When a qualifying project is identified, the Office of Energy Strategy staff works closely with CPS Energy’s program administration team, CLEAResult, to maximize the rebate potential. Moving forward, staff expects to capture rebates on a more regular basis.