Strategic Energy Management (SEM) Summary
Background
SAWS’ existing operations consume significant amounts of electricity as water distribution and treatment are inherently energy intensive. Reducing energy consumption would result in significant cost savings and a reduction in SAWS’ carbon footprint.
| Location | Energy Savings (kWh) | Cost Savings ($) |
| Clouse WRC | 1,201,294 | $108,116 |
| Leon Creek WRC | 1,757,130 | $158,142 |
| Medio Creek WRC | 1,012,447 | $91,120 |
| H2Oaks | 2,022,758 | $182,048 |
| GRAND TOTAL | 5,993,629 | $539,426 |
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 (replace existing equipment with new equipment) and behavioral, operational projects. 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 in 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 2023, wastewater took a significant step forward and implemented several strategic energy conservation measures resulting in more than $500,000 in cost savings (highlighted above). A few project examples include reducing aeration when ammonia is low, automating UV systems, and lighting/HVAC setbacks.
Notes
Energy consumption and cost savings are verified by a software platform called Energy Sensei. Energy Sensei includes models that pull in water/wastewater data, such as flows, and combine it with weather information and energy data from CPSE Energy. These models highlight assumed energy consumption based on specific variables vs. actual energy consumption, and the delta between the two is the energy savings.
2023 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 20,000 tons of cooling capacity to critical facilities including the Convention Center, Alamodome, and Grand Hyatt Hotel. The Port San Antonio chilled water system supplies about 6,800 tons of cooling capacity to Boeing, Standard Aero, Chromalloy, and the Unites States Airforce.
Project Description
In 2023, district cooling implemented a multitude of energy projects including high efficiency chillers, variable frequency drives (VFD), and Delta T correction. The new high efficiency chillers replaced 20+ year old existing chillers, the variable frequency drives were added to chilled water and condenser pump motors, and Delta T correction was made by focusing on customer building’s use of chilled water.
These projects resulted in an operational efficiency of 0.93kWh/ton-hr in 2023 vs 0.99kWh/ton-hr in 2022. At the 45million ton-hrs of chilled water a year produced by SAWS, this equates to annual savings of $226,686.
Notes
Since utilities are a direct pass through to chilled water customers, SAWS can pass these savings on directly to the customers in their monthly bills.
2023 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 |
| Agua Pura/Medina Treatment Plant/Pump Station | PL TO LLP | $6,172 |
| ASR Plant/East Pumps | ELP TO PL | -$65,546 |
| West Top Pump Station | PL TO LLP | -$51,826 |
| Potranco Secondary Pump Station | PL TO LLP | $8,806 |
| Golden Booster Pump Station | PL TO LLP | $7,295 |
| Commerce/Central Chilled Water Plant | SLP TO ELP | $9,912 |
| Lemonwood Primary Pump Station | LLP TO PL | $1,922 |
| Loma Linda Secondary Pump Station | LLP TO PL | $5,434 |
| Marbach 2 (Bear Springs) Primary Pump Station | PL TO LLP | $8,499 |
| Port San Antonio Bldg. #1625 Chilled Water Plant | ELP TO LLP | $35,069 |
| Sutton Secondary Pump Station | LLP TO PL | $11,540 |
| Turtle Creek #2 Primary Pump Station | LLP TO PL | $55,884 |
| Wurzbach Primary Pump Station | ELP to SLP | $79,108 |
| 2023 TOTAL | $112,269 | |
| PROGRAM DECEMBER 2023 YTD | $1,224,872 |
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.
In order 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 previous months of utility data and ends up losing revenues as a result of significant operational changes down the line. Ultimately this step verifies the proposed tariff change is appropriate.
Aside from verifying operational behavior, OES also considers the minimum terms associated with each rate category. PL tariff changes pose little to no risk because SAWS can switch out of that rate at any given time, whereas LLP and ELP rates lock the account into that tariff for a year. Therefore, LLP and ELP requests are only made when operational stability can be verified with high confidence. PL rate requests are also made with high confidence.
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, resulting in four potential bills per account, per month. 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 Annual Cost Savings column of the summary table are real dollars saved by SAWS in 2023.
CPS Energy 2023 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 | Contract kW Reduction | Average kW Reduction | Percentage Reduction | Incentive Amount |
| Chilled Water Plant | 2,500 | 3,511 | 140% | $254,756.12 |
| Basin PS | 1,000 | 758 | 76% | $54,250.19 |
| 34th St PS | 250 | 657 | 263% | $48,158.54 |
| Micron PS | 1,400 | 1,458 | 104% | $106,379.00 |
| Golden PS | 225 | 171 | 76% | $12,785.16 |
| Seale PS | 275 | 482 | 175% | $36,022.61 |
| Leon Creek Recycle | 300 | 255 | 85% | $18,984.10 |
| Pearsall Recycle | 150 | 189 | 126% | $14,070.21 |
| Leon Creek WRC | 125 | 44 | 35% | $3,092.66 |
| Medio Creek WRC | 225 | 7 | 3% | $2,727.12 |
| GRAND TOTALS | 6,450 | 7,534 | 117% | $551,225.71 |
Project Description
CPS Energy’s Demand Response program runs from June 1 through Sept. 30. During this time, CPS Energy can call demand response or “curtailment” events any weekday and events typically take place between 3 p.m. and 6 p.m.
In 2023, SAWS enrolled all feasible locations in Demand Response Option 2, which gives a two-hour notice and pays $70 per kW reduced. In previous years SAWS has participated in both the Option 1 (30-minute notice) and the Option 2 program. In total, CPS Energy called 27 demand response events this year. For reference, SAWS’ average demand reduction of 7.5 MW is enough electricity to power 1,500 Texas homes on a hot summer day.
Electrical demand at Production, Treatment and Recycle locations was reduced by strategically shutting off pumps and motors where 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.
2023 Open/Closed Valve Pilot Summary
Background
SAWS has a diverse and complex water distribution network containing several different pressure zones. In some cases, large valves along the distribution system remain closed after a repair or operational change.
Project Description
When valves inadvertently remain closed, high service pumping head is increased resulting in excess energy use. SAWS’ Master Planning team analyzed the hydraulic model to identify locations where valves may be closed.
Crews were then sent out to the field to verify the valve placement and open if necessary. Opening these valves results in better hydraulic performance and improved pump station energy efficiency. Estimated energy savings $700,000.
To validate the above energy savings, pump station energy intensity was compared before and after the valves were opened. External factors like pumping volume were removed to identify the true savings associated with the valve positioning.
Notes
Moving forward, SAWS’ Master Planning team hopes to use these energy savings as a justification for identifying and opening additional closed valves. OES is not recording these savings for 2023 as they as based on engineering estimates. OES and Master Planning will be conducting field verifications for this pilot in 2024.
CPSE Incentive Rebates Summary 2018 – 2023
| Project | Program Year | Rebate Amount ($) |
| Central CHW Plant VFDs | 2023 | $229,678.30 |
| GRAND TOTALS 2018-2023 | $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 hopes to capture rebates on a more regular basis.