Load Flexibility and Rate Design Considerations for Heat Pump Water - - PowerPoint PPT Presentation

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Load Flexibility and Rate Design Considerations for Heat Pump Water Heaters

William Burke Deepak Aswani

Sacramento Municipal Utility District

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About Sacramento Municipal Utility District

• Not-for-Profit Municipal Electric

Utility

• Sacramento County in California

with about 625,000 accounts

• Vertically integrated with

generation, T&D, and customer facing functions

• Net zero carbon goal by 2040

impacting the generation portfolio, appliance electrification, and load flexibility initiatives

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Present day opportunities for Time-of-Day Rates

• SMUD Residential Time-of-Day Rates

helps align customer costs with utility costs on average

• Provides an opportunity for shared

savings

• However, cost of energy and capacity

(bulk and local) are more complex than Time-of-Day captures

Actual Utility energy

• r capacity costs

vary day to day Day 1 peak Day 1 off-peak Day 2 peak Day 2 off-peak Day 3 peak Day 3 off-peak

…

Day n peak Day n off-peak

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• Changing the water temperature

setpoint to overheat the water allows for load shifting

• Mixing valve keeps temperature

constant for consumed water

• Shift load without the customer

noticing!

Load flexibility with Heat Pump Water Heaters

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Looking beyond Time-of-Day Rates

Greater utility responsibility Greater customer responsibility

Flat monthly bill (cell phone plan) Dynamic rates Volumetric rates Time of Day rates Traditional rate with load shift credit

Aspiration for a simplified customer billing contract that also provides utility load flexibility

Transactive energy (peer to peer trading)

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Pilot design

• Research compares 3 modes of HPWH operation
• 1. Baseline – no active load shaping
• 2. Time of Day (TOD) rate optimization – load shape to reduce on-peak consumption

and increase off-peak consumption

• 3. Utility influenced load shaping based on utility day ahead electricity costs
• Customer contract design
• Default mode is TOD rate optimization
• 120 days/year can be event days – either Baseline or Utility load shaping
• Customer receives $75 up front credit for signing up for the program and $2/month

participation bill credit

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Founded: 2014 Located: Louisville, KY Business Model: SaaS Other Programs:

✓ Glasgow/TVA SET Program (Battery, HPWH, Thermostat) ✓ GMP BYOD Program (Battery) ✓ Belmont Light Peak Reduction Rewards (All Devices) ✓ GMP EV Unlimited Program (EVSE)

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Thermostats Thermostats Water Water Heaters Heaters Storage Storage EVSE EVSE Room AC & Room AC & Mini Mini -Splits Splits

Broad Manufacturer Support

Robustly integrate with a new device in ~2 weeks

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• Water Heater Optimization

Program

• BYOD Enrollment
• Multi Manufacturer Support

with

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Rapid Algorithm Development

Software in the Loop Simulation Explanation

• Models Device Behavior
• Models Human Behavior
• Operate Actual Control Software on Simulated

Devices

Benefits

• Accelerate Time
• Test With No User Disruption
• Replicable experiments
• Faster Development
• Lower Risk

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• Learn Water Use Behavior
• Read from Price Server
• Take Advantage of Repeating

Schedules

• Adjust Schedule to Save

Money

• Ensure Water Delivery

Temperature

TOD Rate Optimization

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• Learn Water Use Behavior
• Integrate with Pricing Server
• Dispatch Based on Hot Water

Capacity and Price

• Optimize Wholesale Cost
• Ensure Water Delivery

Temperature

Wholesale Cost Optimization

Water Heater Arbitrage

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Impact of TOD optimization

• 22 customers (9 GE Geospring

and 13 Rheem)

• TOD optimization

implemented so far

• Utility influenced load shaping

going live in Fall 2019

13% reduction

• vs. baseline

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Program Challenges

• Mixing Valve Support
• Safety Concerns
• Terms and Conditions
• Mixing Valve Safety
• Multi-Manufacture Support
• Different min and max temperatures
• Different data granularity
• Population Size
• Learning benefits from large population

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Customer Learnings

• Simple Enrollment a must
• Few People Change

Behavior

• Fixed Schedules Don’t Work
• Unhappy Customers in

Control Group

• Learning Solved the Problem