UC San Diego Subscription-based Pricing for EV Charging

Last registered on September 28, 2026
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Pre-Trial

Trial Information

General Information

Title
UC San Diego Subscription-based Pricing for EV Charging
RCT ID
AEARCTR-0019785
Initial registration date
September 20, 2026

Initial registration date is when the trial was registered.

It corresponds to when the registration was submitted to the Registry to be reviewed for publication.

First published
September 28, 2026, 8:48 AM EDT

First published corresponds to when the trial was first made public on the Registry after being reviewed.

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Primary Investigator

Name
Ryan Hanna
Affiliation
University of California San Diego
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Other Primary Investigator(s)

PI Name
Teevrat Garg
PI Affiliation
UC San Diego
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PI Name
David Victor
PI Affiliation
UC San Diego
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Additional Trial Information

Status
In development
Start date
2026-09-21
End date
2026-12-31
Keywords
Environment & Energy
Additional Keywords
JEL code(s)
Secondary IDs
Prior work
This trial is based on or builds upon one or more prior RCTs.
Abstract
This experiment will test the effect of subscription-based pricing for electric vehicle (EV) charging on driver charging behavior. Subscription pricing charges an upfront flat monthly fee in return for a lower marginal cost (dollar per kWh) price for charging. The setting is a university campus, comprised mostly of workplace charging, and includes staff, faculty, students, and community members. Drivers are randomized to receive one offer of a subscription pricing plan and invited to enroll. Pricing plans differ in monthly fee and volumetric discount.
External Link(s)

Registration Citation

Citation
Garg, Teevrat, Ryan Hanna and David Victor. 2026. "UC San Diego Subscription-based Pricing for EV Charging." AEA RCT Registry. September 28. https://doi.org/10.1257/rct.19785-1.0
Sponsors & Partners
Experimental Details

Interventions

Intervention(s)
The intervention is the subscription pricing plan offered to drivers. Drivers are assigned to one of four treatment arms (or control) and invited to enroll:

1. Control: the base rate marginal price offered today, with no monthly fee
2. $5/month for 16% off the base rate
3. $5/month for 31% off
4. $10/month for 16% off
5. $10/month for 31% off

Because battery EVs (BEVs) are greater in number at our university, BEV drivers will be assigned to one of groups 1–5. Because there are fewer plug-in hybrid EVs (PHEVs) and they demand less electricity, PHEV drivers will be assigned to one of groups 1–3 (i.e., we will test only the smaller monthly fee).
Intervention Start Date
2026-09-21
Intervention End Date
2026-12-31

Primary Outcomes

Primary Outcomes (end points)
Primary outcomes: (1) total kWh charged on campus; (2) number of days with at least one charging session on campus; (3) the timing of charging, measured as the hour in which sessions are initiated; (4) uptake of the offer.
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary outcomes: Session duration (duration spent plugged in, in hours); charging duration (duration the vehicle was actively charging, in hours).
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
This study is an RCT field trial with a total sample size of 2,261 EV drivers. The randomization is at the individual driver level. To account for differences in driving and charging behavior, the sample is stratified (blocked) into two distinct groups by vehicle type: battery EV (BEV) drivers (n=1,832) and plug-in hybrid EV (PHEV) drivers (n=429).

BEV drivers are randomly allocated to 5 parallel arms, one of four treatment arms or control. Because the treatment is an offer of new pricing and drivers may either accept or decline the offer, we balance the size of each group assuming an opt-in rate of 35 percent. Balancing is done, moreover, on the subset of drivers that have recently charged on the university network. We thus have treatment arms of approx. 421 drivers per arm and a control group with 148 drivers. PHEV drivers are assigned to 3 parallel arms, one of two treatment arms or control, following the same logic. Each treatment arm has approx. 183 drivers and the control group has 64 drivers.

The intervention tests subscription-based pricing for workplace EV charging. Each treatment arm is a unique offer of subscription-based pricing, which charges an upfront flat monthly fee in exchange for lower marginal (dollar per kWh) prices at the charger. For PHEVs, only the lower-cost subscription price will be tested.

Randomization was conducted with computer-generated random assignment.

Outcomes will be tracked using charging station data, which provides the plug-in time, plug-out time, and energy consumption of every session tied to the individual driver. The intervention period is roughly 3 months.
Experimental Design Details
Not available
Randomization Method
Randomization done in office by a computer.
Randomization Unit
Individual
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
2261
Sample size: planned number of observations
2261
Sample size (or number of clusters) by treatment arms
1,832 BEV drivers. Approx 421 drivers per treatment arm. 148 drivers in the control.
429 PHEV drivers. Approx 183 drivers per treatment arm. 64 drivers in the control.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Supporting Documents and Materials
IRB

Institutional Review Boards (IRBs)

IRB Name
UC San Diego Office of IRB Administration (OIA)
IRB Approval Date
2022-12-05
IRB Approval Number
805222
Analysis Plan