Nudges and Money in Green Charging: Demand Response for Renewable Energy Using Electric Vehicles

Last registered on August 11, 2025
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Pre-Trial

Trial Information

General Information

Title
Nudges and Money in Green Charging: Demand Response for Renewable Energy Using Electric Vehicles
RCT ID
AEARCTR-0016549
Initial registration date
August 10, 2025

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
August 11, 2025, 10:15 AM EDT

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

Last updated
August 11, 2025, 11:51 PM EDT

Last updated is the most recent time when changes to the trial's registration were published.

Locations

Country
China
Region
Liyang, Jiangsu

Primary Investigator

Name
Jin Di Zheng
Affiliation
Huazhong University of Science and Technology
Contact Primary Investigator

Other Primary Investigator(s)

PI Name
Huanxiu Guo
PI Affiliation
Nanjing Audit University
Contact Investigator

Additional Trial Information

Status
On going
Start date
2025-08-11
End date
2025-08-24
Keywords
Behavior, Environment & Energy
Additional Keywords
JEL code(s)
C93, D90, Q4, Q5
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
Electric Vehicles (EVs) are increasingly contributing to challenges such as grid strain and peak power demand. While these issues have long existed in modern electric grids, the growing reliance on renewable energy—intermittent by nature—demands greater flexibility in demand response strategies. This study examines how demand response using EVs can help mitigate the instability of renewable energy supply, focusing on the causal effects and mechanisms of information nudges and carbon credit monetary incentives. We conduct a randomized controlled trial (RCT) at solar-powered EV charging stations, in collaboration with a major EV service provider in Liyang, China. Participants are randomly assigned to one of three arms: (i) an information-only nudge emphasizing environmental benefits, (ii) a carbon credit monetary incentive, or (iii) a control group with no intervention. Charging behavior is measured using administrative transaction data, and treatment effects are estimated through a difference-in-differences framework.
External Link(s)

Registration Citation

Citation
Guo, Huanxiu and Jin Di Zheng. 2025. "Nudges and Money in Green Charging: Demand Response for Renewable Energy Using Electric Vehicles." AEA RCT Registry. August 11. https://doi.org/10.1257/rct.16549-1.1
Sponsors & Partners
Experimental Details

Interventions

Intervention(s)
There are two phases of the experiment, with the first phase collecting experimental participants from the existing EV users and the second phase the experiment treatment.

There are three arms of treatment. Arm 1 is the information nudge treatment in which an SMS invitation to charge at a designated PV-storage-charging station on a specific date. The message will emphasize the environmental benefits of the charging behavior and their contributions to the local sustainability goals.

Arm 2 focus on a monetary incentive, in our setting, is converted to a Carbon Credits in the participants' charging accounts. If they manage to charge their cars on a given date, they will receive a reward equivalent to a 40% discount.

Arm 3 is a control treatment where no SMS are sent.
Intervention (Hidden)
Phase 1 – Baseline Data Collection
• Procedure: Distribute an online questionnaire via LiKe Charging’s WeChat public account to existing EV users.
• Purpose: Collect baseline demographic and usage characteristics for stratification and covariate adjustment.

Phase 2 – Randomized Interventions

Arm 1: Information Nudge
Participants receive an SMS invitation to charge at a designated PV-storage-charging station on a specific date, highlighting:
• Environmental benefits (CO₂, SO₂, NOx, and particulate matter reduction per charging session).
• Contribution to local sustainability goals.

Arm 2: Monetary Incentive (Carbon Credits)
Participants receive an SMS invitation with identical environmental messaging plus:
• A carbon credit reward (equivalent to 40% cashback of the charging amount) if they charge on the invited date.

Arm 3: Control
No SMS intervention.
Intervention Start Date
2025-08-14
Intervention End Date
2025-08-24

Primary Outcomes

Primary Outcomes (end points)
Charging uptake rate
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
1) Total kWh charged on the invited date.
2) Charging frequency within the intervention week.
3) Persistence of charging behavior in subsequent weeks.
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
1 Survey phase – We will collect baseline data via an online questionnaire distributed through the company's application channel, including demographics, vehicle characteristics, charging habits, price sensitivity, and environmental attitudes. The first 1,000 respondents will receive a RMB 10 electricity credit, issued after the trial.
2 Experimental phase – These 1,000 users will be randomly allocated into nine groups:
- Control group – No intervention.
- Information-only groups – Four subgroups, each receiving an SMS highlighting the environmental benefits of charging at PV-storage sites, inviting them to charge on Day 0, Day +1, Day +2, or Day +3.
- Subsidy groups – Four subgroups receiving the same environmental message plus a 40% cashback (carbon credit) on their first order if they charge on the invited date.
Experimental Design Details
Randomization Method
coin flip
Randomization Unit
individual user
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
0
Sample size: planned number of observations
1,000 users.
Sample size (or number of clusters) by treatment arms
400 users in arm 1. 400 users in arm 2. 200 in 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
Nanjing Audit University
IRB Approval Date
2025-06-30
IRB Approval Number
N/A
Analysis Plan

Post-Trial

Post Trial Information

Study Withdrawal

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Intervention

Is the intervention completed?
No
Data Collection Complete
Data Publication

Data Publication

Is public data available?
No

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials