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Green growth: can solar adoption in Lagos boost firm profits while reducing emissions?

Last registered on September 08, 2025

Pre-Trial

Trial Information

General Information

Title
Green growth: can solar adoption in Lagos boost firm profits while reducing emissions?
RCT ID
AEARCTR-0016627
Initial registration date
September 04, 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
September 08, 2025, 7:43 AM EDT

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

Locations

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Primary Investigator

Affiliation
Northwestern University

Other Primary Investigator(s)

PI Affiliation
Northwestern University
PI Affiliation
University of Chicago
PI Affiliation
Macquarie University

Additional Trial Information

Status
In development
Start date
2025-09-01
End date
2026-07-31
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
Many small businesses in Lagos, Nigeria struggle with unreliable electricity from the power grid. To keep operating, these firms often rely on fuel-powered generators, which are expensive to run, create air pollution, and generate noise. Solar power systems could offer a cleaner, quieter alternative that might also help businesses save money and operate longer hours. We want to estimate small businesses' demand for small solar power systems, and how adopting solar systems might affect their operations and the local environment. Specifically, we're examining: (1) how much businesses are willing to pay for solar systems, (2) whether providing information about generator inefficiency or offering a free trial increases demand for solar power, (3) whether solar power helps businesses change their business practices, and (4) whether reduced generator use benefits neighboring businesses through less air and noise pollution.
Methods: We're working with approximately 400 small businesses in Lagos markets, randomly divided into three groups. The control group receives basic information about the solar product. The information treatment group additionally receives detailed information about how generators operate inefficiently and waste fuel when used for small loads like phone charging or lighting. The free trial group receives a free one-month trial of a solar system. All businesses will then participate in a pricing BDM mechanism to elicit their willingness to pay for solar systems. We'll survey businesses before and after the intervention, conduct monthly phone surveys for six months, and measure air quality in the markets.
Expected impact: This study will provide evidence on whether solar power can be a practical solution for small businesses facing electricity challenges, while also reducing environmental pollution. The findings could inform policies to support clean energy adoption in Nigeria and other developing countries with similar electricity access challenges.
External Link(s)

Registration Citation

Citation
Beaman, Lori et al. 2025. "Green growth: can solar adoption in Lagos boost firm profits while reducing emissions?." AEA RCT Registry. September 08. https://doi.org/10.1257/rct.16627-1.0
Sponsors & Partners

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Experimental Details

Interventions

Intervention(s)
Intervention Start Date
2025-09-15
Intervention End Date
2025-10-31

Primary Outcomes

Primary Outcomes (end points)
Demand for the solar system
Total monthly energy expenditures
Firm behavior (opening hours)
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Firm productivity
Monthly revenues
Monthly profits
Business expansion indicators (new equipment, staff, etc.)
Air quality measurements (PM2.5, PM10, CO concentrations)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
Study Type: Randomized Controlled Trial (RCT)
Setting: Small retail businesses in Lagos, Nigeria markets
Sample Size: Approximately 400 firms

Randomization: Firms will be randomly assigned to one of three treatment arms:
Control Group (expected n=180): Firms receive basic information about the available solar products.
Information Treatment (expected n=180): Firms receive the same as the control group plus targeted information about generator fuel efficiency relative to load capacity and practical guidance on optimal solar use cases.
Free Trial Treatment (expected n=40): Firms receive a one-month free trial of a solar system before participating in the price elicitation mechanism.
Price Mechanism: All participants will engage in a Becker-DeGroot-Marschak (BDM) mechanism, after free trial month has elapsed, with randomized price offers to create exogenous variation in solar system costs and adoption rates.

Data Collection:
Baseline survey measuring current energy use, business operations, and characteristics
Monthly phone surveys tracking energy costs, operating hours, and generator usage over 6-8 months
Endline survey 8 months after baseline
Air quality monitoring using sensors placed in market locations

Timeline: 1 September 2025 to 31 July 2026
Primary Partner: Oolu-Ignite Solar (West African solar provider)
Experimental Design Details
Not available
Randomization Method
The randomization will be implemented using statistical software (likely Stata or R). The randomization code and seed will be properly documented.
Randomization Unit
All treatment assignments (Control, Information Treatment, and Free Trial) are randomized at the firm level, stratified by market.
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
No cluster randomization is employed in this design.
Sample size: planned number of observations
Primary sample: 400 firms
Sample size (or number of clusters) by treatment arms
Control Group: 180 firms
Receive basic solar product information only

Information Treatment: 180 firms
Receive basic solar product information
Receive additional information about generator efficiency and optimal solar use cases

Free Trial Treatment: 40 firms
Receive basic solar product information
Receive one-month free trial of solar system

Total: 400 firms
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
IRB

Institutional Review Boards (IRBs)

IRB Name
Northwestern University IRB
IRB Approval Date
2025-08-08
IRB Approval Number
STU00224268
IRB Name
Lagos State Health Research Ethics Committee (LSHREC)
IRB Approval Date
2025-07-30
IRB Approval Number
LSHREC/2025/0030
IRB Name
National Health Research Ethics Committee (NHREC)
IRB Approval Date
2025-07-31
IRB Approval Number
NHREC/01/01/2007