Providing rooftop solar power to people with low incomes has benefits for the public and the environment.

But it can’t happen unless the nonprofit organizations that administer programs are able to get in touch with households that qualify for the help and are interested in it. And that’s sometimes difficult.

“It can sound too good to be true when you’ve got someone saying we can give you solar panels at no cost,” said Kim Wolske, a University of Chicago professor of environmental psychology.

She and her colleagues have taken lessons from behavioral science to find ways to dramatically increase the ability of organizations to obtain referrals for new customers. The research, published in the journal Nature Energy, was done in collaboration with GRID Alternatives of California, a nonprofit that works to expand access to rooftop solar and provides job training for installers.

GRID has done thousands of rooftop solar installs and it has a long list of previous customers that it can ask for referrals. In addition, the organization offered $200 to previous customers who submitted referrals of qualified customers. (By qualified, I mean customers who meet standards for having low to moderate incomes, have roofs capable of supporting solar and either own their homes or have permission from the owner to install the panels.)

GRID was interested in looking at ways to generate more referrals at the same time that Wolske and her colleagues were studying this subject.

In the resulting experiment, GRID and the paper’s co-authors sought a new round of referrals from 7,500 or so previous clients. This time they separated the pitches into several groups that would get different messages.

The first group got the same offer as before: a $200 payment for a successful referral.

The second group got that, plus a $1 “thank you” gift, just to show appreciation for the recipient having participated in a GRID program in the past.

The third group got the same as the second group, plus a postage-paid envelope and a referral slip to submit contact information in writing. This was in addition to being able to submit referrals online or by phone, which was already the case.

While the $1 bill and the referral slip may seem like small steps, they substantially increased the response rate. People who received both the $1 and the referral slip provided 7.5 times as many names as those who got neither, and the number of referrals that led to a solar installation was five times higher than those who got neither.

“It really speaks to the importance of designing these programs well, and not just thinking about financial incentives as the only tool to shift behavior,” Wolske said.

The $1 gift is an example of the idea of reciprocity, the paper says. Behavioral scientists have found that giving a gift, even if it’s a small one, will make the recipient much more likely to reciprocate by helping the giver.

I asked Liza Nobel, GRID’s director of outreach marketing, why it’s important to deploy rooftop solar to low- and moderate-income consumers.

She said part of the answer is that these consumers have been disproportionately impacted by climate injustice and pollution. And, they use a large share of their disposable income to meet energy needs. (The Department of Energy has said that the national average energy burden is 8.6 percent of household income in low-income households, which is about three times higher than the burden in non-low-income households.)

“GRID understands that a just transition to clean energy, that benefits everyone, requires that environmental justice communities have access to sustainable energy technologies, like solar and batteries,” she said.

California, Colorado, Massachusetts, Minnesota, New York and Oregon are among the states that have been leaders in developing solar programs that serve low-income households, according to the National Renewable Energy Laboratory.

State programs are poised to expand, thanks to increases in funding by state governments and the availability of funding from several provisions of the federal Inflation Reduction Act.

While the details on implementation are still rolling out, Nobel said she expects the IRA to provide a substantial increase in funding for the programs over the next few years.

So, research like Wolske’s paper is likely going to help meet a need that’s only going to grow.

Other stories about the energy transition to take note of this week:

CATL Says It Has Made a Breakthrough in Cold-Weather EV Charging: CATL, the China-based battery maker, has developed new materials for lithium-ion batteries that would improve charging efficiency for electric vehicles, especially in extreme cold, as Zhang Yan reports for Reuters. But the company provided almost no technical details about how it did this. Faster charging, even in cold temperatures, would be a big step forward for EVs, and CATL, the largest battery maker in the world, wouldn’t make such claims lightly.

Here’s How Dirty Diesel Ships Can Start Decarbonizing Now: Cargo-shipping companies are under increasing pressure to reduce emissions from the world’s merchant fleet, and Maria Gallucci of Canary Media has a good rundown of current efforts in this sector. One of the promising approaches is to increase use of various forms of wind power, including technologies that don’t look at all like sails but are able to capture the wind to help propel ships.

As Texas Cranks Up the AC, Congested Transmission Lines Cause Renewable Power to Go to Waste: Texas has more renewable energy generation online than any other state, and these resources have been essential to meeting high demand for electricity during this summer’s extreme heat. But the state has been limited in its ability to deliver electricity from renewable sources because of a lack of transmission lines to deliver power from where wind and solar farms are located to where demand is highest, as Keaton Peters reports for ICN. This is not a new problem, but it has become more extreme as more renewables come online and electricity demands increase.

State Clean Energy Goals Are a ‘Key Driver’ for Generation Growth, but Impact Differs Between Regions: Renewable power requirements set by states often correlate with that state’s total renewable energy production, but there are exceptions, as Diana DiGangi reports for Utility Dive. A report from Lawrence Berkeley National Laboratory shows how state laws can help to drive results, but I find it especially interesting to look at states where renewable development has far exceeded mandates. The best examples of this are the wind-rich parts of Texas and the Midwest.

Large Utilities Aren’t Jumping to Use New Incentives for Carbon Capture: Despite substantial government incentives, most of the country’s largest electricity producers have no plans to retrofit their plants to use carbon capture technology, as Carlos Anchondo, Jason Plautz and Zach Bright report for E&E News. Most of the companies have no active projects, citing the financial risks and low probability of success of carbon capture retrofits. This is even though the Biden administration’s proposed power plant rules say that carbon capture is one of the only options that would allow old fossil fuel plants to continue to operate in the long run. This reticence by large power producers is happening at the same time that smaller companies are the ones planning to do carbon capture projects, as I wrote about last week with Project Tundra in North Dakota.

Inside Clean Energy is ICN’s weekly bulletin of news and analysis about the energy transition. Send news tips and questions to [email protected].