Whether you mount a photovoltaic system on the roof does not only depend on economic factors or political attitudes: there is obviously also a kind of contagion effect. It has the effect that people are more likely to buy a solar system when there are already many others in their neighborhood, as researchers have found out. This contagion effect is even stronger than, for example, our income or level of education.
Whether it is savings on plastic, waste separation or a plant-based diet – awareness of climate-friendly behavior has been growing in the population for years. And that also applies to electricity generation: Solar cells are increasingly appearing on house roofs with which private individuals can generate electricity in a climate-friendly manner. In Europe in particular, the density of smaller photovoltaic systems is very high.
Investigating influencing factors
But what influences people to buy solar cells for their own house? Scientists working with Kelsey Barton-Henry from the Potsdam Institute for Climate Impact Research have now investigated this question. “In order to create incentives for achieving climate protection goals, it is important to understand the mechanisms that influence individual climate decisions such as the installation of solar modules,” explain the researchers. The team was already aware that role models in people’s immediate surroundings can be relevant for decisions about one’s own energy supply. How much the solar cells on rooftops in the neighborhood influence people to purchase a solar system, the scientists have now examined using the example of the city of Fresno in the US state of California.
“We combined census data for each county with high-resolution satellite data that can identify any solar panel in Fresno,” explains Barton-Henry. “Then we trained various machine learning algorithms to find the connection between people’s socio-economic environment and the likelihood that they have a solar panel.” The research team also compared this effect with influencing factors such as income, unemployment rate or the Level of education and the age of the people who own solar cells.
The “contagion effect” works up to 200 meters
The result: Apparently the likelihood of buying a solar system increases, especially if there are many solar cells in the vicinity of your own house. “In principle, if you see a solar panel from your own window, you are more likely to decide to put one on your own roof,” explains co-author Leonie Wenz. “You might think that other factors are more relevant, for example income or educational background or word of mouth within the same social network as in a school district,” says the researcher. “So we compared all of these different options and we were amazed at the result. It turned out: No, geographic distance is really by far the most important factor. The more solar systems there are in close proximity to my house, the more likely it is that I will also have one. “
However, this “contagion effect” only applies to the immediate surroundings, as the researchers found. “The contagion effect decreases exponentially the further away the nearest solar system is from a house,” reports Barton-Henry’s colleague Anders Levermann. “The probability of having a solar panel on the roof is roughly halved over the length of a football field.” The influence of neighbors on one’s own motivation to install photovoltaic systems therefore only lasts up to a distance of 210 meters. From a radius of 500 meters, the researchers were barely able to determine an infection effect. In addition, it was found that the influence of the immediate environment was somewhat more pronounced in low-income groups with an annual income of 42,000 US dollars than in higher-income groups with around 80,000 US dollars per year. However, this observation could be related to the fact that high-income groups in Fresno tend to live in less densely populated areas, the research team suspects.
Also relevant for political action
According to the scientists, the result of this study can now be relevant for political measures to protect the climate. “The results suggest that ‘sowing’ solar panels in areas where there are only a few, a city district and ultimately the region can be convincing,” says Levermann. “If more solar systems lead to more solar systems, it can lead to a tipping point – a good one this time. Climate researchers describe the tipping point when a threshold is exceeded that results in a sustained change in the state of a system. “It is therefore important to research climate decisions in order to identify positive social tipping points, both small and large – for a secure future for everyone,” says Wenz in conclusion.
Source: Potsdam Institute for Climate Impact Research, Article: Scientific Reports, doi: 10.1038 / s41598-021-87714-w