Participation is the fuel

Adoption of photovoltaic systems has been thought of in some countries as a choice influenced by political preferences. In the US, this polarization may be even stronger due to political polarization around climate change. Now, research shows that photovoltaic adopters can be found in both parties and they are politically active.

The transition towards low-carbon electricity and energy systems are driven by social1, political2 and technical processes operating at multiple, interlinked levels of society3. These transitions are, in part, characterized by changes in how electricity is generated: diffused renewable technologies are reshaping the ways regions are producing electricity, along with ownership and perceptions about the electricity system itself4. In the US, understanding the socio-political landscapes underlying energy transitions is relevant to the operationalization of sustainable transition beyond polarizing climate change related debates5. As a family of technologies, residential solar systems, and especially photovoltaic (PV) systems, offer an excellent perspective for understanding the behaviours of voters. PVs are accessible to households, and the decision regarding whether to install such systems is taken almost solely by family members. In addition, several states have initiated incentive programs aimed at removing barriers to adoption. The success of these systems in the US is evident: in just 10 years, from 2007 to 2017, the number of households adopting PV systems has increased from 13,000 to 1.2 million (Fig. 1), and the electrification of certain sectors, such as transportation, has encouraged adoption by firms and public institutions (for example, commuter lots). Determining whether this growth reflects partisan preferences of PV adopters is key to understanding whether party beliefs affect household energy choices, and, ultimately, whether partisanship can boost or hinder low-carbon transitions, and what role voters play6.

Fig. 1: Annual adoption of PV systems in the US.

Number of residential and non-residential PV systems (left y-axis) installed in the US from 2007–2017 and cumulative number of PVs installed (right y-axis). Adoption has been driven by residential systems since 2007, with spikes in 2015 and 2016. Data from ref. 12.

Writing for Nature Energy, Matto Mildenberger from University of California Santa Barbara and colleagues report a lack of political polarization among PV adopters, finding similar adoption rates for members of both parties7. More importantly, they find adopters are more politically active regardless of political affiliation. Their work analyses an author-built dataset of combined PV-adopting and non-adopting (neighbouring) addresses, created by randomly stratifying PV adopters at the US Census tract level and matching household-level and address-specific demographic and environmental characteristics. Their sampling process makes it possible to subsequently match relevant vendor-provided voter data and control for spatial effects. Their work has one major key finding: differences among residential solar system adopters and non-adopters cannot be explained by party affiliation. This is notable for two reasons. First, previous research has not reached a definitive answer when it comes to adoption behaviour for PV systems and party orientation in the US, and this study gives us a country-wide assessment at a fine scale, controlling for multiple factors, including the lack of differences between partisanship even in the case of first adopters (that is, those adopting first in their Census tract). Second, it tells us that the divide on energy transitions may reside within a more complex landscape than a simplistic ‘Democrats versus Republicans’ or ‘Liberals versus Conservatives’, but, rather, reflects a landscape where voters break away from their current party stance, reminding us that these stances may change or may have already changed. Some partisan differences do, however, emerge when comparing voter contributions: Democrat adopters were slightly more likely to have made donations to their party (0.9% versus 0.3%), whereas Republicans made higher donations to their party (US$657 versus US$500). These results were consistent when the authors controlled for them via a linear probability model, along with other drivers that the literature has previously identified.

Mildenberger et al. find that the political act of adopting residential solar systems is not Democratic or Republican. Rather, it is an act of politically active voters: those adopting PV systems are characterized by a more active voter record. This link between the act of adopting PV systems and political activism is important because it suggests a role for PV adopters as sources of social examples to (potential) agents of an energy transition both ‘on the ground’ and through their political participation. Of course, we do not yet know how much climate and energy issues matter in relation to other issues to these ‘agents’. The agents’ profile emerging from this work opens new opportunities for researchers and policymakers; for example, if partisanship does not influence PV adoption, can adopters, because of their higher political activism, bridge the partisan divide, or will they shape their own party discourse on renewable energy? Would these results still hold if we were to look at large-scale renewable energy technologies?

In addition, the study contributes to previously unexplored questions on PV adoption, such as whether people’s behaviour differs across different political landscapes8. For example, in Germany PV adoption was linked to an increase in votes for the Green Party8, whereas this study shows that in the US this technology has been picked up by politically active voters within the two major parties. This difference highlights how sustainable transitions can be highly context dependent, in this case on the political landscape within which citizens make their choices. Importantly, this contextual finding returns the role of politics (rather than partisanship) in something that may appear as ‘just a technological’ change or an economic issue.

As the discourse around climate change becomes more relevant at national and global scales, identifying new defining characteristics across voters becomes pivotally important for enabling a fast-paced transition toward sustainable, low-carbon electricity and energy systems. Within this broader context, the study from Mildenberger and colleagues7 may help overcome the sense of ‘otherness’ that often results in the perception of issues as politically divisive and polarizing across party lines9, when, in fact, they are not, as well as help deconstruct the imagined geographies of adoption10,11, both physical and political.


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Graziano, M. Participation is the fuel. Nat Energy 4, 1012–1013 (2019).

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