Dozens of US states are considering legislation to allow people to install plug-in solar systems, often called balcony solar. These small arrays require little to no setup and could help cut emissions and power bills. Balcony solar is already popular in Europe, and proponents say that the systems could make solar power more accessible for more people in the US, including renters. As popularity rises, though, some experts caution that there are safety concerns with how balcony solar would work with existing electrical equipment in homes. Let’s talk about what balcony solar is, why it’s unique, and how new testing requirements could affect our progress toward deploying the technology in the US. Plug-in solar systems are designed to be simple to install, often requiring no electrician or specialized worker at all. They’re small, and many can be plugged into existing outlets. People across Germany have installed over a million balcony solar systems.…