A team of engineers and environmental scientists from Mälardalen University, in Sweden, Southwest Jiaotong University, in China and Guizhou University, also in China, has developed a balloon system for producing and delivering electricity to the ground below. Their work is published in the journal Energy.
Some places are not very conducive to the production of solar power, especially in the northern latitudes where snow can periodically cover solar cells. In this new study, the research team has developed a decentralized way to produce solar power almost anywhere. They call it a balloon-integrated photovoltaic system (BIPVS). A balloon is sent aloft with a solar collector, and it sends the electricity produced down to the ground via an electrical cord.
The balloon is a hybrid—it stays aloft with a mix of air and helium. Its top half is made of transparent material that captures sunlight and concentrates it using its refractive properties. The bottom half of the balloon is made of a material that further concentrates the light and in so doing reduces the installation area of the solar cell that hangs below, without sacrificing harvesting efficiency.
Situating the photovoltaic cells on the bottom of the balloon protects them from rain, snow, sleet, or hail. The system also has an exhaust valve for gas exchange to maintain the desired pressure inside the balloon. Next to the solar cells are storage and control modules to manage power flow. Four cables are used to stabilize the balloon, and a rope and an electrical cord are attached to the ground. The balloon is meant to be positioned just high enough to avoid shade from trees or buildings.
The team has tested their system locally, and have used simulations to study the likely performance characteristics of the BIPVS in five major cities across the globe. They found the average monthly production of one of their balloons to be between 3.5 and 4 GWh of power. They also note that, if desired, multiple balloons could be sent aloft to generate as much power as is needed for a given site.