One hurdle that general acceptance of renewable has had to overcome is the problem of aesthetics. Disgruntled citizens complain of wind turbines disrupting their skylines and bulky solar displays lowering their property value, among other things. The chorus of “not in my backyard” has been heard globally in protest against the installation of renewable energy structures. However, in the past years engineers, designers, and artists have been teaming up to brainstorm and implement designs that are not quite purely functional, not quite mere art, but something inbetween. In particular, “solar trees”—statuesque installations that use solar energy as their source of power—have been cropping up all over the world, each with its own distinct look and functionality.
In Israel, if you were to visit the nature park Ramat HaNadiv you would find what looks like a cartoon tree statue. In reality, this metal structure is equipped with solar panel leaves. Dubbed eTree and created be Sologic, this structure is an intersection between art and engineering. The solar panels provide power for charging electronics—up to 35 laptops at a time—as well as shade so that park goers can rest on nearby benches in comfort. Other features of the tree include free Wi-Fi and water fountain options for both humans and pets. At night, the excess energy stored in the battery is used to light up the park.
In Europe, a structure called Solar Tree, designed by Ross Lovegrove, has been featured in a variety of cities including Vienna, Milan and Paris. This tree functions as an artistic street lamp, collecting energy during the day and using it to power LEDs at night. Some of Lovegrove’s Solar Trees also include seating areas, making them more interactive to the public. With Lovegrove’s background as a designer who has featured exhibits in places like New York’s Museum of Modern Art, it is no wonder that of the solar trees I have researched, this one looks the most like it was intended to be a sculpture rather than a work of engineering.
Further east, Singapore has incorporated a different type of solar tree in their 250-acre Gardens by the Bay, a large nature park and tourist destination. There, they have a grove of Supertrees, which in my opinion are the most remarkable variation of this idea, both aesthetically and functionally. These giant solar powered structures, ranging in height from 80 to 160 feet, also use energy from the sun to provide electricity for lights at night. They also help regulate temperature by providing shade and collect rainwater for the park’s irrigation systems. Beyond these mechanical functions, Supertrees also work as vertical gardens: over 200 species of soilless plants can be found planted along the steel frame of their trunks. For the tourists, one of the Supertrees even contains a restaurant at its apex.
In the U.S., solar powered charging stations called Street Charge are being incorporated in urban environments. Beginning with installations in Brooklyn, this design uses three slender solar panels to provide energy so that people on the go have a place to replenish the batteries of their phones using renewable energy. This power station even comes with its own variety of weather-proof phone chargers as well as USB ports so users can charge any device. The slender design occupies minimal space, and the structure is lightweight enough that it can be easily set up with just two people. With simple installation and minimal upkeep, the minds behind Street Charge hope to spread their design to more cities to be used in city plazas, parks, and campuses.
On the West Coast, a different type of charging station made by Envision Solar is also making itself known. Instead of charging phones though, the energy from these panels are used to power electric cars. Also named Solar Tree, this structure can completely charge six cars daily and provide shade for them as it does so. They also come in a smaller design suitable for just one car and ideal for more crowded spaces. As electric vehicles become increasingly popular and cheaper, Solar Tree is an inventive way to drive in an even more sustainable fashion.
Here at Northwestern, there are plans for a solar tree to come to campus. As a member of Northwestern's Engineers for a Sustainable World, I have been helping with the design and analysis of the SmartTree for the past year and am currently one of the project managers. The SmartTree consists of a concrete trunk and eight metal branches, each with its own solar panel leaf. A table and benches surrounding it will serve as an outdoor seating area where students can sit and charge their laptops and cellphones using the solar energy provided by the structure. We hope that bringing the SmartTree to campus will allow students to interact with sustainable energy in a personal manner, and we are very excited to have it built sometime soon!