On July 27, 2017, construction of Canada's first solar sidewalk began on campus at Thompson Rivers University in Kamloops. This 16 module sidewalk is approximately 40' long and the 1.28 kW DC array is expected to produce around 1300 kWh/year. It is a grid-tie system which works without batteries, and it is connected directly to House 4 - the home of the university's Office of Sustainability. We are going through BC Hydro's net metering program.
The solar sidewalk is the prototype for the much larger Solar Compass project that will start at the end of September 2017. It provided our team with an opportunity to develop a quick, low-cost, and aesthetically pleasing installation methodology that takes advantage of existing infrastructure.
Here's the sidewalk before installation. We intentionally picked a challenging location with lots of shade from trees, buildings, and parked vehicles to test out the technology. In the real world, things get in the way!
With the help of a local concrete company, a channel was cut into the existing sidewalk. This channel is approximately 2" deep and 5" wide. It is the raceway for our wiring.
Oliver Zimmermann from Solar Earth Technology (below) hand fabricates bridges from recycled plastic 2X4s. These bridges provide support between modules across the span of the channel and allow us to create a continuous watertight seal around the modules.
We were lucky enough to have two electricians and one electrical engineer working on this project including TRU electrical foundations faculty member Amie Schellenberg, Ben Giudici from Riverside Energy, and staff electrician Gord Setka. Three dedicated TRU electrical students also did a lot of the grunt work. Thanks Eli, Cody and Bryan. Here's Amie working on the wiring.
Once the surface was prepared and wiring connected, the modules were ready to be glued down. They are only 1/4" higher than the existing sidewalk.
For the sidewalk we decided to frame the entire array with stainless steel. Using conductive metals like this required that the equipment have a common and continuous bond. Here's a photo of the first module with bonding. You'll see a bonding ribbon that connects to a green wire that ultimately goes back to the equipment located in the basement of House 4. A big thank you to Harrison Industrial Contracting Inc in Kamloops for donating the bonding ribbons for this project. They responded instantly to our last minute search for these items to keep the project moving forward.
The solar sidewalk project is also located in front of the university's Daycare Centre. Here a youngster tried out the sidewalk in bare feet. He was one of the first people to ever walk on it! The surface of the modules is designed with a surface texture that gives them excellent slip resistance.
Project lead Dr. Michael Mehta stands beside the sidewalk after a long first day of work.
And, the team from Solar Earth Technologies look on proudly at their newest project. They kindly donated the modules to the university, and have worked closely with the project team to make this a reality after 2+ years of development and planning. From the left to right is Brian Johnson, Oliver Zimmermann, and Dr. Jason Wang.
One of the unique features of the solar sidewalk is that the modules have been specially designed for pedestrian traffic. Normally, a solar module used on the ground - where shading and debris are common - would suffer from significant power loss. These modules have cell-level optimization and each of the 20 cells per module have something called a "shunting diode" to bypass cells that are shaded. This prevents the entire module from experiencing reduced power output. You can see the little rectangles in the corners of each cells - these are the diodes.
Here's what the finished solar sidewalk looks like with its stainless steel frame. For the Solar Compass project we are going frameless!
Solar modules produce DC power yet homes and businesses typically use AC power. The wiring from the solar sidewalk goes underground through conduit into House 4 where it runs into a set of micro-inverters to make the power usable. We used recently released, high-performing micro-inverters made by Enphase Energy called the IQ 6+. Here's what they look like when all the wiring is done. There is also an internet-based monitoring system that will be made public soon.
Our team is now getting ready for a 64 module array - the Solar Compass. It will be located here on campus.
Thank you to our team of volunteers, Solar Earth Technologies, TRU for funding the installation of this project through a sustainability grant, and our community partner - the Kamloops Chapter of the BC Sustainable Energy Association.