What better way to teach students about sustainable power than to build a power source, store the energy and then power something the students use? That’s exactly what a handful of AVS parents from the STEM Committee have done, using seed money from one of the past AVS fundraisers: they’ve built a wind turbine and solar panels over the middle school classrooms, called “hangars.” The system is full of teachable moments and questions for both teachers and students.

First, the group purchased a Blue Pacific Solar wind turbine kit. It’s a 520 watt, DIY system available online. It’s the kind of thing people use to power cabins in the mountains for weekend visits.

The first teachable point: sometimes it’s windy, sometimes it’s not. The parents wanted a system that generated reliable power and also stored it. So, they diversified the project, combining the wind turbine with two 260 Watt Trina photovoltaic panels. This way, if there’s sun or wind, AVS gets electricity. Storing it involves two sealed lead acid batteries (two 12 Volt batteries, so a total of 24V, but amplified and inverted from 24V DC to 120/240 Volt AC). There’s also an energy-monitoring device with software that can be read online, so students can see what is being used and what is stored in real time. The idea is that this is a scalable system – more solar panels can be added, with more batteries to provide and store more power.

Okay, so there is a wind turbine with a couple of solar panels and two batteries on the middle school hangars. What can they power? Two outlets, painted green of course, will offer the harnessed energy to students, one each inside the science hangar, the other inside the math hangar. The STEM parents who installed the system – David S., Henry M., Simon T-S, Chris C. and John C. – estimate the power stored in the two batteries might be enough to power most of the middle school chrome books. Another teachable moment for students? – they will need to figure out what it takes to drain the power stored in the batteries.

And another? – building, using and monitoring this sustainable energy system clearly shows that it’s not easy to make the electricity we use at AVS and in our lives more generally. The students and teachers can connect the dots to conservation.

So, if this initial sustainable energy system will power some middle school chrome books, how much more green energy could AVS use? This is yet another teachable point for students to determine: how much electricity the school consumes each month, and how much more could be provided as the wind and solar system is scaled-up. David S., one of the parents who has worked to install this system says, “The next step for us will be to figure out a way the kids can measure how much electricity the school is using and put it in a larger context. Also, there are so many things the math class can do with this system: measure input and output and averages over 24 hours or winter vs. summer seasons. The system is just a great learning tool, providing the teachers a lot of things to work with.”

So, when can the students start powering up their Chromebooks? Most of the green system’s wiring is done, but there are a few programming tweaks to be made before it is operational. Stay tuned.

And this is just the beginning. The system is scalable, and there is talk underway of using more green energy to power the eco cob house built by Mr. Bird and other teachers, turning it into a little “off the grid” house.

***

Special thanks to David S., Henry M., Chris C., Simon T.-S., and John C. They’ve given up precious weekend time to make this happen.

If you would like to get involved in expanding this green energy system at AVS, please contact Ed Walters: ed@altavistaschoolsf.org We would love more parents to help us imagine and build-out the system.