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Eco-Hacking: Open-Source Solutions for Energy Access

September 30, 2015

By Michael Floyd

On August 15, 2015, scores of makers, engineers, designers, and mentors began to arrive at a 16th Century chateau west of Paris for five weeks of open source eco-hacking. Their goal: to refine and prototype a set of twelve open source hardware solutions for a sustainable low-carbon economy. The gathering is called POC21—for “proof of concept”—a cheeky play on “COP21” (the international climate summit scheduled to take place in Paris this December). POC21 transformed the castle and its idyllic grounds into a maker’s paradise: an open source laboratory, accelerator, and rapid prototyping facility. As one participant put it, “The geeks have officially stormed the castle.”

Several of the projects seek to change how we generate, conserve, and monitor the use of energy. Here, we profile three projects that aim to increase our control over our personal energy generation and consumption. If successful, their efforts will move us closer to an efficient, low-carbon, distributed energy system that can be adopted worldwide.


The SunZilla team with their existing prototype at POC21. Photo by Michael Floyd. 

SunZilla is an open source portable solar array. Its photovoltaic panels fold out of a central box that also houses the unit’s electrical system and battery power storage. The device was created by members of Bootschaft, a Berlin-based non-profit, to replace the portable diesel generators so often relied upon to power open-air events like music festivals. Frustrated at having to rely again and again on these loud, polluting, and carbon-intensive behemoths, the group decided to create an alternative. The result, SunZilla, is a stark contrast to diesel generators in every way: it is silent, renewable, and clean—not to mention elegant.

The SunZilla team’s ambitions go well beyond energy generation. They envision a whole range of eventual applications for their system—such as water purification, cooling, heating, and telecommunications—and aim to create an open source development community for plug-and-play modules that will make these applications possible.

“It will really spread, and not be a niche use case,” says team member Vivien Barnier. “The idea is that it’s modular and can be adapted to many diverse use cases, and that it promotes open source development.”


SunZilla’s Prototype 3.0, designed and fabricated at POC21. Photo courtesy of SunZilla.

The team’s new prototype is a step in the right direction, and an invitation to participate in SunZilla’s continuing evolution. The simplified design, compact scale, and readily available materials make the unit easier to build and accessible to more people. As the development community grows, we may soon see SunZillas gracing outdoor spaces worldwide.


Showerloop is an open source hot water recycling system for super efficient personal hygiene. Created by a team from Vantaa (next to Helsinki, Finland), the device captures the hot shower water running down the drain, cleans it, and reuses it. According to Jason Selvarajan, the project’s founder, the system uses up to one-tenth the energy and one-fifteenth the water of a conventional “linear” shower system.

Used (grey) shower water passes through a series of filters (sand, activated carbon, and microfiber) and then through ultraviolet (UV) light sterilization before returning, still hot, back to the showerhead. Selvarajan attests that the recycled water produced is of such high quality that it meets or even exceeds both USA and EU standards for drinking water.


Showerloop founder Jason Selvarajan and his work-in-progress prototype at POC21. Photos by Michael Floyd. 

“Water scarcity is growing, in part because of climate change and in part because of growth,” says Selvarajan. “Long showers feel great, but they’re also excessive or luxurious, like leaving the lights on in an unoccupied room. I was trying to change my lifestyle any way to be sustainable, so there was a conflict really, between pleasure and my own ethics. If you can have a long hot shower, and it’s not as ecologically impactful, it’s so much better.”

In true DIY fashion, the fully automated system runs off an Arduino micro-controller and a Raspberry Pi mini-computer, and can be built from common materials using the tools found in a typical fab lab. An array of built-in sensors monitors water and energy use, tracking user behavior and supporting the cultivation of responsible showering habits. Energy and water efficiency have a direct financial benefit to Showerloop’s users. By saving around 33,000 liters of water and 1 MWh of energy per person per year, the device pays for itself in short order.

Showerloop - prototype render

3D render of the new Showerloop filter system, designed and fabricated at POC21. Photo courtesy of Showerloop.

With the new Showerloop design, Selvarajan has managed to reduce the cost of the required materials by half. The new prototype is elegant and transparent. Having seen it run in the middle of a field at POC21, using nothing but a bucketful of rainwater and electrical power from SunZilla, I’m a believer.

Open Energy Monitor

If SunZilla generates energy and Showerloop saves it, Open Energy Monitor is the piece that ties them both together. The project’s creators, Glyn Hudson and Trystan Lea, were inspired by an interest in sustainable energy, and by a desire to better relate to their own personal energy use at home. The old adage “What gets measured, gets managed” is decidedly true when it comes to energy. Without a window into how much energy we generate and use, we’ll be hard pressed to develop sustainable energy systems.

Open E Mon monitor and simple CMS Open E Mon - NICE CMS

The emonPi and the Open Energy Monitor CMS. Photo courtesy of Open Energy Monitor.

The Welsh team’s latest creation, the emonPi, is an open source solution that does just that. It is a Raspberry Pi and Arduino-based, web-connected energy monitoring unit that can integrate flexibly into any number of small-scale energy systems. It posts data to an online system that provides a graphic representation of a home’s energy generation and use over time. Users can track the performance of their home’s energy systems and quickly visualize how much of a given day’s energy was, for example, supplied by their solar panels, and how much came from the grid.

“At the moment most of us don’t have a good understanding of our energy use,” says Lea, “it’s like a black box for many people. I see Open Energy Monitor as a small component of a larger zero-carbon energy system, providing a smart energy layer so we can see what’s going on. It makes sense within a larger process of learning about where energy comes from, how it gets used, and how to increase our use of renewables.”

Open E Mon w VeloM2

Trystan Lea of Open Energy Monitor collaborates with another project in the POC21 electronics lab. Photo by Bilal Ghalib.

Lea is currently developing software to help homeowners make smart choices when choosing their energy sources, retrofitting their dwellings, using energy, and developing community energy projects. With the creation of such easy-to-use tools, Open Energy Monitor’s potential to inform and empower a broad population grows.

What Next?

It’s up to us to take our energy into our own hands, and we have every reason to do so. Rising energy costs and climate change are forcing the issue. For these energy projects to have maximum positive impact, they need massive uptake. To those of us with technical skills, these solutions are readily accessible, and free step-by-step guides on how to build them will soon be available on the Instructables website. For those of who need a little help, kits and readymade units are (or should soon be) available from the project teams. 

Stay tuned…


Michael Floyd is an experienced creative marketer and sustainability consultant. His work at Autodesk supports and amplifies the positive environmental and social impact of the global maker community. Originally from the U.S., he has been a Londoner for seven years.


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