Our Projects

Small-Scale Biogas in Colder Climates

Three of the gas collectors and water displacement pressure tanks built with Adam Low’s science club students.

January 16, 2010

At the end of 2009 and beginning of 2010, the Culhanes joined Dr. Katey Walter Anthony and her husband Peter Anthony and high school science teacher Adam Low in Alaska. There they built an experimental biogas set up in a 40 ft. conex container in the back of Cordova High School. The digester uses the 3 IBC system that Culhane, Fathy, and Rimoin had designed at Sekem in Egypt to prepare for bringing small-scale biogas to colder climates.

Katey and T.H. had received the first Blackstone Ranch Foundation/National Geographic Innovation Challenge Grant to see if they could harness psychrophilic microbes responsible for climate changing methane release in the permafrost. If their research is successful, they have the chance to improve the prospects for temperate zone and arctic zone biodigesters to offset fossil fuel use.

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Inside the conex six digesters were kept in two separate rooms -- 3 in the 15 C room and 3 in the 25 C room. In each room one digester had psychophiles only, one had mesophiles only and one had a mix of both types of methanogens. The mixed tanks outperformed the others.

Our 20th Biodigester Build

This build at Mike Rimoin’s student housing co-op in Seattle was Solar CITIES 20th biodigester build.

January 16, 2010

A modified Solar CITIES digester using HDPE reactor with solar heat exchanger as reactor and 55 gallon drum telescoping gas collectors. Starter material is elephant dung and manure from 27 other species of animal from the Woodland Park Zoo in Seattle courtesy of horticulturist David Selk and Dan Corum aka “Dr. Doo”.

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Mike Rimoin, who was a Solar CITIES intern in Cairo in 2009 and then helped build a digestor in South L.A., builds his own with Culhane on his birthday in Seattle.

Palestinian Wildlife Society

January 15, 2010

The aim of this project is to use the Biogas in our Arial Home Initiative, and to use this model as an educational model for the Palestinian Communities to encourage them to use this system. Incorporation with Wildlife Society Palestine and the US Consulate EWB Palestine with a help from the American expert Thomas Culhane created the first Biogas system in Palestine.

Renewable Energy in the Latino Community

“Flame on” demonstrated by Alvaro Silva, Director of Solar South Central and Los Angeles and colleague of Solar CITIES, bringing renewable energy systems to the Latino community.

January 5, 2010

Alvaro is the poster-boy for the success of the green-collar immigrant job training concept. As a graduate of Trade Tech College’s renewable energy program and of T.H. Culhane’s early “Eutopia” Class at Jefferson High School in the 1990s where he worked with Culhane on electric and alternative fuel car conversions and green building and solar energy construction. Alvaro worked for Real Goods and for Photovoltaic Installation companies throughout California and now runs his own business in the construction/green retrofit trades and makes instructional videos for the hispanic community. He also brings his ideas to his native Mexico to share with his family and friends and engage in community development.

Building Biodigesters in Alaska

December 5, 2009

In late 2009, after developing our Solar CITIES IBC-based biogas system in Cairo, Egypt in anticipation for building in cold climates, we went to Alaska to experiment with psychrophilic microbial biodigesters in IBC tanks.

Read more about the project in this Free Wheelings blog post.

Experiments with IBCs at Sekem Farm

Students from the Sekem science program inspect the Solar CITIES solar heated IBC biogas system that they helped build

May 12, 2009

At the Sekem Farm and Science School outside of Cairo, Egypt Thomas Culhane, Hanna Fathy and Solar CITIES intern Mike Rimoin deployed their invention of the open-source solar heated three IBC Solar CITIES biodigester. This is perhaps the first use of International Bulk Containers (IBCs) for biogas in the world. Culhane felt it necessary to build a biogas system out of IBCs because he had just won a National Geographic Emerging Explorer’s Blackstone Ranch Innovation Challenge Grant with Dr. Katey Walter Anthony from the University of Fairbanks in Alaska and had to come up with a small scale biogas system that would work in cold weather conditions. The open ARTI India systems they had been building in Cairo wouldn’t work outside in the cold because they would lose heat too quickly. They would also not work indoors because they would create odors and release methane. Meanwhile, typical cylindrical water tanks were either unavailable in Alaska or far too expensive to be feasible.

Culhane and Fathy passed discarded IBCs on the roadside in Cairo and wondered if they could make effective digesters. With a little bit of research, Culhane found that they could be found in almost every country in the world. They are, after all, international bulk containers.

The problem they faced was that unlike the ARTI design, which uses a telescoping tank to hold the gas, the IBC has no storage possibility. Culhane came up with the idea of using three IBCs—one as digester, one to hold the gas, and one to create displacement water pressure to force the gas to the kitchen or generator.

It ended up being easier to produce the gas in an IBC but store it in a typical ARTI. Another option is to use the IBC as the digester and store the gas in a large PVC bag and use a pump to create pressure. But for situations where IBCs are the ONLY tanks available and there are no bags or gas pumps, the the IBC system works rather well.

Culhane, Fathy, and Rimoin tried three different variants of the system. One was a traditional ARTI system with black plastic irrigation pipe surrounding it connected to a solar hot water system. The hot water system is also made with black plastic irrigation pipe as heat exchanger rather than copper. The second was an IBC connected to an ARTI. The third was the three IBC system for places like Alaska where cylindrical water tanks for gas collection are not an option.

Based on these experiments, Solar CITIES demonstrates different options for digesters for different environmental conditions around the world.