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Interview: Biogas researcher Ben Underwood

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Ben Underwood is a young American researcher who recently moved to Kunming to conduct a feasibility study for the development of a large-scale biogas plant. He has previously worked in Kathmandu, Nepal, where he coordinated the installation of five community-scale anaerobic digesters for urban waste. Before moving to the Spring City, he spent six months in Austin, Texas, where he set up his company, Fuelcity. Underwood holds a bachelor's degree in sociology from Bennington College.

GoKunming: Could you tell us a bit about your work here in Kunming?

Ben Underwood: Right now I'm living in Chenggong, working with Yunnan Normal University. I'm working with them to develop a biogas project, also known as anaerobic digestion [AD], which converts organic waste and organic material into methane gas and fertilizer. I am here for one year, on a US government Fulbright Grant, to conduct a feasibility study for a large-scale project, which will process food waste from colleges and cafeterias in the university area.

GK: What is an anaerobic digestion system and how does it work?

Underwood: You could view it as a big can, a big tank filled with bacteria. Anaerobic means there's no oxygen, it's airtight. A massive culture of bacteria is developed inside the biogas tank, which consumes organic material and breaks it down into very simple by-products. The majority of it ends up as methane gas, which you can burn and use for fuel. You can really think of it as an industrial-scale cow stomach.

GK: Why Kunming?

Underwood: I sent a lot of emails out to all over China for different universities I could work with. This is partly because working with a university was a requirement for my government grant, and also because universities have access to laboratories and can do work and research required for the feasibility study, essentially for free. Professor Zhang Wudi [张无敌] replied.

Now that I have been here for a little while I realized Kunming is optimal for renewable energy in general, and biogas in particular. I recently visited the office of a French NGO, Initiative Development. They also work with biogas, but in rural villages, and their office is in the city center on the twenty-fifth floor. So I looked out of their window, and couldn't see any roofs, because they are all covered with solar water-heaters. It could be just because the weather is sunny, but I really think there is a culture and a growing awareness here about developing renewable energy. And then, with regards to biogas in particular, [this technology] needs a warm climate, because biogas works best at body temperature.

GK: Are there other similar ongoing projects in China?

Underwood: There are many large-scale projects in China. Either all the funding or the majority of it comes from the government, which approaches it as a way to manage food waste. Right now, almost all [the food waste] is bought by pig farmers and fed to pigs. This is a rather sensitive topic — the level of sanitation of this food is not high, and that affects the pigs' meat and can ultimately influence people's health. It lies in a legal gray area.

The problem is, selling out food waste as pigs' food [still] makes more sense than giving it away for free to anaerobic digestion projects. So these very large-scale facilities are built, with investments of hundreds of millions of dollars, but many are only operating at about only five percent capacity, because they do not have a stable supply. Even though anaerobic digestion projects are offering to take and dispose waste for free, there's no coordination and no economic incentive for waste-suppliers to give it away.

GK: How has working in China been different so far?

Underwood: From the start I have been pleasantly surprised. Compared with the US or Nepal, China has been by far the easiest place to work on a project. A large part of that I could probably attribute to work with Zhang Wudi and his researchers. The value they see in this project and the resources they've offered me to carry it out have been amazing. What would have been probably three or four months of me going around networking and knocking on people's doors has been eliminated by Zhang Wudi's connections, his guanxi.

Distribution center biogas plant: an industrial scale plant attached to a supermarket chain's distribution center. This is the type of plant Underwood hopes to develop here in Kunming.

GK: What will be the next steps for your project?

Underwood: The feasibility study is going to be written for an audience of investors and by September 2015 we hope we'll be able to show it to investors. It will include contracts with waste suppliers and energy buyers, to show what kind of return [an investor] can get from it, and if government subsidies will be required. The ultimate goal is for my company in the US, Fuelcity, to build a partnership with an entity here in China to operate the plant for profit. This is the difference with the projects I've mentioned earlier — the goal is to make money, so that people will have an interest in making it work at 100 percent capacity.

GK: Will you look for private investors too?

Underwood: Yes. There's a lot of support from the Chinese government available for this kind of project, so I think it will be a partner in the project. But we are also looking into bringing private equity and private investment into the project, just as a way of ensuring quality.

GK: What are the concrete benefits that an AD system can bring to a community?

Underwood: The benefits for the community are my favorite part of any AD projects. Biogas plants, more than any other renewable energy project, require a lot of different kinds of people to be involved. It's usually people who are not in the same circles in society, such as farmers, who buy organic fertilizer, public or private institutions, which buy power, and schools, colleges and restaurants to supply the waste, logistics transportation of materials and transmission of power. The AD system becomes the fulcrum for a community of people, who are eating food, throwing it away, growing it — a biogas plant can tie it all together.

What happens now is that the food goes from the farm to a landfill — about 40 percent of the food produced in the US goes to waste. Here in China it is fed to pigs, and that has its own complexity. Biogas, instead, is a way of closing the loop — the waste is turned into fertilizer, which can be used to grow more food. The direct benefits to the community are that cafeterias and restaurants are able to dispose of waste more cheaply, since we pay them for their waste. The bigger benefit is that [a community] produces its own energy, namely methane. That means it doesn't have to be extracted from underground, and it doesn't add to the CO2 in the atmosphere. [Doing this, we can avoid] extracting methane — taking carbon that is locked into fossil fuel, unlocking it and introducing it into the atmosphere.

GK: What can methane be used for?

Underwood: As transportation fuel, for example, [some] buses and garbage trucks in Kunming are powered by natural gas. A lot of fossil fuels are imported in China and are quite expensive. The idea for us would be to purify the biogas up to a point where you could use it as transportation fuel, and therefore have a really good economic return. Otherwise you can burn it in stoves or use it to generate electricity.

Homescale Biogas Nepal: a Nepali woman cooking with gas produced from cow dung

GK: Can it replace fossil-fuel energy?

Underwood: A biogas plant collects the garbage from the city and turns it into methane, which can be used as fuel. Otherwise the methane gas has to be imported from other countries and piped all the way down to [where it's needed], as opposed to taking the garbage from the city. [That garbage] is produced from food grown here in Yunnan, and turning it into power for the community, this cuts out the chain of value and events. The Chinese government is indeed interested in natural gas as a way to avoid using so much coal.

GK: Do AD systems have any drawbacks, or do they produce any waste?

Underwood: Strictly speaking there is no waste. The biogas is usually two-thirds methane and one-third carbon dioxide, with some other trace gases in there. CO2 is not easily usable, but fertilizer and methane are. [The main problem] is that it's hard to make these projects pay back in a short enough time for people to want to invest in it.

So you either have to find government investment, or subsidies or find other ways to make the project pay out. Generally, for private investments, they have to make their money back in about five years — maximum ten years — which is really hard to do. [Another issue] is that you are working with a lot of different people who normally don't work with each other. You have to motivate them and show them the concrete benefits of such a project.

GK: Could biogas plants be implemented in remote areas, on a family-based scale?

Underwood: Actually, the evolution of AD systems is going [from small scale] towards larger scale. China is trying to be the world leader, with about 40 million home-scale biogas plants. [Unfortunately], maybe a third of them are not in use. The problem is, they are sometimes built not to very high standards, often without setting up a supply chain or a value chain. So people do not have the economic motivation to maintain these plants. Nepal is very successful in home-scale biogas projects, but instead of food waste they use the waste of cows, which most rural families have access to.

Kathmandu kitchen waste digester: a plant Underwood renovated in Kathmandu. The yellow tube visible to the right delivers biogas to a kitchen

GK: Could AD systems utilize other animal waste or waste oil?

Underwood: Not just waste but any organic material, with very few exceptions, can be used for AD. The higher the caloric content of that material, the more methane you can get out of it, the more valuable it is. Waste oil, being very rich in fat, is excellent.

GK: Many places in the world haven't been reached by electricity yet. Do you think in countries where this is still the case, electricity could be bypassed and other, "greener" sources of energy be employed?

Underwood: I have been reading Jigar Shah, the founder of a US company called SunEdison. He is the closest thing to a hero of distributed energy. China is one of the few developing countries that has had some success in extending its power grid to the last village, [at least in Yunnan]. But I'm sure that [many villages] still experience unstable and unreliable power.

To make an analogy — which is directly influenced by Shah's thinking — if you had a cafe, and the only way to connect to the internet was that there is one outlet in the middle of the room and everybody had to run a cord to that outlet, and then we had another cafe that has wi-fi, which one would you choose? That's the difference between central energy distribution and distributed energy distribution.

The future of energy, as I see it, is distributed energy. It's more stable. If one part of it goes down not everybody is affected, whereas if you have one central power source and it goes down then everybody is affected. Also, it gives more power to communities and individuals. Now, government and companies are the only people who can afford to put together million dollar investments to make it. We are looking at a 100,000 USD investment in a biogas plant or a 200,000 USD investment in a solar facility. Or even just 1,000 USD in a home-scale biogas plant. This means giving people the keys to their own energy. It returns power to the people.

Top image: Chiara Ferraris
Diagram: Iona Capital
Factory image: Biocycle Magazine
Other images: Ben Underwood


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For a brief moment, I thought Steve Merchant was in Kunming.

Sounds like a good project, but what about the CO2?

How about using all the plant waste coming out of Dianchi? There must only be thousands of tonnes of organic waste every year...

Hey, Ben Underwood here, aka the Steve Merchant of Kunming.

Alien, to answer your question: the food waste that AD plants break down into CO2 and methane was once plants and animals that incorporated CO2 from the atmosphere. So AD plants don't add any NEW CO2 to the atmosphere.

In fact, by replacing fossil fuels, they reduce the net amount of CO2 in the atmosphere.

Blobbles, you're right about the massive amount of organic matter coming out of Dianchi. The biogas research platform I'm working with at YNNU has been studying the anaerobic digestion of water hyacinth for years.

Any plans to use the plants they scoop up for power generation and fertiliser?

They may not wish to use the plants as a fuel source though - creating an industry based on the stuff you want to eradicate e may mean you never eradicate it...

never heard of biogas before. this seems more interesting and useful than teaching english. ha ha.

@noonbrewdude: Hey, that's good about the CO2 - obvious, I guess, once one sees it.

@blobbles — The Economy and Environment Program for SE Asia did a feasibility study for just such a program last year: www.gmanetwork.com/[...]

Not sure what stage the project's at now.

Wouldn't it be more of a win\win scenario if the farmers got pig feed and you fermented pig waste? Or does pig waste sell for even more?

Hi Ben. Your project sounds really cool. I'm very much into sustainable fuels and farming and water usage and energy. I've lived here in kunming for 6 years I know the city well and I'd love to help out if you need interpreting or some other kind of help let me know.

@AlexKMG — The big problem with feeding untreated food waste to swine, especially if that waste contains or has come into contact with meat, is that it spreads pathogens and makes people and pigs sick. The practice is illegal in the US: definitions.uslegal.com/s/swine-health-protection-act/
But common in China.

I'm not aware of a market for pig waste, though there could be one. The anaerobic digestion of pig waste in China is common practice: www.i-sis.org.uk/BiogasChina.php

@CHinizzle — feel free to PM me and let's set up a time to talk.

good, what about design equation

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