Biodigesters and the Community Energy Revolution. Interviews Joe Russo, ECOregon
Biodigesters and the Community Energy Revolution. Interviews Joe Russo, ECOregon

"Anaerobic digestion (AD) is applicable to a wide range of situations, but synergy is most realized at facilities like Stahlbush Island Farms in Corvallis, OR that: 1) Have access to sizeable organic feedstock at little to no cost; 2) Require electricity and heat which can be provided by a biogas-powered combined heat and power (CHP) unit; and 3) Can utilize the digester effluent as compost, liquid fertilizer and irrigation water. Macronutrients contained in the processing waste, which would have otherwise been exported off site, can be recovered for land application."

"Grower Processor Invests in BioGas Plant", Biocycle, 01/10

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Can anybody put in a biodigester? Talk about the economies of scale and upfront investment per size and type of implementation.

The first step to discover if a project is going to be viable would be to perform a feasibility study. An anaerobic digester feasibility study will include an assessment of the companies waste streams and other locally available feedstocks, case study review, methane and electricity yield estimated description of suitable digester technologies, end product usage, utility interconnection and permitting requirements and financial modeling. A summary report containing the findings of the overall conclusions, recommendations and list of resources is then delivered to the client.

The economies of scale are really determined by a few factors. The first is the amount of waste that is available and if the waste has to be purchased or there is a cost involved in the collection and does the waste have a high Biochemical Methane Potential (BMP)? The second is the amount of grants and funding available to a project. A biogas project in one state can be feasible with small amount of tonnage per day if there is a large amount of incentives and grants in that area. If that state or area is not supportive of renewable, it would take an extremely large amount of waste to get a project of the ground.

The third is the ability to use the power that is generated and sell the extra power back to the power company. If you are not able to sell the power back to the power company or if you have a very low Power Purchase Agreement (PPA) with the power company, the project could have difficulty penciling out.

The upfront investment of the feasibility study on a biogas project is one of the most important factors in determining if a biogas project is financially feasible. There are a number of avenues that can help pay for the cost of the anaerobic digester feasibility that can be perused both on the federal, state and local levels.

Can home owners get one? Are there any planning and/or zoning ordinances in the way - city or county?

A home owner could use the same basic technology to build a small model. One would have to look at both the feedstock (waste) that is going into the anaerobic digester and what can be done with the methane that is produced. Rather than each home owner have an anaerobic digester, it would be better to have a community digester or what is also called a destination digester.

A destination digester would be a biogas plant that the whole community would be able to feed by curb side collection of organic waste. This would add to the amount of feedstock that is going into the biogas plant, thereby increasing the amount of methane that is produced and gaining some economy of scale. Then the community would be able to produce their own electrical and thermal power from fueled by the methane running a CHP unit, essentially making the community self sufficient and off the grid.

Who is green certifying anaerobic digestion and biogas systems? Are there competing eco-labels here?

The digesters themselves are not in any way green certified. However the electrical energy from the methane fueled CHP will get green certified. When the biogas plant is producing power and selling all the power back to the power company, the power company monitors the amount of power that the producer is making. If Renewable Energy Certificates (RECs), also known as green tags are involved, there is a company called Green-e? that is one of the nation's leading voluntary certification programs for many types renewable energy.

Are biodigesters considered a closed-system? What are the operational dangers here?

Anaerobic digestion (AD) is proven technology, immediately available for commercial application from an ample number of qualified venders with flexible designs. Anaerobic digestion has additional benefits with its positive net energy balance, reduction in greenhouse gas emissions and the ability to close the loop on nutrients. When implemented properly, AD has the potential to provide energy independence, carbon emission reduction and waste management solutions while producing renewable energy and co-products - a sustainable solution for many farmers, food processors and manufactures, its customers, its community and the planet.

Given anything under the sun, what makes the best material to "run" a farm biodigester?

Co-digestion is important part of the anaerobic digestion and the amount of methane yield. One of the better materials to feed the biogas plant Fats Oil & Greases or FOG, but it again depends on the quality of the FOG. It has been found at times, by adding as little as 5% to annual ryegrass straw (ARS) and dairy manure blend, you may increase methane potential by 60-90% over dairy manure alone.

The best thing to plan of action is always perform a Biochemical Methane Potential (BMP) of the feedstock that are available in the area and then determine the ideal mix. The BMP is an analytical took that describes the volume of methane that can be produced from a given amount of volatile solid for a particular feedstock.

In your view, how is a biodigester part of a larger, sustainable permaculture strategy?

Keeping any kind of waste out of our landfills and taking advantage of a technology that can be used to benefit the community and the environment. It is about doing the right thing and living in a sustainable world. We need to do what we can when we have the knowledge to make the least amount of impact with our current processing practices.

Do you envision a day when the aggregated grain silos alongside the railroad tracks will include be a large community biodigester coop facility?

I envision a day when every city large or small will take advantage of this technology as part of their strategy to become energy independent. To have a community that has energy security with its peoples support and living a green lifestyle will a robust and healthier community. To me it does not matter how they collect the waste or what we call the resource as long as it is collected and does not have negative impact on the environment. You have to avoid moving or trucking waste over a long distance because there is a point when more energy is used to move the waste than you are generating.

Connections -

Joe Russo, Sales Associate
joe at ecoregon dot com
541. 852. 7598