Last week I had the privilege to attend the Got Manure? biogas conference, which this year took place not too far from Toronto, in Syracuse, New York. I’d wanted to attend the conference the last few years, but wasn’t able to get out to Idaho, Wisconsin or California… a 4.5 hour drive that included a stop at the original Duff’s Famous Wings in Amherst on the way home was well worth it.

Biogas tours

My first day included a full-day tour of 3 area biogas plants: 2 on-farm and 1 community digester.

• Farm 1 – Synergy Dairy – a 2,000 cow dairy farm processing manure and food waste from Wegman’s, a large NY grocery chain in a complete mix digester.  Generating capacity of 1.4 MW it is the largest on-farm digester in NY.  The plant also reduces greenhouse gas emissions by 7,000 tonnes per year and produces 20,000 cubic yards of bedding for the animals.  It began operations in December 2011.
  • Some interesting things I learned here: 1. Cost to transport liquid digestate to nearby fields is 1.5¢/gallon and 2. They used a heat exchanger to cool down outgoing digestate and heat up incoming manure.
• Farm 2 – Patterson Farms – a 950 cow dairy farm processing manure, whey and milk processing waste in a complete mix digester.  Total generating capacity of 405 kW.  This operation was primarily digesting liquids, as solids were separated out of manure before digestion. It began operations in 2005.
  • This operation was much more low-tech in comparison to Synergy and the operator was a lot more ‘seat of his pants’ in terms of what he would accept as feedstock and how he would operate the plant.  Much more like a farmer than a power plant operator, that’s for sure. Here I learned that solid separators typically last 2-5 years and the screens need to be changed more frequently, and that high concentrations of hydrogen sulphide (H2S) are more of an issue for newer, turbo-charged generators than for older diesel engines.
• Community digester – Cayuga County – This digester was taking in manure from 2 farms that are 7 and 12 miles away, respectively and have a total of 1500 cows, as well as about 10,000 tonnes of food waste and 2,000 tonnes of FOG, and processing in a hydraulic mix digester. Generating capacity is 633 kW, and the heat is used in nearby county buildings that are located adjacently to the plant. Two 4500 gallon tanker trucks bring in the raw manure and take out liquid digestate and return it to the farmers as fertilizer. It is just now ramping up its operations.
  • This plant was extremely interesting to me as I have thought plenty about the nuances of creating a centralized digester and transporting manure to and from the plant.  In my case, the plan was to start at the largest of the area’s dairy farms instead of at a non-farm site.  Here the plant was located based on where the heat demand was, at the county buildings. This plant was also pretty expensive at a total price of $9.6 million, and employed 3.5 full-time equivalent employees on an ongoing basis (2 truck drivers, 1 foreman and a p/t assistant)

All around a very interesting day – I also learned about an innovative way to ‘clean’ the liquid digestate by using brine shrimp, who eat the remaining organic material in the liquid and can then be harvested to create animal feed (and an additional revenue source).

What Stood Out From the Conference

The next two days were filled with talks and networking breaks, some of the highlights included:

• Lab research on the digestion of biodegradable plastics is going on in Wisconsin – PLA does not breakdown at typical digestion temperatures, and corn-based plastics tend to turn into gravy and muck things up. PHA-PBA or Telles plastics seem to be the best for anaerobic digestion.
• A dairy farmer may spend as much as 10x more time on manure management as he would on milk marketing
• A biogas plant will remove the equivalent of 0.4 cars from the road each year for every lactating cow contributing manure
• It may cost about 2¢/gallon to transport liquid manure from a lagoon to a field, whereas the nutrient value is worth 6/10¢/gallon.  Meanwhile it would cost 3/10 ¢ to pump it (at Wisconsin fuel and power prices)
• Danish community digesters take in manure from up to 80 surrounding dairy farms and are focused on manure and organic waste as feedstocks, not corn silage as is common in Germany.  Heat is consumed locally through a district energy system.  The future for biogas in Denmark may be in vehicle fuel, not electricity/heat.
• US utility companies are not willing to pay a significant premium, if any at all for the power. Many digesters are on net metering systems, meaning that only excess power is sold to the grid, and often at market rates of 3-7¢/kWh – greatly paling in comparison to FIT rates offered in Ontario or in Europe.  Furthermore, in states where Renewable Portfolio Standards exist, once the utility meets its obligations, it has no interest in purchasing additional renewable power.
• Almost every project would not be feasible if it were not for generous capital grants available from multiple different government agencies.  Tipping fees for food waste was also essential to many of the projects presented.  This compensates for the lack of FIT, but it does create work in negotiating a power purchase agreement with the utility.
• There is a lot of nutrient value in the digestate, it may be worthwhile to separate it out and try to maximize the value of the end product, instead of selling all the liquid or solids as is.
• Many US dairies use sand to bed their cows.  I didn’t know this, but I heard it’s not as common in Ontario.
• Recent EPA data estimates that the US produces 34.76 million tonnes of organic waste each year – only 2.8% does not end up in landfills.
• It is possible to use anaerobic digestion to process deadstock – however marketability of the digestate is limited and it may conflict with local regulations
• You shouldn’t put in just one generator – if two are used when there is maintenance downtime on one, the other can continue running, producing power and revenue at half the volume, which much better than none at all.
• China has 40 million rural digesters and is aiming to have 65 million installed by 2020! These are 100% government paid for.
• Only 28% of the American Public has scientific literacy (as defined by a standardized test available online) – There is a real need in the biogas industry to learn how to talk to people without jargon and being overly technical.  Focus on ‘poo to power’, people love it and it’s easy to get.

Overall, I would say that it was a worthwhile trip – I learned a lot, met some more interesting people in the biogas industry a little further afield and got to see a part of the world I hadn’t seen before.