Cow farts

Continuing on the news item about California regulating cow farts (i.e. methane produced by farm animals) from this morning, I decided to see what kind of benefits could be obtained from "anaerobic digesters", which Wikipedia describes as:

Anaerobic digestion is a collection of processes by which microorganisms break down biodegradable material in the absence of oxygen. The process is used for industrial or domestic purposes to manage waste or to produce fuels.

In researching this, I came across a part of the Environmental Protection Agency's website which has commentary from anaerobic digester operators from across the country. Normally, I might question the objectivity of the EPA website, but they included some negative comments too.

Overall, it seems to create a sustainable operation which also increases the profits of farming by reducing energy costs. It also creates a healthier environment for the animals themselves by reducing methane and phosphorous. The downside is many farms cannot afford to make the initial financial investment, which means state money will be required, although it will make the farms more profitable in the long run. Note that is in the long run, because there is a steep learning curve initially, which is made worse by the fact anaerobic digestion takes several weeks to show results, so any learning mistakes could take weeks to be discovered.

Without government financial support, this won't happen on a widespread basis. On the other hand, because of the fact this tends to make farms more profitable, I think any government financial support to start one of these operations should come in the form of interest-free loans and not government handouts.

From the EPA website, following are some of the positive and negative details of anaerobic digesters.

1. Norman Doll, Chief Operating Officer for Clear Horizons in Waunakee, WI.
Negatives:

Farms using sand bedding – As sand accumulated over time, digester vessels lost up to half of their capacity.

Unplanned liquid recirculation – Liquid digestate, saturated with phosphorous, was unexpectedly coming back from the farm and negatively affecting the process
and skewing nutrient recovery numbers. The 30,000 gallons per day of digestate in the raw manure input stream led to phosphorous precipitating out in the forms of struvite and vivianite, causing problems in the pipes and vessels.

The business model under which these...were built is no longer workable in Wisconsin. When these were built we had the encouragement of government; access to grants; and a utility mandate for a 15% renewable portfolio (i.e., requirement to generate 15% of energy from renewable sources). That’s gone. Utilities will no longer provide favorable power purchase agreements (PPA). Going forward, developers will need to find a new model to make these systems financially viable. Even with our existing systems, when the current PPAs run out, we will need a new revenue source to keep them operating.

There are a lot of safety issues with these types of systems and with livestock operations in general. But the potential for explosion-related injury is small, especially for those outside the facility (because of how the digesters are designed, an explosion would actually go up, not outward). 

Positives:

The project helps manage waste from three dairy farms, as well as some food wastes, restaurant waste grease, and glycerin. The digester meets two of the project’s
primary goals: protecting water quality, and growing crops sustainably. The Wisconsin Department of Natural Resources (DNR) and Dane County also recognized the
project’s potential to control and export phosphorous; they proposed paying for the digester through the sale of byproducts and energy produced by the system. So far,
the digester and advanced phosphorous removal system have allowed the capture and export of about 90 metric tons of phosphorous from the watershed.

2. Dennis Brubaker, Member/Partner of Ideal Family Farms, LLC, in Beavertown, PA.
Negatives:

Our system was designed to handle approximately 50% more feedstock than our farm produces because we anticipated receiving outside food waste products to
maximize capacity. However, we have not been able to make the right connections with food waste sources and are operating at partial system capacity. 

Positives:

Our swine farm consists of a 4,400 head nursery and 10,350 finishing spaces. Manure disposal and energy costs made up a large part of our on-farm operating expenses.When energy costs spiked in 2008, we knew we had to gain more control over our highest operating costs.We looked at wind, solar and digesters. The digester allowed us to generate 2.5 times our on-farm electric needs and offset 50% of our heating costs. It was the most beneficial option. 

We found a way to dispose of 7 million gallons of manure annually and achieve tremendous cost savings. We added revenue to the farm through energy savings
and sale of excess electricity, and are also able to use the waste heat to heat our nursery barn. Our neighbors are happy too; they reported a reduction in odors after
the digester was installed. 

3. Steve Reinford, Owner & Brett Reinford, Manager of Reinford Farms, Inc. in Mifflintown, PA.
Negatives:

Have someone willing to put in the time to make digester ownership successful. It took approximately 20 months from initial research to steady operation of our digester. 

Be prepared for challenges working with your utility— both understanding these requirements and the potentially high costs. 

Be prepared to fund a utility feasibility study, which can run from $10,000 – $12,000.   

Positives:

We have manure from 630 dairy cows. We are a no-till farm and needed to reduce odors when we apply manure. It was not until after we installed the digester that we
realized the other benefits, including revenue from selling back electricity, tipping fees and money savings from capturing the waste heat for on-farm use.

We use the waste heat to dry our corn, heat our house and shop, and heat all of the farm’s hot water. We also pasteurize the calf milk with it.

Additionally, the digestate is separated and we use the solids for bedding. The digester kills many pathogens in the solids, making it safer to use.

4. Alex Ringler, CEO of Renergy in Marengo, OH.
Negatives:

The biggest challenge is the biological process –maintaining the balance of organic materials so the pH is at the right level and the proper energy is produced.
There is a learning curve to maximize efficiency.

You need to really understand the process. It can take years. Our experience took two years from concept to steady operation.

Positives:

Our facilities incorporate all of the hog manure produced at co-located farms on a yearly basis. The digester supplies the farm with 100% renewable energy in the form of electricity, radiant heat and hot water as well as crop nutrition. The operations also create sustainable employment in the community.

The system provides us with combined heat and electricity, crop nutrition and reclaimed water. 

5. Billy Storms (Owner/Operator) & Don Britt (Operator) of Storms Farm in Blandeboro, NC.
Negatives:

It took about six months to get the feedstock and gas
production we wanted. The mix of feedstock is important.
It takes 21 days to see the impact of what you feed
the digester, so we had to learn to wait, which is not
something that usually happens on a farm. 

Positives:

We have a lot of waste to manage with 28,000 hogs and
200,000 chickens – and a lot of phosphorus building
up on the land...A digester coupled with nutrient
recovery will get the phosphorus out of the waste.

We will separate solids to bag and sell/spread on other
farms. Biogas is converted to electricity in an enginegen
set with a biological hydrogen sulfide scrubber. The
electricity that is generated is sold to the NC Electric
Membership Co-Op that sells to all of the co-ops in the
state...

We have more control of our waste and reduced disease
and cost. We use the digester to manage mortalities,
which saves money and reduces disease for our livestock
operation. Also, the hog houses don’t smell since waste is
moved quickly and there is no methane building up in the
hog house. This makes for a healthier environment for the
hogs.