Methane to power: the technology improves
In my last column I made mention of how excited and enthusiastic I was about the movement to create energy from waste. I am still very enthused and optimistic that the adoption of waste to energy technology will continue and escalate.
One of things that has me excited is the fact that the California Department of Food and Agriculture, the Environmental Protection Agency (EPA) and the California/Federal Dairy Digester Working Group last September announced a joint solicitation for dairy digester concept proposals. The fact that such a group even exists is a testament to the dairy digester concept.
According to the press release, California has 1.7 million cows that produce 3.6 million dry tons of manure per year. If not managed properly, it can have a significant impact on the environment. Managed properly, that 3.6 million tons becomes an asset. The way they see it, the ultimate goal is widespread adoption of digester systems to manage manure and nutrients, address air and water quality concerns, reduce greenhouse gas emissions and produce renewable energy and fertilizer.
The working group was convened in 2011 and is a partnership of state, federal, local agencies, academia, industry, non-profits and utilities that came together to identify and remove barriers to develop and permit dairy digesters in California. Right now, there are not many. EPA’s AgSTAR estimates as of May of this year put the number of dairy digesters nationwide at 167, in California there are only 10. Obviously there is a lot of room for digester growth in the Golden State, and the rest of the country for that matter. The U.S. Environmental Protection Agency estimates that California could support 900 dairy digesters, predominantly in the Central Valley. Among the challenges associated with dairy digesters are high upfront costs, long payback periods and permitting requirements that can be confusing, expensive and time-consuming. The working group hopes to overcome those challenges. It has a 90-megawatt renewable bio-energy development target to be achieved by 2016 from dairy and other agriculture operations.
The working group accepted proposals for the development, installation and operation of dairy digesters and co-digesters that could be installed on single farms or at centralized facilities in California up until last Nov. 1. Proposals are being managed by the Central Valley Regional Water Quality Control Board in Rancho Cordova and funding may be provided by the various agencies within the working group for the most viable proposals with the greatest measurable outcome. In many cases, the most lucrative funding is available through the U.S. Department of Agriculture although other federal and states agencies are also financially supporting the efforts.
1,300 methane digesters by 2020
In addition to the California initiative, the Innovation Center for U.S. Dairy has been a huge advocate and facilitator of dairy digester technology adoption for a number of years. With its Dairy Power/Biogas Capture and Transport project, the Innovation Center has a goal to help put 1,300 methane digesters on dairy farms by 2020. Working with regional and national programs, the project addresses existing barriers, such as technology and financing. The Innovation Center has extensive resources on its website that identify funding sources, the market value of digester products, numerous case studies, a digester business model and a dairy power opportunity analysis. See www.usdairy.com for more information.
All of this makes a lot of sense when you recognize that converting manure to energy is about 75% efficient whereas wind is 30% efficient and solar comes in even lower at 12%. In addition to being efficient, manure is abundant. In fact, the Innovation Center estimates that manure from 2,500 cows can provide power to 300 homes.
Why now? Dairy digester technology has been around for decades, so what’s different? For one thing, knowledge and technology have improved. We have learned that digesters can make economic sense now where they would not have in the past. The concept of combining waste streams from a variety of sources with manure can vastly improve methane yields as well as putting those additional waste streams to a beneficial use.
Technology for smaller farms
The concept of creating a community that feeds into digesters is also relatively new and it is a way to get around the notion that in order for a digester to pencil out, one needed to have manure from larger farms – typically 1,000 or more cows. That notion though is also under attack. Recently in Wisconsin, a special small farm digester was installed on a 200-cow dairy farm that when fully complete will provide the farm with its own power and additional power for approximately 20 homes.
Of course, what makes this work is not just the gas; it’s the co-products that add value to the bottom line – namely dairy fiber for bedding and fertilizer because the residual material retains the nutrient value of the manure. The manufacturer of the digester believes their system is even viable for a 100-cow farm. Time will tell, but opening the door to smaller farms could be a real game changer.
So with changes in technology and the efforts in California and by the Innovation Center, it is fairly clear that the time for dairy industry alternative energy is here.