Demand for anaerobic digesters continues to grow moving forward despite economic and technological challenges

By Milos Bezanov

Lower costs of individual projects have generated more economical investment financing for anaerobic digester systems across the US.

Smaller projects, which previously “did not have the funds to put into anaerobic digestion” according to Kristin Taormina, Applied Technologies Inc, would expect to benefit most.

 The are currently just under 250 operating anaerobic digester systems. These systems rely on a lagoon type, controlled environment to convert animal waste (dairy, swine, poultry) into biogas that can be used to generate electricity, co-generation, fuel for furnaces and pipeline gas.

 Although there have been steady and consistent increases in demand over time, recent changes have spiked the markets further “There’s definitely more interest…lower investment costs in North America [for anaerobic digestion]…have led to an increase in the number of customers…[interested in the U.S. market]” Says Andrea Steed, PlanET Biogas .

 Populations feeding digesters vary in size, with the largest, such as Blue Mountain Biogas, LLC at Utah relying on 1,200,0000 swine to generate electricity, yielding 1,059,351 in methane reductions.

Some of the smallest, such as that at UGA Double Bridges Farm, Georgia, only rely on a population of 100 swine to produce boiler and furnace fuel.

Challenges to Anaerobic Digester Systems

With a potential, U.S. capacity for 3000 digester systems, high capital costs, a lack of reliable access to electrical utility buyers and low prices offered by utilities for electricity and digester by-products still inhibit the potential of US markets.

 “ [one of the most frequent challenges we have faced implementing these systems]… is the cheap electrical rates offered by utility services”, explains Steve Dvorak of DVO inc. This process is exacerbated by declining biogas capacity, falling from 521 MW in 2013 to 30MW in 2014.

 Available incentives and renewable energy policies for anaerobic digester systems, ranging from between 14 in Kansas to 200 in California, do help; “more sustainability initiatives, combined with lower natural gas prices [lead us to expect] that demand will continue on this trend” explains Kristin.

 However, declining capacity for biogas and the lack of renewable energy incentives in states with the highest investment levels, such as Wisconsin and Michigan, is affecting DVO inc. and other operators within these regions.

 These trends, combined with the low overall biogas capacity at 8.4GW in 2014, are leading some providers to consider alternative options; “ we will focus more on overseas and other, potential uses of biogas…[generally speaking]…overseas markets seem more favourable towards renewable energy and have renewable energy policies”, Steve Dvorak, DVO inc.

Misconceptions

Recent surveys reveal 14 new anaerobic digester projects in the pipeline.“[although this is] a slight decrease as some federal grants have gone away, the overall trend in new projects has been going up” Kristin Taormina.

 Other challenges also continue to persist “ [One of our main challenges] is a lack of understanding…when people hear “renewable energy” they immediately think solar and wind…nobody really considers anaerobic digestion” explains Andrea Steed, PlanET Biogas.

 Differences in the processes of swine and dairy systems generate misconceptions as potential farmers become increasingly uncertain of the impact of these digestive systems, “Demands and needs are always different for every farm..[and it is essential] to adapt and change to every environment” Andrea Steed

 Lack of documented examples heighten uncertainty among farmers over variables such as herd size, the impact of systems on soil nutrients and the influence of biogas cycles on farmers’ energy needs.

 Established incentives, such as that between the US Department of Agriculture and the dairy industry, which outline commitments to reduce emissions and streamline adoption of anaerobic digesters may mitigate these knowledge problems.

Viability and Technology

Farm size, complexity of technology and location are some the factors influencing the economic viability of digester systems. Dairy systems range between 300 to 10,000 in population sizes, with the two largest being Threemile Canyon Farms in Oregon and AgPower Double A Dairy

 Digester, operating on populations of 24,900 and 15,000 respectively.

 “[For digesters]…sometimes there is an initial, high capital cost…[requiring]…people to change their systems entirely…[making systems economically unviable]” explains Kristin Taormina of Applied Technologies.

 Swine digesters in particular possess much larger populations and have a larger number of farms with higher populations than their dairy counterparts. Seven farms have population sizes ranging from 42,000, 107,000 and larger. Blue Mountain Biogas LLC in Utah is the largest system with 1,200,000.

 However, the introduction of new technologies such as flush collection, increasingly used in North Carolina to replace lagoons with pull-plug manure collection are creating smaller systems. North Carolina currently has the highest concentration of smaller sized swine digesters, most of which range between 4,000 and 30,000.

Technological refinement of digesters to create smaller systems is one way to make digesters more economically viable moving forward, according to Andrea Steed; “ A company in Germany has researched into portable digester systems..[and if this is possible]…I believe this will make systems more economically viable across the board”.

Although locational challenges of swine digesters in areas with low electricity, as mentioned earlier, affects profitability and these challenges are likely to persist moving forward, the sustained, gradual growth of AD systems promises future opportunities; “ [as] AD systems become more and more commonplace, people are becoming increasingly receptive to these systems and actively look for new ways to be environmentally friendly. [there is less fear and uncertainty] and more information on anaerobic digester systems.” Kristin Taormina.