“We are not going to displace huge, huge hunks of our energy requirements with biomass.”
“If you have a ton of biomass, the best way to avoid greenhouse gas emissions is to burn it, and displace coal or even natural gas. You get the biggest bang for your buck.”
Burning biomass to produce energy and heat is nothing new, but doing so at a large scale still cannot compete economically with coal and natural gas. Local, small-scale biomass-to-power systems may prove to be the most efficient way of generating energy from biomass. Already, small-scale production of natural gas from biomass and on-site co-generation of electricity and heat is widespread in Europe. Farm-sized units are in operation in the United States as well.
In introducing the subject of generating heat and power from biomass, Jeffrey Steiner, national program leader for biomass production systems at the USDA Agricultural Research Service and agency lead of the USDA Regional Biomass Centers, noted that today biomass, including grain ethanol, only accounts for more than 4 percent of total U.S. primary energy consumption, a very small number. He also reiterated earlier comments that even the latest Billion-Ton study acknowledged that biomass is not going to displace huge chunks of the nation’s energy needs, as we currently consume it. He did say, though, that biomass is going to be an economic force in the future and that there is money to be made in the biomass arena.
One factor that is complicating the economic development of biomass, said Steiner, is that the United States does not have a policy on biomass, which he contrasted to that of other countries, using Uruguay as an example. While there is the billion ton goal for 2030, there is no policy concerning the optimal uses of the biomass and how producing that much biomass fits into existing structures of agriculture and forestry. There is no clear picture, said Steiner, about soil and water resources, the role of landowners and financiers, and the supply chain that is going to be needed to make biomass an economic reality.
He noted, too, that most of the emphasis of the previous speakers has been on large-scale development, but small-scale pellet stoves and biogas generators are also likely to have their place. In Ireland, for example, small pellet stoves are the predominant source of heat in villages. He also remarked that other factors, such as carbon budgets, can factor into the decisions of how best to use biomass, and again he used Ireland as an example. The very efficient Edenderry Power facility has been burning peat to meet the country’s carbon targets, but peat is not a renewable resource, so the plant is now blending in Miscanthus or willow with the peat to meet its carbon targets. This change has affected feedstock quality and chlorine emissions that now have to be accounted for.
Moving from the large scale to the small scale, Steiner described an on-farm gasification facility in Rockford, Washington, that costs about the same as a combine, some $300,000. This is a very sophisticated piece of equipment that is automated and produces about 30–40 percent syngas. Another example of a small-scale facility is an anaerobic digester near Limerick, Ireland, that takes waste from dairy, chicken, and pig farms and converts it to gas that is then burned to produce electricity that is fed into the national electrical grid.
Steiner noted that there are 186 farm-based anaerobic digesters operating in the United States, as well as about 1,500 wastewater treatment systems that utilize biogas and another 576 landfill operations that harvest biogas. In contrast, Germany has over 12,000 digesters operating. However, burning this biogas as a source of energy may not be the most efficient use of it. It may be more efficient to use it for chemical production or to clean it efficiently and feed it into natural gas pipelines.
Concluding his remarks, Steiner said that there needs to be a transition in thinking about each of these processes linearly and to integrate all aspects of biomass utilization in a way that maximizes efficiency. By doing so, it should be possible to eliminate waste products and instead have them serve as feedstocks for other processes.
One of the main themes of this breakout group’s discussion, which Steiner led, is that the generation of heat and power from biomass may best be done at a smaller rather than larger scale in the United States. This is in contrast to Europe, where economic and political drivers have created a demand for biomass-generated power on a large scale. The point was raised that community-scale or even home-scale digesters that would turn local wastes into gas that would be burned for heat or in a small co-generation facility might be economically viable, and it was noted that a Korean company is making a home-scale system. What is needed, some members of the group noted, was scientific performance data from systems of this scale that would allow a sound case to be made for use of local biomass in this way.
In fact, the many breakout group members said, the field as a whole needs solid modeling to determine the minimum- and maximum-sized operations that make economic sense based on performance metrics. It was also noted by some members that there is a need to develop a matrix identifying which fuel source is most economical at what scale. The group noted, though, that an impediment to performing such modeling work is the absence of such metrics for smaller scale systems. Given that the field of power generation from whatever source is seen as being mature with no need for research, the group commented that such metrics are not likely to be generated soon. Some breakout group members said that a formal analysis of state-of-the-art technologies that are available should be done, particularly in Europe and Asia, to look at how the performance of those systems could inform decision making in the United States.
There is also the perception, the group commented, that large-scale biomass production is slated for liquid fuels production given that there are other ways of making electricity and power sustainably. It was also raised by some participants that first coal, and now natural gas, is so inexpensive that biomass cannot compete in the large-scale power generation area. The one thing on the horizon that could change this economic reality, the group said, is the Environmental Protection Agency’s scientific panel decision in less than three years on how to classify biogenic emissions. If the panel ultimately decides that biogenic emissions should not be included in greenhouse gas emissions accounting schemes, that could be an incentive to use biomass on a large scale for power and heat generation.
Many members of the breakout group noted that the lack of a national policy on the use of biomass to generate power and the lack of public understanding of biomass as a local power resource are topics that need addressing. They went on to note that such policies and public information campaigns need to be data-driven, and those data are largely missing.
Turning to the discussion of the skills needed to move this field forward, the many breakout group members concurred that the field needs to attract chemists and chemical engineers to the field, but doing so will require first overcoming the perception that there are no jobs in the field. In general, though, the breakout group noted that students in technical subjects need education in economics, policy, and sociology in order to be able to communicate within the multidisciplinary teams required to move the field forward. The breakout group also recognized the need for having life-cycle analysis and quantification of uncertainty added to technical programs.
This breakout group did not have much to add on the subject of the transportation infrastructure other than that there is a need to assess the existing infrastructure to see how it can be best used to move biomass. The group noted that transportation needs depend on scale, technology, and economics and again pointed to the need to conduct a systems analysis if the goal is to optimize the existing system to handle expanded use on the relevant geographical and mass scale.
In the ensuing open discussion, a workshop participant noted that the United States produces more power from biomass through direct firing than Europe. What Europe has done is make use of the heat generated during biomass combustion to a far greater degree, largely because of the prevalence of district heating systems in Europe.