5

Heat and Power Production from Biomass

“We are not going to displace huge, huge hunks of our energy requirements with biomass.”
Jeffrey Steiner

“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.”
David Stern



INTRODUCTION

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.

BIOMASS CONVERSION TO HEAT AND POWER

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.



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5 Heat and Power Production from Biomass “We are not going to displace huge, huge hunks of our energy requirements with biomass.” Jeffrey Steiner “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.” David Stern INTRODUCTION ciers, and the supply chain that is going to be needed to make biomass an economic reality. Burning biomass to produce energy and heat is ­ othing n He noted, too, that most of the emphasis of the previous new, but doing so at a large scale still cannot compete speakers has been on large-scale development, but small- economically with coal and natural gas. Local, small-scale scale pellet stoves and biogas generators are also likely biomass-to-power systems may prove to be the most efficient to have their place. In Ireland, for example, small pellet way of generating energy from biomass. Already, small- stoves are the predominant source of heat in villages. He scale production of natural gas from biomass and on-site also remarked that other factors, such as carbon budgets, co-generation of electricity and heat is widespread in Europe. can factor into the decisions of how best to use biomass, Farm-sized units are in operation in the United States as well. and again he used Ireland as an example. The very efficient Edenderry Power facility has been burning peat to meet the BIOMASS CONVERSION TO HEAT AND POWER country’s carbon targets, but peat is not a renewable resource, so the plant is now blending in Miscanthus or willow with In introducing the subject of generating heat and power the peat to meet its carbon targets. This change has affected from biomass, Jeffrey Steiner, national program leader feedstock quality and chlorine emissions that now have to for biomass production systems at the USDA Agricultural be accounted for. Research Service and agency lead of the USDA Regional Moving from the large scale to the small scale, Steiner Biomass Centers, noted that today biomass, including grain described an on-farm gasification facility in Rockford, ethanol, only accounts for more than 4 percent of total U.S. Washington, that costs about the same as a combine, some primary energy consumption, a very small number. He also $300,000. This is a very sophisticated piece of equipment reiterated earlier comments that even the latest Billion-Ton that is automated and produces about 30–40 percent syngas. study acknowledged that biomass is not going to displace Another example of a small-scale facility is an anaerobic huge chunks of the nation’s energy needs, as we currently digester near Limerick, Ireland, that takes waste from dairy, consume it. He did say, though, that biomass is going to be chicken, and pig farms and converts it to gas that is then an economic force in the future and that there is money to burned to produce electricity that is fed into the national be made in the biomass arena. electrical grid. One factor that is complicating the economic develop- Steiner noted that there are 186 farm-based anaerobic ment of biomass, said Steiner, is that the United States does digesters operating in the United States, as well as about not have a policy on biomass, which he contrasted to that of 1,500 wastewater treatment systems that utilize biogas other countries, using Uruguay as an example. While there and another 576 landfill operations that harvest biogas. In is the billion ton goal for 2030, there is no policy concern- contrast, Germany has over 12,000 digesters operating. ing the optimal uses of the biomass and how producing that However, burning this biogas as a source of energy may not much biomass fits into existing structures of agriculture be the most efficient use of it. It may be more efficient to and forestry. There is no clear picture, said Steiner, about use it for chemical production or to clean it efficiently and soil and water resources, the role of landowners and finan- feed it into natural gas pipelines. 27

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28 OPPORTUNITIES AND OBSTACLES IN LARGE-SCALE BIOMASS UTILIZATION Concluding his remarks, Steiner said that there needs and power sustainably. It was also raised by some partici- to be a transition in thinking about each of these processes pants that first coal, and now natural gas, is so inexpensive linearly and to integrate all aspects of biomass utilization in that biomass cannot compete in the large-scale power gen- a way that maximizes efficiency. By doing so, it should be eration area. The one thing on the horizon that could change possible to eliminate waste products and instead have them this economic reality, the group said, is the Environmental serve as feedstocks for other processes. 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 BREAKOUT DISCUSSION not be included in greenhouse gas emissions accounting One of the main themes of this breakout group’s discus- schemes, that could be an incentive to use biomass on a large sion, which Steiner led, is that the generation of heat and scale for power and heat generation. power from biomass may best be done at a smaller rather than Many members of the breakout group noted that the lack larger scale in the United States. This is in contrast to Europe, of a national policy on the use of biomass to generate power where economic and political drivers have created a demand and the lack of public understanding of biomass as a local for biomass-generated power on a large scale. The point was power resource are topics that need addressing. They went on raised that community-scale or even home-scale digesters that to note that such policies and public information campaigns would turn local wastes into gas that would be burned for heat need to be data-driven, and those data are largely missing. or in a small co-generation facility might be economically Turning to the discussion of the skills needed to move this viable, and it was noted that a Korean company is making a field forward, the many breakout group members concurred home-scale system. What is needed, some members of the that the field needs to attract chemists and chemical engineers group noted, was scientific performance data from systems to the field, but doing so will require first overcoming the per- of this scale that would allow a sound case to be made for use ception that there are no jobs in the field. In general, though, of local biomass in this way. the breakout group noted that students in technical subjects In fact, the many breakout group members said, the field need education in economics, policy, and sociology in order as a whole needs solid modeling to determine the minimum- to be able to communicate within the multidisciplinary teams and maximum-sized operations that make economic sense required to move the field forward. The breakout group also based on performance metrics. It was also noted by some recognized the need for having life-cycle analysis and quan- members that there is a need to develop a matrix identifying tification of uncertainty added to technical programs. which fuel source is most economical at what scale. The This breakout group did not have much to add on the sub- group noted, though, that an impediment to performing such ject of the transportation infrastructure other than that there is modeling work is the absence of such metrics for smaller a need to assess the existing infrastructure to see how it can scale systems. Given that the field of power generation from be best used to move biomass. The group noted that transpor- whatever source is seen as being mature with no need for tation needs depend on scale, technology, and economics and research, the group commented that such metrics are not again pointed to the need to conduct a systems analysis if the likely to be generated soon. Some breakout group members goal is to optimize the existing system to handle expanded said that a formal analysis of state-of-the-art technologies use on the relevant geographical and mass scale. that are available should be done, particularly in Europe and In the ensuing open discussion, a workshop participant Asia, to look at how the performance of those systems could noted that the United States produces more power from inform decision making in the United States. biomass through direct firing than Europe. What Europe There is also the perception, the group commented, that has done is make use of the heat generated during biomass large-scale biomass production is slated for liquid fuels pro- combustion to a far greater degree, largely because of the duction given that there are other ways of making electricity prevalence of district heating systems in Europe.