Renewable Energy: Biomass
By Anne Cosgrove
Published in the September 2010 issue of Today’s Facility Manager
As more facility managers (fms) consider the use of renewable energy, it is important they evaluate the various source types (e.g., biomass, wind, solar, geothermal) for their particular needs. Fms can keep several aspects in mind during the evaluation and decision making process. Questions to consider include: What environmental and operational benefits might we gain? Can our site/building accommodate the physical infrastructure? What are the costs/savings, and what financing options are available?
Biomass energy is that derived from the processing of plant materials in equipment specifically designed for that use. Facility applications include space heating, cooling, and electricity production in combined heat and power (CHP) scenarios.
The most common fuel source for a biomass system is low grade wood (usually in the form of chips or pellets). However, other sources—some already in use and others under research—are food crops, grassy and woody plants, residues from agriculture or forestry, oil rich algae, and the organic components of municipal and industrial wastes.
The sustainability of biomass energy sources is due to the fact that plant based materials are continuously grown, providing a steady supply. In the case of wood sourcing, the common practice is to use waste from forestry operations that would otherwise be disposed of in another way. Sustainable forestry and sourcing are crucial if biomass is to contribute effectively to reduced fossil fuel use and carbon dioxide (CO2) emissions into the atmosphere.
There’s a balancing act to consider with biomass, because burning wood does release CO2. However, when compared to the use of fossil fuels (e.g., oil, natural gas), biomass proponents assert the practice does work to reduce the amount of C02 in the atmosphere. This is because burning fossil fuels releases C02 that had already been captured and stored for millions of years—essentially adding “new” greenhouse gas to the atmosphere. Meanwhile, proponents state that as long as replacement trees are grown at the same rate they are burned, biomass does not add to the overall C02 in the air.
A Case Study: Vermont Fuels For Schools
The prevalence of biomass in facility settings is still relatively low; however, organizations with these types of systems in place are finding cost savings after the initial investment is made. Heating is currently the most prevalent application for biomass in facility settings.
In 2001, the Vermont Fuels for Schools (VFFS) program was initiated to promote the use of renewable, local resources to heat public schools. This was a collaboration of the Biomass Energy Resource Center (BERC), the Vermont Superintendents Association’s School Energy Management Program, and the state’s Department of Education, Department of Public Service, and Department of Forests, Parks, and Recreation. In response, the state legislature voted to provide financial assistance to schools for biomass capital improvements. As a result, VFFS was instrumental in 42 schools converting to biomass. However, funding eventually ran out, and a moratorium was enacted in 2007.
Christopher Recchia, executive director of BERC, located in Montpelier, VT, says, “The Fuels for Schools program brought the state to a point where now about a third of Vermont schoolchildren attend a wood heated school. It was very well supported by the public.” Founded in 2001, BERC is a national non-profit organization that assists individual facilities, state and local governments, and utilities to maximize the use of local energy resources. Recchia states that most of the biomass systems installed under the program range in capacity from one to three million Btus (British thermal units).
The operators of these schools meet each year to discuss operations and gauge the ongoing performance of the systems. The most recent meeting studied the 2008-09 heating season, and the 43 schools in attendance represented 5.57 million square feet. It was reported that 81% of the Btus produced in the schools was from the biomass systems (the remaining 19% was from back up boilers using “traditional” fuel sources). And compared to the fuel sources used previous to biomass implementation, total cost savings was $2.23 million.
Says Recchia, “While biomass offers a number of benefits from a public policy perspective, cost is probably the most compelling reason for a local school district to convert. On a Btu basis, biomass fuel is generally less than half the cost of fuel oil. There are also savings with natural gas, though these are comparably less, particularly when gas prices are low.”
Evaluating Biomass Potential
Financial assistance, a relatively high number of heating days, and local supply of wood biomass created the successful scenario for the Vermont public schools. The price of the fuel that had been used previously was also a factor to consider when trying to determine if biomass would be beneficial.
The same factors should be taken into account by fms considering biomass for their buildings. State and local incentives are available in a number of locations (visit www.dsireusa.org to search for current programs). On the federal level, the Thermal Energy and Efficiency Act (S. 1621) was introduced in August 2009, and in July 2010 the Thermal Renewable Energy and Efficiency Act (H.R. 5805) was proposed. Both of these bills call for incentives to promote thermal energy, and while utilities would be the main intended recipients of any that result, fms may want to watch these developments.
On the facility level, Recchia advises the first thing fms do is identify what type of fuel they are using for the potential application and what the current fuel usage is—preferably on an hourly basis for one year. “This type of data will provide very good base information for where the peaks are,” he says, “and it will help to size the biomass facility accurately for the building.”
Biomass boiler systems are usually sized to about 85% of peak demand. Recchia explains, “This is because the systems are most efficient running at full load. If a system is sized to meet 100% of the demand on the coldest days, it will be oversized for the other times. So we’ve found that facilities reap maximum efficiency at 85%.” Backup boilers tapping traditional fuel sources are used to augment the biomass and serve the peak demands.
The equipment for a biomass system can usually be accommodated in the space vacated by existing boilers (more space is needed if the facility plans to retain one or two boilers as backup). Additional space—often a separate building—is needed for wood storage and should be taken into account during evaluation.
Sourcing the wood is another area fms should evaluate, for both environmental and economic reasons. The northeastern United States is a promising area in this regard, due to high heating demands and the prevalence of forests. Additionally, Recchia points out that more than 80% of the nation’s home heating oil is used in the northeast. “There’s a good correlation between displacing fossil fuels with a local supply,” he explains. “Geography matters for two reasons. One is because of where the forest resources are. The type of fuel a facility currently uses is also important to the analysis.”
Even if regional forest resources are available, fms will want to ensure the wood they purchase as fuel is sustainably harvested. Currently, there are no official procurement standards, but in researching suppliers, fms should be able to determine a desirable source. The Forest Stewardship Council (FSC), which identifies sustainable wood production, is a possible source going forward but there is currently not enough FSC wood to support biomass projects.
“Fully half of our work at BERC is focused on sustainable forestry and sustainable fuel supply,” says Recchia. “We encourage facilities to establish procurement standards that start to identify where the material is sourced from and how sustainably it’s managed. This is not unique to biomass.”
The ideal scenario is the use of low grade wood (often classified as waste) for biomass facility consumption. So a supply chain that incorporates that type of material brings a facility that much closer to a sustainable system.
Compared to some other renewable energy sources, biomass is just starting to gain ground in the market. Debate over the impact of CO2 emissions released by burning biomass will continue, and even Recchia states that biomass is not a “silver bullet.” Biomass as part of an energy strategy can be successful both environmentally and economically if sourcing, pricing, and an organization’s physical infrastructure allow.
Research for this article was based in part on an interview with Recchia at the Biomass Energy Resource Center (www.biomasscenter.org).
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