Numerous environmental and aesthetic issues may arise from the siting and operation of bioenergy facilities. The types and magnitude will depend on the nature of the operation. State and federal permits may be required, particularly for air and water aspects. Very large proposals may trigger the need for a formal environmental impact statement under the National or Wisconsin Environmental Policy Act. Developers and entrepreneurs should get in touch with regulatory agencies early in the process so applicable environmental regulations are understood and obeyed.
This page provides a brief introduction to some of the potential environmental issues involved in bioenergy and biofuels facilities.
The goal of the federal Clean Water Act is “fishable, swimmable waters” throughout the nation. State agencies enforce the Act, and in Wisconsin, the WI Department of Natural Resources requires a Wisconsin Pollutant Discharge Elimination System permit for most discharges to surface waters. Limits on discharges are particularly stringent on lakes and rivers designated as Outstanding or Exceptional Resource waters (blue on map) and waters that are considered already significantly impaired (red). Permits may also mandate conditions such as pre-treatment before discharge. Piping wastewater to sewage treatment plants (STP) may provide an alternative to surface discharge. Reuse of water within a facility can reduce the amount of contaminated water generated, making on-site or STP treatment viable options.
Some bioenergy facilities require large volumes of water for operation. These include fermentation ethanol plants without water re-use and biomass conversion with steam generators (cooling water). Much of Wisconsin has abundant water resources, but water supply could be a limiting factor in some areas. Moreover, with the exception of the Great Lakes and few other large lakes and rivers, use of surface water for industrial purposes is discouraged, leaving groundwater as the primary source. This map depicts areas of the state where geologic conditions significantly limit groundwater availability or where groundwater withdrawals have already created significant drawdowns, along with location of high capacity supply wells that might be tapped to provide water for facilities.
Several air pollutants may result from biofuel and bionenergy production, depending on the process. Particulate matter is generated with the handling and processing of feedstocks. Combustion for heating or drying in any system results in greenhouse gases and ozone precursors. Fermentation generates CO2. Volatile organic compounds are generated in fermentation ethanol and biodiesel production as well as carbon monoxide and other “criteria pollutants.” Methane and ammonia may escape from digesters and biogas facilities. Discharge permits are required for plants expected to exceed threshold limits. Permits may impose requirements to use “best available control technology,” or may not be issued at all in counties in the state where ambient air quality degradation consistently exceeds standards. This map depicts counties where ozone or particulate matter restriction exist.
Dust, noise, odor, traffic, light pollution, and visual blight may degrade quality of life in and around bioenergy facilities. These are not generally regulated by state or federal agencies, but clearly enter into community decisions such as zoning changes and building permits. For example, odor related issues resulted in condition on a plant in Sparta. Dust and noise are common complaints near residential areas, and large truck traffic can be an issue when transportation infrastructure is inadequate. A comprehensive land use plan that clearly spells out what kinds of facilities a community intends to support and under what conditions is the best pre-emptive approach to ensure that this type of land use conflict doesn’t occur.
Greenhouse Gas Issues
The efficiency of bioenergy conversion from a greenhouse gas perspective has been the subject of much research and debate. Plants capture energy from the sun and use it to convert CO2 from the atmosphere into carbon in plant biomass which becomes fuel or feedstock. To convert this to energy for human use, it is again combined with oxygen, generating CO2. Ideally, the CO2 generated through combustion would be captured and not released again to the atmosphere, but this is not generally feasible with current technology. Realistically, we hope that bioenergy can replace fossil fuels and result in a comparative reduction of CO2 for equivalent amounts of energy. This is a complex comparison, because much energy goes into converting energy resources (whether plant material or fossil fuels extracted from the earth) into a useful form such as liquid fuel or boiler feedstock. For example, hauling and drying corn for fermentation entails diesel and natural gas use. Studies show, depending on conditions, efficiencies near 1:1 – as much energy from fossil fuels may go into ethanol production as we derive from the fuel. Choices that favor more efficient operations and technologies are needed. For fermentation ethanol, this might include reducing haul distances and utilizing wetter feedstocks and distillers grains (byproduct of fermentation generally fed to cattle). Current research and development should result in more efficient ways to produce liquid fuels in the near future, though as with any new technology, we will need to carefully assess potential environmental impacts and net energy efficiency. (http://www.deq.state.ne.us/Publica.nsf/Pages/06-192)