Viewpoint

During the 2007 United Nations Framework Convention on Climate Change, the United States formally agreed to join the international consensus that is working to halve greenhouse gas emissions by 2050. This will soon lead to new federal, state, and local government initiatives to reduce greenhouse gas emissions in the United States. The decomposition and treatment of municipal solid waste releases several greenhouse gases, notably methane, carbon dioxide, and nitrous oxides. As such, the municipal solid waste industry faces an emerging regulatory and financial framework for developing resource recovery solutions.

Emerging Regulatory Framework
Due to changes in federal, state, and local legislation, regulatory initiatives continue to develop for the solid waste industry and focus on renewable energy and greenhouse gas reduction. These initiatives include:

• Federal production tax credits (PTC) provide a tax incentive of $0.019/KWh for the production of renewable energy. They apply to the first 10 years of a renewable energy facility's operation, provided the projects are in operation by December 31, 2008. Landfill gas and municipal solid waste (MSW) facilities currently receive a lesser tax credit, approximately $0.01/KWh. A coalition of clean energy supporters is currently lobbying to secure a longer PTC extension to boost development of clean, renewable electricity.
• Current renewable energy contracts have been developed by several states to promote renewable energy projects, including biomass, landfill gas, wood, and digester gas. The power purchase rates vary by state and can partially offset the costs associated with processing municipal wastes and help reduce tipping fees paid by local users.
• Renewable energy certificates (RECs) are a tradable environmental commodity, with each REC representing one megawatt-hour of electricity generated from a renewable energy source. They are currently traded under a voluntary program with an equivalent price fluctuating between $0.01 and $0.05 per kilowatt hour (KWh), depending on the location of the facility producing the RECs, supply/demand situation, and whether the REC will be used for renewable portfolio standards compliance. Currently, there are no federal regulations regarding RECs; however, several states have initiatives or mandates in development that could possibly lead to an unpredictable market.
• Carbon dioxide offsets can be purchased to counteract the impact of pollutants from industrial activity. This market is young and voluntary, and standards have yet to be established. The prices of CO2 reduction offsets can range dramatically, but average about $10/ton of CO2-equivalent.

Integrating Waste Processing Systems
Communities can realize significant technical, economic, and operational benefits by integrating multiple processes into their renewable energy projects. While community needs are unique and the availability of options can vary, several opportunities exist for integrating existing and future solid waste, recycling, renewable energy, and utility processes. These include:

• Transfer station operations
• Material recovery facility operations
• Construction and demolition recycling 
• Municipal biomass processing and recycling
• Water treatment and distribution
• Wastewater treatment
• Drying and processing of biosolids
• Reclaimed water treatment and distribution
• Stormwater collection, treatment, storage, and distribution

Reducing Internal Energy Costs
Several new technological advancements allow municipalities to generate power from municipal wastes. Doing so can replace high-priced energy purchased from the electric grid, which is typically derived from fossil fuels, and capture the full value of a municipality's own renewable power. 

•  Waste-to-energy projects have been used to successfully provide electric power for municipal infrastructure, including water and wastewater treatment, reclaimed water and stormwater management, recycling facilities and transfer stations, composting facilities, and public buildings that are located adjacent to the waste-to-energy facility.
• Steam energy from municipal waste-to-energy projects can be used for drying and stabilizing wastewater treatment plant biosolids, distilling potable and ultra-pure water, maintaining optimal temperature for anaerobic digestion process, and producing cellulosic ethanol and biodiesel fuels. 
• Biogas can be used to offset or reduce demand for natural gas typically used in the operation of anaerobic digestion processes, thermal drying of wastewater biosolids, and process heat for future production of cellulosic ethanol and biodiesel fuels.

Paul L. Hauck, P.E., is a senior environmental engineer with more than 34 years of engineering experience in the nuclear and electric power generation, municipal solid waste-to-energy construction, public works, and fuel ethanol industries.