From Carbone to clean air, continuing controversy and confusion surround waste to energy. Factors such as ash management, interstate transportation and the Clean Air Act Amendments of 1990 (CAAA) present issues that must be addressed.
Waste to energy is far from dead, however. States like Massachusetts have projected that waste-to-energy (WTE) facilities will be responsible for recycling 50 percent of the state's total waste stream into electricity, with other recycling accounting for most of the remaining waste stream, according to the Department of Environmental Protection's (DEP) Solid Waste Master Plan.
Massachusetts' commitment to waste to energy extends over nearly two decades. For example, the state's North East Solid Waste Committee (NESWC), a regional consortium representing 23 communities, was formed in the early 1980s to develop a 1,500-tons-per-day (tpd) mass burn WTE facility in North Andover, Mass. The communities entered into a 20-year contract which pays for the entire debt service as well as most of the operational costs of Massachusetts Ref-usetech Inc., a wholly owned subsidiary of Wheelabrator, which owns and operates the facility.
During the project's developmental stages, the state predicted that most unlined landfills would soon close and that this recycling project would be a safe and cost-effective way to regionally manage municipal solid waste. Today, NESWC delivers approximately 205,000 tons of waste annually to the plant, nearly half of the waste it processes.
However, NESWC is currently paying one of the highest tipping fees in Massachusetts ($91.50 per ton), or approximately twice the statewide average. As a result, it hired Environmental Futures Inc., Boston, to address the factors affecting its bottom line.
Clean Air The WTE community has addressed clean air issues for years. After shifting regulatory signals, today's facilities finally know what must be implemented, although compliance deadlines still have not been addressed.
CAAA's Title V permitting requirements have been initiated in many states, including Massachusetts. However, the Massachusetts program has been delayed because EPA has not provided final emission standards. The outcome will affect NESWC taxpayers, who are responsible for any change-in-law retrofits.
To meet current standards, the facility employs ESPs and dry lime injection. In the future, this technology will not be sufficient. Estimates to retrofit the NESWC facility range from $30 to $60 million.
Several questions need to be answered before implementing a new technology. For example, the Clean Air Act requires operators to change from the Best Available Control Technology, EPA's current standard, to Maximum Achievable Control Technology, which ties required emissions limits to the performance of the upper percentage of the best performing facilities in each size category.
Facilities need to research their options before implementing new systems. NESWC, for example, must decide if they will allow the owner/operator to implement a "soup-to-nuts" approach or if they will seek a more traditional, competitively bid procurement process. The competitive bid has certain appeal, considering that the soups-to-nuts approach cost the consortium's sister plant, a 1,600-tpd facility in Saugus, Mass., more than $100 million to implement.
Managing Ash EPA uses the Toxicity Characteristic Leaching Procedure (TCLP) to characterize WTE ash for its hazardous potential.
TCLPs are not useful for predicting what will happen in an ash monofill, according to the EPA's Oliver Fordham, a speaker at last year's Ash VII conference. Fordham pointed to a newer method, Synthetic Precipitation Leaching Procedure (SPLP), which is being considered for future ash characterizing. However, earlier this year, the EPA decided to continue to require quarterly TCLP testing of ash.
To meet the TCLP standard, many facilities have implemented ash stabilization systems. NESWC has implemented a temporary system until regulations are clarified and competing technologies have been reviewed. Although they are currently passing the quarterly TCLPs, NESWC is concerned that the target will shift again and that the long-term environmental impacts of various stabilization technologies are still unknown.
To address the "point of generation" question, EPA decided that combined ash will be tested as it leaves the "four walls" of WTE facilities. Now, WTE facilities such as NESWC's, do not have to install numerous sampling sites for fly and bottom ash.
Ash recycling is another important issue. An impressive array of technologies for recycling WTE ash exists. These systems range from low-tech methods which use screened bottom ash as aggregate in roads to newer technologies such as high-temperature vitrification. Ash from the NESWC facility is being used by operators of a pilot project to discover what safe products can be recovered once the ash has been melted. Until the risks associated with ash recycling are addressed, the North East Solid Waste Committee must continue to spend nearly $4.5 million annually to bury ash in a monofill.
The Effects Of Flow Control The Carbone ruling has undermined the financial stability of publicly-bonded WTE projects and the viability of future projects. Many municipalities and regional consortia won't be able to ensure a satisfactory throughput to their WTE facilities by statute or regulation.
Now that the competition for waste has become fierce and the region's tipping fees have been dramatically lowered, NESWC taxpayers must make up the difference for reduced tonnage at the facility. The projected revenue loss contributes further to the high tipping fees.
Money received for power generated is another issue that dramatically impacts the financial stability of WTE facilities. For example, the price that the power utility was supposed to pay for NESWC electricity was originally tied to the avoided cost of fuel. NESWC's high tipping fees can be attributed to the oil prices projected during the project's developmental stages in the late 1970s and early 1980s. At that time, oil prices were projected to continue to rise as they did during the Middle East crises. However, as oil prices plummeted, so did the revenue NESWC received for its power.
As a consequence, the revenue has been only 25 to 40 percent of what other plants in Massachusetts receive with power purchase contracts that had been negotiated in later years. In addition, unlike NESWC, most other facilities also were receiving capacity credit payments. To correct these inequities, the consortium received a $14 million settlement from the power utility through a series of negotiations.
Ensuring Throughput "Put or Pay" or Guaranteed Annual Tonnage (GAT) provisions are common in WTE projects. These provisions ensure that a facility will have enough incoming refuse to convince the bonding community of the project's viability for the bond's term. Today, however, most GAT contracts include provisions which reduce the guaranteed tonnage for recycling. NESWC does not have such a provision, and must pay twice for tons diverted to recycling. Because of economic conditions, few members can meet their GAT without brokering waste from outside their borders. Since spot prices are currently lower than the debt-service-driven tip fees, members reportedly lose on every ton brokered.
Nonetheless, all members have initiated recycling programs. In fact, the consortium received a $350,000 state grant to partially subsidize recycling costs as well as the recycling coordinator's salary.
The financial viability of WTE facilities also can be affected by the remaining capacity at nearby landfills as well as the facility's ability to find alternative sources of fuel during regional solid waste shortfalls. To address this problem, NESWC conducted a pilot test on the co-combustion of sewage sludge with MSW. Without altering the facility's burning practices, approximately 10 percent of de-watered sludge was used in the combustion mix. The pilot proved good burnout rates and nominal emissions.
The success of this industry is dependent upon addressing genuine risks. All parties, including regulators and the regulated community, interest groups, Congress and the public, must play an active role in addressing the issues that affect WTE. After all, the main objective is to find a safe, reliable and cost-effective method of waste management.
By working together to address these issues, WTE will continue to contribute to an integrated solid waste management system.