Waste Gasification and Pyrolysis: High Risk, Low Yield Processes

[Page 1] Waste Gasification & Pyrolysis: High Risk, Low Yield Processes for Waste Management A Technology Risk Analysis GAIA March 2017 [Page 2] Report available at no-burn.org/gasification-pyrolysis-risk-analysis Lead authors: Neil Tangri and Monica Wilson. We appreciate assistance and review provided by: Shlomo Dowen, Jane Bremmer, Bradley Angel, Anne Larracas, and others. [Page 3] Executive Summary Gasification and pyrolysis attempt to convert solid waste into synthetic gas or oils, followed by combustion (meaning they are regulated in U.S. and EU as waste incinerators). Companies have been experimenting with these technologies for over three decades. This report finds that while there is little data available on the operations of attempted commercial facilities, there are numerous examples of plants that have been forced to shut down due to technical failures and financial failures. In addition, other projects have failed in the proposals stage ? after raising significant investments ? due to community opposition and government scrutiny into false and exaggerated claims. Over $2 billion was invested in the projects listed in this report alone, all of which closed or were canceled before commencing operations. Companies involved include Air Products & Chemicals, Thermoselect, Plasco, Compact Power, Caithness, Interserve, and Brightstar. Technical and economic challenges for gasification projects include failing to meet projected energy generation, revenue generation, and emission targets. Gasification plants also have historically sought public subsidies to be profitable. In particular, vendors seek renewable energy subsidies, however, such facilities would emit carbon dioxide from fossil fuel-sourced material including waste plastic and coal, contradicting the purpose of ?renewable energy.? We conclude that the potential returns on waste gasification are smaller and more uncertain, and the risks much higher, than proponents claim. Municipal programs that rely on waste prevention strategies, source separation, intensive recycling and composting, and redesign of no-value products have demonstrated economic and technical success. Waste Gasification and Pyrolysis Technology Risk Assessment 1 [Page 4] Introduction As the world grapples with increasing amounts of waste, entrepreneurs and local governments are looking for new ways to treat and dispose of solid waste, which includes a bewildering variety of plastic and composite materials. There is renewed interest in gasification and pyrolysis in some regions around the world, which, although not new processes, aim to dramatically reduce waste volume while producing energy. Investors who may be interested in supporting these practices, particularly in developing countries, would be well served by investigating previous efforts and resulting impacts on local waste systems. This document analyzes technology proponents? claims, documented challenges at operating facilities, and offers guidance to potential investors and regulators. What are gasification and pyrolysis technologies? Gasification and pyrolysis are energy-intensive processes that attempt to reduce the volume of waste by converting it into synthetic gas or oils, followed by combustion. Waste gasification is classified as a form of incineration by the European Union and U.S. Environmental Protection Agency (USA 40 CFR §60.51a; EU Directive 2010/75/EU Art 3.40) as it includes both thermal treatment of waste and in most cases leads to the combustion of the resulting gases (either on site or as a distributed fuel). Gasification subjects solid waste to high heat (generally above 600C) in a starved-oxygen environment. Oxygen levels are kept low to prevent immediate combustion; instead, the carbon-based fraction of the solid waste decomposes into synthetic gas (syngas) and a solid residue, known as slag, ash, or char. It should be noted that starved oxygen or oxygen free operating conditions (claimed by multiple vendors) are difficult to implement during commercial scale operations. Syngas is composed primarily of carbon monoxide, hydrogen, and carbon dioxide, with contaminants [1]. The syngas has sufficient calorific value to be burned for energy, but requires advanced pollution control systems (APC).[2] Operating facilities have frequently failed to produce enough energy to be financially successful.[3] Byproducts resulting from these processes include air emissions, slag (a form of solid waste), fly ash from the air pollution control equipment (requiring special handling due to its toxicity), and liquid wastes and/or wastewater. Pyrolysis is a similar approach which applies heat with no added oxygen in order to generate oils and/or syngas (as well as solid waste outputs) and requires more homogenous waste streams. Some vendors offer smaller facilities for fuel generation, compared to typical gasification vendors (see box ?The Waste to Fuels approach?). Plasma arc applies a higher temperature in gasification, and occasionally to pyrolysis processes. This is a much higher energy process than gasification and pyrolysis, further increasing cost barriers. The differences between each of these processes are not always clear,[5] there are variations within each overarching approach, and vendors often claim that their process has unique attributes. Most mixed municipal solid waste technologies attempt to treat large quantities of heterogeneous mixed waste streams. This can be appealing to governments which do not want to source separate waste and seek a single, technological solution. However, the approach of looking for a technology fix for mixed waste treatment presents unique challenges, and is not as successful as more comprehensive source separation strategies. Gasification, pyrolysis and plasma arc technologies are most applied for homogeneous material streams. The heterogeneous nature of municipal waste is not well suited to this type of technology. Waste Gasification and Pyrolysis Technology Risk Assessment 2 [Page 5] The 'Waste-to-Fuels' Approach Some companies propose to use pyrolysis and gasification to turn waste into fuels that would be combusted at other locations, a process that has not been successfully applied at a large scale. This would require additional gas cleaning steps to make the fuel work, and these steps are energy intensive, which reduces overall efficiency.[4] Such an approach raises additional concerns about emissions and monitoring given the inherently distributed use of such fuels. Additionally, smaller combustion units are not generally equipped with the air pollution control or monitoring equipment that is required at large, centralized facilities. This can result in excessive emissions of Persistent Organic Pollutants (POPs) such as dioxins and PCBs; lead, arsenic, mercury, and heavy metals; polycyclic aromatic hydrocarbons, such as those produced from the combustion of flame retardants, and other pollutants subject to regulatory scrutiny. When such oils are distributed for different uses in vehicles, boilers, for example, off site emissions may be nearly impossible to monitor. Biogas Anaerobic digestion and similar biological processes are sometimes described as ?waste to energy? because these technologies generate biogas from organics materials like food and plant debris. As biological processes (as opposed to thermal processes) they are beyond the scope of this paper. A 2008 U.S. study[6] for a government agency surveyed a large range of gasification and plasma technologies and found these processes are unproven on a commercial scale for treating MSW in the U.S. It also found that solid and liquid residuals may be hazardous, and further more, that the technologies require pre-treatment of waste and are more expensive than conventional incineration or landfilling. Gasification has a more than three-decade long track record with which to test vendor claims about the technology?s suitability for waste treatment.[7] Unfortunately, gasification plants have made very little operational data available.[8],[9],[10],[11] Project proponents routinely use projected or target data but the short operational history of most facilities and the lack of ongoing monitoring makes it impossible to conduct post-hoc verification of these targets or even basic mass and energy balance calculations.[12] Compared to gasification processes, fewer facilities have attempted to use pyrolysis and plasma processes at a similar scale.[13] Similar to gasification, little operational data is available. Information about some facilities is included in the cases in this paper. Existing data does show that dozens of projects have failed, for a variety of technical and financial reasons, as discussed below. These failures highlight a widespread inability to meet projected energy generation, revenue generation, and emissions targets, or to simply maintain consistent operation. The primary lessons to be drawn are that the benefits of waste gasification are smaller and more uncertain, and the risks much higher, than technology proponents claim. Waste Gasification and Pyrolysis Technology Risk Assessment 3 [Page 6] Public investments in gasification and pyrolysis in the UK The United Kingdom provides an interesting case study of public investments in these processes due to a series of now-expired incentives that supported the financing of new gasification, pyrolysis, and plasma facilities. In 2006, DEFRA (Department for Environment, Food, and Rural Affairs) began the New Technologies Demonstrator Programme (NTDP) to ?overcome the perceived risks of implementing new technologies in England and to provide accurate and impartial technical, environmental and economic data.?[14] The NTDP was intended to spend £32 million[15] on 10 projects.[16] Resulting projects were subsequently evaluated and found to be largely unsuccessful:[17] of the four gasification and pyrolysis projects, two projects did not proceed to operational status during the program, a third was not able to run long enough to study the process and was closed,[18] and the fourth project had numerous problems and remains under reconstruction.[19],[20] Gasification attempts in the UK depend on high tipping fees and public subsidies to support operations. However, future public subsidy options seem limited. These technologies are excluded from the UK?s Feed in Tariff program. The national Renewable Obligation Certificates provided a second funding opportunity, but this program will not accept new generating capacity after March 2017. A new national government program called Contract for Difference is still accepting applications from proposed gasification projects in the near term, but has yet to make a decision about inclusion of gasification in future years. Waste Gasification and Pyrolysis Technology Risk Assessment 4 [Page 7] Risks and Challenges Technology Risks and Operational Challenges Decades of attempts to apply gasification, pyrolysis, and plasma arc to municipal waste have exposed the underlying complications with this approach, as evidenced by the high failure rate of these plants. Of the commercial-scale facilities that have been established in Europe, United Kingdom, Canada, and the U.S., many have had trouble maintaining regular operations and producing sufficient energy to remain in business.[21] Operations have been impaired for technical reasons including: Please see the list of - Inability to meet pollution control limits (described in the following environmental risk section), notable cases in the - Corrosive damage to equipment (such as the collapse of the roof deployment of and steel chimney of a waste gasification plant in Hamm-Uentrop, Germany, see environmental risk section), gasification, - Problems maintaining satisfactory reaction temperatures, and - Energy inefficiency. pyrolysis, and Gasification has been most widely employed on uniform fuels such as coal plasma arc at the or wood chips, but even these face serious technical obstacles.[22],[23] A end of this report 2010 report by the German development agency GTZ (now called GIZ) on gasification of biomass concluded that although biomass gasification is for information ?theoretically an interesting option for rural development,? severe challenges are unsolved, specifically: ?There is no reliable technology readily about facilities available. High costs for technical development, repair and maintenance around the world. make it unprofitable. Dangerous threats exist to the environment and health due to carcinogenic waste.?[24] In comparison, modern unsorted MSW streams are extremely heterogeneous and thus more technically complex to treat and manage than wood chips. Municipal solid waste streams typically include large proportions of food waste, yard trimmings, plastics, metals, paper, electronics, furniture, household hazardous waste, etc. They can also vary temporally: for example, displaying strong seasonality in moisture content in tropical climates.[25] As gasification operates above the boiling point of water, high moisture content dramatically reduces process energy efficiency. Varying composition and moisture content of the waste presents challenges to maintaining stable operations, particularly reaction vessel temperatures, which are crucial to syngas production. The UK Government Energy from Waste Guide describes that syngas needs to be cleaned to be burned in a gas turbine or engine, and that the cleaning is an energy-intensive process. This overall process may be less efficient than conventional incineration.[26] Waste Gasification and Pyrolysis Technology Risk Assessment 5 [Page 8] Reliable energy generation is a common problem at gasification plants. While some technology vendors claim that the syngas can be sold as a chemical feedstock, in practice, it generally is too contaminated and too dilute to be sold as a commercial product.[27] Instead, most vendors intend to burn syngas on-site to produce energy. Even then, many operators find that the energy produced is little more than that demanded to operate the energy intensive system.[28] This problem is exacerbated in developing countries, where the waste stream is comparatively higher in organics (i.e. food and biomass). This results in a syngas so low in calorific value that it cannot even produce energy, demonstrating the unsuitability of these technologies for large-scale MSW management in developing countries.[29] Even in developed countries, with higher calorific value waste streams, gasification plants are challenged to meet projected energy production targets (see in Notable Cases section of this paper including Scotgen, Thermoselect, Plasco cases). One approach to address these issues is to co-fire waste with fossil fuels. Fossil fuels are added to waste for gasification in at least some facilities in Japan (Hitachi Metals[30] & JFE Steel[31] add coke). Another approach is to add relatively small amounts of syngas (up to 10%) to burn with coal. Exact energy balance data for these practices is not available. It should be noted that this approach increases reliance on continued combustion of fossil fuels, which increases regulatory risk (described below) and should exclude the technologies from receiving renewable energy subsidies. Another approach is pre-treatment of the waste, by removing wet organics and inert material while retaining the high-energy plastics in the waste stream. But this eliminates the primary attraction of gasification as a ?one size fits all? technology to treat waste.[32] Higher concentrations of plastics, which are also fossil fuels, increases tarring[33] and again should eliminate the possibility of renewable energy subsidies. Prominent proponents of ?waste to energy? acknowledge these shortcomings of applying gasification processes to waste. As Hakan Rylander, former President of International Solid Waste Association (ISWA) and CEO of the South Scania Waste Company (Sweden), a conventional waste incineration company, writes, ?Waste is not a homogenous fuel. It has so far turned out to be too heterogenous to be able to treat in a gasification or pyrolysis process, irrespective of how you pre-treat the waste. It is absolutely not applicable for mixed MSW with today's technology. Another very negative factor is that the energy balance very often has turned out to be negative.?[34] It is not always possible to distinguish between technological and financial failure: many plants are shut down before achieving stable operations, as the costs become excessive (see Financial Risk, below). Conventional ?waste to energy? incineration Waste gasification, pyrolysis, or plasma has similar drawbacks to combustion in conventional ?waste to energy? incinerators. Cost is a striking factor as these facilities have been shown are the most expensive treatment option for waste.[35] Consequences also include: - 20-30% of the weight of waste is left as ash.[36] Rather than avoiding landfills, incineration is merely a step before landfilling wastes that become more hazardous through combustion. - Carbon intense emissions, and emissions of persistent organic pollutants (dioxin, furans, mercury), heavy metals, particulate matter, nanoparticles, and other pollutants.[37] - In China, a 2015 report on the country?s 160 existing and operating MSW incinerators found that 40% have incomplete air emission data and only 8% have dioxin emission data available to the public. Among those that have incomplete data, 69% have a record of violating new environmental standards.[38] Waste Gasification and Pyrolysis Technology Risk Assessment 6 [Page 9] Financial Risk Many gasification projects have failed because of financial non-viability. Examples include: - The 2016 cancellation of two Tees Valley, UK gasification projects which lost U.S. company Air Products between US$900 million and $1 billion.[39] - The Thermoselect gasification facility in Karlsruhe, Germany lost over $500 million in 5 years of operations. - In the UK, Interserve left the "energy-from-waste" field after losing £70 million on gasification projects, and other companies have gone bankrupt attempting to construct gasification or similar processes, include Energos, BCB Environmental, Waste2Energy, Biossence, Compact Power, and New Earth Solutions Group.[40],[41] A 2013 U.S. industry trade journal estimated the following capital costs for facilities with 15 MW output: Estimated Costs (in U.S. Dollars) [42] Ranges for Capital Costs for each of the Thermal Technologies: Low Range High Range Direct Combustion (Mass Burn and RDF) ranges from $7,000 to $10,000 per kW. 105,000,000 150,000,000 Pyrolysis ranges from $8,000 to $11,500 per kW. 120,000,000 172,500,000 Conventional Gasification ranges from $7,500 to $11,000 per kW. 112,500,000 165,000,000 Plasma Arc Gasification ranges from $8,000 to $11,500 per kW 120,000,000 172,500,000 In general, costs are higher and more uncertain than project proponents foresee, and revenues are lower and more uncertain. Research on facilities in Europe finds that many facilities have failed due to economic problems, citing inadequate revenues and costs from preparing feedstock.[43] Additionally, when the facility does not operate as intended or shuts down for repair, companies with contracts to treat waste must cover the added costs of sending that waste elsewhere. The high capital costs and high energy consumption of gasification make it financially unattractive compared to other waste management strategies, including recycling, composting, and landfilling. In order to recoup these costs, financial models often count on charging tipping fees (also called gate fees, these are disposal costs charged to waste generators, e.g., municipalities). These projects also need to derive income from the syngas. Some technology vendors also claim that that the slag can be sold as a building material, a practice which raises risks and potential liability for health impacts to building habitants and workers. An additional financial challenge is the cost of pre-treatment of the waste. This waste as delivered to the facility is often unsuitable for gasification: it has too much moisture content, too little calorific value, or too great an inert content. Some facilities have disclosed the use of additional conventional fossil fuels, or have added a waste separation process to create a suitable feedstock.[44] This can be a major additional operational expense. Recently, there have been calls to provide additional public financing in more countries through renewable energy incentives and subsidies, such as a Feed-In-Tariff (see Regulatory Risk, below). Waste Gasification and Pyrolysis Technology Risk Assessment 7 [Page 10] Regulatory Risk As a technology still under development, gasification relies upon a strong regulatory environment, including real time environmental emissions monitoring, to ensure operational safety and compliance. Few governments today have the capacity, technical knowledge, or regulatory framework in place to ensure safe operation of gasification facilities, but due to the environmental and health risks inherent with these technologies, investors should anticipate an evolving, and increasingly stringent future regulatory environment. On the other hand, the industry?s financial challenges have led to calls for public subsidies, for example, in the form of a Feed-in Tariff (FIT).[45] The "Many operators FIT is an electricity production subsidy that has had success in encouraging widespread adoption of renewable energy, most notably solar photovoltaic in find that the Europe. Unlike FITs designed to provide widespread subsidies to homeowners for switching to solar panels, a gasification FIT would benefit only a handful of commercial operators, and could not expect to enjoy the energy produced kind of popularity that a solar PV FIT does. Advocates of renewable energy programs have joined others in calling for renewable energy policies like Feed is little more In Tariffs to exclude ?waste to energy? approaches such as gasification. This would leave the operator?s balance sheet extremely vulnerable to any change in policy. than that Even more problematic is that while vendors often tout syngas as a ?green? or ?renewable? energy source, syngas created from primarily fossil-fuel derived demanded to plastics and other nonrenewable resources are essentially fossil fuel. For example, a gasification incinerator accepting only plastics would generate entirely fossil-fuel derived syngas and electricity. These are not renewable operate the fuels from a scientific perspective, and in fact, even the syngas coming from the biomass portion of wastes is not necessarily climate-neutral. energy intensive This poor carbon performance of waste gasification works directly against efforts to decarbonize electricity grids, making long-term inclusion of system." gasification in renewable energy schemes particularly vulnerable to regulatory corrections. One example is the recent move by the European Union to discourage renewable energy subsidies for waste incineration, and require mandatory separation of organics.[46] An additional risk is found in those jurisdictions where vendors have created regulatory confusion by describing technologies as non-combustion. The syngas created during the initial high temperature treatment phase of gasification is nearly always intended to be combusted, either on site or as fuel, disqualifying these processes from any regulatory definition that includes ?non-combustion.? Furthermore, most countries are signatory to the Stockholm Convention[47] and obliged therefore to reduce and eliminate releases from unintentionally produced POP (persistent organic pollutants), such as those created through conventional waste incineration, waste gasification, pyrolysis, and plasma arc. Waste Gasification and Pyrolysis Technology Risk Assessment 8 [Page 11] Environmental Risk Although gasification is billed in academic studies and vendor documents as a ?cleaner? form of combustion than conventional ?waste to energy? incineration, the data does not support this claim. While operating facilities rarely disclose comprehensive emissions data, regulatory agencies and media reports described serious and repeated emissions violations at numerous facilities (see the ?Notable Cases? section in this paper). As long as gasification is used on a mixed waste stream or plastics waste stream ? which includes chlorinated materials and heavy metals ? it will result in a similar emissions profile as conventional incineration. Emissions may include NOx, SOx, hydrocarbons, carbon monoxide, particulate matter (PM), heavy metals, greenhouse gas emissions such as CO2, and dioxins/furans.[48] Mixed plastics contain chemicals that lead to hazardous emissions in such systems. Polyvinyl chloride (frequently called PVC or vinyl) is a common plastic that contains chlorine, a precursor to dioxin creation when heated or burned. Manufacturers introduce additives including lead, arsenic, chromium, and phthalates to improve PVC?s ductility, strength, and rigidity. These additives, and their combustion byproducts, represent an emissions challenge for gasification or any thermal treatment of mixed plastics. Syngas combustion requires significant air pollution control measures, particularly since it is contaminated with particulates, tar, alkali metals, chlorides and sulfides.[49] Some of these must be scrubbed out before the syngas is burned to avoid serious damage to the combustion engine.[50] Others must be filtered out of the exhaust gases post-combustion. This requires two stages of pollution control, each creating its own waste product: hazardous wastewater and fly ash. Even modern pollution control technologies do not always prevent serious emissions and equipment damage, as was dramatically demonstrated by the collapse of the roof and steel chimney of a waste gasification plant in Hamm-Uentrop, Germany, destroying the power plant. The collapse was attributed to corrosion from acidic flue gases.[51] The disposal of the remaining outputs has also been controversial. The fly ash, wastewater, and slag are all contaminated to some degree with a variety of toxic contaminants, including dioxins, mercury, and heavy metals. In addition, water consumption and contamination was a significant problem at the short-lived but large scale Thermoselect facility in Germany.[52] Reputational Risk For a technology with an intermittent track record, gasification has already acquired a negative reputation in