Athanasios Rentizelas

Combined municipal solid waste and biomass system optimization for district energy applications

Municipal Solid Waste (MSW) disposal has been a controversial issue in many countries over the past years, due to disagreement among the various stakeholders on the waste management policies and technologies to be adopted. One of the ways of treating/disposing MSW is energy recovery, as waste is considered to contain a considerable amount of bio-waste and therefore can lead to renewable energy production. The overall efficiency can be very high in the cases of co-generation or tri-generation. In this paper a model is presented, aiming to support decision makers in issues relating to Municipal Solid Waste energy recovery. The idea of using more fuel sources, including MSW and agricultural residue biomass that may exist in a rural area, is explored. The model aims at optimizing the system specifications, such as the capacity of the base-load Waste-to-Energy facility, the capacity of the peak-load biomass boiler and the location of the facility. Furthermore, it defines the quantity of each potential fuel source that should be used annually, in order to maximize the financial yield of the investment. The results of an energy tri-generation case study application at a rural area of Greece, using mixed MSW and biomass, indicate positive financial yield of investment. In addition, a sensitivity analysis is performed on the effect of the most important parameters of the model on the optimum solution, pinpointing the parameters of interest rate, investment cost and heating oil price, as those requiring the attention of the decision makers. Finally, the sensitivity analysis is enhanced by a stochastic analysis to determine the effect of the volatility of parameters on the robustness of the model and the solution obtained.

Incorporating uncertainty in optimal investment decisions

Investment decisions are now more crucial than ever. The investors are in need of sound arguments, which will be able to shape the investment specifications and appraise their uncertain nature. This paper proposes an innovative approach that merges optimisation and risk analysis in one single method. The two-step investment appraisal approach reaches an optimum through a Genetic Algorithm optimisation and then assesses the environments risk through a Monte Carlo simulation. The approach, thus, offers the best investment characteristics, as well as information about its implied risk. The use of the method is illustrated through an extensive Case Study.

Electricity and combined heat and power from municipal solid waste; theoretically optimal investment decision time and emissions trading implications

Waste management has become a great social concern for modern societies. Landfill emissions have been identified among the major contributors of global warming and climate changes with significant impact in national economies. The energy industry constitutes an additional greenhouse gas emitter, while at the same time it is characterized by significant costs and uncertain fuel prices. The above implications have triggered different policies and measures worldwide to address the management of municipal solid wastes on the one hand and the impacts from energy production on the other. Emerging methods of energy recovery from waste may address both concerns simultaneously. In this work a comparative study of co-generation investments based on municipal solid waste is presented, focusing on the evolution of their economical performance over time. A real-options algorithm has been adopted investigating different options of energy recovery from waste: incineration, gasification and landfill biogas exploitation. The financial contributors are identified and the impact of greenhouse gas trading is analysed in terms of financial yields, considering landfilling as the baseline scenario. The results indicate an advantage of combined heat and power over solely electricity production. Gasification, has failed in some European installations. Incineration on the other hand, proves to be more attractive than the competing alternatives, mainly due to its higher power production efficiency, lower investment costs and lower emission rates. Although these characteristics may not drastically change over time, either immediate or irreversible investment decisions might be reconsidered under the current selling prices of heat, power and CO 2 allowances.

Quantitative risk analysis for road tunnels complying with EU regulations

Tunnels have improved the connection of regions within the European Commission (EC) and have been used lately as a catalyst for economic development of previously isolated regions. However, the increasing number of these important infrastructures is raising upfront an endogenous problem, which is the severity of accidents that may occur. These risks have much greater impact when heavy goods vehicles (HGVs) or dangerous goods (DGs) are involved in the accident. As a result, the EC launched the EC Directive 2004/54/EC. In order to achieve a minimum acceptable level of safety, the EC Directive 2004/54/EC suggests, apart from the measures imposed based on tunnel characteristics, the implementation of a risk analysis in cases such as the opening of the road tunnel to DGs. The most widely accepted method for such quantitative risk analysis (QRA) is the OECD/PIARC QRA Model. This research exploits the QRA Model to perform a QRA for five illustrative cases in order to explore the sufficiency of the minimum tunnel safety measures imposed by the Directive when transportation of HGVs and DGs is allowed through the tunnel. The research concludes that, at least for tunnels with marginal values of the EC Directive classes for length and traffic, the risk exposure (F/N curves) lays over the acceptable safety limits of ALARP (as low as reasonably practicable) models. Thus, the manager of the tunnel should take seriously into account the provision of the Directive for further risk analysis and consider more safety measures as well as take into account the risk associated with the alternative routes.

Effect of greenhouse gas emissions trading on investment decisions for biomass-to-energy production

This chapter looks at the effect of greenhouse gas emissions trading on investment decisions for biomass-to-energy production

Decisions under uncertainty in municipal solid waste cogeneration investments

The issue of Municipal Solid Waste (MSW) management is an ever increasing problem for all countries. Developed countries face the problem of dealing with very large amounts of MSW per capita, forcing them to develop new technologies and systems. On the other hand, countries with developing or transitional economies may generate lower amounts of MSW per capita, but the rate of increase is high and the current practices of MSW management are not as advanced as those of developed countries. Therefore, countries with developing or transitional economies may benefit from adopting MSW management technologies used by developed economies. One aspect of MSW management in developed economies is the energy recovery from MSW. The advantages of this type of technologies are mainly the significantly reduced waste volume for landfilling, the reduction of total greenhouse gas emissions, the potential for generating electricity or co-generation of electricity and heat. In this work, a comparative study of the most prominent co-generation technologies using MSW as a fuel source is presented, focusing on the evolution of their economical performance over time. An algorithm based on real-options has been applied for four technologies of MSW energy recovery: (1) incineration, (2) gasification, (3) landfill biogas exploitation using a pipeline system and (4) anaerobic digestion facilities. The financial contributors are identified and the impact of greenhouse gas trading is analyzed in terms of financial yields, considering landfilling as the baseline scenario. The greenhouse gas trading system presents an opportunity for investing in environmentally friendly technologies for MSW energy recovery, through the Clean Development Mechanism (CDM), in most developing countries. The results of this work indicate an advantage of combined heat and power over solely electricity generation. The most attractive technology among the ones examined proves to be incineration, mainly due to its higher power production efficiency, lower investment costs and lower emission rates. Despite the fact that these characteristics may not drastically change over time, either immediate or irreversible investment decisions might be reconsidered under the current selling prices of heat, power and CO2 allowances.

Environmental performance measurement for green supply chains: A systematic analysis and review of quantitative methods

Purpose The majority of the environmental impacts in a typical supply chain can arise beyond the focal firm boundaries. However, no standardised method to quantify these impacts at the supply chain level currently exists. The purpose of this paper is to identify the quantitative methods developed to measure the environmental performance of supply chains and evaluate their key features. Design/methodology/approach A systematic literature review is conducted at the intersection of performance measurement and green supply chain management (GSCM) fields, covering 78 publications in peer-reviewed academic journals. The literature is reviewed according to several perspectives, including the environmental aspects considered, the main purpose of measurement, model types and the extent of supply chain covered by performance measurements. Findings Adopted environmental metrics show a low degree of standardisation and focus on natural resources, energy and emissions to air. The visibility and traceability of environmental aspects are still limited; the assessment of environmental impacts does not span in most cases beyond the direct business partners of the focal firms. A trade-off was observed between the range of environmental aspects and the extent of the supply chain considered with no method suitable for a holistic evaluation of the environmental supply chain performance identified. Three major streams of research developing in the field are identified, based on different scope. Originality/value This paper is the first attempt to examine in detail what tiers of the supply chain are actually involved in green performance assessment, ultimately contributing to clarify the scope of the supply chain dimension in GSCM performance measurement research. The work also recognises which methods are applicable to extended supply chains and explores how different methodologies perform in terms of supply chain extent covered.

Biomass supply chains

The chapter discusses the biomass supply chain, which bears the role of supplying an energy conversion plant with biomass, at the correct quantity, time and quality specifications. The chapter first categorizes the biomass and waste streams and presents analytically the biomass supply chain, discussing its structure and characteristics. It then proceeds in reviewing the latest advances in biomass supply chains. The issue of integrating biomass energy conversion into waste management systems is tackled and the advantages and limitations of using biomass, in supply chain terms, are presented. The chapter concludes with future trends in biomass supply chain and logistics, and proposing sources of further information

Improving Safety in Greek Road Tunnels

Tunnels are regarded as one of the most important infrastructures in Europe, as they may improve the connection of regions and aid economic development through facilitating the transportation of people and goods. In order to achieve a minimum acceptable level of safety, the EC issued Directive 2004/54/EC, which describes specific safety measures that have to be taken for all road tunnels in the trans-European road network. In parallel, there are several qualitative or quantitative methods for measuring road tunnel safety, while the method that seems to be the most accepted by administrative authorities for quantitative risk analysis is the OECD/PIARC QRA Model (QRAM), which has been developed by INERIS, WS-Atkins and the Institute for Risk Research. QRAM is based on engineering software that aids quantitatively assessment of the societal risk due to transporting goods and dangerous goods with Heavy Goods Vehicles (HGV) through road tunnels. The aim of this paper is to expose the effectiveness of the measures imposed by the EC in Greek road tunnels. A typical road tunnel, as designed and implemented after Directive 2004/54/EC, is compared to the same tunnel as if it was developed before the Directive was put into action. The comparison is made on the basis of the societal risk existing in the two cases. The conclusion of the paper, based on the outcome of the risk analysis with the QRAM method, is that the safety of Greek Tunnels is significantly improved due to the implementation of the measures imposed by the EC Directive 2004/54/EC.