Paulo Ferrão

Urban Metabolism: Methodological Advances in Urban Material Flow Accounting Based on the Lisbon Case Study

Urban metabolism studies have been established for only a few cities worldwide, and difficulties obtaining adequate statistical data are universal. Constraints and peculiarities call for innovative methods to quantify the materials entering and leaving city boundaries. Such methods include the extrapolation of data at the country or the region level based, namely, on sales, population, commuters, workers, and waste produced. The work described in this article offers a new methodology developed specifically for quantifying urban material flows, making possible the regular compilation of data pertinent to the characterization of a citys metabolism. This methodology was tested in a case study that characterized the urban metabolism of the city of Lisbon by quantifying Lisbons material balance for 2004. With this aim, four variables were characterized and linked to material flows associated with the city: absolute consumption of materials/products per category, throughput of materials in the urban system per material category, material intensity of economic activities, and waste flows per treatment technology. Results show that annual material consumption in Lisbon totals 11.223 million tonnes (20 tonnes per capita), and material outputs sum 2.149 million tonnes. Nonrenewable resources represent almost 80% of the total material consumption, and renewables consumption (biomass) constitutes only 18% of the total consumption. The remaining portion is made up of nonspecified materials. A seemingly excessive consumption amount of nonrenewable materials compared to renewables may be the result of a large investment in building construction and a significant shift toward private car traveling, to the detriment of public transportation.

A new environmental Kuznets curve? Relationship between direct material input and income per capita: evidence from industrialised countries

Abstract Many studies have focused on the quantification of the input of materials into the economy. However, the insights provided by those studies have generally been limited. This paper attempts to bring analytical value to the discussion on “dematerialization” considering direct material input (DMI) per capita as the dependent variable in a test of the environmental Kuznets curve (EKC). The explanatory variable is, as usual, gross domestic product per capita. The quadratic and cubic versions of the EKC are tested econometrically, using panel data ranging from 1960 to 1998 for 16 industrialised countries. The results indicate a strong and robust support for both the quadratic and cubic EKC relationships between material input and income, in industrialised economies. While the statistical support to both types of evolution may seem contradictory, it suggests that as industrialised economies grow, the intensity of material consumption first increases, but eventually starts exhibiting a decreasing trend after a certain income threshold is reached. The inverted-U, or quadratic, relationship is confirmed, even though for the ranges of income considered in this study, the trend is mostly on the increasing part of the inverted-U curve. However, the statistical support to the cubic specification suggests that these results need to be regarded with caution. Overall, the statistically stronger models are the quadratic and cubic models with country random effects, and the cubic model with country and year fixed effects.

Electric Vehicles and their impact to the electric grid in isolated systems

Energy systems are frequently based on imported fossil fuels, and this is a problem in different dimensions including, the environmental, the economic and the security of supply, the latter being particularly relevant for any isolated system, like Islands. Renewable energy is regarded as a solution to this problem, particularly considering its transformation in electricity but this does not include the impact of the transportation sector, which represents a significant component of the imported fuels consumption. The other main limitations associated to renewable electricity consists on the need to increase the storage capacity that might attenuate the effect of renewable energy sources intermittence and disparity between supply and demand. In both these main problems associated with renewable energy management, the Plug-in Electric Vehicles (EV) could be a part of the solution in that the use of the vehicle to grid (V2G) technology can provide storage of electric energy during low demand times and use it to match the demand in peak hours and/or to avoid fossil fuel consumption. However, could the large scale EV penetration lead to increasing the fraction of electricity from renewable? Is the usage of EV batteries like as a storage system truly the best solution? Is the EV a better solution for the vehicles owner than the internal combustion vehicle from an economical point of view? This paper analyses a case study in the Island of São Miguel in Azores, where energy systems modeling is used to assess how far large scale EV penetration may lead to increasing the potential for the use of renewable electricity, and discusses the possible revenues for EV owners from providing vehicle to grid power.

Design for recycling in the automobile industry: new approaches and new tools

This paper presents novel design for recycling (DfR) strategies that were incorporated in a new software tool, combining the use of emerging technologies dedicated to automobile shredder residue recycling, together with design for dismantling strategies. Extended producer responsibility enforces manufacturers to maintain product responsibility along its life cycle. As a consequence, manufacturers are under pressure to dispose of products in an environmentally responsible manner. The auto industry has been particularly involved in these processes and, in particular, European Union directives stipulate minimum reuse and recovery rates for end-of-life vehicles. This framework provides a motivation for the increasing use of dedicated design for recycling tools and practices. The current end-of-life vehicle processing is embodied by two industries: dismantling and shredding. If until recently dismantling was a key strategy in DfR, the auto industry has been investing in the development of automated technologies to promote the recycling of automobile shredder residue, as an alternative of more labour-intensive dismantling activities. However, existing DfR tools emphasize design for dismantling as a major DfR strategy, based on the belief that a product is to be disassembled at the end of its life. This paper introduces a new approach that includes, as an end-of-life processing strategy, postshredding sorting of materials and subsequent recycling, and describes a new DfR tool that provides the identification of economically optimum recycling strategies aimed at achieving given recycling and reuse rates, by adequately combining dismantling, shredding, and postshredding activities.

A Material Flow Accounting Case Study of the Lisbon Metropolitan Area Using the Urban Metabolism Analyst Model

Summary: This article describes a new methodological framework to account for urban material flows and stocks, using material flow accounting (MFA) as the underlying method. The proposed model, urban metabolism analyst (UMAn), bridges seven major gaps in previous urban metabolism studies: lack of a unified methodology; lack of material flows data at the urban level; limited categorizations of material types; limited results about material flows as they are related to economic activities; limited understanding of the origin and destination of flows; lack of understanding about the dynamics of added stock; and lack of knowledge about the magnitude of the flow of materials that are imported and then, to a great extent, exported. To explore and validate the UMAn model, a case study of the Lisbon Metropolitan Area was used. An annual time series of material flows from 2003 to 2009 is disaggregated by the model into 28 material types, 55 economic activity categories, and 18 municipalities. Additionally, an annual projection of the obsolescence of materials for 2010-2050 was performed. The results of the case study validate the proposed methodology, which broadens the contribution of existing urban MFA studies and presents pioneering information in the field of urban metabolism. In particular, the model associates material flows with economic activities and their spatial location within the urban area.

Life cycle activity analysis: logistics and environmental policies for bottled water in Portugal

Abstract. An innovative mathematical programming decision support model –Life Cycle Activity Analysis (LCAA)– is presented, integrating considerations of optimal allocations of resources and impacts upon the environment during the life cycle of products. LCAA is based on the classical formulation of activity analysis and on the life cycle assessment framework. The concept of linear activities is extended to embrace mass and energy fluxes over the entire life cycle of products including their environmental impacts. Special attention is given to the presence of loops in the product chains, such as those occurring when materials/products are recovered (reused, recycled.). An application brought from the Portuguese bottled water industry is described. The model features alternative activities for production technologies and product recovery strategies and permits the joint consideration of monetary costs and environmental burdens. The results obtained under five scenarios, including distinct disposal strategies and environmental constraints, are discussed.Zusammenfassung. In diesem Beitrag wird ein innovatives mathematisches Entscheidungsunterstützungsmodell – die Life Cycle Activity Analysis (LCAA) – präsentiert, welches die optimale Allokation von Ressourcen und Auswirkungen auf die Umwelt während des Lebenszyklusses eines Produktes beinhaltet. LCAA basiert auf der klassischen Formulierung der Aktivitätsanalyse und auf dem methodischen Gerüst des Life Cycle Assessments. Das Konzept der linearen Aktivitätsanalyse wird erweitert, um Massen- und Energieflüsse während des gesamten Produktlebenszyklusses sowie deren Auswirkungen auf die Umwelt einbezogen. Eine besondere Aufmerksamkeit wird auf bestehende Zyklen in Prozessketten gelegt, die bei der Wiederverwendung / Verwertung von Materialien/Produkten auftreten. Es eine Anwendung aus der portugiesischen Flaschenwasser-Industrie vorgestellt. Das Modell zeichnet sich durch verschiedene alternative Aktivitäten für Produktionstechnologien und Wiederverwendungsstrategien aus und erlaubt die gleichzeitige Betrachtung von monetären Kosten und Umweltbelastungen. Die Ergebnisse, die aus fünf Szenarien zu verschiedenen Entsorgungsstrategien und Umweltschutzrestriktionen gewonnen werden, werden diskutiert.

A Comparison Between Conventional LCA and Hybrid EIO-LCA: Analyzing Crystal Giftware Contribution to Global Warming Potential

The growing concern of European citizens with environmental quality and the European Commission’s determination to develop stronger environmental policies has contributed to the development and optimization of environmental management tools to support decision-makers in industry and government. These tools help to pro-actively identify sustainable options, optimized according to environmental, social, and economic criteria. In line with recent European Commission initiatives, an Integrated Product Policy (IPP) approach is to be considered in any economic sector. IPP addresses the whole life cycle of a product, and seeks to avoid shifting environmental problems from one phase of the product life cycle to another. This vision has emphasized the role of Life Cycle Assessment (LCA) methods, (see, for example, Guinée et al. 2002), which are frequently used with the purpose of accounting for environmental impacts of products and services. These methods show practical limitations, considering that each industry is dependent, directly or indirectly, on all other industries. Consequently, this approach is expensive and timeconsuming because resource input and environmental discharge data have to be estimated for each of the modeled processes of the life cycle of a product or service. The LCA based model has the following advantages: it is accurate within a defined system boundary; it is independent from price fluctuation, and it facilitates unit process level analysis. The disadvantages of this model are related with its high cost for complex product systems, and inherently, it provides incomplete system

Price forecasting in the day-ahead Iberian electricity market using a conjectural variations ARIMA model

Price forecast is a matter of concern for all participants in electricity markets, from suppliers to consumers through policy makers, which are interested in the accurate forecast of day-ahead electricity prices either for better decisions making or for an improved evaluation of the effectiveness of market rules and structure. This paper describes a methodology to forecast market prices in an electricity market using an ARIMA model applied to the conjectural variations of the firms acting in an electricity market. This methodology is applied to the Iberian electricity market to forecast market prices in the 24 hours of a working day. The methodology was then compared with two other methodologies, one called naïve and the other a direct forecast of market prices using also an ARIMA model. Results show that the conjectural variations price forecast performs better than the naïve and that it performs slightly better than the direct price forecast.

EXPERIMENTAL ANALYSIS OF THE DRYING KINETICS OF A FOOD PRODUCT

ABSTRACT A laboratory system allowing for the characterization of the thin-layer drying kinetics of olive bagasse at relatively high temperatures was designed and constructed. The system, which permits a wide range of operating velocities and temperatures, up to 700°C, allowed the weight loss of the sample to be monitored continuously. Constant drying conditions were maintained using an on-line computer. The drying conditions investigated in this study included combustion products of atmospheric air and propane with dry-bulb temperatures ranging from 125°C to 250°C, relative humidity lower than 1% and gas velocities ranging from 0.5 to 2.0 m/s.

Stochastic programming of vehicle to building interactions with uncertainty in PEVs driving for a medium office building

The large scale penetration of electric vehicles (EVs) will introduce technical challenges to the distribution grid, but also carries the potential for vehicle-to-grid services. Namely, if available in large enough numbers, EVs can be used as a distributed energy resource (DER) and their presence can influence optimal DER investment and scheduling decisions in microgrids. In this work, a novel EV fleet aggregator model is introduced in a stochastic formulation of DER-CAM [1], an optimization tool used to address DER investment and scheduling problems. This is used to assess the impact of EV interconnections on optimal DER solutions considering uncertainty in EV driving schedules. Optimization results indicate that EVs can have a significant impact on DER investments, particularly if considering short payback periods. Furthermore, results suggest that uncertainty in driving schedules carries little significance to total energy costs, which is corroborated by results obtained with the stochastic formulation of the problem.