Urban PM2.5 Atlas: Air Quality in European cities

Many European cities suffer from poor air quality and regularly exceed both the European standards prescribed by the Air Quality Directive and the guidelines recommended by the World Health Organization. This is particularly the case for fine particulate matter (PM10) for which both the daily and yearly average limit values are regularly exceeded in many cities and several regions in Europe. Similar conclusions hold for PM2.5 where few cities manage to keep concentrations below the levels recommended by the WHO. Actions have been proposed and taken at the international, national and urban scales to reduce air pollution. While they have undoubtedly resulted in an overall improvement of the air quality over the years, there are still problems which are localised in specific regions and many cities. A key issue is thus to determine at which scale to act in order to abate these remaining air pollution problems most effectively. Central to this for cities, is a quantitative assessment of the different origins of air pollution in the city (urban, regional, national and transboundary) to support the design of efficient and effective air quality plans, which are a legal obligation for countries and regions whenever exceedances occur. The “Screening for High Emission Reduction Potentials for Air quality” tool (SHERPA) has been developed by the Joint Research Centre to quantify the origins of air pollution in cities and regions. In this Atlas, both the spatial (urban, country…) and sectoral (transport, residential, agriculture…) contributions are quantified for 150 European urban areas in Europe, where many of the current exceedances to the air quality EU limit values and WHO guidelines are reported. There is a need to provide information to improve air quality policy governance, to support authorities in choosing the most efficient actions at the appropriate administrative level and scale. In particular, actions at the local level focusing on the urban scale and at national/international level needs to be carefully balanced. Key conclusions are: • For many cities, local actions at the city scale are an effective means of improving air quality in that city. The overall conclusion is that cities have a role to play by taking actions at their own scale. It is important to emphasise that the emissions in cities contribute significantly to country and EU overall PM concentrations, reinforcing the important role of cities in reducing the air pollution through a multilevel approach. • Impacts of abatement measures on air quality are city specific The impact of a given abatement measure on air quality differs from city to city, even for cities that are located in the same country. Actions taken at different scales or in different activity sectors therefore lead to impacts on air quality that are city-specific. The diversity of possible responses to abatement measures stresses the need to take into account these city-specific circumstances when designing air quality plans. Actions that are efficient in one city might not be efficient in others. • Sectoral measures addressing agriculture at country or EU scale would have a clear benefit on urban air quality. Although agricultural emissions are limited in the "city" as defined here, agriculture considerably impacts air quality in many EU cities. The extent of the impact of agriculture on air quality is indicative of the potential of EU- or country-wide measures addressing this sector. Moreover, other sectoral measures can have an important potential at the urban scale even though they are applied at EU or country scale. This is the case of road transport where the EURO norms are, in practice, most effective in the areas where traffic is most important, i.e. cities.JRC.C.5-Air and Climat

Urban NO2 Atlas

The Atlas shows, for selected cities, the likely effects of the implementation of “Traffic Policies” intended to reduce urban NO2 concentrations. As NO2 pollution in urban areas is mainly caused by traffic, the analysis focuses on assessing the relative contribution to the NO2 concentration in ambient air from different types of vehicles. The results, obtained for a selected number of cities in Europe show that, depending on the size of the selected “Inner Area” (by this name, we mean the area over which traffic measures are applied), one could reduce on average up to 40% the NO2 urban background concentrations. Of this average reduction, roughly 15% is linked to passenger diesel cars, 13% to trucks and 6% to vans (mostly diesel); while the remaining share is associated to other type of vehicles (buses, gasoline cars, etc…). This Atlas provides a first indication of the relative effectiveness of mobility policies aimed at reducing urban NO2 pollution concentrations in European cities. However, considering the specific assumptions in the applied approach, as on traffic flows, fleet composition, emission factors, size of the “Inner Area”, etc…, the results may not be as accurate as they would be when using detailed local data. The SHERPA-City methodology and tool applied in this Atlas can be used by local authorities to assess a broad range of air quality measures, including technological (e.g. fleet renewal, new technologies) and soft measures (i.e. promotion of walking and cycling). Such measures can be assessed alone or in combination.JRC.C.5-Air and Climat

Biomass To Liquids:Thermo-Economic Analysis and Multi-Objective Optimisation

Biomass is the major source of renewable carbon which can be used to substitute fossil carbon in fuels and chemical products. This thesis addresses the modelling, design and thermoeconomic evaluation and optimisation of processes converting Biomass to Liquids (BtL) for the effective exploitation of a renewable, yet limited, resource. The focus is on thermochemical conversion, through gasification and Fischer-Tropsch (F-T) synthesis, producing drop-in fuels which could be used in the current infrastructure. Given the number of potential technological options and process configurations, a methodology is developed for a systematic comparison in terms of several performance indicators. The analysis is carried out through a framework combining thermochemical modelling, economic evaluation, process integration and multi-objective optimisation. Particular attention is given to the representation of biomass and its coherent modelling in terms of its elemental composition. Experimental data from previous studies is used to develop new thermochemical models for torrefaction and for fluidized bed gasification. Other technologies included in this study are air and steam drying, entrained flow gasification, tar reforming, high temperature tar cracking, water and gas quench and radiant panels, hot and cold gas cleaning, water gas shift, high temperature steam and steam/carbon dioxide electrolysis and F-T synthesis and upgrading. The final comparison, through the multi-objective optimisation, provides a better understanding of the trade-offs of different technological options and process variables in terms of competing economic and thermodynamic objectives. For 200MWth biomass input plant capacities, production costs are in the range of 1.0-1.4 euro/l for technologies producing up to about 0.5 kJFT /kJth and close to being neutral in terms of electricity balance. For technologies using electrolysis the conversion can increase to 0.8 kJFT /kJth with production costs of 1.8 euro/l. The electricity storage capacity, in this case, is of 0.5 kJe/kJFT , corresponding to a net electricity requirement of about 0.4 kJe/kJth. This work stems from the collaboration between LTB (Biomass Technology Laboratory) of CEA/Liten in Grenoble, France, and IPESE (Industrial Process and Energy Systems Engineering) of EPFL in Lausanne, Switzerland

Biomass Modelling: estimating thermodynamic properties from the elemental composition

In the context of modelling biomass conversion processes, the accurate representation of biomass, which is a complex and highly variable material, is of crucial importance. This study provides a rather simple and flexible way to represent biomass, especially suited in the context of thermochemical conversion processes. The procedure to represent the enthalpy of formation, the Gibbs free energy and the exergy of biomass in terms of its elemental composition (C, H, O, N, S) and moisture content is outlined. The correlations relating the heating value to the elemental composition of biomass are evaluated through a database of over one hundred raw and pretreated biomass samples. Results show that such correlations can predict the higher heating value (HHV) within an accuracy of 1.93% and 2.38%. One of the correlations is then applied to represent the enthalpy of formation of biomass as a linear function of the elemental composition. The procedure is extended to estimate the Gibbs free energy of formation and subsequently the exergy of biomass, which are expressed as linear functions of the elemental composition. The method proposed for the estimate of exergy allows taking directly into account the composition of the reference environment. Results show that the method proposed in this study agrees within 1% accuracy with the widely used correlation proposed by Szargut et al. (1988). The values obtained for Exergy, over the range of compositions of the samples considered, vary in general between 105% and 115% of the lower heating value (LHV) and 103% and 107% of the higher heating value obtained using the literature correlation by Boie (1953). On the basis of these correlations, this study provides the thermodynamic properties of C, H, O, N, S and bound water ‘pseudo-compounds’ that can be used in the thermodynamic properties evaluation packages used in flowsheeting software and in numerical simulations for a coherent description of biomass as a function of its composition

Process Integration of Lignocellulosic Biomass Pre-treatment in the Thermo-Chemical Production of F-T Fuels. Centralised Versus Decentralised Scenarios

The purpose of this study is to evaluate, in terms of process integration, the centralised and decentralised pre-treatment of lignocellulosic biomass for its thermo-chemical conversion into liquid fuels through gasification and Fischer-Tropsch (F-T) synthesis (biomass to liquids, BtL). The aim is to quantify the process integration benefits of a centralised configuration in comparison to the energy savings obtained through the transportation of a higher energy density fuel, in this case torrefied biomass instead of raw biomass. The analysis is carried out through the detailed energy and mass balances, and the pinch analysis of the centralised and decentralised configurations

Multi-level policies for air quality: implications of national and sub-national emission reductions on population exposure

Poor air quality and related health impacts are still an issue in many cities and regions worldwide. Integrated Assessment Models (IAMs) can support the design of measures to reduce the emissions of precursors affecting air pollution. In this study, we apply the SHERPA (Screening for High Emission Reductions Potentials for Air quality) model to compare spatial and sectoral emission reductions, given country-scale emission targets. Different approaches are tested: a) country uniform emission reductions; b) emission reductions targeting urban areas; c) emission reductions targeting preferential sectors. As a case study, we apply the approaches to the implementation of the National Emission Ceiling Directive. Results are evaluated in terms of the reduction in average population exposure to PM2.5 overall in a country and in its main cities. Results indicate that the reduction of population exposure to PM2.5 highly depends on the way emission reductions are implemented. This work also shows the usefulness of the SHERPA model to support national authorities implementing national emission reductions targets while, at the same time, addressing their local air quality issues.JRC.C.5-Air and Climat

Thermo-economic analysis and multi-objective optimisation of lignocellulosic biomass conversion to Fischer-Tropsch fuels

This paper addresses the techno-economic evaluation and optimisation of processes converting lignocellulosic biomass into liquid fuels, through the development of a suitable framework and the modelling and design of Biomass to Liquids (BTL) processes. In particular, the focus is on the production of drop-in fuels through gasification and Fischer-Tropsch (FT) synthesis. Several conversion technologies are presented and evaluated in the literature, but the comparison of different options is hazardous because of the different assumptions and methodologies adopted in each study. A systematic and consistent approach is therefore developed to explore the trade-offs of alternative process configurations and of the operating conditions. The comparison presented in this study explores the trade-offs of different technological options in terms of competing economic and thermodynamic objectives. Results show that for 200 MWth biomass input plant capacities, production costs are in the range of 1.0-1.4 €/l for technologies producing up to about 0.5 kJFT/kJth and close to being neutral in terms of electricity balance. For technologies using electrolysis the conversion can increase to 0.8 kJFT/kJth with production costs of 1.8 €/l. The electricity storage capacity, in this case, is of 0.5 kJe/kJFT, corresponding to a net electricity requirement of about 0.4 kJ e/kJth

On the Assessment of the CO2 Mitigation Potential of Woody Biomass

Woody biomass, a renewable energy resource, accumulates solar energy in form of carbon hydrates produced from atmospheric CO2 and H2O. It is, therefore, a means of CO2 mitigation for society as long as the biogenic carbon released to the atmosphere when delivering its energy content by oxidation can be accumulated again during growth of new woody biomass. Even when considering the complete life cycle, usually, only a small amount of fossil CO2 is emitted. However, woody biomass availability is limited by land requirement and, therefore, it is important to maximize its CO2 mitigation potential in the energy system. In this study, we consider woody biomass not only as a source of renewable energy but also as a source of carbon for seasonal storage of solar electricity. A first analysis is carried out based on the mitigation effect of woody biomass usage pathways, which is the avoided fossil CO2 emissions obtained by using one unit of woody biomass to provide energy services, as alternative to fossil fuels. Results show that woody biomass usage pathways can achieve up to 9.55 times the mitigation effect obtained through combustion of woody biomass, which is taken as a reference. Applying energy system modeling and multi-objective optimization techniques, the role of woody biomass technological choices in the energy transition is then analyzed at a country scale. The analysis is applied to Switzerland, demonstrating that the use of woody biomass in gasification–methanation systems, coupled with electrolysers and combined with an intensive deployment of PV panels and efficient technologies, could reduce the natural gas imports to zero. Electrolysers are used to boost synthetic natural gas production by hydrogen injection into the methanation reaction. The hydrogen used is produced when there is excess of solar electricity. The efficient technologies, such as heat pumps and battery electric vehicles, allow increasing the overall efficiency of the energy system while generating demand for the solar electricity

Investment and production costs of synthetic fuels - A literature survey

Synthetic fuels, or synfuels, can be produced from gas, coal and biomass. The conversion of gas and coal is well established but lignocellulosic biomass conversion is slow to develop. This paper addresses the issue of the production cost of second generation biofuels via the thermo-chemical route, biomass to liquids (BtL). Techno-economic studies help identify promising conversion processes, but also introduce a false confidence in the technology that may lead to ill fated decisions. A large number of techno-economic studies have been published since the year 2000 showing a large variability in the results. This paper analyses the published data and presents causes of the observed variability, including a comparison with coal and gas to liquids. Large uncertainties remain however with regard to the precision of the economic predictions. It will be shown that the spread in the economic source data accounts for much of the spread in the predictions. These uncertainties affect both CtL and BtL cost predictions. It will be shown however that the results are relatively coherent and that most of the differences between the costs of synthetic fuels can be traced back to economies of scale considering mature technology. (C) 2014 Elsevier Ltd. All rights reserved