Vented hydrogen deflagrations in containers: Effect of congestion for homogeneous and inhomogeneous mixtures

This paper summarises the results from 66 vented hydrogen deflagration experiments performed in 20-foot shipping containers: 42 tests with initially homogeneous and quiescent mixtures, and 24 tests with inhomogeneous mixtures. Other parameters investigated include hydrogen concentration, vent area, type of venting device, ignition position, and the level and type of congestion inside the container. The results confirm that internal congestion can increase the maximum reduced explosion pressure in vented deflagrations significantly, compared to vented deflagrations in empty enclosures. As such, it is important to incorporate the effect of congestion in the theoretical and/or empirical correlations recommended in standards and guidelines for explosion protection. The work reported here is a deliverable from work package 2 (WP2) in the project “Improving hydrogen safety for energy applications through pre-normative research on vented deflagrations” (HySEA). The project received funding from the Fuel Cells and Hydrogen Joint Undertaking (FCH JU).     

Towards a future with large penetration of distributed generation: Is the current regulation of electricity distribution ready? Regulatory recommendations under a European perspective

The European Energy Policy promotes renewable energy sources and energy efficiency as means to mitigate environmental impact, increase security of supply and ensure economic competitiveness. As a result, the penetration levels of distributed generation (DG) in electricity networks are bound to increase. Distribution networks and distribution system operators (DSOs) will be especially affected by growing levels of DG. This paper reviews the current regulation of distribution in the European Union Member States, focusing on those aspects that might hinder the future integration of DG. Several regulatory issues that may hinder a successful integration of DG have been identified. Recommendations to improve the current situation are proposed. Regarding economic signals sent to DG, connection charges and cost-reflective use-of-system charges together with incentives to provide ancillary services are the key aspects. Concerning DSOs regulation, unbundling from generation and supply according to the European Electricity Directive, incentives for optimal planning and network operation considering DG, including energy losses and quality of service, and innovation schemes to migrate to active networks are the most relevant topics.     

Simulating vented hydrogen deflagrations: Improved modelling in the CFD tool FLACS-hydrogen

This paper describes validation of the computational fluid dynamics tool FLACS-Hydrogen. The validation study focuses on concentration and pressure data from vented deflagration experiments performed in 20-foot shipping containers as part of the project Improving hydrogen safety for energy applications through pre-normative research on vented deflagrations (HySEA), funded by the Fuel Cells and Hydrogen 2 Joint Undertaking (FCH 2 JU). The paper presents results for tests involving inhomogeneous hydrogen-air clouds generated from realistic releases performed during the HySEA project. For both experiments and simulations, the peak overpressures obtained for the stratified mixtures are higher than those measured for lean homogeneous mixtures with the same amount of hydrogen. Using an in-house version of FLACS-Hydrogen with the numerical solver Flacs3 and improved physics models results in significantly improved predictions of the peak overpressures, compared to the predictions by the standard Flacs2 solver. The paper includes suggestions for further improvements to the model system.     

Distributed generation and distribution market diversity in Europe

The unbundling of the electricity power system will play a key role on the deployment of distributed generation (DG) in European distribution systems evolving towards Smart Grids. The present paper firstly reviews the relevant European Union (EU) regulatory framework: specific attention is paid to the concept of unbundling of power distribution sector in Europe. Afterwards, the focus is on the current state of penetration of DG technologies in the EU Member States and the corresponding interrelations with distribution features. A comparison between the unbundling of the distribution and supply markets using econometric indicators such as the Herfindahl–Hirschmann (I_HH) and the Shannon–Wiener (I_SW) indices is then presented. Finally, a comparative analysis between these indices and the current level of penetration of distributed generation in most EU is shown; policy recommendations conclude the paper.     

An exploration of possible design options for a binding energy savings target in Europe

As Europe is not on track in meeting its 2020 energy savings target, there has been quite some debate to make the energy savings target binding instead of indicative. Although the final draft text of the Energy Efficiency Directive left the option of a binding target explicitly open for the period beyond 2014, this statement has watered down in the adopted Directive: If still not on track mid-2014, the European Commission will propose “further measures.” In this paper, we argue that a binding energy savings target could be the first EU legal initiative to look beyond 2020 serving as a beacon for other policies such as for renewables and greenhouse gases that need redefinition after 2020. We therefore explore four possible design options of a binding savings target and assess their feasibility. We conclude that a binding target at Member State level (opposed to an EU-wide target like for the EU Emission Trading System (ETS)) is the most feasible. A binding target at Member State level would ensure political accountability and commitment to deliver results while providing flexibility to choose and apply the most suitable tools to achieve the target. It could provide a framework to guide ambitious and coherent implementation of EU energy efficiency policies, as well as the strengthening of national policies. Furthermore, binding targets at Member State level will make Member States take an ambitious position in Brussels when new energy or CO₂ performance standards for appliances and transport modes are to be set. A Member State binding target applied to end-users (excluding ETS companies) is a design option that covers the vast majority of the cost-effective energy savings potential, maintains the flexibility for ETS companies, and supports the most cost-effective achievement of a greater share of renewables.     

A post-2020 EU energy technology policy: Revisiting the strategic energy technology plan

With the European Strategic Energy Technology Plan (SET Plan) expiring in 2020, the EU needs to revisit its energy technology policy for the post-2020 horizon and to establish a policy framework that fosters the achievement of ambitious EU commitments for decarbonization by 2050. We discuss options for a post-2020 EU energy technology policy, taking account of uncertain technology developments, uncertain carbon prices and the highly competitive global market for energy technologies. We propose a revised SET Plan that enables policy makers to be pro-active in pushing innovation in promising technologies, no matter what policy context will be realized in the future. In particular, a revised SET Plan should include a more technology-specific focus, provide the basis for planning and prioritization among decarbonization technologies, and should be based on a comprehensive approach across sectors. Selected technology targets and EU funding of innovation should be in line with the SET Plan prioritization.     

The European renewable energy target for 2030 – An impact assessment of the electricity sector

The European Union set binding targets for the reduction of greenhouse gases (GHG) and the share of renewable energy (RE) in final energy consumption by 2020. The European Council agreed to continue with this strategy through to 2030 by setting a RE target of 27% in addition to a GHG reduction target of 40%. We provide a detailed sectoral impact assessment by analyzing the implications for the electricity sector in terms of economic costs and the regional distribution of investments and shares of electricity generated from renewable energy sources (RES-E). According to the Impact Analysis by the European Commission the 27% RE target corresponds to a RES-E share of 49%. Our model-based sensitivity analysis on underlying technological and institutional assumptions shows that the cost-effective RES-E share varies between 43% and 56%. Secondly, we quantify the economic costs of these variants and those which would be incurred with higher shares. The long-term additional costs for higher RES-E shares would be less than 1% of total system costs. The third aspect relates to the regional distribution of EU-wide efforts for upscaling renewables. We point out that delivering high RES-E shares in a cost-effective manner involves considerably different efforts by the Member States.     

Consequence models for vented hydrogen deflagrations: CFD vs. engineering models

This paper compares two approaches for predicting the consequences of vented hydrogen deflagrations: empirical engineering models (EMs) and computational fluid dynamics (CFD) simulations. The study is part of the project ‘Improving hydrogen safety for energy applications through pre-normative research on vented deflagrations’ (HySEA), funded by the Fuel Cells and Hydrogen 2 Joint Undertaking (FCH JU) under grant agreement No 671461. The HySEA project focuses on vented hydrogen deflagrations in containers and smaller enclosures with internal congestion representative of industrial applications. Data from experiments conducted as part of the HySEA project are used to evaluate predictions from a selection of EMs and the CFD tool FLACS. The experiments involve various obstacle and venting configurations, and initially quiescent homogeneous hydrogen-air mixtures with hydrogen concentrations in the range 15–24 vol%. There is a significant scatter in the maximum reduced overpressures predicted by the different EMs in the present study. For certain configurations, there is an order of magnitude difference between the different EM predictions. Two versions of the CFD tool FLACS are used in the present study: i) the standard commercial release FLACS v10.7r2, and ii) an in-house development version termed FLACS-beta. The commercial release generally over-predicts the maximum overpressures measured in the experiments, while the development version of FLACS gives improved results for several configurations.     

Energy efficiency governance in the EU-28: analysis of institutional,human, financial,and political dimensions

The European Union in line with its climate and energy strategy has presented a renewed ambition for the post-2020 period, towards 2030, through the Clean Energy for All Europeans policy package proposals. A new binding target of minimum 30% for energy efficiency improvements is in the horizon, as well as the identified need for a stronger governance framework to support its delivery. This research contributes to a better understanding of energy efficiency governance by analysing a set of indicators covering aspects related to institutional, human, financial, and political dimensions. The results obtained provide a more detailed perspective on the European Union level and Member State governance capacities. These indicate the need to develop institutional capacities related to the transposition of legislation and directives. In parallel, the disparities between individual Member State governance capacities should be considered when devising and implementing future policies. The implications for policymakers include the need for a more robust governance monitoring and reporting system, including the development of transparent and comparable indicators, as well as a more comprehensive assessment of the impact of good governance on delivering energy efficiency improvements.     

Full-scale tunnel experiments: Blast wave and fireball evolution following hydrogen tank rupture

In the framework of the HyTunnel-CS European project sponsored by Clean Hydrogen Joint Undertaking (CH JU), a number of tests were conducted in a full-scale tunnel in France. These tests are devoted to safety of hydrogen-fuelled vehicles having a compressed gas storage. The goal of the study is to develop recommendations for Regulations, Codes and Standards (RCS) for inherently safer use of hydrogen vehicles in enclosed transportation systems. Two sets of tests have been performed, (a) five tests with compressed hydrogen tanks, (b) two tests with compressed helium tanks. The hydrogen gas pressure varied between 47 bar and 610 bar. The blast wave overpressures are recorded together with fireball characteristics. The obtained experimental data are compared to existing engineering correlations and it is confirmed that not only the mechanical energy of compressed gas but also a fraction of chemical energy contribute to the blast wave strength.     

Electricity generation from renewable energy sources in Poland

AbstractFor the European Union's Member States 2001/77/EC Directive on the promotion of electricity produced from renewable energy sources in the internal electricity market determined targets for 2010 of 21% share of electricity from renewable energy sources in total electricity consumption. Particular Member States adopted different measures for development of renewable and in consequence they achieved different results. Poland, being Member State of the EU since 2004 has accepted target of 7.5% for electricity generated from renewable energy sources until 2010. Currently, in this decade, new 2009/28/EC Directive on the promotion of the use of energy from renewable sources plays significant role in development of renewable energy sources. Directive set new target for 2020. Nowadays is a time for summary and assessment of results fulfilling Directives and monitor progress of new targets. Article presents measures implemented for renewable source energy development, also current state and perspectives of using of renewable energy sources in Poland and in the EU.     

Methodology proposal for territorial distribution of greenhouse gas reduction percentages in the EU according to the strategic energy policy goal

A 20% reduction of greenhouse gas (GHG) emissions by 2020 is one of the main objectives of the European Union (EU) energy policy. However, this overall objective does not specify how it should be distributed among the Member States, according to each one’s particular characteristics. Consequently, in this article a non-linear distribution methodology with dynamic objective targets for reducing GHG emissions is proposed. The goal of this methodology is to promote debate over the weighting of these overall objectives, according to the context and characteristics of each member state. First, an analysis is conducted of the situation of greenhouse gas emissions in the reference year (1990) used by the EU for reaching its goal of reducing them by 20% by 2020, and its progress from 1990 to 2007. Then, the methodology proposed was applied for the year 2020 on two territorial aggregation levels following the EUROSTAT Nomenclature of Territorial Units for Statistics (NUTS), in the EU-15 and EU-27 member countries and on a regional level in 19 Spanish Autonomous Communities and Cities (NUTS-2). Weighting is done based on CO₂ intensity, GHG emissions per capita and GHG emissions per GDP. Finally, several recommendations are provided for the formulation of energy policies.     

Forest owner motivations and attitudes towards supplying biomass for energy in Europe

The European Commission expects the use of biomass for energy in the EU to increase significantly between 2010 and 2020 to meet a legally binding target to cover at least 20% of EU's total energy use from renewable sources in 2020. According to estimates made by the member states of the EU, the direct supply of biomass from forests is expected to increase by 45% on a volume basis between 2006 and 2020 in response to increasing demand (Beurskens LWM, Hekkenberg M, Vethman P. Renewable energy projections as published in the national renewable energy action plans of the European Member states. ECN and EEA; 2011. http://https://www.ecn.nl/docs/library/report/2010/e10069.pdf [accessed 25.04.2014]; Dees M, Yousef A, Ermert J. Analysis of the quantitative tables of the national renewable energy action plans prepared by the 27 European Union Member States in 2010. BEE working paper D7.2. Biomass Energy Europe project. FELIS – Department of Remote Sensing and landscape information Systems, University of Freiburg, Germany; 2011). Our aims were to test the hypotheses that European private forest owners' attitudes towards supplying woody biomass for energy (1) can be explained by their responses to changes in prices and markets and (2) are positive so that the forest biomass share of the EU 2020 renewable energy target can be met. Based on survey data collected in 2010 from 800 private forest owners in Sweden, Germany and Portugal our results show that the respondents' attitudes towards supplying woody biomass for energy cannot be explained as direct responses to changes in prices and markets. Our results, furthermore, imply that European private forest owners cannot be expected to supply the requested amounts of woody biomass for energy to meet the forest biomass share of the EU 2020 renewable energy target, at least if stemwood is to play the important role as studies by Verkerk PJ, Anttila P, Eggers J, Lindner M, Asikainen A. The realisable potential supply of woody biomass from forests in the European Union. For Ecol Manag 2011;261: 2007–2015, UNECE and FAO. The European forest sector outlook study II 2010–2030. United Nations, New York and Geneva; 2011 [abbreviated to EFSOS II] and Elbersen B, Staritsky I, Hengeveld G, Schelhaas MJ, Naeff H, Böttcher H. Atlas of EU biomass potentials; 2012. Available from: http://www.biomassfutures.eu [accessed 14.10.2013] suggest.     

Electric energy restructuring in the European Union: Integration,subsidiarity and the challenge of harmonization

In 1996, the European Union (EU) instituted Directive 96/92/EC that aims to establish a competitive, secure and transparent EU-wide internal electric energy market. The process of electricity market restructuring in the EU is being guided primarily by the principle of subsidiarity. As an organizational concept, the principle of subsidiarity allows Member States to establish their own implementation strategies and methods as a means of achieving the EU-mandated goal of electric energy restructuring. Historically, the structure of the electric energy industry in place among the Member States exhibited widely disparate organizational and functional characteristics with regard to ownership, control and regulation. Under these varied and contrasting political and economic conditions, the goal of a EU-wide harmonized electric energy market becomes very challenging. In this paper, I describe the policy mechanisms and the market conditions mandated by the EU directive aimed at liberalizing the electric energy market. I then assess the role of political culture, historical resource endowment and geographical conditions in the utility restructuring strategies of some key Member States and its effects on the overall goals of a harmonized internal electric energy market. Finally, I argue that European electric energy restructuring must be understood within the context of the political and economic milieu that spawned the individual Member States’ electric energy industry.     

Large-scale integration of renewable and distributed generation of electricity in Spain: Current situation and future needs

Similar to other European countries, mechanisms for the promotion of electricity generation from renewable energy sources (RESs) and combined heat and power (CHP) production have caused a significant growth in distributed generation (DG) in Spain. Low DG/RES penetration levels do not have a major impact on electricity systems. However, several problems arise as DG shares increase. Smarter distribution grids are deemed necessary to facilitate DG/RES integration. This involves modifying the way distribution networks are currently planned and operated. Furthermore, DG and demand should also adopt a more active role. This paper reviews the current situation of DG/RES in Spain including penetration rates, support payments for DG/RES, level of market integration, economic regulation of Distribution System Operators (DSOs), smart metering implementation, grid operation and planning, and incentives for DSO innovation. This paper identifies several improvements that could be made to the treatment of DG/RES. Key aspects of an efficient DG/RES integration are identified and several regulatory changes specific to the Spanish situation are recommended.     

Solar power tower as heat and electricity source for a solid oxide electrolyzer: a case study

High‐temperature steam electrolysis (HTSE) consists of the splitting of steam into hydrogen and oxygen at high temperature in solid oxide electrolyzers. Performing the electrolysis process at high temperatures offers the advantage of achieving higher efficiencies as compared to the conventional water electrolysis. Furthermore, this allows the direct use of process heat to generate steam. This paper is related to the FCH JU (Fuel Cells and Hydrogen Joint Undertaking) project ADEL (ADvanced ELectrolyser For hydrogen Production with Renewable Energy Sources), which investigates different carbon‐free energy sources to be coupled to the HTSE process. Renewable energy sources are able to provide the high‐temperature steam electrolysis (HTSE) process with heat and power. This paper investigates the capability of Concentrating Solar Power (CSP) technologies to provide the HTSE process with the necessary energy demand. The layout of the plant is shown in the following figure. The design of commercial‐scale high‐temperature steam electrolysis has been carried out. The HTSE plant is coupled to an air cooled solar tower. The configuration and the operating parameters of the solar tower are based on those of the solar tower of Jülich (Germany), which is operated by DLR. This paper presents the results of process analysis performed to evaluate the hydrogen production from a HTSE plant coupled to an 80MWth air solar tower. Additionally, the dynamic behavior of the system during energy fluctuations has been analyzed. The receiver‐to‐hydrogen efficiency (based on the Higher Heating Value of hydrogen) is 26% at a hydrogen production rate of 680 kg/h in steady‐state operation. The overall solar‐to‐hydrogen efficiency is calculated to be at 18%. Moreover, the analysis under transient conditions shows that a steady‐state operation of the plant is only possible for 8 h. Copyright © 2015 John Wiley & Sons, Ltd.     

Electricity produced from renewable energy sources—What target are we aiming for?

In 2001, the European Commission (hereafter “EC”) formulated an ambitious target of 21% of total community electricity consumption to be generated with renewable energy sources by 2010. Moreover, national indicative targets per Member State were specified. In practice, the latter are implemented in all Member States as national production targets, achievable exclusively through an increase of the domestic production of electricity produced from renewable energy sources (hereafter “RES-E”). However, in this article it will be shown that this is not in line with the EC's intent. Looking at the legislative process resulting in the Directive on the promotion of RES-E, it is demonstrated that instead the EC aimed for European trade in renewable electricity through national consumption targets.     

情景分析法应用于能源需求与碳排放预测

能源是关系到国计民生的重要资源,国家日益倡导节能减排,能源需求预测与规划已成为了一个地区重要的任务。本文以全国十强县之一—江阴作为代表,应用情景分析法,预测2011～2020年能源需求与碳排放,以此反映我国经济发达县市能源需求和碳排放趋势。     

Transition towards a low carbon economy: A computable general equilibrium analysis for Poland

In the transition to sustainable economic structures the European Union assumes a leading role with its climate and energy package which sets ambitious greenhouse gas emission reduction targets by 2020. Among EU Member States, Poland with its heavy energy system reliance on coal is particularly worried on the pending trade-offs between emission regulation and economic growth. In our computable general equilibrium analysis of the EU climate and energy package we show that economic adjustment cost for Poland hinge crucially on restrictions to where-flexibility of emission abatement, revenue recycling, and technological options in the power system. We conclude that more comprehensive flexibility provisions at the EU level and a diligent policy implementation at the national level could achieve the transition towards a low carbon economy at little cost thereby broadening societal support.     

Advanced m-CHP fuel cell system based on a novel bio-ethanol fluidized bed membrane reformer

Distributed power generation via Micro Combined Heat and Power (m-CHP) systems, has been proven to over-come disadvantages of centralized generation since it can give savings in terms of Primary Energy consumption and energy costs.The FluidCELL FCH JU/FP7 project aims at providing the Proof of Concept of an advanced high performance, cost effective bio-ethanol m-CHP cogeneration Fuel Cell system for decentralized off-grid applications by end of 2017. The main idea of FluidCELL is to develop a new bio-ethanol membrane reformer for pure hydrogen production (3.2 Nm³/h) based on Membrane Reactors in order to intensify the process of hydrogen production through the integration of reforming and purification in one single unit. The novel reactor could be more efficient than the state-of-the-art technology due to an optimal design aimed at circumventing mass and heat transfer resistances. Moreover, the design and optimization of the subcomponents for the BoP could also be improved. Particular attention has to be devoted to the optimized thermal integration that can improve the overall efficiency of the system at >90% and reducing the cost due to low temperature reforming. The main results obtained until now in terms of performance of the catalysts, membranes and the membrane reactors will be presented in this work.