METHODOLOGY FOR ESTIMATING BIOMASS ENERGY POTENTIAL AND ITS APPLICATION TO COLOMBIA

This paper presents a methodology to estimate the biomass energy potential and its associated uncertainty at a country level when quality and availability of data are limited. The current biomass energy potential in Colombia is assessed following the proposed methodology and results are compared to existing assessment studies. The proposed methodology is a bottom-up resource-focused approach with statistical analysis that uses a Monte Carlo algorithm to stochastically estimate the theoretical and the technical biomass energy potential. The paper also includes a proposed approach to quantify uncertainty combining a probabilistic propagation of uncertainty, a sensitivity analysis and a set of disaggregated sub-models to estimate reliability of predictions and reduce the associated uncertainty. Results predict a theoretical energy potential of 0.744 EJ and a technical potential of 0.059 EJ in 2010, which might account for 1.2% of the annual primary energy production (4.93 EJ)

Bioenergy technology roadmap for Colombia

The importance of using bioenergy for reducing oil dependence and greenhouse gas (GHG) emissions, diversifying the energy portfolio and supporting rural development is been increasingly recognized in Colombia. Against this background, this roadmap provides a long-term vision and goals to sustainably deploy biofuel and biomass technologies in Colombia until 2030. The roadmap identifies barriers to bioenergy deployment and suggests specific actions that should be taken by stakeholders to accomplish the proposed goals. It adopts a methodology from the International Energy Agency for developing technology roadmaps and combines detailed energy modeling with experienced advice from over 30 bioenergy experts from the government, academia, industry and non-governmental organizations.Based on expert feedback, the roadmap defines two visions, which are translated into two scenarios for detailed evaluation:The first vision, which is analyzed in Scenario I, focuses on new technologies and targets their deployment for the production of biomethane, biomass-based power generation and combined-heat-and-power (CHP). It fixes the current mandate for blending first generation liquid biofuels. The second vision, which is analyzed in Scenario II, combines new and traditional technologies and targets a combination of new technologies for the production of biomethane, electricity and CHP with further growth of first generation biofuels. A detailed set of goals, milestones, technologies, policies and barriers are defined for each of the two visions. Long-term goals in the bioenergy area include: Biodiesel: increase the quota mandate to B20 in 2020 and B30 in 2030. Bioethanol: a) increase the quota mandate to E20 in 2025 and b) implement an E85 fuel program in 2030. Renewable diesel: achieve a 10% contribution (on an energy basis) of renewable diesel to the total diesel fuel production in 2030. Biomethane: use 5% of biomass residues and animal waste resources nationwide to produce biomethane to be injected into the natural gas network by 2030. Power generation and CHP: a) achieve a renewable power target of 10% by 2025, b) use 5% of the biogas from animal waste and municipal water treatment plants nationwide by 2030, c) use 100% of the biogas produced in the water treatment process of biodiesel production plants by 2030, d) use 10% of the municipal landfill gas produced nationwide by 2030. A detailed energy system model for Colombia is set up and used to evaluate impacts on energy demand, supply, infrastructure and GHG emissions for Scenarios I and II and a baseline scenario that assumes no change in policies or deployment of new technologies. A land use and trade model that is linked to the energy system model is used to estimate land requirements for accomplishing the roadmap targets. A subset of Scenario II (Scenario II with expansion) considers a significant expansion in the cultivation of land beyond the Valley of the Cauca River.Results for the baseline show significant reductions in the share of bioenergy in the primary energy demand and various sectors. In contrast, Scenarios I and II are characterized by an increased share of bioenergy. In both scenarios, the bioenergy share for power generation and natural gas supply grows to about 6% in 2030. However, the share of bioenergy in the primary energy demand still declines to about 10% in 2030.Relative to the baseline, in Scenario I, bioenergy-induced emissions reduction amounts to about 11 mio tons of CO2-eq. and savings in fossil fuels of 2 mio tons of oil equivalent (TOE). The share of bioenergy in road transport remains unchanged. In Scenario I, an increase in land for producing liquid biofuels and woodfuel to 0.67 mio ha by 2030 is expected. Scenario I can accomplish long-term emission targets with available land and turns out to be the most effective scenario in terms of emission reduction per additional hectare of land. In Scenario II bioenergy-induced emissions reduction relative to the baseline amounts to about 20 mio tons of CO2-eq. and savings in fossil fuels of about 4.5 mio TOE (Scenario II with expansion: 22 mio tons of CO2-eq. and 5.4 mio TOE). The share of bioenergy in road transport grows to 24%. An increase in land for producing liquid biofuels and woodfuel to 1.1 mio ha by 2030 is expected in Scenario II (Scenario II with expansion: 1.3 mio ha). However, emissions reductions per additional hectare of land are about four to five times less compared to Scenario I. The roadmap shows that the most effective policy measures to reduce greenhouse gas emissions would address power generation and CHP applications, which account for more than 50% in emission reductions. The bulk of these reductions in emissions come from avoiding methane release via landfill gas and biogas from animal waste through combustion in reciprocating engines, followed by CO2 emission reduction in biomass-based power generation, and policies on first generation biofuels (i.e. bioethanol, biodiesel and renewable diesel).</p

Simulation und Analyse des dynamischen Verhaltens von Kraftwerken mit oxidkeramischer Brennstoffzelle (SOFC)

Solid oxide fuel cell (SOFC) systems are especially advantageous for a highly efficient and lowemission energy supply. Due to the very limited operating experience with this fuel cell type, the aim of this work is the development of a generalized dynamic system simulation for SOFC power plants. In this way, interactions between subsystems can be analysed before system operation, and resource-saving operating strategies can be developed. The system simulations presented in this work are based on a common generic modelling concept for all process units. The modelling details are derived from the existing components of a 20 kW fuel cell system, which is currently under construction at Forschungszentrum JÜlich. Numerous measurement data are therefore available, and are used to thoroughly validate all component models. This work is focused on dynamic simulation results for all operating conditions such as heat-up, start-up, nominal and part-load operation as weil as shutdown. Operating strategies are thus optimized regarding energy and time requirements. For the SOFC system analysed, simulated heat-up times from room temperature to 600°C are ab out five hours under the given constraints. Subsequent electrochemical start-up to nominal load takes an additional hour. As the analysis shows, both load reduction as weil as load increase can be performed rapidly if the system is close to its operating temperature. Stable SOFC system operation is possible even at low current densities. Heat input to keep the system on temperature is only required in the case of several hours of pure stand-by operation. During shutdown, all system components can be brought back to room temperature within a day if a high cooling flow is used. The simulations are carried out for an SOFC system with separate steam production for the reforming unit. Simulation of an additional system configuration, where anode off-gas is recycled, shows the possibility of a further increase in overall system efficiency

Cost and Performance of Carbon Dioxide Capture from Power Generation

This working paper evaluates cost and performance trends related to carbon dioxide (CO2) capture from power generation, based on extensive analysis of data from major engineering studies published between 2006 and 2010. Since individual studies use different methodologies and boundary conditions, study estimates for over 50 CO2 capture installations are re-evaluated on a consistent basis and updated to current cost levels. The paper discusses the need for further standardisation of evaluation methodologies and additional data for specific CO2 capture routes. Further analysis for non-OECD countries is considered crucial for global energy scenario models, and for improving the skills and knowledge developing countries need to evaluate the role of CCS in their national energy contexts.

Performance Evaluation of an Organic Rankine Cycle Fed by Waste Heat Recovered from CO2 Capture Section

Natural gas-fueled combined cycle (NGCC) allows to reach the best performance among power plants fed by fossil fuels, but causes considerable CO2 emissions. With the aim of reducing greenhouse gases impact, NGCC could be integrated with post-combustion CO2 removal systems, typically based on chemical solvents like amines, that cause very large net efficiency penalties (about 9-12 percentage points at 90% overall CO2 capture). To reduce these high capture penalties, exhaust gas recirculation (EGR) has been studied. To further enhance the overall plant efficiency, the recovery of available low temperature heat from the solvent-based CO2 removal systems could be also performed. Low temperature heat is available in flue gas coolers (80-100°C), in the amine reboiler water cooling (130-140°C) and in the splitter condenser (100-130 °C). This waste thermal energy could be recovered by means of an Organic Rankine Cycle (ORC) that is able to convert heat into electricity efficiently even at comparably low temperatures. N-Butane was found to be as the most promising organic working fluid for the cycle operating temperatures and pressures. ORC produces additional electrical power improving the global performance of the power plant, for example, up to 1-1.5 percentage points in efficiency