Community Based Bioenergy Systems - Technologies for Energy from Agricultural Biomass Sources

Transcription

1 Community Based Bioenergy Systems - Technologies for Energy from Agricultural Biomass Sources Conference on Community Based Renewables: Thai-German Cooperation on Sustainable Energy Development Sept. 2 nd, 2013, Ministry of Foreign Affairs, Narathip Room, Sri Ayudhya Road, Bangkok (Thailand) (Mirko Barz) Community Based RE BKK

2 Content: - Motivation - The role of biomass within a renewable energy economy - Agricultural Residues as Energy Source - Example Straw as Energy Source for Power Generation - Example Agro waste as Source for Biogas Production Community Based RE BKK

3 Motivation Ecological, economic and social challenges of the 21st master century! Energy supply as the central task We need a change of the global energy supply economy Global Energy demand Quelle: Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt an der ETH Zürich (Informationsdiens Wissenschaft) Community Based RE BKK

4 Motivation Status quo of the global energy economy - Energy economy is fossil dominated! Environmental Problems - global warming, - air pollution (emissions of harmful substances, acid rain etc.) - devastated landscapes after mining of fossil fuels -. Limited resources on fossil fuels Dependence on imports of fossil fuels - political crisis in middle east - competition (fight) Increasing prices of fossil fuels - development of the raw oil price Responsibility for future generation.. Necessity to develop a sustainable energy economy! Community Based RE BKK

5 Attributes of a Sustainable Energy Economy: Environmental compatibility Profitability Competitiveness Protection of natural Resources Resource security Sustainability encompasses not only ecological aspects, but also economical, social aspects an the penetration into all areas of society, which must always be considered collectively and in their interactions. Sustainability is achieved when it "meets the needs of the present without compromising the ability of the future generations to meet their own needs". (Definition formulated by the Brundtland Commision and adopted by the Rio Conference 1992) Community Based RE BKK

6 3 pillar policy to achieve a sustainable energy economy Increase of the energy efficiency within generation and utilization (short term target) Increase of the share of renewable energies within the energy mix (short term intermediate term target) 100 % Renewable based energy economy (intermediate/long term target) Source: Engineering news (Petronel Smith) Community Based RE BKK

7 Agricultural Residues as Bioenergy Sources - Currently, around 5.1 billion dry tones of agricultural residues are produced globally (IEA 2010) - This amount represents approx. 75 EJ or respectively 15 % of the current global primary energy demand of 500 EJ Picture source: Ecopanel Systems Ltd. - Depending on the location it is assumed that % of the agricultural residues could generally be used for bioenergy production on a sustainable basis Community Based RE BKK

8 The role of biomass within a renewable energy economy Biomass can make a significant contribution to future energy supply!!! (I) (II) Residues from agriculture and forestry ~ 100 EJ, Surplus forest production ~ 80EJ, (III) Energy crops ~ 120 EJ, (IV) Additional energy crops (areas with degraded soils and moderate water security) ~70 EJ, (V) Additional potential when agricultural productivity increases faster than historic trends, thereby producing more food from the same land area ~140 EJ Source: IEA - MAIN REPORT 'Bioenergy - a sustainable and reliable energy source. A review of status and prospects (2009) Community Based RE BKK

9 Agricultural Residues as Bioenergy Sources Source: Biomass energy in ASEAN member countries Community Based RE BKK

10 Agricultural Residues as Energy Sources Advantages: Food or fuel discussion using agricultural residues no competition with food; No additional land required; Energetic use can reduce environmental problems (e.g. harmful emissions from open field burning and reduce fossil fuel based GHG emissions) Decentralized local utilization contributes to: - income generation, Community Based - rural development Energy Systems Disadvantages: low energy density not suitable for long distance transportation of fuels Seasonal availability Competition to other uses, e.g. animal feed or conservation of soil fertilizity (nutrient cycle) Community Based RE BKK

11 Agricultural Residues as Energy Sources Many agricultural residues can potentially be used as bioenergy sources. Examples: crop residues such as - straw (field based residue) or - husks (process based residue) Animal manures and slurries Byproducts from industrial processing of agricultural products - bagasse from sugar industry - EFB from palm oil industry - wastes from food processing industries The most significant division is between those residues that are predominantly dry (such as straw) suitable for thermo-chemical conversion routes and those that are wet (such as animal slurry) suitable for biological conversion routes Community Based RE BKK

12 Conversion routes Agricultural residues Dry residues, such as straw Pre-conversion logistics Harvesting / collecting Transportation Preparation - Storage Wet residues such as manure Thermo-chemical conversion Bio-chemical conversion Physico-chemical conversion Combustion Gasification Pyrolysis Alcohol fermentaiton Biogas fermentation Compacting Solid / liquid / Gaseous fuels Electric energy Thermal energy Combustion The favorable conversion pathways for heat and power generation from dry agro-residues are: - A) direct combustion of straw combined with conventional steam cycle processes - B) Pyrolysis/Gasification of straw to generate (secondary) liquid or gaseous biofuels to use them in IGE, gas turbines or FC s - C) combined BIGCC (Biomass Integrated Gasification Combined Cycle) technologies The favorable conversion pathway for heat and power generation from wet agro-residues are: - Biogas systems (covered lagoon and plug flow versus CSTR and UASB) Community Based RE BKK

13 Example Straw as Energy Source Straw applies to a wide range of crops delivering straw, including all cereals such as wheat, rice, maize, sunflower and other oil seeds (e.g. rape) etc. Straw is one of the most promising agricultural residues, suitable for energy generation It s estimated that approx billion ton of straw (dry matter) are produced globally each year Only a fraction of these amount is used for agricultural purposes or energy production The availability of «excess»-straw for energy generation depends on regional conditions and varies in a wide range (0 to 60% of the produced mass). Photo source: Thrän, D. (DBFZ) Community Based RE BKK

14 Example rice straw as energy source Potential GHG reduction through power generation from biomass in Thailand Source: W. Siemers, (JGSEE 2009) Community Based RE BKK

15 Example Straw as Energy Source Aspect: Biomass can provide various forms of Energy (heat, electricity and transport fuels) Storaged chemical Energy Straw Biomass Direct combustion Heat Conversion to secondary fuels (e.g. gasification) CHP cogeneration Heat Electricity Storaged chemical Energy Combustion engine (in cars) Mechanical/kinetic Energy Community Based RE BKK

16 Example rice straw as energy source Advantage of direct combustion of rice straw: - Thermal power plants for solid fuels are state of art - Proven and robust technology - Commercial operated systems for straw combustion in many countries since > 20 years (e.g. Denmark) - Technology is available in Thailand too! Community Based RE BKK

17 Example rice straw as energy source Suitable Technologies are available in Thailand! Thai Boiler manufacturer (such as e.g. BIB) are offering first-class boiler and combustion systems based on license agreements with German boiler manufacturer.. Community Based RE BKK

18 Case study: Setup of a 10 MW straw fired power plant in Thailand Source: M.K. Delivand; Assessing the feasibility of Process Chains for Energy production from Rice straw in Thailand, Dissertation at the Joint Graduate School of Energy and Environment, King Mongkut s University of Technology Thonburi Fuel demand for a 10 MW power plant Assumptions Nominal capacity of the plant Annual operation hours 10 MW e 6000 hrs Overall efficiency of the plant based on LHV 23% Low heating value of rice straw MJ/kg Moisture content (MC) 11% Annual rice straw demand on dry basis (db) Annual rice straw demand on wet basis (wb) 75,798 ton db /year 84,135 ton wb /year Loss of rice straw during handling and storage 10% Actual annual rice straw demand for the projected plant 92,549 t/yr Community Based RE BKK

19 1000 THB/kW Case study: Setup of a 10 MW straw fired power plant in Thailand Source: M.K. Delivand; Assessing the feasibility of Process Chains for Energy production from Rice straw in Thailand, Dissertation at the Joint Graduate School of Energy and Environment,King Mongkut s University of Technology Thonburi Capacity MWe Specific Investment Cost Major components Cost provided from Thai Boiler Manufacturer % of total capital cost 5 MW e 10 MW e 20 MW e Boiler including fuel handling, fan and pumps Steam turbine and condenser Heat exchanger Civil work and building facility Electricity transmission Fumes treatment Others Total Community Based RE BKK

20 Case study: Setup of a 10 MW straw fired power plant in Thailand Source: M.K. Delivand; Assessing the feasibility of Process Chains for Energy production from Rice straw in Thailand Results Economic parameters in Investment scenario 30% equity, 70% loan (based on model of DEDE Economic and Financial Analysis of RE Power Development in Thailand) Parameter Capacity 5 MW e Capacity 10 MW e Capacity 20 MW e NPV (MB) IRR (%) PB (year) From the economic view the use of rice straw for power generation is promising! There are still a number of some barriers to be solved, as: - high logistic efforts to collect and store the straw, - higher investment and equipment costs compared to power plants using only woody biomass sources, - lack of technical know-how and experiences in Thailand -... Cooperation between Universities, Manufacturers and Investors can help to solve problems Community Based RE BKK

21 Example Biogas Technologies for Agricultural Biomass Biogas technologies are state of the art and widely disseminated in Thailand First introduction of Biogas technologies in Thailand started around 1950 using the Indian floating drum System 1988 the Thai-German Biogas Program, a joint initiative of the Thai government, the German international development agency GTZ (GIZ) and Chiang Mai University was launched to promote the Thai biogas industry by introducing improved technologies (The program introduced new biogas recovery technology to mitigate growing environmental concerns due to the open-air dumping of waste) Community Based RE BKK

22 R&D at ERDI (CMU) Community Based RE BKK

23 Status of Biogas production in Thailand Thailand has seen a rapid expansion of biogas facilities in agriculture and industry, recovering biogas from waste and wastewater during the past decades. Source: P. Chaiprasert, Thai-German Bioenergy Workshop, Bangkok 2011 Community Based RE BKK

24 Status of Biogas production in Thailand Between 2005 and 2010, the amount of biogas-based grid electricity went from 2 to 214 GWh. Since the target for 2022 under the REDP (2008) has been already exceeded, a new target for biogas has been set (the new plan set the biogas target at 600 MW in 2021) Status of Biogas Projects under VSPP (December 2011) Grid Electricity from Biogas Community Based RE BKK

25 An enourmous Potential for Biogas Production is still available in Thailand Source: Chaiprasert, P Biogas Production from Agricultural Wastes in Thailand. Journal of Sustainable Energy & Environment Special Issue (2011) Community Based RE BKK

26 Status of Biogas production in Thailand Although Thailand is an agricultural country with a large volume of potential biogas feedstocks, only two major sources are currently used for biogas production. These are: wastewaters from cassava starch factories and pig farms Bio-methane and Energy Potential from the residues of four agro-industries in Thailand a tripling of the current power generation from biogas would be possible, using only the agricultural residues considered in four of Thailand s agro industries. It is obvious that the total power generation potential from biogas in Thailand is much higher! Community Based RE BKK

27 New Support for the Biogas Sector in Thailand A new support programme Distributed Green Generation for Community Enterprises was passed by the National Energy Policy Council (NEPC) in February New target is to push the development of biogas power generation using energy crops as feedstock and to enhance the development of distributed and community-based renewable energy systems. political target: setup new biogas projects with a capacity of 10,000 MW within 10 years. With the new policy, a FIT of 4.5 Baht (11.24 Cent) per kwh shall be granted for the duration of 20 years to systems smaller than 1 MW. Great Interest of investors is expected since technolo- gies are available Remark: the installed capacity of biogas plants in Germany is currently approx MW Source: Fachverband Biogas Community Based RE BKK

28 Technological requirements to use energy crops and/or agrowastes with high solid content as substrates The currently installed systems, using wastewaters from cassava starch factories and pig farms are mostly plug flow or covered lagoon systems for industrial applications and fixed dome systems for small scale applications. For the efficient biogas production from energy crops as feedstock advanced technologies with improved mixing devices and operated under constant mesophilic conditions are favorable.. Community Based RE BKK

29 Technological requirements to use energy crops and/or agrowastes with high solid content as substrates Since CSTR (continuous-flow stirred tank reactor) biogas systems can deal with materials with contents of high solid suspension It s expected that this technology will be used for the future deployment of the biogas sector in Thailand. Most important Advantage: The Technology is available on the Thai market! No technological limitations to reach the governmental targets.. Community Based RE BKK

30 Alternative Options to use Biogas in Thailand - Biomethane A promizing option of biogas utilization is the production and feeding-in of Biomethane into the natural gas grid. The great advantage is that the Biomethane can be used in energy provision where it achieves the greatest benefit (efficiency): in combined heat and power units (CHP) with cogeneration of heat and electricity. as fuel to substitute natural gas and to run NGV ( Natural Gas Vehicle (NGV) have been registerd in Thailand in 2012). Community Based RE BKK

31 Biomethane as fuel for NGV Traveled kilometer of a car using Biometrhan produced from energy crops from 1 ha agricultural land. Community Based RE BKK

32 Biogas Upgrading to Biomethan Biogas is a mixture of gases, mainly consisting from methane (CH4) and carbon dioxide (CO2) and small amounts of other gases (impurities such as e.g. H2S, NH3 etc.). Upgrading of biogas to biomethane means, the resulting gas has to reach the qualities of the gas Grid. This requires the removal of unwanted and/or inert compounds such as - carbon dioxide, - water, - hydrogen sulphide, - nitrogen, - oxygen, - ammonia, Concentrations of these impurities are dependent on the composition of the substrate from which the gas was produced technological aspects of the digestion process - siloxanes and - particles. Target: i.e., get it to 97% methane Community Based RE BKK

33 Biogas Upgrading to Biomethan To upgrade raw Biogas to Biomethane 4 to 5 steps are required_ 1. Desulfurization (e.g. biological removal + activated carbon) 2. Removal of Water Vapor 3. Removal of Carbon Dioxide 4. Compressing the Biomethane Optional measure: Odouring Several technologies for biogas upgrading are commercially available. Community Based RE BKK

34 Removal of Carbon Dioxide Pressure Swing Adsorption (PSA) Carbon dioxide adsorption by activated carbon or zeolites under pressure The activated carbon or the zeolites can be regenerated by decrease in pressure Water and hydrogen sulphide have first to be removed since they will deactivate the carbon Water Scrubbing Most common upgrading technology Principle is that carbon dioxide dissolves in water (more soluble that methane) Lead to the increase of the methane concentration Water is regenerated in desorption column (carbon dioxide is released) Organic physical scrubbing Similar to water scrubbing Carbon dioxide is absorbed in an organic solvent such as polyethylene glycol Organic solution is regenerating by heating Chemical scrubbing Chemical scrubbers use amine solution Selective reaction, whereby carbon dioxide binds chemically to the liquid Low methane losses Regeneration is possible by heating Other technologies (separation by membranes or kryogene processes are currently under development Community Based RE BKK

35 Status of biomethane production in Germany - Currently 105 plants to upgrade biogas to biomethane are in operation. - Most of the plants (32) use the principle of chemical scrubbing and (31) pressurized water scrubbing, - Caused by the high efforts to regenerate the amine solution for chemical scrubbing (demand on energy), it s expected that the share of water scrubbing will increase in the future - Pressurized water scrubbing might be the favorable solution for installing biomethane production in Thailand Community Based RE BKK

36 Where is the benefit for communities and rural development? DEDE aims to encourage local farmers to form community-based enterprises or cooperatives to cultivate energy crops as feedstock for biogas production. The development can contribute to the: Creation of jobs in rural areas, Increase of higher value farm products (local value creation by agricultural value added), Increase of income for rural population (idea: farmers income minimum contracts of 300 Baht per ton of feedstock should be guaranteed), Development of rural infrastructures. Critical point (risks) The increase of the production of energy crops can influence the prices for food products (food versus fuel discussion) Impacts on the environment (land use change and biodiversity) are possible. Accompanying research activities (e.g. Environmental Life Cycle Assessment and Social Life Cycle Assessment) are required! Community Based RE BKK

37 contact: Prof. Dr. Mirko Barz Community Based RE BKK