1 Development of BIOMASS Supply and Demand in the PRIMES Energy Model 1. Introduction The work performed so far has involved the following tasks: 1. Specification of the biomass module 2. Development of a very detailed database using a large number of independent studies 3. Model development and testing 4. Integration with the PRIMES energy model 2. The design of the complete biomass module topography The first step in the model development process was to identify the biomass module topography. A thorough literature review has been conducted in order to gain detailed insights on the current and future conversion chains of biomass to final energy products. A general outline of the biomass conversion chains was identified and is presented in Figure 1. A primary commodity is produced/derived from the primary resource. The primary commodity is, in general, passed through a pre-process that produces a secondary/intermediate commodity. The secondary commodity is the input to the transformation process from which the final energy product is derived. 3. Biomass Classification The primary production of biomass has been classified into five categories, namely energy crops, agricultural residues, forestry, aquatic biomass and wastes. Depending on the type of the plants that are cultivated, energy crops are further distinguished into hay, sugar, oil and wood crops. This classification is dictated by the Primary Resource Production of primary commodity Primary Commodity Pre-processing of primary commodity Use of final commodity Final Commodity Transformation of secondary commodity Secondary Commodity Figure 1: Biomass conversion chain.
2 Energy Crops Table 1: Primary Biomass Production Agricultural residues Forestry Aquatic Biomass Waste Hay Crops Sugar Crops Wood Crops Oil Crops Hay Residues Sugar Residues Wood Residues Oil Residues Wood Platform Wood Residues Algae Industrial Solid Industrial Bagasse Industrial Pulp Used vegetable oil Municipal Solid Sewage Sludge Landfill Gas Organic Manure Animal Platform differentiation of the methods that each plant type may be processed with and the final outputs that derive from them. The same applies for agricultural residues. Forestry is split into wood platform, i.e. organised and controlled cutting of whole trees for energy use, and wood residues, i.e. the collecting of forestry residues only. Five types of waste have also been identified. These are industrial solid, industrial wet, pulp and bagasse, used vegetable oil, municipal solid waste, sewage sludge, landfill gas, organic manure and animal wastes. This classification was based both on further processing differentiation as well as on data availability. 4. The collection of technical and economic data The construction of the biomass database was one of the most difficult and time consuming tasks in the model development process. The literature has been extensively surveyed in order to establish reliable, quantitative technical and economic data for each stage of the biomass conversion chain. The biomass database includes the EU28 countries and consists of the following data: technical potential of biomass primary resource yield rates of energy crops and by-product yield rates capital, variable and fixed costs of each process including transportation costs prices and demand data for by-products capacity factors, availability and technical lifetime of each process energy efficiency rates and energy consumption of each processes fuel input and output blending for each transformation process emission for each process policy data (taxes, targets on final biomass energy use, agricultural policy data)
3 In addition data on production potentials and prices of both final and secondary commodities from countries outside the EU28 had to be collected to enable the modelling of international trading. Although there is a rich literature regarding the energy use of biomass, the process of collecting, analysing, filtering and final selection of the most reliable data was very complicated and time consuming, especially regarding the techno-economic data for future technologies and future potential projections, where big differences between different sources were often observed. Moreover, in most of the cases the appropriate data had to be craved from a variety of different and often contradictive information, following logical conclusions and plausible assumptions. In such cases consultation from experts on the matter was also taken into account to assist the final data selection. 5. Model development 5.1. General structure Based on the general biomass conversion chain outline a complete, to the extent possible, list of the biomass conversion chains from primary resource to final commodity has been identified. The biomass conversion chains that where identified during the model specification and data collection process have been categorised appropriately to form the biomass system that in total includes twenty (20) primary resources, fifteen (15) secondary and twelve (12) final transformation processes that produce a total number of twelve (12) final biomass energy products. Blending of final biomass energy products with conventional ones (e.g. co-firing) has also been included in the model. On Table 2 and 3 the processes and the final energy products are listed respectively. Table 2: Secondary and final transformation processes Secondary Transformation Pellettising Wood preparation Sugar pre-treatment Plant Oil pre-treatment Solid waste pre-treatment Liquid waste pre-treatment Gas waste conditioning Final Transformation (Bio Industries) Biochemical Enzymatic hydrolysis Anaerobic digestion Catalytic conversion Transesterification Thermo chemical Pyrolysis Hydrothermal Partial oxydation Gasification Partial oxidation Fluidized bed Steam flow Screw Auger Blending Bio-fuels, bio-gas, co-firing solid combustion, hydrogen, methanol.
4 Table 3: Final biomass energy products Solids Liquid Gaseous Solid biomass for direct combustion Pellets Charcoal Mass burn waste Refuse derived fuel Pure vegetable oil Bio-ethanol Bio-diesel Bio-methanol Bio- Bio-gas Bio-hydrogen 5.2. Model description The complete biomass module topography has been modelled as a network where the nodes denote the processes and the links denote the energy forms or commodities. This work was conducted using the GAMS modelling tool. A schematic representation of the different conversion chains is presented is the Annex. The biomass system model is incorporated in the PRIMES large scale energy model for Europe. It is an economic supply model that computes the optimal use of resources and investment in secondary and final transformation, so as to meet a given demand of final biomass energy products, driven by the rest of sectors as in PRIMES model. The primary supply of biomass and waste has been linked with resource origin, availability and concurrent use (land, forestry, municipal or industrial waste etc). The total primary production levels for each primary commodity are restricted by the technical potential of the appropriate primary resource. The actual production levels are defined by the model based on economic grounds and availability. The model also includes non-linear supply curves with decreasing marginal productivity. The decision on investment for the secondary and final transformation processes is endogenous using technology vintages and dynamics of technology development and taking into account economies of scale. The model also computes the prices of final biomass-related products that are intertemporally necessary to cover the total long term marginal cost of biomass supply, including return on initial fixed costs. These prices are conveyed to demand sectors (e.g. power generation, motor fuel consumers, other biomass users) which react and modify their demand behaviour, taking into account supply possibilities from other sub-systems (e.g. hydrocarbons). Supply and demand interact until market equilibrium is reached. The model is used for several types of policy analysis regarding the biomass sector. Biomass supply and final prices may be influenced by technology progress and learning, volume of demand (economies of scale), taxes or subsidies, environmental measures such as biomass end use targets, as well as agricultural and waste management policies.
5 Biomass Module Demand Prices rest of PRIMES supply module Demand Prices Prices Demand PRIMES Demand Module Figure 2: Graphical representation of the interaction between modules
6 Annex Internation al Trade Bio ethanol Fischer Tropsch Bio-diesel Sugar Crops Biomass Sugar Sugar pretreatment and transport Processed biomass sugar Gasification - partial oxidation - fluidized bed - screw auger - steam flow Synthetic Gas Catalytic conversion to gas Biogas Reforming Hydrogen Anaerobic digestion Figure 3: The Sugar Platform Conversion Chain
7 Direct combustion or co-firing Liquefaction Pyrolysis Bio diesel Straw packaging and transport Straw Acid Hydrolysis and Bio ethanol Enzymatic Hydrolysis and Fischer Tropsch FT-diesel Hay Crops Biomass Hay Gasification - partial oxidation - fluidized bed - screw auger - steam flow Synthetic Gas Pelletising and transport Agropellets Catalytic conversion to gas Biogas Reforming Hydrogen International Trade Anaerobic digestion Figure 4: The Hay Platform Conversion Chain
8 Internation al Trade Direct blending with diesel PVO blend Transesterificati on Oil Seeds Pressing, cleaning Pure Vegetable Oil Heterogeneous catalytic esterification Biodiesel Oil Crops Hydrothermal Upgrading Agricultural residues from oil crops Straw packaging and transport Straw see Hay conversion chain Internation al Trade Figure 5: The Oil Platform Conversion Chain
9 Charcoal Production Charcoal International Trade Liquefaction pyrolysis Biodiesel Wood Crops Trees Cultivation, cutting etc Wood preparation and transport Wood for further processing Acid Hydrolysis and Bioethanol Forest Whole trees Forest Residues Cutting, transport etc Cutting, collecting etc Wood International Trade Pelletising and transport Wood for direct combustion Pellets Enzymatic Hydrolysis and Gasification - partial oxidation - fluidized bed - screw auger - steam flow Synthetic Gas Fischer Tropsch Bio-diesel International Trade Direct Combustion or Co-firing Reforming Hydrogen Figure 6: The Wood Platform Conversion Chain
10 Hydrothermal upgrading Biodiesel Industrial organic waste wet Wet organic waste conditioning and trasport Black Liquor In-situ combustion Industrial organic waste solid Mass burn waste conditioning and transport Mass burn waste Direct combustion Fischer Tropsch FT-diesel Municipal waste solid Landfill gas Refused derived fuel preparation and transport Direct in situ combustion RFD Gasification - partial oxidation - fluidized bed - screw auger - steam flow Synthetic Gas Sewage sludge Sewage sludge conditioning Conditioned Sewage sludge Hydrothermal upgrading Biodiesel Reforming Hydrogen Manure Manure pretreatment Conditined manure Anaerobic digestion Biogas Figure 7: The Waste Platform Conversion Chain