Biomass gasification for sustainable energy production: A review

Gasification process is considered as one of the best routes of energy recovery from biomass by producing syngas mostly including H₂, CO, and CH₄. Biomass as the main renewable energy resources has great advantages regarding its diversity, availability, and sustainability for supplying energy needs in heat, electricity production, biofuel production for transportation, etc. Various gasifiers based on the gasifying process and agents have been examined. This paper reviewed the theory of biomass gasification by comparing and analyzing different gasification models-designs and configurations, also different operational conditions. It aimed to bring a holistic approach for hydrogen rich syngas production based on the present technologies, techno-economic analysis, and industrial/commercialization pathways. The biomass gasification technologies need to be improved for hydrogen production regarding the global environmental and economic issues. The review provided better insights into the enhancement of syngas production from biomass.     

A roadmap for production of sustainable,consistent and reliable electric power from agricultural biomass- An Indian perspective

The utilization of agricultural biomass for production of electric power can help to reduce the environmental emissions while achieving energy security and sustainable development. This paper presents a methodology for estimating the power production potential of agricultural biomass in a country. Further, the methodology has been applied to develop a roadmap for producing reliable power in India. The present study reveals that about 650 Mt/year of agricultural biomass is generated in India, while about one-third of this has been found to be surplus for energy applications. The cereal crops have major contribution (64.60%) in production of surplus biomass followed by sugarcane (24.60%) and cotton (10.68%). The energy potential of these resources is of the order of 3.72 EJ, which represents a significant proportion of the primary energy consumption in the country. These biomass resources can produce electric power of 23–35 GW depending upon the efficiency of thermal conversion. The delivery of biomass to the plants and selection of appropriate technology have been found as the major issues that need to be resolved carefully. In the end, the study summarizes various technological options for biomass collection and utilization that can be used for producing clean and consistent power supply.     

Sustainable development of rural energy and its appraising system in China

The local biomass resources have been used in rural China for quite a long time, which has a close connection with and will inevitably affect the environment. In recent years, China has experienced rapid economic growth and equally rapid increases in energy use, especially commercial energy, in rural areas. As a result, energy induced environmental degradation has also increased in rural China. This paper discusses the relationship between China’s rural energy and its sustainable development. It brings forward the index system for appraising the sustainable development of rural energy (SDRE), calculates the weighing of each index with analytic hierarchy process (AHP), puts forward the quantification method and provides the basis for the research of the rural energy for sustainable development in different areas and periods.     

Designing optimal supply chains for anaerobic bio-digestion/energy generation complexes with distributed small farm feedstock sourcing

Anaerobic bio-digestion/energy generation (ABD/EG) complexes that use animal waste have become increasingly important as renewable energy sources and logistics considerations are essential as animal biomass is of costly transportation due to its high weight per unit of energy generated. To ensure overall economic viability it is necessary to take into account the supply chain network when designing such a complex for at least two main reasons. First, these complexes provide power from energy sources which otherwise would go to waste and a well-designed supply chain network will significantly lower long-term operating costs. Second, because they provide an outlet for farm manure (their feedstock), these complexes allow farmers to expand production capacity whenever environmentally sound animal waste disposal is an active constraint to operations. This paper presents a methodology to design a supply chain which maximizes contribution and minimizes gas loss in the commonly found configuration in which feedstock providers are numerous small farms without on-site bio-digestion units, i.e., a configuration in which in-natura biomass is transported from those small farms to supply a nearby ABD/EG complex serving the region. The paper details three layers of analysis for designing optimal animal waste supply for anaerobic bio-digestion, including model formulation and mathematical solution for each stage. The broadest layer in the methodology is the identification of the optimal ABD/EG complex positioning given farm locations and consequent biomass transportation costs. The middle layer is the specification of the optimal logistics and transportation system, including the prioritization of supplying farms. The operational layer includes scheduling optimal biomass collection from each farm to minimize biogas loss.     

System analysis for effective use of palm oil waste as energy resources

Biomass refers to renewable energy sources and comes from biological materials such as trees, plants, manure as well as municipal solid wastes. Effective utilization of biomass as an energy resource requires the use of an optimization model to take into account biomass availability, transportation distances, and the scales and locations of power facilities within a region. In this study, we develop a new analytical tool that integrates cost, energy savings, greenhouse gas considerations, scenario analysis, and a Geographic Information System (GIS) to provide a comprehensive analysis of alternative systems for optimizing biomass energy production. The goal is to find a system that optimizes the use of biomass waste by analyzing the cost, net avoided CO₂ emission, and net energy savings with the objective of profit maximization. In this paper, we describe an application of the modeling tool described above to one of the fastest growing agriculture industries in Asia, the palm oil industry, for the case of Malaysia. Five scenarios utilizing palm oil waste as energy resources are discussed. The scenario of installing of new Combined Heat and Power (CHP) plants in the region yielded a number of benefits in terms of net energy savings, net avoided CO₂ emission, and profits. The results also demonstrate the benefits of utilizing excess heat for biomass pre-treatment. The choice of a suitable CHP plant scale, management strategies for biomass seasonal availability, and market price of biomass are also important factors for effective use of the biomass in a region.     

Energetic optimization of microalgal cultivation in photobioreactors for biodiesel production

Traditionally, algal cultivation in sparged photobioreactors has been optimized to maximize biomass productivity. In this study, an energy-based methodology is presented to maximize the net energy gain of the cultivation process by minimizing the energy input for sparging and by maximizing the energy output. Options for minimizing energy input through optimal gas-to-culture volume ratio and CO₂-air ratio and options for maximizing lipid production through optimal levels of nutrition and CO₂ are presented and validated with results from 900-mL bubble column reactors. In contrast to the traditional practice, the proposed energy-based optimization resulted in positive net energy gains. In single stage approach under optimal conditions (CO₂ enrichment of 0.5%, gas-to-culture volume ratio of 0.18 min⁻¹, and nitrate level of 1 mM), tests with Nannochloropsis salina resulted in positive net energy gain of 20 W/m³. In a test under nitrate starvation, the net energy gain in a reactor sparged with CO₂ enrichment of 0.5% was double that in the reactor sparged with ambient air (8 vs. 19 W/m³).     

Using biomass: A system perturbation analysis

As a consequence of current energy and climate policies, several regional and federal measures are being implemented in Belgium to encourage the utilization of biofuels for automotive applications. The use of biomass for power and/or heat production also gets growing support through CHP and/or CO₂ certificates and most probably through new upcoming European directives. As a result, many investors, policy makers and energy companies are investigating these so-called biomass routes and there is definitely a need to gain more insight in this complex matter.This paper presents an analysis and comparison of the most promising options for utilizing the limited biomass resources in Belgium. To allow for a systematic comparison, a new method called System Perturbation Analysis (SPA) was developed. SPA differs from a classical Life Cycle Analysis (LCA) mainly because it looks to geographical system balances of resources and the resulting effects, rather than comparing well-to-wheel trajectories. Therefore SPA is able to identify the best usage of limited resources such as hectares, wood waste or imports, in terms of fossil energy savings or GHG emissions within a given system (in casu: Belgium). Comparative results of such a SPA assessment are presented and discussed in this paper, including the use of wood for transport, heat and power applications. All the considered biofuel scenarios have positive energy and CO₂eq balances. The use of wood appears as a good choice in terms of efficiency, CO₂ abatement and surface requirements.     

Biomass potential in Andalusia,from grapevines,olives, fruit trees and poplar,for providing heating in homes

Conventional energy resources, has been shown to be limited and they are producing environmental degradation. So the transition to an energy model based on the use of renewable energy is an urgent need. The energy and environmental policies are evidence of this and they are being implemented out a multitude of countries worldwide, furthermore one important element in this transition is the increased use of biomass for energy production.Agricultural residues are produced in huge quantities in all countries; most of these could be used for energy generation. This property increases the value of waste materials and reduces the environmental impacts of waste disposal. This paper analyzes the situation of biomass energy resources in Andalusia, and quantifies the pruning obtained from different crop kinds: grapevines, olives, fruit trees and poplar plantations. All this biomass is destined for energetic use in domestic heating. In addition, it could be some additional revenue for fruit producers, whereas to achieve a more sustainable bioenergetic system.We estimate the measures of the planting area of all mentioned crops in Andalusia. The main goal is to determine the amount of usable energy from the biomass. But we consider only pruning of trees.The results show that most of the biomass is originated from olive pruning. Besides the entire biomass from crops with grapevines, olives, fruit trees and growing part of poplar plantations, we could supply a large percentage of the total energy consumed for annual home heating in Andalusia (2007).     

An evaluation of biomass co-firing in Europe

Reduction of the emissions of greenhouses gases, increasing the share of renewable energy sources (RES) in the energy balance, increasing electricity production from renewable energy sources and decreasing energy dependency represent the main goals of all current strategies in Europe. Biomass co-firing in large coal-based thermal power plants provides a considerable opportunity to increase the share of RES in the primary energy balance and the share of electricity from RES in gross electricity consumption in a country. Biomass-coal co-firing means reducing CO₂ and SO₂, emissions and it may also reduce NO_x emissions, and also represents a near-term, low-risk, low-cost and sustainable energy development. Biomass-coal co-firing is the most effective measure to reduce CO₂ emissions, because it substitutes coal, which has the most intensive CO₂ emissions per kWh electricity production, by biomass, with a zero net emission of CO₂. Biomass co-firing experience worldwide are reviewed in this paper. Biomass co-firing has been successfully demonstrated in over 150 installations worldwide for most combinations of fuels and boiler types in the range of 50–700 MWe, although a number of very small plants have also been involved. More than a hundred of these have been in Europe. A key indicator for the assessment of biomass co-firing is intrduced and used to evaluate all available biomass co-firing technologies.     

A comparative study of critical factors influencing the renewable energy systems use in the Indian context

The use of renewable energy technologies in developing countries has steadily increased over the past few decades. The widespread use of renewable sources requires a greater understanding of the available options. In order to ascertain the quantum of acceptance of renewable energy sources in the context of possible deterioration of the environment, on account of the increased use of fossil fuels, a Delphi study had been conducted. The feedback from the study was collected and analysed, so as to arrive at a general consensus. By the year 2020, the renewable energy contribution is expected to be 25% of the total energy use in India. At that time, the main resources utilised would be biomass, wind and solar in the order of their quantum of use. Using skewness and rank correlation analysis the results of the Delphi study were studied. It is identified that price, equipment efficiency and technology are the critical factors for commercialising renewable energy sources as denoted by skewness coefficients of 11.6, 5.55 and 0.68, respectively. Rank correlation indicates that the correlation between biomass gasifier electric conversion and biogas electric conversion for lighting is positive, denoting the possibility of integration of the two systems. Similarly, it has been analysed for integrated systems in the area of cooking, pumping, heating, cooling and transportation. This study will help in the formation of strategies which will ensure the development of the optimal integrated energy systems for continuous power supply.     

Steady-state modelling of hybrid energy system for off grid electrification of cluster of villages

Electrification of villages from the main grid leads to large investments and losses, and this forms the basis of decentralized Hybrid Energy System. In order to evaluate the techno-economic performance of hybrid energy system for remote rural area electrification, a mixed integer linear mathematical programming model (time-series) has been developed to determine the optimal operation, optimal configuration including the assessment of the economic penetration levels of photovoltaic array area, and cost optimization for a hybrid energy generation system consisting of small/micro hydro based power generation, biogas based power generation, biomass (fuelwood) based power generation, photovoltaic array, a battery bank and a fossil fuel generator. An optimum control algorithm written in C++, based on combined dispatch strategy, allowing easy handling of the models and data of hybrid energy system components is presented. A special feature of the proposed model is that a cost constant (cost/unit) for each of the proposed resource is introduced in the cost objective function in such a way that resources with lesser unit cost share the greater of the total energy demand in an attempt to optimize the objective function.To demonstrate the use of model and algorithm, a case study for a rural remote area is also presented.     

Standalone hybrid system energy management optimization for remote village considering methane production from livestock manure

Recently, many efforts have been done to overcome increasing fuel consumption. One of the vital solutions is utilization of standalone renewable energy resources hybrid systems. This paper attempts to develop a cost-effective methodology to ascertain optimal design and energy management for a remote village. Different energy resources such as wind and solar, fuel cell, and energy storage systems are employed to satisfy total demands including agriculture, residential, school, and health center. Different hydrogen production methods are proposed to verify the efficiency of the developed methodology. In the proposed village, different waste types such as rice husk, maize straw, livestock, and residential wastes are used to generate the required hydrogen for fuel cells to generate electricity. The main objective of the proposed methodology is minimizing the total cost of the village including total costs of each Distributed Generation (DG), cost of natural gas consumption, penalty for interruption the demands, and cost of CO₂ emission. A Particle Swarm Optimization (PSO) algorithm is employed to solve the optimization problem by minimizing the total system costs while the customers required Loss of Power Supply Probability (LPSP) is satisfied. The suggested hybrid system not only increases the renewable energy penetration but also decreases the natural gas consumption. The results achieved in the course of the present study depict that utilization of energy produced from different types of wastes plays a significant role in conserving fossil fuels and overcoming the fossil fuels depletion. It is concluded from the results that there is about a 17.46% reduction in natural gas consumption when all available waste is utilized. In addition, considering 100% availability for the animal manure reduces the natural gas consumption by reformer from 2.373 to 1.605 million liters which means reduction of the natural gas consumption is 32.35%. The results conclude that H₂ produced by livestock waste is dominating among available wastes. However, there is about 18% reduction in the Cost of Energy (COE), when 100% availability is considered for this type of waste.     

Reviewing optimisation criteria for energy systems analyses of renewable energy integration

The utilisation of fluctuating renewable energy sources is increasing world-wide; however, so is the concern about how to integrate these resources into the energy systems. The design of optimal energy resource mixes in climate change mitigation actions is a challenge faced in many places. This optimisation may be implemented according to economic objectives or with a focus on techno-operational aims and within these two main groupings, several different criteria may potentially be applied to the design process.In this article, a series of optimisation criteria are reviewed and subsequently applied to an energy system model of Western Denmark in an analysis of how to use heat pumps for the integration of wind power.The analyses demonstrate that the fact whether the system in question is modelled as operated in island mode or not has a large impact on the definition of the optimal wind power level. If energy savings and CO₂ emission reductions beyond the system boundary are not included in the analysis, then it is either not feasible to expand wind power to a high degree or it is conversely more feasible to install relocation technologies that can utilise any excess production. The analyses also demonstrate that different optimisation criteria render different optimal designs.     

Methodology based on Geographic Information Systems for biomass logistics and transport optimisation

The aim of this study is to contribute by outlining a procedure for achieving an optimal use of agricultural and forest residue biomass. In this regard, it develops and applies a methodology focused on logistics and transport strategies that can be used to locate a network of bioenergy plants around the region. This methodology was developed using a Geographic Information Systems and it provides information on the spatial distribution of biomass residues. This is accomplished by taking into consideration the amount of residue left within a rectangle with an area of 1 km², and making a regular grid overlap for the region under consideration. The centroid of each square will be evaluated and classified as “origin” (source of biomass collection) or “destination” (potential location of the bioenergy plant) depending on technical, economic, environmental and social constraints. The study focuses on mapping potential sites for tapping biomass energy and optimal locations for bioenergy plants. To identify and map optimal locations it is necessary to evaluate the time, distance and transport costs involved in the road transportation of biomass by means of a network analysis. The methodology was applied in the Valencian Community because the intense agricultural, agro-alimentary and timber activity in the region means there is a high potential for biomass.     

Taxing CO2 and subsidising biomass: analysed in a macroeconomic and sectoral model

This paper analyses the combination of taxes and subsidies as an instrument to enable a reduction in CO₂ emission. The objective of the study is to compare recycling of a CO₂ tax revenue as a subsidy for biomass use as opposed to traditional recycling such as reduced income or corporate taxation.A model of Denmark’s energy supply sector is used to analyse the effect of a CO₂ tax combined with using the tax revenue for biomass subsidies. The energy supply model is linked to a macroeconomic model such that the macroeconomic consequences of tax policies can be analysed along with the consequences for specific sectors such as agriculture. Electricity and heat are produced at heat and power plants utilising fuels which minimise total fuel cost, while the authorities regulate capacity expansion technologies. The effect of fuel taxes and subsidies on fuels is very sensitive to the fuel substitution possibilities of the power plants and also to the extent to which expansion technologies have been regulated.It is shown how a relatively small CO₂ tax of 15 US$/tCO₂ and subsidies for biomass can produce significant shifts in the fuel input-mix, when the expansion of production capacity is regulated to ensure a flexible fuel mix. The main finding is that recycling to biomass use will reduce the level of CO₂ tax necessary to achieve a specific emission reduction. Policies to ensure a more intensive use of such relatively expensive renewable energy sources as biomass could be implemented with only small taxes and subsidies.     

Estimating GHG emission mitigation supply curves of large-scale biomass use on a country level

This study evaluates the possible influences of a large-scale introduction of biomass material and energy systems and their market volumes on land, material and energy market prices and their feedback to greenhouse gas (GHG) emission mitigation costs. GHG emission mitigation supply curves for large-scale biomass use were compiled using a methodology that combines a bottom-up analysis of biomass applications, biomass cost supply curves and market prices of land, biomaterials and bioenergy carriers. These market prices depend on the scale of biomass use and the market volume of materials and energy carriers and were estimated using own-price elasticities of demand. The methodology was demonstrated for a case study of Poland in the year 2015 applying different scenarios on economic development and trade in Europe. For the key technologies considered, i.e. medium density fibreboard, poly lactic acid, electricity and methanol production, GHG emission mitigation costs increase strongly with the scale of biomass production. Large-scale introduction of biomass use decreases the GHG emission reduction potential at costs below 50 €/Mg CO_2eq with about 13–70% depending on the scenario. Biomaterial production accounts for only a small part of this GHG emission reduction potential due to relatively small material markets and the subsequent strong decrease of biomaterial market prices at large scale of production. GHG emission mitigation costs depend strongly on biomass supply curves, own-price elasticity of land and market volumes of bioenergy carriers. The analysis shows that these influences should be taken into account for developing biomass implementations strategies.     

Diversification criteria for power systems

Growing power demand, fuel availability and prices, technology changes, the environmental impacts of energy consumption, the changing regulatory environments and the uncertainties around such elements make the planning for optimal power mix a challenging task. The diversity approach is advocated as a most appropriate planning methodology for the optimal energy mix (Hickey et al., 2010). Shannon Wiener Index (SWI), which is the most cited diversity metric has been used to assess power systems diversity mainly from an energy perspective. To our best knowledge, there is no rigorous justification why energy has been the main variable used in diversification exercises rather than other variables such as capacity. We use a stylized power generation framework to show that diversity based on energy or capacity could lead to different outcomes in terms of vulnerability to fuel exposure, among others. We also introduce a Shannon Wiener Index ratio (SWIR) that we believe captures better the diversity of a power system compared to the standard SWI.     

开发利用生物质能是我国农林业发展的重要领域

我国有丰富的生物质资源,开发潜力巨大。农林业部门要担当重任,充分利用土地资源,发展能源农业和能源林业,使生物质能成为我国立足国内开发的一个主要能源品种,为我国能源安全和全球环境保护做出贡献。同时,生物质能开发利用也将是建立以农村为上游的一个新型能源产业链,形成新的经济增长点,增加农民收入,成为新农村建设的一个重要领域。     

Development of geothermal energy utilization in Turkey: a review

Renewable energy is accepted as a key source for the future, not only for Turkey but also for the world. Turkey has a considerably high level of renewable energy sources that can be a part of the total energy network in the country. Turkey is located in the Mediterranean sector of Alpine–Himalayan Tectonic Belt and has a place among the first seven countries in the world in the abundance of geothermal resources. The share of its potential used is, however, only about 2–3%.The main objective of the present study is to review the development of geothermal energy (GE) utilization in Turkey, giving its historical development and opportunities. GE is used for electric power generation and direct utilization in Turkey, which is among the first five countries in the world in geothermal direct use applications. Direct use of geothermal resources has expanded rapidly last 36 years from space heating of single buildings to district heating, greenhouse heating, industrial usage, modern balneology and physical treatment facilities.Turkey presently has one operating geothermal power plant, located near Denizli City in Western Anatolia with an installed capacity of 20.4 MW_e and an electrical energy production of 89,597 MW h in 2001. Recently, the total installed capacity has reached 820 MW_t for direct use. The total area of geothermal heated greenhouses exceeded over 35 ha with a total heating capacity of 81 MW_t. Ground-source (or geothermal) heat pumps (GSHPs) have also been put on the Turkish market since 1998. Though there are no Turkish GSHP manufactures as yet, 207 units have been installed in the country to date, representing a total capacity of 3 MW.GE is a relatively benign energy source, displaying fossil fuels and thus reducing greenhouse gas emissions. So, it is expected that GE development will significantly speed up in the country if the geothermal law becomes effective.