Possibilities and sustainability of “biomass for power” solutions in the case of a coal-based power utility

This paper investigates the possibilities and the sustainability of “biomass for power” solutions on a real power system. The case example is JP Elektroprivreda BiH d.d.—Sarajevo (EPBiH), a typical conventional coal-based power utility operating in the region of South East Europe. Biomass use is one of the solutions considered in EPBiH as a means of increasing shares of renewable energy sources (RES) in final energy production and reducing CO₂ emissions. This ultimately is a requirement for all conventional coal-based power utilities on track to meet their greenhouse gas (GHG) cut targets by 2050. The paper offers a discussion of possible options as a function of sustainability principles, considering environmental, economic and social aspects of biomass use. In the case of EPBiH, the most beneficial would be waste woody biomass and energy crop co-firing on existing coal-based power plants, as suggested by biomass market analyses and associated technological studies. To assess the sustainability of the different biomass co-firing options, a multicriteria sustainability assessment (MSA) and single criteria analysis (SCA) were used. Four different options were considered, based on different ratios of biomass for co-firing: 0 wt%-reference case, and 5, 7 and 10 wt% of biomass. Both the MSA and the SCA confirmed that the option with the highest share of biomass is the most preferable one for the considered case. In addition to that, the CO₂ parameter proved to be a key sustainability indicator, effecting the most decision making with regard to preference of options from the point of sustainability. Following up on the results of the analyses, the long-term projection of biomass use in EPBiH has shown an increase in biomass utilization of up to 450,000 t/y in 2030 and beyond, with associated CO₂ cuts of up to 395,000 t/y. This resulted in a 4 % CO₂ cut achieved with biomass co-firing, compared to the 1990 CO₂ emission level. It should be noted that the proposed assessment model for biomass use may be applied to any conventional coal-based power utility as an option in contributing to meeting specific CO₂ cut targets, provided that the set of input data is available and reliable.     

Energy production from biomass and its relevance to urban planning and compatibility assessment: two applicative cases in Italy

While the demand for energy in Italy continues to increase, the European Union Directive 2009/28/EC has set a goal of obtaining 20 % of all energy from renewable sources by 2020. It is required both for efficient energy utilization and the development of renewable energy plants, including biomass. In this context, we consider the use of residues from forest maintenance, residues from livestock, the use of energy crops, the recovery of food waste, and the residuals from agro-industrial activities. At the same time, it is necessary to consider the consequent environmental impact. In this study, we applied these considerations to two specific areas in Italy, with different characteristics using the tool of environmental balance. This approach presents a substantial innovation for performing a quantitative analysis of the environmental impact. The specific-considered cases can also indicate a general methodology, useful for energy production compatibility planning.     

The potential of biomass supply for energetic utilization in a small Italian region: Basilicata

The European Union Directive 2009/28/EC (European Parliament and of the Council of 23 April 2009 on the promotion of the use of energy from renewable sources and amending and subsequently repealing directives 2001/77/EC and 2003/30/EC, Directive 2009/28/EC) establishes a common framework for the use of energy from renewable sources in order to reduce both greenhouse gas emissions and reliance on fossil fuels from foreign markets; more specifically the EU has the ambitious goal of reaching a 20 % share of energy from renewable sources in the overall energy mix by 2020. These objectives could drive policies that offer substantial economic subsidies for the use of renewable energy, both in Italy and in many other European countries. For all these reasons, biomass (one of the major sources of renewable energy) plants are getting a lot of attention in Italy, but it is necessary to determine whether using of this type of energy is environmentally beneficial and economically feasible. In this study, we evaluate the energy and so the environmental aspects by considering both current and potential biomass supplies available for energy utilization in a small region in the South of Italy: Basilicata, as well as the consequences of this energy conversion at both the local and the global scale.     

Biomass-based gasifiers for internal combustion (IC) engines—A review

The world is facing severe problems of energy crisis and environmental problem. This situation makes people to focus their attention on sustainable energy resources for their survival. Biomass is recognized to be the major potential source for energy production. There are ranges of biomass utilization technologies that produce useful energy from biomass. Gasification is one of the important techniques out of direct combustion, anaerobic digestion – Biogas, ethanol production. Gasification enables conversion of these materials into combustible gas (producer gas), mechanical and electrical power, synthetic fuels, and chemical. The gasification of biomass into useful fuel enhances its potential as a renewable energy resource. This paper gives a comprehensive review of the techniques used for utilizing biomass, experimental investigation on biomass fuels, characterization, merits, demerits and challenges faced by biomass fuels.     

Effects of feedstocks on the process integration of biohydrogen production

Future production of hydrogen must be sustainable. To obtain it, renewable resources have to be employed for its production. Fermentation of biomasses could be a viable way. The process evaluated is a two-step fermentation to produce hydrogen from biomass. Process options with barley straws, PSP, and thick juice as feedstocks have been compared on the basis of process balances. Aspen Plus has been used to calculate mass and energy balances taking into account the integration of the process. Results show that the production of hydrogen as energy carrier is technically feasible with all the considered feedstocks and thanks to heat integration, second generation biomass (PSP and barley straws) are competitive with food crops (thick juice).     

Comparison of ecological footprint for biobased PHA production from animal residues utilizing different energy resources

Realizing a sustainable development of our planet requires a reduction of waste production, harmful emissions, and higher energy efficiency as well as utilization of renewable energy sources. One pathway to this end is the design of sustainable biorefinery concepts. Utilizing waste streams as raw material is gaining great importance in this respect. This reduces environmental burden and may at the same time contribute to economic performance of biorefineries. This paper investigates the utilization of slaughtering waste to produce biodegradable polyesters, polyhydroxyalkanoates (PHA), via bioconversion. PHA are the target product while production of high quality biodiesel along with meat and bone meal (MBM) as by-products improves the economic performance of the process. The paper focuses on ecological comparison of different production scenarios and the effect of geographical location of production plants taking different energy production technologies and resources into account; ecological footprint evaluation using Sustainable Process Index methodology was applied. Keeping in mind that the carbon source for PHA production is produced from waste by energy intensive rendering process, the effect of available energy mixes in different countries becomes significant. Ecological footprint results from the current study show a bandwidth from 372,950 to 956,060 m²/t PHA production, depending on the energy mix used in the process which is compared to 2,508,409 m²/t for low density polyethylene.     

Life cycle assessment of oil palm empty fruit bunch delignification using natural malic acid-based low-transition-temperature mixtures: a gate-to-gate case study

In future biorefineries, the development of cheap and environmentally friendly solvents for biomass pretreatment is highly desirable. In this sense, low-transition-temperature mixtures (LTTMs) have high potential to serve as green solvents for replacing conventional pretreatment technologies. In this study, a life cycle assessment of LTTMs pretreatment was conducted to determine the environmental impacts caused by biomass delignification. A gate-to-gate analysis which started with harvested oil palm empty fruit bunch and ended with lignin was selected. The environmental impacts such as acidification potential, global warming potential, eutrophication potential, photochemical ozone creation potential, human toxicity potential and volatile organic compounds emission were evaluated. The comparable environmental balances of commercial l-malic acid and cactus malic acid-based LTTMs pretreatment processes verified the suitability of the process with natural malic acid as the source of proton donor. This study concludes that biomass delignification using natural cactus malic acid-based LTTMs had promising features such as high delignification efficiency and environmentally friendly compared to commercial l-malic acid-based LTTMs. Based on environmental point of view, the overall process of biomass delignification using sucrose-based LTTMs had lower CO₂ emissions compared to the monosodium glutamate- and choline chloride-based LTTMs. These findings are important for verifying the greenness and sustainability of LTTMs to be applied at industrial scale.     

Steel mill slags energy potential: the case of the steel factory of Arcelor-Mittal in Asturias (Spain)

Slag accounts for most of the residuals or by-products of the steel manufacturing process and represents a not inconsiderable amount of energy waste and CO₂ emissions. Energy recovery from steel mill slags is not actually performed because of the difficulty of the industrial implementation, but the actual demand and the incentives for new electricity generation plants based on renewable energies and on industrial waste heat recovery offer a new opportunity to evaluate the feasibility of this process. This article presents a review of the slag energy potential on a global scale, and a proposal for a recovery plant in the factories of Arcelor-Mittal in Asturias (Spain), based on a steam Rankine cycle for electricity production in a turbine. The plant production and viability have been analyzed using the typical technical and economic values for this kind of plant. Also, a parametric study has been performed on the heat recuperator efficiency and investment rate.     

Models for organics removal from vinasse from ethanol production

Global ethanol production generates almost 100 billion liters per year of a high-strength liquid waste called vinasse. One sustainable method of treating vinasse using environmental biotechnology is anaerobic digestion, which generates biogas that can be used as a renewable energy resource. Although a number of models have been developed for predicting biogas generation rates, no previous study has modeled liquid organic removal rates for vinasse treatment. The goal of this research was thus to develop models for predicting liquid-phase organic removal rates for anaerobic treatment of vinasse. 6-L laboratory-scale batch reactors were filled with vinasse of six different compositions and operated at three different mesophilic temperatures (30, 35, 40 °C). Biochemical and chemical oxygen demand (BOD and COD) were measured over time using Standard Methods 5210B and 5220C. Based on data collected, multiple linear regression equations (R² = 0.79 and 0.94) were developed to predict first-order rate constants k_BOD and k_COD as functions of temperature and vinasse composition (initial values of nitrogen, potassium, phosphorous, and sulfur). The first-order models developed require a small number of readily available input parameters. They apply to treatment of vinasse from ethanol produced from corn and milo; future work can test their applicability to ethanol produced from other feedstocks. The models can be used for sizing/design of reactors for anaerobic treatment of vinasse.     

A life cycle assessment of biomass cofiring in a coal-fired power plant

The generation of electricity, and the consumption of energy in general, often result in adverse effects on the environment. Coal-fired power plants generate over half of the electricity used in the U.S., and therefore play a significant role in any discussion of energy and the environment. By cofiring biomass, currently operating coal plants have an opportunity to reduce the impact they have, but to what degree, and with what trade-offs? A life cycle assessment has been conducted on a coal-fired power system that cofires wood residue. The assessment was conducted in a cradle-to-grave manner to cover all processes necessary for the operation of the power plant, including raw material extraction, feed preparation, transportation, and waste disposal and recycling. Cofiring was found to significantly reduce the environmental footprint of the average coal-fired power plant. At rates of 5% and 15% by heat input, cofiring reduces greenhouse gas emissions on a CO₂-equivalent basis by 5.4% and 18.2%, respectively. Emissions of SO₂, NO _x , non-methane hydrocarbons, particulates, and carbon monoxide are also reduced with cofiring. Additionally, total system energy consumption is lowered by 3.5% and 12.4% for the 5% and 15% cofiring cases, respectively. Finally, resource consumption and solid waste generation were found to be much less for systems that cofire. Electronic Publication     

Analysis of methane yields from energy crops and agricultural by-products and estimation of energy potential from sustainable crop rotation systems in EU-27

Currently an increasing demand for renewable energy can be observed. A part of this demand could be covered by the production of energy from agrarian biomass. Due to the limited availability of arable land, food and feed production are starting to compete for agrarian resources. A way out of this dilemma is to develop concepts that are based on otherwise unused agrarian biomass like straw and include new technologies for the fermentation of lignocellulosic biomass. In this paper, the energy potentials of two different cropping systems are compared. In the energy-based crop rotation system all crops were used either for biogas or ethanol production. In the biorefinery-based approach, the various crops were used in cascades for the production of food as well as feed. Experimental laboratory work and field trials were combined to calculate energy and biomass yields of the crops under investigation. The results demonstrate that steam explosion pretreatment of wheat straw led to a 30% increase in the specific methane yield. The calculated energy output of the biorefinery-based crop rotation system amounted to a total of 126 GJ ha⁻¹ year⁻¹. Extrapolating this energy output to the total arable land of the EU-27 member states, 13,608 PJ of energy could be produced. Therefore, biorefinery-based crop rotation systems could provide approximately three times more energy to the European population than energy-based crop rotation systems.     

Economic and environmental evaluation of coal-and-biomass-to-liquids-and-electricity plants equipped with carbon capture and storage

Among various clean energy technologies, one innovative option for reducing the emission of greenhouse gases (GHGs) and criteria pollutants involves pairing carbon capture and storage (CCS) with the production of synthetic fuels and electricity from a combination of coal and sustainably sourced biomass. With a relatively pure CO₂ stream as an inherent byproduct of the process, most of the resulting GHG emissions can be eliminated by simply compressing the CO₂ for pipeline transport. Subsequent storage of the CO₂ output in underground reservoirs can result in very low—perhaps even near-zero—net GHG emissions, depending on the fraction of biomass as input and its CO₂ signature. To examine the potential market penetration and environmental impact of coal-and-biomass-to-liquids-and-electricity (CBtLE), a system-wide sensitivity analysis was performed using the MARKet ALlocation energy model. CBtLE was found to be most competitive in scenarios with a combination of high oil prices, low CCS costs, and, unexpectedly, non-stringent carbon policies. In the scheme considered here (30 % biomass input on an energy basis and 85 % carbon capture), CBtLE fails to achieve significant market share in deep decarbonization scenarios, regardless of oil prices and CCS costs. Such facilities would likely require higher fractions of biomass feedstock and captured CO₂ to successfully compete in a carbon-constrained energy system.     

Technology assessment for clean energy technologies: The case of the Pacific Northwest

This study presents a technology assessment for clean power generation in the Pacific Northwest. Our goal is to incorporate clean production principles into the evaluation process for power alternatives. Two types of technologies are considered: one is for a renewable energy source (wind) and the other is for a traditional, fossil fuel based energy source (coal). The Analytical Hierarchy Process is used to assess the feasibility of both the wind energy and clean burning coal energy technologies. Criteria such as location, cost, feasibility, and availability are used for evaluations. For the wind energy, cost was determined to be the most important criterion when making a technology decision. For the SO₂ emissions technology, the regenerative process was determined to be the best technology to scrub SO₂ emissions from the air. Additionally, efforts towards renewable energy in Oregon should continue. Both federal and state governments offer tax credits that can help mitigate costs and facilitate the adoption of renewable energy options for power companies.     

Enhanced Biogas Production from the Anaerobic Batch Treatment of Banana Peels

Waste disposal management and the energy crisis are important challenges facing most countries. The fruit-processing industry generates daily several tons of wastes, of which the major share comes from banana farms. Anaerobic digestion (AD) technology has been applied to the treatment of wastewater, animal slurry, food waste, and agricultural residues, with the primary goals of energy production and waste elimination. This study examines the effect of organic loading (OL) and cow manure (CM) addition on AD performance when treating banana peel waste (BPW). The maximum daily biogas production rates of banana peels (BPs) with a CM content of 10%, 20%, and 30% at 18 and 22 g of volatile solids (g_vs) per liter were 50.20, 48.66, and 62.78 mL·(g_vs·d)⁻¹ and 40.49, 29.57, and 46.54 mL·(g_vs·d)⁻¹, respectively. However, the daily biogas yield showed no clear interdependence with OL or CM content. In addition, a kinetic analysis using first-order and cone models showed that the kinetic parameters can be influenced by the process parameters.     

A Technological Overview of Biogas Production from Biowaste

The current irrational use of fossil fuels and the impact of greenhouse gases on the environment are driving research into renewable energy production from organic resources and waste. The global energy demand is high, and most of this energy is produced from fossil resources. Recent studies report that anaerobic digestion (AD) is an efficient alternative technology that combines biofuel production with sustainable waste management, and various technological trends exist in the biogas industry that enhance the production and quality of biogas. Further investments in AD are expected to meet with increasing success due to the low cost of available feedstocks and the wide range of uses for biogas (i.e., for heating, electricity, and fuel). Biogas production is growing in the European energy market and offers an economical alternative for bioenergy production. The objective of this work is to provide an overview of biogas production from lignocellulosic waste, thus providing information toward crucial issues in the biogas economy.     

Comparing End-Use Potential for Industrial Food-Waste Sources

Approximately one quarter of the global edible food supply is wasted. The drivers of food waste can occur at any level between production, harvest, distribution, processing, and the consumer. While the drivers vary globally, the industrialized regions of North America, Europe, and Asia share similar situations; in each of these regions the largest loss of food waste occurs with the consumer, at approximately 51% of total waste generated. As a consequence, handling waste falls on municipal solid waste operations. In the United States, food waste constitutes 15% of the solid waste stream by weight, contributes 3.4 × 10⁷ t of carbon dioxide (CO₂) equivalent emissions, and costs 1.9 billion USD in disposal fees. The levels of carbon, nutrients, and moisture in food waste make bioprocessing into higher value products an attractive method for mitigation. Opportunities include extraction of nutraceuticals and bioactive compounds, or conversion to a variety of volatile acids—including lactic, acetic, and propionic acids—that can be recovered and sold at a profit. The conversion of waste into volatile acids can be paired with bioenergy production, including hydrogen or biogas. This present review compares the potential for upgrading industrial food waste to either specialty products or methane. Higher value uses of industrial food waste could alleviate approximately 1.9 × 10⁸ t of CO₂ equivalent emissions. As an example, potato peel could be upgraded to lactic acid via fermentation to recover 5600 million USD per year, or could be converted to methane via anaerobic digestion, resulting in a revenue of 900 million USD per year. The potential value to be recovered is significant, and food-waste valorization will help to close the loop for various food industries.     

Pomace waste management scenarios in Québec--impact on greenhouse gas emissions

Fruit processing industries generate tremendous amount of solid wastes which is almost 35-40% dry weight of the total produce used for the manufacturing of juices. These solid wastes, referred to as, “pomace” contain high moisture content (70-75%) and biodegradable organic load (high BOD and COD values) so that their management is an important issue. During the management of these pomace wastes by different strategies comprising incineration, landfill, composting, solid-state fermentation to produce high-value enzymes and animal feed, there is production of greenhouse gases (GHG) which must be taken into account. In this perspective, this study is unique that discusses the GHG emission analysis of agro-industrial waste management strategies, especially apple pomace waste management and repercussions of value-addition of these wastes in terms of their sustainability using life cycle assessment (LCA) model. The results of the analysis indicated that, among all the apple pomace management sub-models for a functional unit, solid-state fermentation to produce enzymes was the most effective method for reducing GHG emissions (906.81 tons CO₂ eq. per year), while apple pomace landfill resulted in higher GHG emissions (1841.00 tons CO₂ eq. per year). The assessment and inventory of GHG emissions during solid-state fermentation gave positive indications of environmental sustainability for the use of this strategy to manage apple pomace and other agricultural wastes, particularly in Quebec and also extended to other countries. The analysis and use of parameters in this study were drawn from various analytical approaches and data sources. There was absence of some data in the literature which led to consideration of some assumptions in order to calculate GHG emissions. Hence, supplementary experimental studies will be very important to calculate the GHG emissions coefficients during agro-industrial waste management.     

A systematic technique for cost-effective CO<Subscript>2</Subscript> emission reduction in process plants

There has been growing interests to reduce the environmental impact caused by greenhouse gas emissions from process plants through various energy conservation strategies. CO₂ emissions are closely linked to energy generation, conversion, transmission and utilisation. Various studies on the design of energy-efficient processes, optimal mix of renewable energy and hybrid power system are driven to reduce reliance on fossil fuel as well as CO₂ emissions reduction. This paper presents a systematic technique in the form of graphical visualisation tool for cost-effective CO₂ emission reduction strategies in industry. The methodology is performed in four steps. The first step involves calculating the energy consumption of a process plant. This is followed by identification of potential strategies to reduce CO₂ emissions using the CO₂ management hierarchy as a guide. In the third step, the development of “Investment” versus “CO₂ Reduction” (ICO₂) plot is constructed to measure the optimal CO₂ emission reductions achieved from the implementation of possible CO₂ reduction strategies. The Systematic Hierarchical Approach for Resilient Process Screening (Wan Alwi and Manan in AIChE J 11:3981–3988, 2006) method is used in the fourth step via substitution or partial implementation of the various CO₂ reduction options in order to meet the cost-effective emission reduction within the desired investment limit or payback period (PP). An illustrative case study on a palm oil refinery plant has been used to demonstrate the implementation of the method in reduction of CO₂ emissions. The developed graphical tool provides an insight-based approach for systematic CO₂ emission reduction in the palm oil refinery considering both heat and power energy sources. Result shows that 31.2 % reduction in CO₂ emissions can be achieved with an investment of USD 38,212 and PP of 10 months based on the present energy prices in Malaysia.     

Eco-efficiency assessment of pulp and paper industry in Myanmar

This paper presents the eco-efficiency assessment of the pulp and paper industry in Myanmar by using the key indicators such as raw material consumption, energy consumption, total waste output, water consumption, and CO₂ emissions. The study was carried out by using quantitative methods for data analysis of the production, consumptions and emissions from fiscal year 2001–2005. The results revealed that the level of economic and environmental performance using the eco-efficiency ratio for each fiscal year has decreased since year 2002, and factory tried to increase the level of eco-efficiency again in year 2005. There was the positive aspect that factory could optimize the waste utilization by transferring lime mud to the cement factory in the last two fiscal years. This analysis showed the root causes that led to the losses of material, energy and water consumption and discussed how to conserve those utilities.     

Modeling,simulation and intensification of hydroprocessing of micro-algae oil to produce renewable aviation fuel

Micro-algae are photosynthetic organisms, which represent a promissory renewable raw material for biofuels production, since they can be cultivated in non-fertile lands, avoiding the competition with food crops for land use. From micro-algae, oil can be obtained oil that can be converted to biodiesel, green diesel and biojet fuel. In particular, the renewable aviation fuel is one of the less explored biofuels; nevertheless, for the aviation sector, this is the best alternative to reduce CO₂ emissions, allowing its sustainable development. In order to produce hydrocarbons in the boiling point range of jet fuel, we need to transform the micro-algae oil. A number of research projects report the use of micro-algae oil for the production of biojet fuel through the hydrotreating process. However, the application of process intensification strategies for the hydroprocessing of micro-algae oil has not been reported. Therefore, in this work we propose the modeling, simulation and intensification of the hydrotreating process to produce biojet fuel, considering micro-algae oil as raw material. The hydroprocessing of micro-algae oil is modeled in Aspen Plus processes simulator, based on data from an experimental study recently reported. The produced renewable hydrocarbons are purified through conventional and intensified distillation sequences; thereby, conventional and intensified hydrotreating processes are defined and evaluated in terms of total annual costs, CO₂ emissions and biojet fuel price. Simulation results show that the implementation of intensification strategies leads to the production of biojet fuel with reduced carbon dioxide emissions, 34% less, and a competitive price per liter, 78% cheaper than fossil jet fuel price.