Sustainable transport strategy for promoting zero-emission electric scooters in Taiwan

In Taiwan, the government considers the zero-emission scooters to be a sustainable form of transport like walking, cycling and public transport, which play a vital role to support sustainable urban mobility. Therefore, the development of zero-emission scooters is an important strategy in constructing the sustainable transport network of Taiwan. It is also the government's priorities about the policy of emission-reduction and energy-conservation in the transportation sector. Recently, Taiwan launched a new program for subsidy of purchasing zero-emission scooters, which aimed to shift the petroleum-powered scooters to the electric scooters. The present paper is providing an update review of the promotional programs in developing zero-emission scooters in Taiwan. It introduces the status of the establishment and progress of policy, standards, subsidies to users and manufacturers, practice infrastructure, and technology development. Moreover, the contribution of replacing petrol scooters by zero-emission scooters such as battery-powered electric scooters and fuel cell scooters to reduction in greenhouse gas (GHG) emission and improvement in energy efficiency is evaluated.     

Concept of cleaner production in Vojvodina

The Autonomous Province of Vojvodina is an autonomous province in Serbia, containing about 27% of its total population according to the 2002 Census. It is located in the northern part of the country, in the Pannonia plain. The importance of sector of the environment protection becomes even larger and observable, especially with respect of the strategic determination of Government of the AP of Vojvodina, the Republic of Serbia on the association with the European economic area (EEA) and joining with the states – members of the European Union (EU). Restitution of the concept of the cleaner production (CP) significantly helps to companies and the responsible persons (especially in the domain of industry) to harmonize their business activities with law demands concerning the environment protection, as well as to improve their processes and the process sequences. This makes a starting base for the obtaining of the integrated license for the installations that are included in a list of installations that have to obtain an integrated licenses (some 250 installations), on the basis of the Law on the integrated prevention and control of pollution of Vojvodina, the Republic of Serbia, for which the dead point is the year 2015.     

Potential development of bioethanol production in Vojvodina

The Autonomous Province of Vojvodina is an Autonomous Province in Serbia, containing about 27% of its total population according to the 2002 Census. Contribution of renewable energy sources in total energy consumption of Vojvodina contemporary amounts to less than 1%, apropos 280 GWh/year. By combining of methods of introduction of new and renewable sources, systematic application of methods for increasing of energetic efficacy, as well as of introduction of the new technologies, percentage of contribution of the non-conventional energy sources in Vojvodina could be increased to as much as 20%. This paper presents the potential of development of bioethanol production in Vojvodina. Production of bioethanol on small farms can be successfully applied for processing of only 30 kg of corn per day, with obtaining of crude ethanol in the so-called “brandy ladle” and use of lygnocellulosic agricultural wastes as an energy source. In a case of construction of a larger number of such plants, the only possible solution is seen in the principle of construction of the so-called “satellite plants”, which will on small farm produce crude ethanol, with obtaining and consumption of stillage for animal feeding, and consumption of agricultural wastes as energetic fuels. If stillage is to be used as feed in wet feeding, it is estimated that, because of restrictions established by the magnitude of animal farm, the upper limit of capacity of such enterprises that process is at some 10–15 tons of corn per day, and production of 3000–3500 hL of absolute ethanol per day. In such a case, for animal feeding necessary is to have herd with 1300–1700 of milking cows or 5000–25,000 heads of sheep and/or pigs. Technological model of separate grain processing ad bioethanol production from dextrose hydrolysates of starch is interesting for countries possessing plants for bioethanol production from molasses and plants for cereals processing into starch and dextrose hydrolysates of starch.     

Commercialization potential of microalgae for biofuels production

Microalgae feedstocks are gaining interest in the present day energy scenario due to their fast growth potential coupled with relatively high lipid, carbohydrate and nutrients contents. All of these properties render them an excellent source for biofuels such as biodiesel, bioethanol and biomethane; as well as a number of other valuable pharmaceutical and nutraceutical products. The present review is a critical appraisal of the commercialization potential of microalgae biofuels. The available literature on various aspects of microalgae, e.g. its cultivation, life cycle assessment, and conceptualization of an algal biorefinery, has been scanned and a critical analysis has been presented. A critical evaluation of the available information suggests that the economic viability of the process in terms of minimizing the operational and maintenance cost along with maximization of oil-rich microalgae production is the key factor, for successful commercialization of microalgae-based fuels.     

Comparative cost analysis of algal oil production for biofuels

Economic analysis is an essential evaluation for considering feasibility and viability of large-scale, photoautotrophic algae-based, biofuel production. Thus far, economic analysis has been conducted on a scenario-by-scenario basis which does not allow for cross-comparisons. In 2008, a comparative study was carried out using a cross-section of cost analyses consisting of 12 public studies. The resulting triacylglyceride cost had a spread of two orders of magnitude excluding two studies which were intended for specialty chemicals. The cost spread can be largely attributed to disparate assumptions and uncertainties in economic and process inputs. To address this disparity, four partners from research, academia, and industry collaborated on a harmonization study to estimate algal oil production costs based on a common framework. The updated cost comparison based on a normalized set of input assumptions was found to greatly reduce economic variability, resulting in algal oil production costs ranging from $10.87 gallon⁻¹ to $13.32 gallon⁻¹.     

Resource demand implications for US algae biofuels production scale-up

Photosynthetic microalgae with the potential for high biomass and oil productivities have long been viewed as a promising class of feedstock for biofuels to displace petroleum-based transportation fuels. Algae offer the additional benefits of potentially being produced without using high-value arable land and fresh water, thereby reducing the competition for those resources between expanding biofuels production and conventional agriculture. Algae growth can also be enhanced by the use of supplemental CO₂ that could be supplied by redirecting concentrated CO₂ emissions from stationary industrial sources such as fossil-fired power plants, cement plants, fermentation industries, and others. In this way, algae may offer an effective means to capture carbon emissions for reuse in renewable fuels and co-products, while at the same time displacing fossil carbon fuels to help bring about a net reduction in overall carbon emissions. Significant displacement of petroleum fuels will require that algae feedstock production reach large volumes that will put demands on key resources. This scenario-based analysis provides a high-level assessment of land, water, CO₂ and nutrient (nitrogen, phosphorus) demands resulting from algae biofuel feedstock production reaching target levels of 10 billion gallons per year (BGY), 20 BGY, 50 BGY, and 100 BGY for four different geographical regions of the United States. Different algae productivities are assumed for each scenario region, where relative productivities are nominally based on annual average solar insolation. The projected resource demands are compared with data that provide an indication of the resource level potentially available in each of the scenario regions. The results suggest that significant resource supply challenges can be expected to emerge as regional algae biofuel production capacity approaches levels of about 10 BGY. The details depend on the geographic region, the target feedstock production volume, and the level of algae productivity that can be achieved. The implications are that the supply of CO₂, nutrients, and water, in particular, can be expected to severely limit the extent to which US production of algae biofuel can be sustainably expanded unless approaches are developed to mitigate these resource constraints in parallel to emergence of a viable algae technology. Land requirements appear to be the least restrictive, particularly in the Western half of the country where larger quantities of potentially suitable classes of land exist. Within the limited scope and assumptions of this analysis, sustainable photosynthetic microalgae biofuel feedstock production in the US in excess of about 10 BGY will likely be a challenge due to other water, CO₂ and nutrient resource limitations. Developing algae production approaches that can effectively use non-fresh water resources and minimize both water and nutrient requirements will help reduce resource constraints. Providing adequate CO₂ resources for enhanced algae production appears the biggest challenge, and could emerge as a constraint at oil production levels below 10 BGY.     

Carbon recycling for zero-emission carbon-neutral transportation

Abstract

Converting current internal combustion engines to operate in closed-cycle, lean-burn mode with pure oxygen could generate an exhaust stream of >99% carbon dioxide. The ease of capture of this carbon, relative to the dilute CO₂ in current exhaust gases, points the way to a feasible route to zero-emission transportation. Prospects for implementing such an approach, which would include re-synthesis of fuel from the captured CO₂ and water using renewable power, are considered.     

Feedback effect and transportation costs in biofuels production

Consumption of oil derivatives in the production process usually controls the real costs of liquid fuels obtained from biomass. Since carrying of the raw material for conversion is responsible for most of the consumption, biomass transportation costs are discussed as functions of production scale and agricultural and industrial yields.     

Harnessing biofuels: A global Renaissance in energy production?

Biofuel, peoples’ long awaiting alternative fuel, is yet to struggle a long way to reach in retail outlet all over the world as an economical and environmental friendly fuel. Biofuels include bioethanol, biodiesel, biogas, bio-synthetic gas (bio-syngas), bio-oil, bio-char, Fischer-Tropsch liquids, and biohydrogen. Among these bioethanol, biodiesel, biogas are predominant which can be produced either using chemical catalyst or biocatalyst from biomass. At present, the conventional process involves the chemical catalyst while a rigorous research is focused on using a biocatalyst. This review brings out the advantages and disadvantages of using different type of catalyst in biofuel production and emphasis on new technologies as an alternative to conventional technologies.     

Biomass upgrading by torrefaction for the production of biofuels: A review

An overview of the research on biomass upgrading by torrefaction for the production of biofuels is presented. Torrefaction is a thermal conversion method of biomass in the low temperature range of 200–300 °C. Biomass is pre-treated to produce a high quality solid biofuel that can be used for combustion and gasification. In this review the characteristics of torrefaction are described and a short history of torrefaction is given. Torrefaction is based on the removal of oxygen from biomass which aims to produce a fuel with increased energy density by decomposing the reactive hemicellulose fraction. Different reaction conditions (temperature, inert gas, reaction time) and biomass resources lead to various solid, liquid and gaseous products. A short overview of the different mass and energy balances is presented. Finally, the technology options and the most promising torrefaction applications and their economic potential are described.     

Dual role of microalgae: Phycoremediation of domestic wastewater and biomass production for sustainable biofuels production

Global threats of fuel shortages in the near future and climate change due to green-house gas emissions are posing serious challenges and hence and it is imperative to explore means for sustainable ways of averting the consequences. The dual application of microalgae for phycoremediation and biomass production for sustainable biofuels production is a feasible option. The use of high rate algal ponds (HRAPs) for nutrient removal has been in existence for some decades though the technology has not been fully harnessed for wastewater treatment. Therefore this paper discusses current knowledge regarding wastewater treatment using HRAPs and microalgal biomass production techniques using wastewater streams. The biomass harvesting methods and lipid extraction protocols are discussed in detail. Finally the paper discusses biodiesel production via transesterification of the lipids and other biofuels such as biomethane and bioethanol which are described using the biorefinery approach.     

Energy management strategies for a zero-emission hybrid domestic ferry

The paper presents three approaches for the sizing and control of a maritime hybrid power-plant equipped with proton exchange membrane fuel cells and batteries. The study focuses on three different power-plant configurations, including the energy management strategy and the power-plant component sizing. The components sizing is performed following the definition of the energy management strategy using the sequential optimization approach. These configurations are tested using a dynamic model developed in Simulink. The simulations are carried out to validate the technical feasibility of each configuration for maritime use. Each energy management strategy is developed to allow for the optimization of a chosen set of parameters, such as hydrogen consumption and fuel cell degradation. It is observed that in the hybrid power-plant optimization there are always trade-offs, and the optimization should be carried out by prioritizing primary factors the ship owner considers most important for day-to-day operations.     

Comparison of dairy wastewater and synthetic medium for biofuels production by microalgae cultivation

This study is concerned with comparing raw dairy wastewater (DWW) with blue-green medium (BG11 medium) for biofuel production. Three microalgae strains (Chlorella sp., Scenedesmus sp., and Chlorella zofingiensis) were cultured in tubular bubble column photobioreactors with two media separately. After 8 days of cultivation, DWW was demonstrated to be more suitable medium for microalgae biomass and lipid production than BG11 medium. The biomass and lipid produced within wastewater provided suitable feedstocks for anaerobic digestion and biodiesel conversion. Nutrients in wastewater were efficiently removed (>90% total nitrogen removal, approximately 100% ammonia removal, and >85% total phosphorus removal) during this process.     

Prospects of using microalgae for biofuels production: Results of a Delphi study

Advanced biofuels, such as those obtained from microalgae, are widely accepted as better choices for achieving goals of incorporating renewables and non-food fuel sources into the transportation sector, and for overcoming land use issues due to biofuel crops. Main challenges are currently the feasibility of large-scale commercialization of microalgae biofuels, since there are still some technical problems to overcome (e.g. the high energy consumption associated with biomass processing) and the majority of economic and financial analyses are based on pilot-scale projects. Therefore, this article presents the results of a Delphi study aiming to identify the main obstacles and most critical issues affecting the potential of large-scale commercialization of microalgae biodiesel and its incorporation into the fuel market. According to the authors' knowledge, this is the first Delphi study with this objective. The respondents are worldwide market specialists in the survey themes that ranged from biofuels economics to their environmental sustainability. One of the key findings is that most of the experts believe that production of microalgae biofuels will achieve its full commercial scale until 2020, and that from 2021 till 2030 it could represent from 1% to 5% of the worldwide fuel consumption. The study results also showed that environmental issues are where expert opinion differs more.     

Outlook for advanced biofuels

To assess which biofuels have the better potential for the short-term or the longer term (2030), and what developments are necessary to improve the performance of biofuels, the production of four promising biofuels—methanol, ethanol, hydrogen, and synthetic diesel—is systematically analysed. This present paper summarises, normalises and compares earlier reported work. First, the key technologies for the production of these fuels, such as gasification, gas processing, synthesis, hydrolysis, and fermentation, and their improvement options are studied and modelled. Then, the production facility's technological and economic performance is analysed, applying variations in technology and scale. Finally, likely biofuels chains (including distribution to cars, and end-use) are compared on an equal economic basis, such as costs per kilometre driven. Production costs of these fuels range 16–22 €/GJ_HHV now, down to 9–13 €/GJ_HHV in future (2030). This performance assumes both certain technological developments as well as the availability of biomass at 3 €/GJ_HHV. The feedstock costs strongly influence the resulting biofuel costs by 2–3 €/GJ_fuel for each €/GJ_HHV feedstock difference. In biomass producing regions such as Latin America or the former USSR, the four fuels could be produced at 7–11 €/GJ_HHV compared to diesel and gasoline costs of 7 and 8 €/GJ (excluding distribution, excise and VAT; at crude oil prices of ∼35 €/bbl or 5.7 €/GJ). The uncertainties in the biofuels production costs of the four selected biofuels are 15–30%. When applied in cars, biofuels have driving costs in ICEVs of about 0.18–0.24 €/km now (fuel excise duty and VAT excluded) and may be about 0.18 in future. The cars’ contribution to these costs is much larger than the fuels’ contribution. Large-scale gasification, thorough gas cleaning, and micro-biological processes for hydrolysis and fermentation are key major fields for RD&D efforts, next to consistent market development and larger scale deployment of those technologies.     

Combined production of second-generation biofuels and electricity from sugarcane residues

This paper describes a preliminary analysis of two technological routes (based on hydrolysis and on gasification + Fischer–Tropsch conversion process) of biofuels production from cellulosic materials. In this paper it was considered the integration of the two alternative routes to a conventional distillery of ethanol production based on fermentation of sugarcane juice. Sugarcane bagasse is the biomass considered as input in both second-generation routes. Results show that the integration of gasification + FT process to a conventional distillery is slightly more efficient (from an energetic point of view) and also offers the advantage of products diversification (ethanol from the conventional plant, plus diesel, gasoline and more surplus electricity regarding the hydrolysis route). Considering typical Brazilian conditions, at this stage it is not possible to foresee any significant advantage of any of the alternatives, but potentially the gasification route would have an advantage regarding avoided GHG emissions depending on the emission factor of the electric sector in which cogeneration units will be installed.     

The price for biofuels sustainability

The production and usage of biofuels has increased worldwide, seeking goals of energy security, low-carbon energy and rural development. As biofuels trade increased, the European Union introduced sustainability regulations in an attempt to reduce the risks associated with biofuels. Producers were then confronted with costs of sustainability certification, in order to access the EU market. Hopes were that sustainably-produced biofuels would be rewarded with higher prices in the EU. Based on a review of recent literature, interviews with traders and price data from Platts, this paper explores whether sustainability premiums emerged and if so, did they represent an attracting feature in the market for sustainable biofuels. This article finds that premiums for ethanol and biodiesel evolved differently between 2011 and 2012, but have been in general very small or inexistent, with certified fuels becoming the new norm in the market. For different reasons, there has been an apparent convergence between biofuel policies in the EU and the US. As market operators perceive a long-term trend for full certification in the biofuels market, producers in developing countries are likely to face additional challenges in terms of finance and capacity to cope with the sustainability requirements.     

Characterization of paper mill sludge as a renewable feedstock for sustainable hydrogen and biofuels production

Paper and pulp mills generate substantial quantities of cellulose-rich sludge materials that are disposed in landfills at a large scale. For sustainability purposes, sludge materials can be bioprocessed to produce renewable fuels and useful chemicals. The enzymatic hydrolysis of cellulose is the process bottleneck that affects the conversion economics directly by using zero-cost raw materials. In order to study and optimize the process, the characteristics of the sludge raw materials should be first evaluated. In this work, sludge samples were obtained from paper mills located at different locations in Wisconsin and Minnesota. Part of the sludge samples was washed (de-ashed) with hydrochloric acid while the other part remained unwashed. The samples were subjected to multiple spectroscopic analyses techniques to evaluate the morphological properties of cellulose fibers and to estimate the total structural carbohydrate content. The results showed that the de-ashing process changed some fiber characteristics and cellulose crystallinity structure in all sludge samples. Sludge sample A (obtained from Kraft pulp and recycled paper mill region) showed a high percentage of fiber, with crystalline cellulose, compared to the other two sludge samples suggesting that sludge A is a valuable source to make value-added products. Aspen Plus mass and energy calculations performed in view of the ‘zero’ cost and the reliable supply of sludge raw materials producing 2 mol H₂/mol glucose. Moreover, the results showed that extracting crystalline cellulose from these sludge samples is more profitable than crystalline cellulose made from the other lignocellulosic feedstocks. The results reported here showed that the utilization of these sludge materials would be an economically attractive and promising alternative for the production of hydrogen.     

Co-pyrolysis of waste plastic and solid biomass for synergistic production of biofuels and chemicals-A review

The amount of plastics disposed from modern lifestyles have increased sharply in recent years. Solid biomass is an abundant energy resource that exists worldwide. Transformation of these waste plastics and solid biomass feedstock mixtures via co-pyrolysis can provide synergistic product enhancement for fuels and value-added products. The produced products can be used as chemicals and pollutant sorbents to foster eco-friendly pathways for waste management and sustainability. Progress into this avenue of waste disposal and energy production is the focus of this review. Properties of characteristic solid feedstock mixtures are discussed with focus on elemental composition, proximate analysis, and heating value. Effective H to C ratio of the different feedstocks is evaluated for asserting the quality of petrochemical equivalent products produced from co-pyrolysis of plastic wastes and biomass. The characteristics of polyethylene terephthalate (PET), high density and low-density polyethylene (HDPE & LDPE), polyvinyl chloride (PVC), polypropylene (PP), polystyrene (PS) and other major plastic waste components are discussed with focus on synergistic effects attainable by co-pyrolyzing them with biomass. State-of-the-art experimental methods for co-pyrolysis investigation are reviewed in detail using TGA, pyrolyzer, fixed bed reactor, fluidized bed reactor, microwave, and multi-step reactors using GC, MS, and FTIR diagnostics. In addition, different catalytic co-pyrolysis reactors are compared and discussed at different ratios of feedstock to catalyst, reactor temperature, and other operational parameters along with an in-depth understanding of several catalytic processing (ZSM-5 based catalyst, transition metal-based catalyst, multipurpose catalysts and ex-situ catalyst) for favorable products yield. Co-pyrolysis of waste plastic and solid biomass mixtures are reviewed for insights into liquid products for fuels and chemicals, as well as yield and composition of gases and solid residues evolved along with surface characteristics of the solid residues obtained from the selected configurations. The challenges and opportunities envisioned for the development in co-pyrolysis of several solid organic waste and plastic feedstock mixtures are also discussed. The goal was to provide favorable feasible pathways for clean and efficient disposal of plastic wastes with the incorporation of waste biomass for enhanced synergistic effects in waste disposal along with the recovery of energy and value-added products.     

Opportunity for profitable investments in cellulosic biofuels

Research efforts to allow large-scale conversion of cellulose into biofuels are being undertaken in the US and EU. These efforts are designed to increase logistic and conversion efficiencies, enhancing the economic competitiveness of cellulosic biofuels. However, not enough attention has been paid to the future market conditions for cellulosic biofuels, which will determine whether the necessary private investment will be available to allow a cellulosic biofuels industry to emerge. We examine the future market for cellulosic biofuels, differentiating between cellulosic ethanol and ‘drop-in’ cellulosic biofuels that can be transported with petroleum fuels and have equivalent energy values. We show that emergence of a cellulosic ethanol industry is unlikely without costly government subsidies, in part because of strong competition from conventional ethanol and limits on ethanol blending. If production costs of drop-in cellulosic biofuels fall enough to become competitive, then their expansion will not necessarily cause feedstock prices to rise. As long as local supplies of feedstocks that have no or low-valued alternative uses exist, then expansion will not cause prices to rise significantly. If cellulosic feedstocks come from dedicated biomass crops, then the supply curves will have a steeper slope because of competition for land.