Strategies for augmenting sugarcane biomass availability for power production in Mauritius

Field biomass productivity has a direct bearing on the electricity production potential of sugarcane bio-energy systems. Inclusion of cane tops and leaves (CT and L) and trash in the fuel chain can potentially boost the field biomass productivity. The results of field assessments carried out in Mauritius indicate that fresh CT and L occur at the rate of 31.3% of that of fresh cane with a moisture content of 69%. Cane trash, with a moisture content of 19.3%, represents 10.2% of fresh cane weight. On a bagasse equivalent basis, the inclusion of CT and L in the fuel chain has the potential to increase bagasse production by a factor of 1.62. The inclusion of trash in the fuel chain can potentially boost bagasse production by a factor of 3.25.     

Power requirements and field performance in harvesting energycane and sugarcane

Energycane is emerging as a candidate bioenergy crop, and it resembles sugarcane in stature and cultivation practices. Preliminary trials indicated that sugarcane billet harvesters have insufficient power to harvest energycane. This study quantified the power requirements of selected harvester components and field performance of harvesters for sugarcane and energycane. The elevator pour rate for energycane was lower (43.3 Mg h⁻¹, wet weight) than for sugarcane (132.7 Mg h⁻¹, wet weight). At the observed pour rates, power consumption of the basecutter, elevator, and the entire harvester was comparable for energycane and sugarcane. However, the power requirements of the chopper were 1.65 times higher for energycane than for sugarcane. Greater stem damage and higher stubble heights were observed for energycane compared to sugarcane. Overflowing of the elevator was observed for energycane because of lower bulk density of the biomass (billets and trash, 143.8 kg m⁻³) compared to sugarcane (predominantly billets, 349.4 kg m⁻³). The field capacity of the harvester for energycane (0.32 ha h⁻¹) was lower than for sugarcane (0.61 ha h⁻¹), and the harvesting cost for energycane (5.91 $ Mg⁻¹) was considerably higher than for sugarcane (1.87 $ Mg⁻¹). Design modifications to the existing sugarcane harvester models would be needed to adapt them to harvest energycane.     

Extended sugarcane biomass utilisation for exportable electricity production in Mauritius

The availability and exportable electricity-production potential of bagasse and sugarcane residues are estimated for various technologies which determine steam production and utilisation at cogenerating sugar factories. Almost 565 kg of fibrous sugarcane biomass (expressed as kilogrammes of bagasse at 50% moisture) are potentially available for exportable electricity production for every tonne of cane milled. A “bagasse proper only” strategy would utilise 28% of the fibrous cane biomass and can potentially produce between 60 to 180 kW h of electricity per tonne of millable cane. Use of cane tops and leaves as a bagasse extender would utilise another 32% of the sugarcane biomass and the electricity output could range between 146 and 401 kW h/t of millable cane. The extreme case where 100% of the fibrous sugar cane biomass is utilised has the potential of producing up to 678 kW h/t of millable cane.     

Potential and costs for the production of electrolytic hydrogen in alcohol and sugar cane plants in the central and south regions of Brazil

This project verified the potential for the production of hydrogen via water electrolysis by using the exceeding electrical energy resultant from alcohol and sugar plants that use sugar cane bagasse as fuel. The studies were carried out in cogeneration plants authorized by the Electrical Energy National Agency (ANEEL). The processing history of sugar cane considered was based on the 2006/2007 harvests. The total bagasse produced, electrical energy generated and exceeding electrical energy in a year were calculated. It was obtained an average energy consumption value of 5.2 kWh Nm⁻³ and the hydrogen production costs regarding the amount of sugar cane processed that ranged from US$ 0.50 to US$ 0.75 Nm⁻³. The results pointed that the costs for the production of hydrogen via the bagasse exceeding energy are close to the production costs that use other sources of energy. As the energy generated from the bagasse is a renewable one, this alternative for the production of hydrogen is economical and environmentally viable.     

Prospects and challenges for green hydrogen production and utilization in the Philippines

The Philippines is exploring different alternative sources of energy to make the country less dependent on imported fossil fuels and to reduce significantly the country's CO₂ emissions. Given the abundance of renewable energy potential in the country, green hydrogen from renewables is a promising fuel because it can be utilized as an energy carrier and can provide a source of clean and sustainable energy with no emissions. This paper aims to review the prospects and challenges for the potential use of green hydrogen in several production and utilization pathways in the Philippines. The study identified green hydrogen production routes from available renewable energy sources in the country, including geothermal, hydropower, wind, solar, biomass, and ocean. Opportunities for several utilization pathways include transportation, industry, utility, and energy storage. From the analysis, this study proposes a roadmap for a green hydrogen economy in the country by 2050, divided into three phases: I–green hydrogen as industrial feedstock, II–green hydrogen as fuel cell technology, and III–commercialization of green hydrogen. On the other hand, the analysis identified several challenges, including technical, economic, and social aspects, as well as the corresponding policy implications for the realization of a green hydrogen economy that can be applied in the Philippines and other developing countries.     

In the path for creating Research-to-business new opportunities on green hydrogen between Italy and Brazil

On September 22, 2021, 5 experts from Brazil and 5 from Italy discussed the future of research-to-business (R2B) cooperation between Italy and Brazil on green hydrogen (H₂) and related technologies. The workshop discussed some priorities of the Brazilian policies and elucidated the strengths and the weaknesses of the biggest economy among the Latin American countries. Because of its territorial and underground resources its social and economic activities, Brazil offers an excellent basin for supporting an H₂-based economy. A well-established connection between Brazilian Universities and EU research organisations already exists in up-to-date research activities and frameworks for grants programmes. Nevertheless, Brazil has some difficulties creating new economies through the industrialisation of research achievements. On the other hand, Italy has a long tradition of creating and exporting technologies because its enterprises are generally prone to creating new business.In this communication, we reported the argued discussions between Brazilian and Italian players on green hydrogen that discussed how to improve the technological interaction between the two countries. This meeting discussed the entire value chain for green hydrogen, from the production to the end-user, and included distribution and commercialisation of green H₂ and related technologies.     

Assessment of sustainable biomass resource for energy use in China

This paper assesses the sustainable biomass resource for energy in China. Assessment has been carried out for the following resources: (i) agricultural residues, (ii) forest residues, and (iii) municipal solid waste (MSW). The potential of each resource is estimated for the base years 2008, 2008, and 2007. The energy potentials of these resources in 2008, 2008, and 2007 are estimated to be 14.7, 3.9, and 0.2 EJ, respectively. The total potential including the energy of 6.4 EJ from the proposed low-input high-diversity (LIHD) grassland biomass on the untilled lands for the base years 1996 is equal to about 30.2% of China’s energy consumption in 2008. Furthermore it is projected that sustainable biomass use for energy will reduce net emissions of green house gases (GHG) of 3276.7 million tonnes, and help in emission-reduction target of China and the world.     

A model to estimate fossil CO2 emissions during the harvesting of forest residues for energy—with an application on the case of chipping

In order to fulfil the targets set by the Kyoto protocol, Belgium established a series of regulations for renewable electricity and put in place a virtual market of green certificates. Their attribution is correlated to the reduction of fossil CO₂ emissions. For biomass, emissions occurring during harvest have a significant impact. This paper proposes a model to estimate CO₂ emissions during this step and applies it to the chipping of poplar forest residues in Southern Belgium. The factors entering into the CO₂ ratio per MWh of biofuel are modelled according to the most influential characteristic of forest residues, i.e. mean initial diameter. The results show that if the diameter of the chipped material increased from 4 to 16 cm (factor 4), the CO₂ emissions per MWh decreased by a factor 7. This stresses the value of modelling the emissions in order to identify the most critical supply routes for attribution and valuation of the green certificates.     

A novel use for sugarcane bagasse hemicellulosic fraction: Xylitol enzymatic production

The excess of sugarcane bagasse (SCB) from the sugar-alcohol industry is considered a by-product with great potential for many bioproducts production. This work had as objective to verify the performance of sugarcane bagasse hemicellulosic hydrolysate (SCBHH) as source of sugars for enzymatic or in vitro xylitol production. For this purpose, xylitol enzymatic production was evaluated using different concentrations of treated SCBHH in the commercial reaction media. The weak acid hydrolysis of SCB provided a hydrolysate with 18 g L⁻¹ and 6 g L⁻¹ of xylose and glucose, respectively. Considering the reactions, changes at xylose-xylitol conversion efficiency and volumetric productivity in xylitol were not observed for the control experiment and using 20 and 40% v.v⁻¹ of SCBHH in the reaction media. The conversion efficiency achieved 100% in all the experiments tested. The results showed that treated SCBHH is suitable as xylose and glucose source for the enzymatic xylitol production and that this process has potential as an alternative for traditional xylitol production ways.     

Prospects for the production of green hydrogen: Review of countries with high potential

The article provides a review of the current hydrogen production and the prospects for the development of the production of “green” hydrogen using renewable energy sources in various countries of the world that are leaders in this field. The potential of hydrogen energy in such countries and regions as Australia, the European Union, India, Canada, China, the Russian Federation, United States of America, South Korea, the Republic of South Africa, Japan and the northern countries of Africa is considered. These countries have significant potential for the production of hydrogen and “green” hydrogen, in particular through mining of fossil fuels and the use of renewable energy sources. The quantitative indicators of the production of “green” hydrogen in the future and the direction of its export are considered; the most developed hydrogen technologies in these countries are presented. The production of “green” hydrogen in most countries is the way to transition from the consumption of fossil fuels to the clean energy of the future, which will significantly improve the environmental situation, reduce greenhouse gas emissions and improve the energy independence of the regions.     

Estimating global production and supply costs for green hydrogen and hydrogen-based green energy commodities

Green energy commodities are expected to be central in decarbonising the global energy system. Such green energy commodities could be hydrogen or other hydrogen-based energy commodities produced from renewable energy sources (RES) such as solar or wind energy. We quantify the production cost and potentials of hydrogen and hydrogen-based energy commodities ammonia, methane, methanol, gasoline, diesel and kerosene in 113 countries. Moreover, we evaluate total supply costs to Germany, considering both pipeline-based and maritime transport. We determine production costs by optimising the investment and operation of commodity production from dedicated RES based on country-level RES potentials and country-specific weighted average costs of capital. Analysing the geographic distribution of production and supply costs, we find that production costs dominate the supply cost composition for liquid or easily liquefiable commodities, while transport costs dominate for gaseous commodities. In the case of Germany, importing green ammonia could be more cost-efficient than domestic production from locally produced or imported hydrogen. Green ammonia could be supplied to Germany from many regions worldwide at below the cost of domestic production, with costs ranging from 624 to 874 $/t NH₃ and Norway being the cheapest supplier. Ammonia production using imported hydrogen from Spain could be cost-effective if a pan-European hydrogen pipeline grid based on repurposed natural gas pipelines exists.     

Recovery rates of logging residue harvesting in Norway spruce (Picea abies (L.) Karsten) dominated stands

A significant amount of logging residues is available for recovery in clear-cut areas. The forest residues’ potential has usually been estimated using biomass models. In Norway spruce (Picea abies) dominated stands, a large share of material is left on site especially due to dropping of needles as residues are left on site to dry in small heaps. In this study, we compared the measured dry weight of logging residues at a power plant with the potential biomass estimations made at a stand level. The study was performed in eight Norway spruce dominated stands, three of which were located in eastern Finland (North Karelia region) with the remainder being in Central Finland. The dry weights of branches, needles and stem tops were estimated using biomass models developed for individual trees by Repola et al. [1]. These dry weights were also compared with Swedish biomass models produced by Marklund [2]. The diameter and tree height information of each harvested tree served as input data in these model-based computations. Tree diameter information was obtained straight from the harvester’s stem value files, while the height information was obtained from models using the data from the stem value files as input. Inventory data before logging was used as a control material for harvester based estimates to spot possible measurement errors on the harvester measurement data. In addition, inventory data were used to get the crown height information, which was not available in the harvester measurement data. It was found that the average recovery rate was approximately 62% when applying Repola’s et al. [1] models and 61% when applying Marklund’s [2] models. However, variation between the logging sites was high. According this study, at least a third of the residues remains on the logging site if they are seasoned during the spring and summertime in small heaps.     

Prototype for the harvesting of cultivated herbaceous energy crops,an economic and technical evaluation

The scope of this study was to evaluate a multi-purpose prototype, the biotriturator, for the harvesting of biomass species cultivated in Northern Italy that would allow the baling of biomass to reduce the handling and storage costs. Harvesting trials were conducted on two herbaceous perennials: giant reed (Arundo donax L.) and switchgrass (Panicum virgatum L.), plus a herbaceous annual fiber sorghum (Sorghum bicolor L. Moench).A technical and economic evaluation compared three harvesting systems in which the biomass was shredded with the biotriturator. The first system was a cutting-shredding-baling in the same operation. The second required two successive steps, the first was cutting and shredding with the biotriturator, the second was baling. The third harvesting system required three successive steps: cutting and shredding with the biotriturator, windrowing with star wheel rakes and baling. While the first and second systems were evaluated on the two perennial crops the third was evaluated on an annual crop.Considering the hectares that can be covered by the biotriturator (170 ha of sorghum and 270 of switchgrass, with an average annual use of 200 h) and the total harvest cost (9.9–12.1 € Mg⁻¹ dry biomass), the harvesting system represents an effective solution for situations like that in Italy, where average farm sizes are small.     

Agricultural residue production and potentials for energy and materials services

Agricultural residues are potentially major contributors of resources for energy and material production. We provide regional and global estimates of the amount of residues from major crops and address the sources of uncertainty in the estimation of the amount of agricultural residues produced globally. Data and methods available currently limit the use of resource estimates for energy or production planning. We develop function based multipliers to estimate the global production of agricultural residues. The multipliers are applied to the production of the, on a global scale, six most important crops: barley, maize, rice, soybean, sugar cane and wheat in 227 countries and territories of the world. We find a global production of residues from these six crops of ${3.7}_{-1.0}^{+1.3}$ Pg dry matter yr⁻¹. North and South America, Eastern, South-Eastern and Southern Asia and Eastern Europe each produce more than 200 Tg yr⁻¹. The theoretical energy potential from the selected crop residues is estimated to 65 EJ yr⁻¹ corresponding to 15% of the global primary energy consumption or 66% of the world's energy consumption for transport. Development towards high input agriculture can increase the global residue production by ∼1.3 Pg dry matter yr⁻¹.     

Prospects of green hydrogen in Poland: A techno-economic analysis using a Monte Carlo approach

The European Commission's plan to decarbonize the economy using innovative energy carriers has brought into question whether the national targets for developing electrolysis technologies are sufficiently ambitious to establish a local hydrogen production industry. While several research works have explored the economic viability of individual green hydrogen production and storage facilities in the Western European Member States, only a few studies have examined the prospects of large-scale green hydrogen production units in Poland. In this study, a Monte Carlo-based model is proposed and developed to investigate the underlying economic and technical factors that may impact the success of the Polish green hydrogen strategy. Moreover, it analyzes the economics of renewable hydrogen at different stages of technological development and market adoption. This is achieved by characterizing the local meteorological conditions of Polish NUTS-2 regions and comparing the levelized cost of hydrogen in such regions in 2020, 2030, and 2050. The results show the geographical locations where the deployment of large-scale hydrogen production units will be most cost effective.     

Integrated harvesting of energy wood and pulpwood in first thinnings using the two-pile cutting method

In order to increase the harvesting volumes of energy wood and pulpwood from first thinnings, harvesting costs have to be reduced significantly. Metsäteho Oy studied the integrated harvesting of pulpwood and energy wood based on a two-pile method, where industrial roundwood (pulpwood) and energy wood fractions are stacked into two separate piles when cutting a first-thinning stand. The productivity and cost levels of the integrated, two-pile cutting method were determined, and the harvesting costs of the two-pile method were compared with those of conventional separate wood harvesting methods.In the time studies, when the size of removal was 50 dm³, the productivity in conventional whole-tree cutting was 6% higher than in integrated cutting. With a stem size of 100 dm³, the productivity of whole-tree cutting was 7% higher than in integrated cutting. The results indicated, however, that integrated harvesting based on the two-pile cutting method enables harvesting costs to be decreased to below the current cost level of separate pulpwood harvesting in first-thinning stands. The greatest cost-saving potential lies in small-sized (d_1.3 = 7-11 cm) first thinnings. The costs of forest haulage after integrated pulpwood and energy wood cutting were higher than those of separate wood harvesting because of lower removals in integrated harvesting. The results showed that when integrated wood harvesting is based on the two-pile cutting method, the removals of both energy wood and pulpwood should be more than 20-25 m³ ha⁻¹ at the integrated harvesting sites in order to achieve economically viable integrated procurement.     

Techno-economic analysis of hydropower based green ammonia plant for urea production in Nepal

This study presents a detailed design, economic, sensitivity and uncertainty analysis for establishing a hydropower based green ammonia plant for use in urea manufacturing in the context of Nepal. The electrolyzer plant for producing hydrogen was simulated with the help of DWSIM while the air separation and ammonia synthesis units were simulated with the help of Aspen Plus for producing 1245 ton/day of ammonia to meet the annual urea demand of Nepal. The capitalized cost of the electrolyzer, air separation and the ammonia synthesis unit of this size were calculated to be 26 million, 7 million and 9 million USD/year respectively. The levelized cost of hydrogen (H₂) and ammonia (NH₃) were found to be 3602 and 826 USD/ton respectively. Economic profitability analysis showed profitability of the plant with ROI and IRR of 38% and 26% respectively with a payback period of three years after operation. The sensitivity analysis showed strong sensitivity on the utility (electricity) cost for both the electrolyzer and ammonia synthesis unit which presents a strong opportunity for Nepal. The levelized cost for H₂ and NH₃ varied between 2845 USD/ton and 4361 USD/ton and 634 USD/ton and 1018 USD/ton respectively for ±30% variation in the utility (electricity) cost. Uncertainty analysis using Monte Carlo method showed the possible minimum levelized cost of H₂ and NH₃ to be 2340 USD/ton and 418 USD/ton respectively. This study illustrates the potential of hydropower based ammonia synthesis for urea manufacturing and provides an important baseline value for policymakers to make investment decisions and to formulate policies for this pathway of production.     

Biomass briquetting and its perspectives in Brazil

A study of the status of biomass briquetting and its perspectives in Brazil was conducted including determination of the availability and characteristics of the agro-residues for briquetting. Wood residues, rice husk and coffee husk were characterized and identified as the more promising agro-residues for briquetting in the short-term in Brazil. A survey was carried out in order to determine the number of briquetting factories in Brazil, and also to determine: used briquetting technologies, briquettes production, briquettes sale prices, the status of biomass briquetting market and its future perspectives.     

Predictive models of forest logging residues in Romanian spruce and beech forests

Forest logging residues are systematically left after exploitation. In Romania, logging residues were traditionally used by population for fuel but have not been considered at large scale for industrialization. The estimation of the resource needed a more accurate assessment and the development of devoted biomass models for large-scale applications. Our study aims at estimating the amount of logging residues based on direct biomass measurements for the two main species of Romanian Carpathian forests: Norway spruce and beech. A country-scale field measurement campaign resulted in the sampling of 100 Norway spruce and 74 beech trees. Models of logging residues biomass were developed for both species. The amount of potential logging residues per tree was greater in beech than in Norway spruce. The models developed, nonlinear by essence, showed that diameter-based equations enable the evaluation of individual logging residues potential. Using tree height as an additional independent variable did not improve the models. The models fitted were applied to yield tables in order to estimate the resource potential in spruce and beech stands for each productivity class, and its dynamic during the production cycle. The calculations proved that the potential amount of logging residue is larger in spruce stands. The amount in beech is very sensitive to the productivity class, unlike in spruce stands. The potential biomass produced during early thinnings is however greater in beech stands than in spruce ones. A more systematic and organized collecting of residues could offer a fast answer to the need of increasing renewable energy share.     

Optimizing peracetic acid pretreatment conditions for improved simultaneous saccharification and co-fermentation (SSCF) of sugar cane bagasse to ethanol fuel

The use of several lignocellulosic materials for ethanol fuel production has been studied exhaustively in the U.S.A.. Strong environmental legislation has been driving efforts by enterprises, state agencies, and universities to make ethanol from biomass economically viable. Production costs for ethanol from biomass have been decreasing year by year as a consequence of this massive effort. Pretreatment, enzyme recovery, and development of efficient microorganisms are some promising areas of study for reducing process costs.Sugar cane bagasse constitutes the most important lignocellulosic material to be considered in Brazil as new technology such as the production of ethanol fuel. At present, most bagasse is burned, and because of its moisture content, has a low value fuel. Ethanol production would result in a value-added product. The bagasse is available at the sugar mill site at no additional cost because harvesting, transportation and storage costs are borne by the sugar production.The present paper presents an alternative pretreatment with low energy input where biomass is treated in a silo type system without need for expensive capitalization. Experimentally, ground sugar cane bagasse is placed in plastic bags and a peracetic acid solution is added to the biomass at concentrations of 0, 6, 9, 15, 21, 30, and 60% w/w of peracetic acid based on oven dried biomass. The ratio of solution to wood is 6:1; a seven day storage period had been used. Tests using hydrolyzing enzymes as an indicator for SSCF have been performed to evaluate the pretreatment efficiency.As an auxiliary method, a series of pre-pretreatments using stoichiometric amounts of sodium hydroxide and ammonium hydroxide based on 4-methyl-glucuronic acid and acetate content in the sugar cane bagasse have been performed before addition of peracetic acid. The alkaline solutions are added to the raw bagasse in a ratio of 17:1 solution to biomass and mixed for 24 hours at room temperature. Biomass is filtered and washed to a neutral pH before the peracetic acid addition.According to enzymatic hydrolysis results, peracetic acid is a powerful chemical for improving enzymatic digestibility in sugar cane bagasse with no need for using high temperatures. Basic pre-pretreatments are helpful in reducing peracetic acid requirements in the pretreatment.