Comparative Techno-economic Analysis Research Articles

A Comparative Techno-Economic Analysis of Organic and Conventional Nigella sativa L. Crop Production in Greece

Nigella sativa L. is considered to be an alternative crop offering innovative and high-quality products. A case study was implemented on an existing farm to determine the prospects of N. sativa production in Greece and to assess the economic outcomes of the cultivation of this crop under organic and conventional cropping systems. The total production cost of organic N. sativa seeds was 6.09 €/kg, while the cost of conventional seeds was 4.77 €/kg. The organic and conventional N. sativa seed selling prices were 17.04 and 12.01 €/kg, respectively. Moreover, the financial performance of farm is better after the introduction of N. sativa crop under organic cropping system, where the net profit increased by 63.8% compared to the initial profit of the farm, while the increase in the conventional was less at 49.2%. N

A Comparative Techno-Economic Analysis of Different Desalination Technologies in Off-Grid Islands

Freshwater in off-grid islands is sourced from rain, groundwater, or mainland imports, which are unreliable, limited, and expensive, respectively. Sustainable freshwater generation from desalination of abundant seawater is another alternative worth exploring. Model-based techno-economic simulations have focused on reverse osmosis desalination due to its low energy consumption and decreasing costs. However, reverse osmosis requires frequent and costly membrane replacement. Other desalination technologies have advantages such as less stringent feedwater requirements, but detailed studies are yet to be done. In this work, a techno-economic comparison of multi-effect distillation, multi-stage flash, mechanical vapor compression, and reverse osmosis coupled with solar photovoltaic-lithium ion-diesel hybrid system was performed by comparing power flows to study the interaction between energy and desalination components. Optimization with projected costs were then performed to investigate future trends. Lastly, we used stochastic generation and demand profiles to infer uncertainties in energy and desalination unit sizing. Reverse osmosis is favorable due to low energy and water costs, as well as possible compatibility with renewable energy systems. Multi-effect distillation and multi-stage flash may also be advantageous for low-risk applications due to system robustness.

Multi-Scale Analysis of Integrated C1 (CH4 and CO2) Utilization Catalytic Processes: Impacts of Catalysts Characteristics up to Industrial-Scale Process Flowsheeting, Part II: Techno-Economic Analysis of Integrated C1 Utilization Process Scenarios

In the second part of this paper (Part II), the potentials and characteristics of an industrial-scale Oxidative Coupling of Methane (OCM) process integrated with CO2-hydrogenation, ethane dehydrogenation, and methane reforming processes are highlighted. This novel process concept comprises a direct conversion of methane to ethane and ethylene and further conversion of the resulted carbon dioxide and remaining unreacted methane, respectively, to methanol and syngas. In this context, the selected experimental results of the catalytic CO2-hydrogenation to methanol reported in the first part of this paper (Part I), were utilized to represent its industrial-scale performance. The experimental results of the mini plant-scale operation of an OCM reactor and CO2 removal units along with the experimental and industrial data available for representing the operation and performance of all process-units in the integrated process structures were utilized to perform a comparative techno-economic environmental analysis using Aspen-Plus simulation and an Aspen Economic Process Analyzer. The experimental procedure and the results of testing the sequence of OCM and CO2-hydrogenation reactors are particularly discussed in this context. It was observed that in the sequential operation of these reactors, ethylene will be also hydrogenated to ethane over the investigated catalysts. Therefore, the parallel-operation of these reactors was found to be a promising alternative in such an integrated process. The main assumptions and the conceptual conclusions made in this analysis are reviewed and discussed in this paper in the light of the practical limitations encountered in the experimentations. In the context of a multi-scale analysis, the contributions of the design and operating parameters in the scale of catalyst and reactor as well as in the process-scale represented by analyzing the type and operating conditions of the downstream-units and the process-flowsheets on the economic and environmental performance of the integrated process structures were studied. Moreover, the economic impacts of extra ethylene and methanol produced respectively via the integrated ethane dehydrogenation and CO2-hydrogenation sections were analyzed in detail. The required capital investment was found to be even smaller than the yearly operating cost of the plant. The environmental impacts and sustainability of the integrated OCM process were found to be enhanced by securing a minimum direct CO2-emission and energy-efficient conversion of CO2 and the unreacted CH4, respectively, to methanol and syngas. Besides producing such value-added by-products, efficient operation of downstream process-units was secured by minimizing the energy usage and ethylene losses. Under the considered conditions in this analysis, the specifications of the finally selected integrated OCM process structure, providing the fastest return of investments (less than 8 years), are highlighted.

Grid-independent PV system hybridization with fuel cell-battery/supercapacitor: Optimum sizing and comparative techno-economic analysis

In this paper, a comparative techno-economic assessment of two different hybrid energy storage system configurations viz. fuel cell-battery energy storage system (FC-BESS) and fuel cell-supercapacitor energy storage system (FC-SCESS), incorporated in a grid-independent photovoltaic (PV) based power system for a residential building is performed. Firstly, load for the residential building is calculated and accordingly optimum sizing of various constituents of the PV system is obtained using HOMER. Subsequently, the economic analysis for both configurations is performed in terms of cost of energy, net present cost, initial cost, and operating and maintenance cost. The simulation results of HOMER suggest that for grid-independent PV based power system, FC-SCESS configuration is better from the economic point of view. As HOMER’s inability to perform detailed technical analysis, MATLAB/Simulink models of both configurations are built and comparative analysis is performed in terms of different technical aspects such as active power balance, DC link voltage (VDC) regulation etc. From MATLAB results, it is observed that FC-SCESS configuration performs better by regulating the VDC more effectively and thereby helps maintain the active power balance between various constituents of the power system. Furthermore, feasibility of hardware implementation of each configuration is verified using hardware-in-loop real-time digital simulator.

Design and Comparative Techno-Economic Analysis of Two Solar Polygeneration Systems Applied for Electricity, Cooling and Fresh Water Production

Two solar polygeneration systems were investigated for electricity, cooling and fresh water production. In the first scenario (LFPS), the linear Fresnel (LF) solar field was used as thermal source of the Organic Rankine Cycle (ORC), absorption chiller (ACH) and multi-effect desalination (MED) unit. In the second scenario (PVPS), photovoltaic (PV) panels were considered as the electricity source to supply the electricity load that is required for lighting, electrical devices, compression chiller (CCH) and reverse osmosis (RO) units. A techno-economic comparison was made between two scenarios based on the land use factor (F), capacity utilization factor (CUF), payback period, levelized cost of electricity (LCE), levelized cost of cooling energy (LCC) and levelized cost of water (LCW). The calculations were conducted for four different locations in order to determine the effect of solar radiation level on the LCE, LCC and LCW of systems in both scenarios. The results showed that the LCE and LCW of PVPS is lower than that of LFPS and the LCC of LFPS is lower than that of PVPS. Also, the payback period of LFPS and PVPS systems are obtained as 13.97 years and 13.54 years, respectively, if no incentive is considered for the electricity sale.

Biogas based polygeneration plant options utilizing dairy farms waste: A Bolivian case

This study presents a comparative techno-economic feasibility analysis for two polygeneration plant solutions, applied to low-income dairy farms in Bolivia. The first option considers an internally fired microturbine (IFMT) and, the second, an internal combustion engine (ICE). They are integrated with an absorption refrigeration system and a fertilizer dryer. Biogas, produced with farms waste, fuels these power generators. The levelized costs of biogas for cooking, electricity, cooling and fertilizers were determined. The cost of biogas, for both options, was found to be 0.020 USD/kWh, which is lower than the subsidized price of LPG. The most competitive cost of electricity was determined for the ICE plant option; it was found to be 0.082 USD/kWh and is lower than the subsidized cost of fossil fuel-based electricity. The cost of cooling was found to be around 0.082 USD/kWh, which is slightly higher than the cost of cooling supplied by using grid electricity. In a realistic scenario, the shorter payback period was found to be 4.4 years for the ICE plant option. From this, the ICE-based plant was found as the most feasible option. Additionally, if no subsidies are applied to the fossil fuel-based services, the proposed polygeneration systems are a highly competitive alternative.

Comparative techno-economic analysis of algal biofuel production via hydrothermal liquefaction: One stage versus two stages

Hydrothermal liquefaction is a promising process for conversion of algae to bio-oil that is especially suitable for the high moisture content of algal feedstock. A two-stage sequential hydrothermal liquefaction (SEQHTL) alternative was developed to facilitate production of co-products in addition to bio-oil at reduced temperatures and pressures compared with conventional one-stage direct hydrothermal liquefaction (DHTL). In this study, Aspen simulation and comprehensive techno-economic analysis were conducted for both SEQHTL and DHTL processes to assess their performance when used to convert the same algal strain (Chlorella sorokiniana) to bio-oil intermediates. The technical and economic evaluation also included the subsequent upgrading of the bio-crude to biofuels via hydrotreatment. The minimum fuel selling price for SEQHTL and DHTL was $1.61/L, and $2.10/L, respectively. The milder operating conditions of SEQHTL process resulted in both reduced capital and operating cost. The total installed cost of the facilities for hydrothermal processing 1215 metric tons/day of algae was $89 million for SEQHTL and $112 million for DHTL. A higher energy returned on energy invested was realized by SEQHTL (6.73) owing to its greater amount of fuel blendstock produced and less energy required for production in comparison with DHTL (5.31). The sensitivity analysis showed that improving the yield and quality of both the bio-oil and co-products, as well as increasing the feed concentration, may lead to a much lower production cost. This study provided new insights of hydrothermal liquefaction process design with highlighting the potential of recycling of nutrient streams and fractionation algal biomass at milder operating conditions.

Comparative technoeconomic process analysis of industrial-scale microencapsulation of bioactives in cross-linked alginate

Calcium alginate microencapsulation is a popular laboratory technique, but implementing the traditional external gelation process in the food industry requires a series of costly unit operations. Alternatively, a consolidated process accomplishes alginate cross-linking in situ during spray-drying to form cross-linked alginate microcapsules (‘the CLAMs process’). This work conducted technoeconomic analysis in SuperPro Designer to compare the process economics of both microencapsulation systems, initially for encapsulating emulsified fish oil. At all production scales examined, the capital investment and annual operating cost were lower for the CLAMs process. The CLAMs process' economic advantage stemmed from reducing the number of unit procedures. Upon modifying the models for microencapsulating hydrophilic cargo (e.g. enzymes, vitamins, microbial concentrates), the CLAMs process remained favorable at all cargo material costs and cargo loadings examined. This work demonstrates the utility of technoeconomic analysis for evaluating microencapsulation processes and may justify applying the CLAMs process at the industrial scale.

Comparative techno-economic analysis of oil-based and coal-based ethylene glycol processes

Traditional ethylene glycol production is heavily dependent on oil. In the background of richness of coal and scarcity of oil, more and more coal to ethylene glycol (CTEG) plants have been successfully operated to relieve the shortage of ethylene glycol in China. Thus, it is an urgent work to answer the following question: between oil-based and coal-based ethylene glycol routes, which is the better choice? A comparative techno-economic analysis of oil-based and coal-based ethylene glycol processes is conducted to identify the opportunities and challenges of CTEG industry. Results show that CTEG process has prominent advantage in total production cost, which is about 16% lower than that of oil to ethylene glycol (OTEG) process. However, it is criticized by many shortcomings, such as higher energy consumption, lower exergy efficiency, higher total capital investment, and higher CO2 emissions compared with OTEG process. Facing with these restrictive problems of CTEG process, several possible measures are proposed to improve the technoeconomic performance. In addition, the effects of several key economic parameters on the competitiveness of OTEG and CTEG processes are investigated and compared. Results show that the development of CTEG industry has a cost advantage and is promising due to the abundant reserve and low-price of coal in China. However, it should reduce the energy consumption and emissions before the large-scale development of CTEG industry.

Hydrogenation and TMP Coupling Process: Novel Process Design, Techno-Economic Analysis, Environmental Assessment and Thermo-Economic Optimization

The production of high-quality gasoline and light olefins harbors tremendous industrial and economic significance. In this paper, a novel process is proposed for converting inferior light cycle oil (LCO) into propylene and ethylene, as well as the high-octane-number gasoline with rich BTX contents. The unique feature for the novel process is the integration of LCO selective hydrogenation unit with two-stage riser catalytic cracking. For comparative techno-economic and environmental analyses, typical two-stage riser catalytic cracking for maximizing the propylene (TMP) process and conventional residue fluid catalytic cracking (RFCC) process models are developed. Based on the detailed process modeling and simulation results, techno-economic evaluation and environmental assessment have been performed. It is found that the novel process, coupled hydrogenation and TMP process, has a favorable impact on both the economic and environmental performances. The HTMP process has the highest net present value that means 2.13 times of TMP and 4.94 times of RFCC process, and reduces 15.26 t CO2 equivalents per million dollars output value compared with the TMP process. Moreover, we conduct the thermo-economic optimization for the HTMP process based on the exergy analysis. The result shows that full scale hydrogenation and recycling of hydro-LCO and increasing of the second riser outlet temperature could significantly increase the profitability of this novel process.

Comparative techno-economic analysis of biofuel production through gasification, thermal liquefaction and pyrolysis of sugarcane bagasse

Techno-economic models for three plants in Queensland, Australia using thermochemical conversion of 10 tonnes per hour of sugarcane bagasse to liquid crude biofuels were developed. Thermochemical conversion was chosen to maximise yield from second-generation feedstock. The process models highlighted the differences in mass and energy flows of each process. Factory models were generated reflecting current methods in heat and material recovery. Liquefaction generated the highest amount of product per kg feed, followed by pyrolysis and gasification. Key parameters affecting plant economics were also highlighted. Based on net present values, the profitability was ranked as follows: pyrolysis > liquefaction > gasification. The plants were all sensitive to product price, thermochemical conversion ratio and refining conversion ratio, thereby affecting profitability the most. Conversion ratios sharply affect the minimum selling price of products, but attenuated by high product volumes. Varying tax rates and capital costs do not affect the minimum selling price as much as conversion ratios, therefore, incentives around improving conversion rates and increasing product volume are recommended.

A comprehensive assessment of alternative absorber-exchanger designs for hybrid PVT-water collectors

In this paper, 26 alternative absorber-exchanger designs for hybrid PV-Thermal (PVT) solar collectors are proposed and compared against a reference-case, commercial sheet-and-tube PVT collector. The collectors involve different geometric design features based on the conventional sheet-and-tube configuration, and also on a newer flat-box structure constructed from alternative polymeric materials with the aim of maintaining or even improving heat transfer and overall (thermal and electrical) performance while achieving reductions in the overall weight and cost of the collectors. The main contributions of this research include: (i) the development and validation of a detailed 3-D computational finite-element model of the proposed PVT collector designs involving multi-physics processes (heat transfer, fluid dynamics and solid mechanics); (ii) results from comparative techno-economic analyses of the proposed PVT designs; and, (iii) further insights from thermal stress and structural deformation analyses of the proposed collectors, which are crucial for ensuring long lifetimes and especially important in the case of polymeric collectors. The results show that, in general, the flat-box designs (characterised by a thin absorber plate) are not sensitive to the flow-channel size or construction material, at least within the range of investigation. A PVT collector featuring a polycarbonate (PC) flat-box design with 3 × 2 mm rectangular channels appears to be a particularly promising alternative to commercial PVT collectors, achieving a slightly improved thermal performance compared to the reference case (with a 4% higher optical efficiency and 15% lower linear heat-loss coefficient), while also lowering the weight (by around 9%) and investment cost (by about 21%) of the collector. The structural analysis shows that the maximum von Mises stress experienced in the absorber-exchanger of the PC flat-box collector is considerably lower than that in the copper sheet-and-tube collector (<13% vs. 64% of the material’s yield stress), which is attributed to the larger thermal expansion of the PC absorber-exchanger, that leads to lower stresses. Therefore, the proposed PC flat-box design is not expected to suffer higher strains than the commercially-available PVT collector.

Co2 Capture in the Cement and Iron and Steel Sectors: A Homogenised Techno-Economic Review

The need to get affordable products is a global concern and a techno-economic evaluation is important to identify the most cost-effective CO2 capture routes. To date, the economic performance of CO2 capture in the iron and steel and cement sectors has been investigated in various studies, although many of them are outdated or fail to look into the assumptions underlying the costs. An updated and transparent techno-economic comparison is required. The objective of this work is to do a consistent comparative techno-economic analysis of CO2 capture technologies and configurations for the iron and steel and cement sectors. Economic data from the literature have been assessed through the standardization of key input parameters such as plant size, capacity factor, CO2 emissions, and economic factors, such as inflation rate, plant lifetime, labour costs and energy prices. The calculation of the CAPEX and OPEX was done through a homogeneous common method and key economic performance metrics such as the cost of CO2 captured, CO2 avoided and steel and cement manufacturing are used to evaluate the economic performance.

Financial viability of biofuel and biochar production from forest biomass in the face of market price volatility and uncertainty

A comparative techno-economic analysis of two different thermochemical biomass conversion pathways was conducted to examine the effects of fuel price and other variables on project financial performance. Monte Carlo simulation was used to quantify the effects of uncertainty and volatility of ten critical variables: biofuel, biochar and feedstock prices, discount rate, capital investment, labor cost, loan terms, feedstock drying, and biofuel and biochar conversion rates. Market prices for biofuel and biochar have the largest impact on net present value (NPV) of any variable considered, due in part to the high levels of uncertainty associated with future prices of both. Across the ranges of input values for these variables in simulation analysis, hearth-based pyrolysis biochar production had the highest likelihood of profitability with a mean NPV of $41.5 million and only 20% of outcomes resulting in a net loss, while 68% of outcomes for auger-based biochar-biofuel coproduction represented a financial loss, including a mean NPV of -$24.2 million. However, when additional revenue from Renewable Identification Numbers (RINs) credits generated by biofuel production is considered, financial outcomes of biochar-biofuel coproduction improve to 50% likelihood of experiencing a net loss. Findings of the very strong impact of market prices on financial outcomes, relative to other important technical and economic variables, can inform effective targeting of future renewable energy policy, as well as the design of future techno-economic analyses, which do not currently focus on the effect of market prices on profitability.

The development of a techno-economic model for the extraction, transportation, upgrading, and shipping of Canadian oil sands products to the Asia-Pacific region

The diversification of Canadian oil sands markets is imperative for the long-term economic growth of oil sands products. To ensure a competitive place in the global market, supply chain costs of oil sands must be as low as possible. This study conducts a comparative techno-economic analysis of potential pathways for the transportation of Canadian oil sands products (synthetic crude oil and diluted bitumen) to seaport destinations in the Asia-Pacific region. We developed data-intensive techno-economic models to estimate total supply chain costs from the production site in Alberta to ports in China, Japan, and India. Four pathways were developed using production (steam assisted gravity drainage), transportation (production-upgrader-port in Vancouver), upgrading, and shipping operations. A sensitivity analysis was conducted to identify cost ranges with their occurrence probability measures and evaluate the effect of key parameters for each stage of operation. Supply chain costs (C$ per barrel of bitumen) to China, Japan, and India are from 61–87, 60–86, and 62–90, respectively. Overall supply chain costs of dilbit (a blend of bitumen and diluent) and synthetic crude oil (SCO) are affected most by production and upgrading costs. The production and upgrading costs are influenced by capital cost, while pipeline lifetime and capacity highly impact transportation (pipeline) and shipping costs, respectively. The developed models can be used to predict total supply chain costs of different pathways in Canadian oil sand markets.

An Operator view on the Introduction of White Boxes into Optical Networks

Hardware and software disaggregation is a recognized strategy for achieving efficiency and cost reduction within datacentre warehouse. More recently this approach has been applied to high-bandwidth inter-datacenter connectivity at the transport layer. Telecom Operators look with great interest at this approach which promises savings that could make the difference in years of ever decreasing margins on revenues. This paper presents and analyzes how disaggregation models in the wavelength division multiplexing (WDM) transport layer could replace the established aggregated model based on mono-vendor systems. Three optical disaggregation models are presented implying different levels of involvement of the telecom operator in WDM system design, assembly, and integration. The impact on the network lifecycle of each model is then analyzed with particular reference to the roles of the operator, the equipment vendors, and the system integrator. The issue of organizational changes and heavy redefinition of processes is addressed and a comparative techno economic analysis is also offered.

Comparative techno-economic analysis of single-step and two-step biodiesel production with supercritical methanol based on process simulation

Two alternative processes for biodiesel production from used/waste cooking oil, the single-step supercritical transesterification and the two-step process consisting of oil hydrolysis and subsequent supercritical methyl esterification, were designed and simulated using the Aspen Plus 8.8 software and assessed from a techno-economic point of view. Detailed operating conditions, material and energy flows, and equipment designs were provided for biodiesel plants with 15,000t and 30,000t annual inlet capacities. Results revealed that both technologies offer a techno-economically viable solution for biodiesel production from low quality feedstocks such as used cooking oil. The two-step process requires milder operating conditions, lower investment and overall production costs per unit of biodiesel produced, however, it has higher process energy requirements. Total capital investments for a 15,000t capacity plant which applies the single- or the two-step process were estimated as 6.1 million EUR or 5.8 million EUR, respectively, whereas the production cost of biodiesel are estimated as 0.824EUR/kg and 0.786EUR/kg for the single- and two-step processes, respectively (at used cooking oil price of 0.500EUR/kg). Higher plant capacities have lower production and capital costs per unit of biodiesel output. Supercritical transesterification should lead to a clean, flexible and modular method to process used cooking oil for the production of a more valuable product.

Manufacturing Ethylene from Wet Shale Gas and Biomass: Comparative Technoeconomic Analysis and Environmental Life Cycle Assessment

This paper presents comparative technoeconomic and environmental analyses of three ethylene manufacturing pathways based on ethane-rich shale gas, corn stover, and corn grain. The shale-gas-based pathway includes two processing steps, namely, shale gas processing to produce ethane and ethane steam cracking to manufacture ethylene. The two biomass-based pathways also contain two processing steps each, namely, bioethanol production via fermentation and ethylene manufacturing via bioethanol dehydration. A distributed–centralized processing network that consists of distributed ethane/bioethanol production and centralized ethylene manufacturing is employed for each of the three pathways. Detailed process simulation models are developed for major processing steps, and the three pathways are then modeled on five different ethylene production scales. On the basis of the detailed mass and energy balances and life cycle inventory results, we conduct technoeconomic and life cycle analyses to systematically compare t...

A comparative technoeconomic analysis of pathways for commercial electrochemical CO2 reduction to liquid products

Electrochemical reduction of CO2 to fuels and chemicals is currently a focus of significant research effort as a technology that can simultaneously mitigate greenhouse gas emissions while storing renewable electricity for use on demand. Herein, the economics of CO2 reduction to select liquid products is analyzed.

CO2-free coal-fired power generation by partial oxy-fuel and post-combustion CO2 capture: Techno-economic analysis

Among the carbon capture and storage (CCS) technologies suitable for power generation plants, partial oxy-combustion coupled with post combustion CO2 capture is gaining interest, since such a hybrid configuration could allow to reduce the size and enhance the performance of post-combustion CO2 capture by operating combustion with air enriched with oxygen and reducing the dilution of flue gas. Moreover, partial oxy-combustion is a potential candidate for the retrofit of existing steam plants because it could be based on an almost conventional boiler and requires a smaller CO2 capture section.This work presents the results of a comparative techno-economic analysis of a 1000 MWth partial oxy-combustion plant based on an ultra-supercritical pulverized coal combustion power plant integrated with a post-combustion CO2 capture system and geological storage in saline aquifer. In particular, plant performance is assessed by using simulation models implemented through Aspen Plus 7.3 and Gate Cycle 5.40 commercial tools, whereas economic performance are evaluated on the basis of the expected annual cash flow. The analysis shows that, for new plants, this hybrid approach is not feasible from the economic point of view and full oxy-combustion potentially remains the most profitable technology even if, in the short-term period, the lack of commercial experience will continue to involve a high financial risk.