Efficiency Of Electricity Production Research Articles

Utilisation of biomass gasification by-products for onsite energy production.

Small scale biomass gasification is a sector with growth and increasing applications owing to the environmental goals of the European Union and the incentivised policies of most European countries. This study addresses two aspects, which are at the centre of attention concerning the operation and development of small scale gasifiers; reuse of waste and increase of energy efficiency. Several authors have denoted that the low electrical efficiency of these systems is the main barrier for further commercial development. In addition, gasification has several by-products that have no further use and are discarded as waste. In the framework of this manuscript, a secondary reactor is introduced and modelled. The main operating principle is the utilisation of char and flue gases for further energy production. These by-products are reformed into secondary producer gas by means of a secondary reactor. In addition, a set of heat exchangers capture the waste heat and optimise the process. This case study is modelled in a MATLAB-Cantera environment. The model is non-stoichiometric and applies the Gibbs minimisation principle. The simulations show that some of the thermal energy is depleted during the process owing to the preheating of flue gases. Nonetheless, the addition of a secondary reactor results in an increase of the electrical power production efficiency and the combined heat and power (CHP) efficiency.

Comparing the Life Cycle Energy Consumption, Global Warming and Eutrophication Potentials of Several Water and Waste Service Options

Managing the water-energy-nutrient nexus for the built environment requires, in part, a full system analysis of energy consumption, global warming and eutrophication potentials of municipal water services. As an example, we evaluated the life cycle energy use, greenhouse gas (GHG) emissions and aqueous nutrient releases of the whole anthropogenic municipal water cycle starting from raw water extraction to wastewater treatment and reuse/discharge for five municipal water and wastewater systems. The assessed options included conventional centralized services and four alternative options following the principles of source-separation and water fit-for-purpose. The comparative life cycle assessment identified that centralized drinking water supply coupled with blackwater energy recovery and on-site greywater treatment and reuse was the most energy- and carbon-efficient water service system evaluated, while the conventional (drinking water and sewerage) centralized system ranked as the most energy- and carbon-intensive system. The electricity generated from blackwater and food residuals co-digestion was estimated to offset at least 40% of life cycle energy consumption for water/waste services. The dry composting toilet option demonstrated the lowest life cycle eutrophication potential. The nutrients in wastewater effluent are the dominating contributors for the eutrophication potential for the assessed system configurations. Among the parameters for which variability and sensitivity were evaluated, the carbon intensity of the local electricity grid and the efficiency of electricity production by the co-digestion with the energy recovery process were the most important for determining the relative global warming potential results.

Utilisation of waste heat from the power plant by use of the ORC aided with bleed steam and extra source of heat

Utilization of waste heat recovered from the exhaust gases of the power generation unit by means of ORC (organic Rankine cycles) installation is considered. The waste heat is available in the form of a stream of hot water having temperature of 90 °C in the amount of 200 MWt. To increase evaporation temperature of ORC working fluid the heat of steam from the extraction points from the low-pressure part of steam turbine is used. Subsequently additional heat from compressor cooling of the carbon dioxide capture and storage installation is also considered as a way to provide extra heat to the ORC. Thermodynamic analysis of the supercritical plant with and without incorporation of ORC was accomplished using a commercial code Aspen Plus. For ORC considered were four working fluids such as n-pentane, ethanol, R236ea and R245fa. Determined were major parameter describing the operational features of the hybrid power plant such as the change of the unit power, efficiency and increase of electricity production of the hybrid installation consisting of the reference plant and the ORC. The highest thermal efficiency of the ORC is obtained in the case ethanol as working fluid, whereas the highest amount of electricity is produced in the case of R236ea.

Performances of microbial fuel cells fed with rejected wastewater from BioCH4 and BioH2 processes treating molasses wastewater

ABSTRACTAn integrated process involving conventional anaerobic digestion and microbial fuel cells (MFCs) has attracted attention recently to produce sustainable energy and to treat wastewater efficiently. To evaluate the possibility of CH4-producing process (BioCH4)-MFC or H2-producing process (BioH2)-MFC integrating systems, the MFC performances were investigated using rejected wastewater from a BioCH4 reactor (RWCH4) or BioH2 reactor (RWH2) treating molasses wastewater. When RWCH4 or RWH2 was fed into a single-chamber MFC reactor (designated as AC-MFCCH4 and AC-MFCH2, respectively) at different hydraulic retention times (HRT) of 1–7 d, both MFC systems showed maximum electricity production efficiencies at a HRT of 3 d. In the AC-MFCCH4 reactor, the average current density and average power density were 60.5 mA·m−2 and 8.8 mW·m−2, respectively. The AC-MFCH2 reactor generated an average current density of 71.4 mA·m−2 and an average power density of 12.0 mW·m−2. The COD removal rates were 45.7% in the AC-MFCCH4 reactor and 90.3% in the AC-MFCH2 reactor. There were no significant differences of the eubacterial community structures between the MFC systems, where Proteobacteria was remarkably dominant in both MFC systems. However, the archaeal community structures were significantly different where Methanothrix (89.3%) was remarkably dominant in the AC-MFCCH4 system, while Methanothrix (52.5%) and Methanosarcina (33.5%) were abundant in the AC-MFCH2 system. These findings demonstrate that the utilization of MFCs after the BioCH4 or BioH2 process is advantageous for energy recovery as well as COD removal from molasses wastewater.

Effect of turbine materials on power generation efficiency from free water vortex hydro power plant

The objective of this research was to study the effect of turbine materials on power generation efficiency from the water free vortex hydro power plant made of steel and aluminium. These turbines consisted of five blades and were twisted with angles along the height of water. These blades were the maximum width of 45 cm. and height of 32 cm. These turbines were made and experimented for the water free vortex hydro power plant in the laboratory with the water flow rate of 0.68, 1.33, 1.61, 2.31, 2.96 and 3.63 m3/min and an electrical load of 20, 40, 60, 80 and 100 W respectively. The experimental results were calculated to find out the torque, electric power, and electricity production efficiency. From the experiment, the results showed that the maximum power generation efficiency of steel and aluminium turbine were 33.56% and 34.79% respectively. From the result at the maximum water flow rate of 3.63 m3/min, it was found that the torque value and electricity production efficiency of aluminium turbine was higher than that of steel turbine at the average of 8.4% and 8.14%, respectively. This result showed that light weight of water turbine can increase the torque and power generation efficiency.

Experimental Determination of Optical and Thermal Properties of Semi-transparent Photovoltaic Modules Based on Dye-sensitized Solar Cells

The demand for energy efficiency of buildings and on-site electricity production is rising. Building integrated photovoltaic can provide a part of the electricity demand. Many studies are related to the module efficiency. However, architectural integration, optical and thermal properties also require attention. Semi-transparent modules are especially interesting for architectural integration in the glazed part of the façade. Dye sensitized solar cells, offering color and semi-transparency, are in the process of market introduction. However, dye-sensitized solar cells are fragile and there are not many examples of architectural integration due to the technical challenge of introducing these cells in a glazing. A glazing containing colored photovoltaic modules could be used to design an active façade.In order to determine the thermal behaviour of the building, the precise optical and thermal properties of the used materials need to be known. Performances of semi-transparent photovoltaic modules based on dye-sensitized solar cells were investigated. These modules come from the same manufacturer, using the same technology. However, they differ in terms of shades and nuances. Common practice is to indicate optical properties at normal angle of incidence. Yet, for most latitudes, the properties for a large range of angles of incidence are more relevant. Therefore, the spectral transmittance and the reflectance were measured at 12 angles of incidence ranging from 0° to 75°. From these data, the solar direct transmittance τe, the solar direct reflectance ρe and the visible transmittance τv and selectivity were calculated.The solar gain factor was determined on a prototype double glazing under illumination with a solar simulator by measuring the temperatures of the external and inner surface of the product. Combined with the values of absorptance obtained from the transmittance and reflectance values, this measurement allows us to determine the internal heat transfer coefficient qi and thus the solar gain factor of the double glazing (also called total energetic transmittance or g-value).Final performance of a façade containing these modules will depend on the composition of the double glazing in which they will be laminated. The performance of the module itself will help to determine the best composition for each climate. For instance, a solar protection coating may be needed. The modules can be laminated to a glass pane and then be assembled in a double glazing. Therefore the architectural integration is facilitated and compatible with existing façade systems. In highly glazed building, a part of the façade could then be a photovoltaic façade and deliver a fraction of the energy demand while providing colourful options to enhance the aesthetic of the building.

Effect of Transition Temperature on Efficiency of PV/PCM Panels

Due to the fact that efficiency of PV panels decreases by approximately 0.5%/K, possibilities to stabilize the temperature on the panel's surface are considered in this paper. The aim of this investigation is to determine the transition temperature of PCM layer that allows avoiding rapid temperature fluctuations on the PV back surface. To meet the stated goal, dynamic simulations of thermal and electrical performance of PV/PCM panels were carried out using ESP-r software.Based on the obtained results, it can be concluded that additional PCM layer on the back side of PV panel can effectively increase the efficiency of electricity production with PCM transition temperature about 20°C.

The Effects of Coal Switching and Improvements in Electricity Production Efficiency and Consumption on CO2 Mitigation Goals in China

Although the average CO2 emission for a person in China is only about 1/4 that of a person in the US, the government of China still made a commitment to ensure that CO2 emissions will reach their peak in 2030 because of the ever-increasing pressure of global warming. In this work, we examined the effects of coal switching, efficiency improvements in thermal power generation and the electricity consumption of economic activities on realizing this goal. An improved STIRPAT model was developed to create the scenarios. In order to make the estimated elasticities more consistent with different variables selected to construct the formulation, a double-layer STIRPAT model was constructed, and by integrating the two equations obtained by regressing the series in each layer, we finally got the equation to describe the long-run relationship among CO2 emissions (Ic), the share of coal in overall energy consumption (FMC), coal intensity of thermal power generation (CIp) and electricity intensity of GDP (EIelec). The long term elasticities represented by the equation show that the growth of CO2 emissions in China is quite sensitive to FMC, CIp and EIelec. After that, five scenarios were developed in order to examine the effects of China’s possible different CO2 emission reduction policies, focusing on improving FMC, CIp and EIelec respectively. Through a rigorous analysis, we found that in order to realize the committed CO2 emissions mitigating goal, China should obviously accelerate the pace in switching from coal to low carbon fuels, coupled with a consistent improvement in electricity efficiency of economic activities and a slightly slower improvement in the coal efficiency of thermal power generation.

Coating-type three-dimensional acetate-driven microbial fuel cells

This study uses sodium acetate as fuel to construct bioelectricity in coating-type three-dimensional microbial fuel cells anode. The coating-type three-dimensional anode was constructed using iron net as structural support, adhering a layer of carbon felt as primary coating and using carbon powder and 30% PTFE solution mixture as coating. The efficiency of electricity production and wastewater treatment were analyzed for the three-dimensional acetate-fed (C2H3NaO2) microbial fuel cells with the various ratio of the coating mixture. The results showed that the efficiency of electricity production was significantly improved when using the homemade coating-type microbial fuel cells anode compared with the one without coating on the iron net, which the apparent internal resistance was decreased by 59.4% and the maximum power density was increased by 1.5 times. It was found the electricity production was greatly influenced by the ratio of the carbon powder and PTFE in the coating. The electricity production was the highest with apparent internal resistance of 190 Ω, and maximum power density of 5189.4 mW m(-3) when 750 mg of carbon powder and 10 ml of PTFE (i.e., ratio 75:1) was used in the coating. With the efficiency of electricity production, wide distribution and low cost of the raw materials, the homemade acetate-fed microbial fuel cells provides a valuable reference to the development of the composition microbial fuel cell anode production.

Accessement of Wind Power Potential in Katsina State from Meteorological Data

For the need to exploit and optimize the use of all available sources of energy in providing available power supply for industrial and economic development of the rural communities. Nigerian government has initiated some programs in 2005 to look into the potentialities of wind as a means for power generation. In order to complement this effort, surface synoptic wind speed observation data (2008-2013) from NOAA-NCDC for Nigeria was used to analyze the wind characteristics of katsina (13.007’ N; 07.661’ E; Altitude 05060.0 m; Air density 1.18 kg/m3). A modified form of an empirical relation for calculating wind power density and energy with height was proposed and uses to analyze site wind profile and the efficiency of electricity production for power generation in Katsina. The measurements have been performed for a period of 6years from January to December in order to cover all seasonal variation of the wind condition. The results showed that katsina falls under Class 7 of the International system of wind classification by recording annual values of mean wind speed extrapolated at 50m height to be in the range of 3.5-5.5 m/s, average power density of 160.6 W/m 2 and an average of 29.6Kwh/year of energy can be produced for each month of a year respectively, making the site very suitable for wind turbine applications for power generation.

Process aspects in combustion and gasification Waste-to-Energy (WtE) units

The utilisation of energy in waste, Waste to Energy (WtE), has become increasingly important. Waste is a wide concept, and to focus, the feedstock dealt with here is mostly municipal solid waste. It is found that combustion in grate-fired furnaces is by far the most common mode of fuel conversion compared to fluidized beds and rotary furnaces. Combinations of pyrolysis in rotary furnace or gasification in fluidized or fixed bed with high-temperature combustion are applied particularly in Japan in systems whose purpose is to melt ashes and destroy dioxins. Recently, also in Japan more emphasis is put on WtE. In countries with high heat demand, WtE in the form of heat and power can be quite efficient even in simple grate-fired systems, whereas in warm regions only electricity is generated, and for this product the efficiency of boilers (the steam data) is limited by corrosion from the flue gas. However, combination of cleaned gas from gasification with combustion provides a means to enhance the efficiency of electricity production considerably. Finally, the impact of sorting on the properties of the waste to be fed to boilers or gasifiers is discussed. The description intends to be general, but examples are mostly taken from Europe.

The influence of the size of the CHP (combined heat and power) system integrated with a biomass fueled gas generator and piston engine on the thermodynamic and economic effectiveness of electricity and heat generation

This paper analyzes the possibility and the cost of using gas from biomass gasification in the production of electricity and generation of heat using a piston engine in which the power in the supplied biomass is no more than 50 MW. A mathematical model that allows for thermodynamic and economic analysis was designed. The input data regarding the gas generator and the process gas were collected in real experiments on the research installation. Electricity and heat production efficiencies and the electric and heat power of the system were primarily used as indicators of the thermodynamic effectiveness. For the economic analysis, discount methods were adopted that consider the legal and economic environment of such investments. Given the assumptions, the analysis shows that positive economic indicators can characterize the considered systems. The work also included sensitivity analysis of change of the selected characteristic quantities on the evaluation indices. The economic viability of such systems is strongly influenced by many factors, mainly price of fuel and green certificates. When the price of fuel is higher than 9.62 €/GJ or the price of certificates lower than 26.75 €/MWh the NPV (net present value) and NPVR (net present value ratio) indices do not reach positive values for any size of installation.

The Impact of Liberalization on the Production of Electricity in Japan: Stochastic Frontier Analysis

This study aims to measure the impact of liberalization on the efficiency of electricity production in Japan using Stochastic Frontier Analysis (SFA). In addition, this study also aims to examine whether or not economies of scale exist in the electricity generation sector and the transmission sector, and whether or not economies of scope exist between electricity generation and transmission. Since 1995, liberalization of the electricity market in Japan has been phased in and regulations on entry have been relaxed three times. One motivation for these regularity changes has been to improve the efficiency of electricity production by introducing competition. Using a panel data set on the nine main power companies in Japan over the period 1970-2010, estimates of fixed-effects and stochastic frontier models of the cost function are obtained and compared. Estimates of the cost function show that liberalization has improved cost efficiency when both frontier models and non-frontier models are estimated. Estimates of the fixed-effects model are used to calculate economies of scale and economies scope because the data support the fixed-effects model. Economies of scope are found to exist for all nine power companies, while overall economies of scope declined in the 1970s and have improved little by little since the 1980s.

Feasibility of Solid Fuel CLC Plant Investment in the Future Energy Systems Including High Share of Solar and Wind

It is predicted that share of solar and wind energy will be increased in the future energy systems. The competitiveness of these technologies is further improved if strict climate policy and for example consequent high costs for CO2 emissions or emission performance standards will be applied, leading to increased electricity prices. This will bring demand for more flexible large scale energy production and/or energy storages due to the intermittency of solar and wind energy production at different timeframes, for example between day and night and different seasons. In addition, it is notable that future integration of electricity markets and grids will expand the area impacted by intermittent renewables. Possible and predicted high economic value for CO2 emissions and emission standards are also a rationale for the development of CCS technologies. After the investment, variable operational expenditures of solar and wind power are low in comparison with other low carbon technologies and therefore these plants are utilised before others. This will impact also on the utilisation rates of plants equipped with CCS. In this paper techno-economic analyses of industrial scale Chemical Looping Combustion (CLC) power plant are presented in different market situations. Feasibility of CLC investment and the utilization of such plant is investigated and compared to oxyfuel and air combustion references in energy system which contain high share of solar and wind power. The CC-Skynet™ toolkit, created by VTT during Finnish CCS projects, enables comparison of economic feasibility of different CCS technologies in different market scenarios, including varying prices for electricity, CO2 emission allowances, fuels, plant utilisation rates, etc. In addition, in the case of CLC, sensitivity analysis are possible also for example for prices of different oxygen carriers, investments etc. The toolkit is highly versatile but it does not include modelling of any physical phenomena which are required as inputs. The economics of CCS are evaluated from investor's (local energy company) point of view including the effects on the existing energy system. Effect of CCS on greenhouse gas (GHG) emissions and operation economics of the CCS cases are compared to the reference energy system with varying parameters of operation. Electricity production efficiency of CLC power plant is higher than in power plants based on solid fuel and other CO2 capture technologies, because CLC does not require large air separation unit or solvent regeneration. Higher net efficiency in electricity production by CLC results lower specific production costs in comparison to other CCS technologies. This probably leads to higher utilisation rate for CLC which is important for example in terms of payback time for the investment or required break- even price for CO2 emissions. Results show that CLC may be more competitive in comparison to other CCS technologies due to higher electrical efficiency. Economic feasibility is dependent on several factors which are uncertain in the case of future energy system. However, it is probable that high CO2 prices lead to increased electric price such that electrical efficiency has large dominant effect on feasibility. Investment costs do not dominate in comparison between CCS technologies. Feasibility of CCS is different between geographical locations due sensitivity of transport and storage.

Variant Analysis of the Structure and Parameters of SOFC Hybrid Systems

The paper presents a variant analysis of the structure of SOFC hybrid system. The systems are divided into two gropus: atmospheric and pressurized. The main parameter of such systems are indicated and commented. The comparison of various configurations is shown in a view of efficiency obtained. The ultra high efficiency (65% HHV, 72% LHV) of electricity production seems to be possible by systems like these.

Efficiency and sustainability analysis of biogas and electricity production from a large-scale biogas project in China: an emergy evaluation based on LCA

Abstract Biogas, which plays an important role in energy production and environmental protection, is developing at a large-scale in China to accommodate the modernization and fast pace that the Chinese agricultural sector has experienced over the last decade due to the rapid development of large-scale farms and stockbreeding in recent years. This study introduced life cycle assessment (LCA) into emergy evaluation to analyze each production step of a large-scale biogas project in China and to compare the economic and ecological performance of the biogas production system (BPS) and biogas plus electricity production system (BEPS) of a project. Our findings indicated that the energy return rate of biogas production system was lower than that of traditional energy production system currently. Emergy efficiency of the large-scale biogas project was 77.9–95.6% higher than that of the small-scale biogas project. The emission mitigation intensity was also 125.7–172.7 times higher for the large-scale plant than for the small-scale plant. The sustainability of the large-scale biogas project was 1.16–11.87 times higher than that of other renewable energy production systems, but 66.0–74.4% lower than that of the small-scale biogas project due to an insufficient amount of raw material inputs and the higher cost of equipment investment in anaerobic fermentation and electricity generation steps. Moreover, the economic and ecological performance of BEPS was worse than that of BPS. We suggested that the sustainability of the large-scale biogas project would be improved by measures: first, providing a suitable quantity and ratio of raw materials; second, reducing the equipment investment of fermentation and the generator; third, using the electricity from the biogas system.

Microbial biofuel cell operating effectively through carbon nanotube blended with gold–titania nanocomposites modified electrode

In this study, we have explored the possibility to fabricate microbial biofuel cell operating with carbon nanotube–gold–titania nanocomposites (CNT/Au/TiO2) as anode modifier. The results demonstrate that the CNT/Au/TiO2 electrode could be utilized as a new and effective microbial fuel cell (MFC) anode, which integrate the advantages of relevant nanocomposites such as high conductivity, high specific surface area, and easy adsorption of the microorganism. It is evident that the three-dimensional network nanostructures of CNT/Au/TiO2 are propitious to improve the relevant anode surface area and thus the adsorption of the microorganism, which can efficiently promote the electronic transfer rate between the probe and electrode. Meanwhile, it is noted that open circuit voltage of the CNT/Au/TiO2 nanocomposites modified carbon paper anode increased to 0.77V, which is more than twice that of the open circuit voltage obtained with bare carbon paper anode (0.36V). And the MFC equipped with CNT/Au/TiO2 nanocomposites modified carbon paper anode delivers a maximum power density of 2.4mWm−2, which is three times larger than that obtained from the MFC with bare carbon paper. This observation illustrates that the CNT/Au/TiO2 nanocomposites modified electrode could obviously increase the relevant electron transfer rate and promote the electron exchange at electrode surface, which could readily provide enhanced stability and relatively long life-span to facilitate the high electricity production efficiency, suggesting its promising prospect application in MFCs.

Deregulation or Governmental Intervention? A Counterfactual Perspective on China's Electricity Market Reform

AbstractThe long‐standing severe power shortage in China has provoked much debate on whether China should further promote market‐oriented electricity reform. The present paper addresses this issue by analyzing the impacts of deregulation of the electricity generation sector and retailing activities on other sectors, the macroeconomy and electricity users. A counterfactual scenario analysis is used based on a simplified computable general equilibrium framework. We find that deregulation can significantly improve the efficiency of electricity production, increase employment and enhance household welfare. These nontrivial findings can help to resolve many controversies about governmental intervention during China's economic transition. Our findings have two implications relating to policy feasibility and applicability; that is, competition in the electricity retail market should be phased in, and the necessary arrangements for unemployment in incumbent firms should be considered.

The Theoretical Modelling and Optimization of a 10 KWP Photovoltaic Thermal System for a Student Hostel in Singapore

Current commercial photovoltaic (PV) conversion efficiency (flat plate modules) is about 6--20%, depending on the materials used for the module construction. Since only a small fraction (<10%) of the incident solar energy is reflected and/or transmitted, a large fraction of the solar radiation is converted into heat. If this heat can be harvested as well, the overall energy efficiency of such an integrated photovoltaic thermal (PVT) hybrid system will be greatly improved. At the same time, pumping water through the PV modules will cool (if Twater < Tmodule) the solar cells and improve their electricity production efficiency. This article describes the design and numerical simulation of a PVT system for producing electricity and hot water in a student hostel in Singapore. The nominal electrical power output is 10 kWp (kilowatt peak). Thermal models were developed based on basic energy balance equations and average climatic conditions for Singapore over a typical year were used. A survey of the hot water usage pattern over a typical week was carried out and used in the simulation. The optimum mass flow rate in the collectors is found to be 0.039 kg/(s m2) and the optimum storage tank capacity for hot water is 2500 kg for a showering load of around 6000 kg/day. The average thermal and electrical efficiency of the system are 43% and 12%, respectively. The requirement of auxiliary electric energy for water heating is predicted to be reduced by 94%.

Effects of steam pretreatment and co-production with ethanol on the energy efficiency and process economics of combined biogas, heat and electricity production from industrial hemp

BackgroundThe study presented here has used the commercial flow sheeting program Aspen Plus™ to evaluate techno-economic aspects of large-scale hemp-based processes for producing transportation fuels. The co-production of biogas, district heat and power from chopped and steam-pretreated hemp, and the co-production of ethanol, biogas, heat and power from steam-pretreated hemp were analysed. The analyses include assessments of heat demand, energy efficiency and process economics in terms of annual cash flows and minimum biogas and ethanol selling prices (MBSP and MESP).ResultsProducing biogas, heat and power from chopped hemp has the highest overall energy efficiency, 84% of the theoretical maximum (based on lower heating values), providing that the maximum capacity of district heat is delivered. The combined production of ethanol, biogas, heat and power has the highest energy efficiency (49%) if district heat is not produced. Neither the inclusion of steam pretreatment nor co-production with ethanol has a large impact on the MBSP. Ethanol is more expensive to produce than biogas is, but this is compensated for by its higher market price. None of the scenarios examined are economically viable, since the MBSP (EUR 103–128 per MWh) is higher than the market price of biogas (EUR 67 per MWh). The largest contribution to the cost is the cost of feedstock. Decreasing the retention time in the biogas process for low solids streams by partly replacing continuous stirred tank reactors by high-rate bioreactors decreases the MBSP. Also, recycling part of the liquid from the effluent from anaerobic digestion decreases the MBSP. The production and prices of methane and ethanol influence the process economics more than the production and prices of electricity and district heat.ConclusionsTo reduce the production cost of ethanol and biogas from biomass, the use of feedstocks that are cheaper than hemp, give higher output of ethanol and biogas, or combined production with higher value products are primarily suggested. Further, practical investigations on increased substrate concentration in biogas and ethanol production, recycling of the liquid in anaerobic digestion and separation of low solids flows into solid and a liquid fraction for improved reactor applications deserves further attention.