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Electric vehicles (EVs) are considered a substitute for fossil-fueled vehicles due to rising fossil fuel prices and accompanying environmental concerns, and their use is predicted to increase dramatically shortly. However, the widespread use of EVs and their large-scale integration into the energy system will present several operational and technological hurdles. In the energy industry, an innovative solution known as the EVs smart parking lot (SPL) is introduced to handle EV charging and discharging electricity and energy supply challenges. This paper investigates social equity access and mobile charging stations (MCSs) for EVs, where the owner of MCSs is the EV parking lot. Accordingly, a new self-scheduling model for SPLs is presented in this paper that incorporates scheduling of the MCSs as temporary charging infrastructures while considering social equity access and optimizes SPL energy generation and storage schedule. The main objectives of this research are to (i) develop MCSs accessibility measures and quantify the equity impacts of MCSs locations by modeling prioritized demand based on several indices; (ii) determine the optimal set-points of SPL components (i.e., combined heat and power (CHP), photovoltaic system, electrical and heat-energy storage, and MCSs) to manage electrical peak demand and to maximize the economic benefits of SPLs. Results indicate that the proposed demand prioritization function model can meet the required EV charging demands for prioritized events, and the self-scheduling model for SPLs satisfies the charging demand of the EVs in the SPL location. Also, the social equity access to the EV charging stations is satisfied by analyzing the operation of MCSs around the prioritized demand of the prioritized events and social equity access indices.

Abstract Vinasse is a residue from bioethanol production that is produced in large quantities in Brazil and Europe and is applied to fields as a source of plant nutrients (fertirrigation). A side effect of this use is greenhouse gas (GHG) emissions during storage and transport in open channels to fields, and from fertirrigated soils. This study assessed GHG emissions in experiments simulating this vinasse management system, and the potential for reducing emissions of methane (CH4) and nitrous oxide (N2O) from vinasse via anaerobic digestion (AD) in biogas plants. During 21 days’ storage of untreated vinasse, 29% of dry matter (DM) and 40% of volatile solids (VS) were lost, which resulted in cumulative CH4 emissions of up to 43.8 kg CO2eq kg−1 C-vinasse. In contrast, there were no CH4 emissions from AD-treated vinasse (digestate) during storage. GHG emission was related to the biochemical characteristics of the untreated and digested vinasse. The accumulation of oxidised nitrogen (N) compounds was up to four-fold higher in soil amended with untreated vinasse than from digestate-amended soil. The N2O emissions from soil amended with untreated vinasse were also higher than from soil amended with digestate, ranging from 0.173 to 0.193 kg CO2eq m−2 in the former and from 0.045 to 0.100 kg CO2eq m−2 in the latter. Extrapolation of the results to a Brazilian case indicated that AD treatment prior to storage/transport and field application could reduce GHG emissions from the vinasse management chain by at least 48%, with further reductions from the use of biogas in power production.

Distributed cogeneration has played a key role in the implementation of sustainable energy policies for three decades. However, increasing penetration levels of intermittent renewables is challenging that position. The paradigmatic case of West Denmark indicates that distributed operators are capitulating as wind power penetration levels are moving above 25%; some operators are retiring cogeneration units entirely, while other operators are making way for heat-only boilers. This development is jeopardizing the system-wide energy, economic, and environmental benefits that distributed cogeneration still has to offer.The solution is for distributed operators to adapt their technology and operational strategies to achieve a better co-existence between cogeneration and wind power.Four options for doing so are analysed including a new concept that integrates a high pressure compression heat pump using low-temperature heat recovered from flue gasses in combination with an intermediate cold storage, which enables the independent operation of heat pump and cogenerator.It is found that an electric boiler provides consistent improvements in the intermittency-friendliness of distributed cogeneration. However, well-designed heat pump concepts are more cost-effective than electric boilers, and in future markets where the gas/electricity price ratio is likely to increase, compression heat pumps in combination with intermediate thermal storages represent a superior potential for combining an intermittency-friendly pattern of operation with the efficient use of electricity in heating and cooling production.

Electrolysis occupies a dominant position in the long-term application of hydrogen energy, as it can use the power surplus directly from renewable energies to produce hydrogen. Alkaline water electrolysis (AWE) is a mature and reliable technology standing out from other types of electrolysis because of its simplicity and low cost. Several multiphysics processes inside the AWE cell, such as the electrochemical, thermal, and fluidic processes. Developing the multiphysics model to quantify the relationship between these physics fields is essential for cell design. This paper establishes a three-dimensional numerical model to consider the quantitative relationship between the electrochemical process and fluidic process inside the cell of industrial AWE. The model considers the structural design of industrial AWE equipment, revealing that the shunting current effect introduced by the structure design cannot be ignored in the model. The simulation results present that the multiphysics model considering the bubble effect can estimate the current–voltage (I-V) characteristic curve more accurately with a relative error smaller than 5%, especially at a current density higher than 2500 A/m2. The model established is supposed to advance the development of water electrolysis models and guide the electrolyzer design of industrial AWE cell.

Abstract The necessity of increasing the methane productivity of manure based biogas plants has triggered the application of anaerobic digestion to the separated solid fraction of manure, with the challenge that its high lignocellulosic fibers content is difficult to digest and thus makes anaerobic digestion process slow and economically unfavourable. In the present study, aqueous ammonia soaking (AAS) was investigated as a pretreatment method to increase methane potential of swine manure fibers. 3 days at 22 °C were the optimal conditions among the ones tested (1, 3, and 5 days at 22 and 55 °C) for increasing the methane potential of manure fibers. AAS pretreatment exhibited a significant effect on methane production rate and potential. It was found that AAS for 3 days at 22 °C resulted at a 30–80% and 178% increase in methane yield from digested and raw manure fibers, respectively. Batch anaerobic digestion of AAS-treated digested manure fibers could stand loadings as high as 100 g TS/l inoculum with no inhibition problems. Enzymatic hydrolysis tests applied to AAS-pretreated fibers resulted to 80% and 65% hydrolysis efficiency of glucan and xylan compared to insignificant numbers for non-pretreated fibers confirming thus that AAS effect on methane yield and production rate is due to the facilitation of hydrolysis step of anaerobic digestion process. This is attributed to AAS directly affecting the disintegration step and thus releasing carbohydrates, which can be further hydrolyzed, from the lignocellulosic matrix.

Optimization of biogas production from olive-mill wastewater (OMW) was attempted by codigesting with diluted poultry-manure (DPM) at mesophilic conditions. A series of laboratory experiments were performed in continuously-operating reactors, fed with mixtures of OMW and DPM at various concentrations. It was concluded that codigestion of OMW with DPM is possible without any dilution of OMW or addition of any chemicals. Biogas production was slightly higher when OMW was added to DPM up to a critical concentration (about 40%, expressed as contribution of OMW to the volatile solids of the mixture), after which production is decreased. The results were further verified by scaling up to a continuously-operating pilot-plant reactor digesting DPM, and confirmed that no negative impact was imposed by adding OMW up to the above critical value.

Abstract Determination of biochemical methane potential (BMP) by fermentation tests is time-consuming and costly, and therefore not useful for operators of full-scale biogas digesters. A great advantage of NIRS in determining BMP is the reduction in measurement time from at least one month for chemical determination to a couple of minutes for production of near infrared spectroscopy (NIRS) spectra. An innovative NIRS method that can be used as an alternative to current BMP tests was developed in this study. We tested the Partial Least Squares (PLS) model for a rapid determination of BMP using NIRS by applying a series of pre-processing methods with caution. A total of 88 plant biomass samples of a wide variety were used for model prediction. The standard error of the best PLS model was 37 CH 4 NL kg −1 VS, where BMP of the test set was between 136.2 and 477.9 CH 4 NL kg −1 VS. Coefficient of determination ( R 2 ) and residual prediction deviation (RPD) were 0.84 and 2.49, respectively. This shows that the new NIRS model is moderately successful in application and could be an alternative modern tool to overcome the problems of current BMP methods.

Renewable-energy sources and energy efficiency are important elements in Danish Energy Policy. The implementation of wind power and combined heat- and power production (CHP) have already led to substantial fuel savings, and both technologies are intended for further expansion in the coming decade. Today, approximately 50% of both Danish electricity and heat demand are produced via CHP, and more than 15% of the electricity demands are produced by wind turbines. However, the electricity production from these technologies is linked to fluctuations either in wind or in heat demands rather than fluctuations in demand for electricity. Consequently, the electricity production exceeds the demand during certain periods and creates a problem of “surplus production”. This paper discusses and analyses different national strategies for solving this problem.   Udgivelsesdato: SEP-NOV