• Energy Research
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The design and assessment of net-zero buildings commonly focus exclusively on the operational phase, ignoring the embodied environmental impacts over the building life cycle. An analysis is presented on the consequences of integrating embodied impacts into the assessment of the environmental advantageousness of net-zero concepts. Fundamental issues needing consideration in the design process - based on the evaluation of primary energy use and related greenhouse gas emissions - are examined by comparing three net-zero building design and assessment cases: (1) no embodied impacts included, net balance limited to the operation stage only; (2) embodied impacts included but evaluated separately from the operation stage; and (3) embodied impacts included with the operation stage in a life cycle approach. A review of recent developments in research, standardization activities and design practice and the presentation of a case study of a residential building in Norway highlight the critical importance of performance indicator definitions and system boundaries. A practical checklist is presented to guide the process of incorporating embodied impacts across the building life cycle phases in net-zero design. Its implications are considered on overall environmental impact assessment of buildings. Research and development challenges, as well as recommendations for designers and other stakeholders, are identified.

The Municipal Solid Waste Management (MSWM) sector has developed considerably during the past century, paving the way for maximum resource (materials and energy) recovery and minimising environmental impacts such as global warming associated with it. The current study is assessing the historical development of MSWM in the municipality of Aalborg, Denmark throughout the period of 1970 to 2010, and its implications regarding Global Warming Potential (GWP(100)), using the Life Cycle Assessment (LCA) approach. Historical data regarding MSW composition, and different treatment technologies such as incineration, recycling and composting has been used in order to perform the analysis. The LCA results show a continuous improvement in environmental performance of MSWM from 1970 to 2010 mainly due to the changes in treatment options, improved efficiency of various treatment technologies and increasing focus on recycling, resulting in a shift from net emission of 618 kg CO(2)-eq.tonne(-1) to net saving of 670 kg CO(2)-eq.tonne(-1) of MSWM.

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.

Most agricultural wastes are valuable resources that should be recycled and used for industrial purposes and for energy recovery. If unsuitably handled and managed, agricultural wastes become an environmental problem and a hazard for human and animal health. The management of agricultural wastes is considered as an important target in the global waste management strategy. Any kind of waste can become a hazard factor for humans, animals, and vegetation, if its concentration in the environment is excessive. Water quality is affected if manure runs into water streams as a result of inappropriate and excessive land application, spillage, overflow, or deliberate dumping. The nutrients and organic matter contained in manure can pollute the ground water by leaching or by runoff when manure is applied at rates exceeding crop fertilizer requirements. In such cases, arrangements should be made to move excess manure to other cropland, or to use it for other purposes. The wastes of agricultural origin can be contaminated with crop and animal disease-causing organisms and chemicals and with chemical and physical contaminants. Some of the main issues related to optimum utilization of agricultural wastes refer, therefore, to the control of chemical pollutants (organic and inorganic), breaking the chain of diseases transmission by the inactivation of pathogens and other biological hazards, and the removal of physical impurities.

The utilization of combined heat and power (CHP) units is a key way to enhance renewable energy accommodation. However, carbon emissions of CHP challenge the pollution and economic optimization of integrated energy system (IES). To tackle this challenge, we propose a novel model and optimal dispatch for CHP with power-to-gas (P2G) and carbon capture system (CCS), which solves the problems of the carbon source required for P2G and the CHP's carbon emissions by the optimal dispatch in IES. The model takes the CHP, P2G, and CCS as a whole system. The operation rule of the model is developed, and its coupling characteristics of electric power, heat power, gas power and carbon are analyzed. Correspondingly, the optimization strategy of IES considers the proposed model and carbon trading mechanism. The optimal dispatch model of IES is established and solved by YALMIP, and GUROBI. Our method is verified by simulation. Compared with other conventional models, the accommodation capacity of renewable energy with the proposed method is enhanced, and the carbon emissions and operating costs of IES are also reduced.

The energy consumption and greenhouse gases emissions in natural gas city gate stations are important issues in the natural gas industry. In order to improve efficiency, have a cleaner environment and achieve economic benefits, the present study aims to propose an optimal system for the indirect water bath heaters in natural gas city gate stations. The optimization procedure is carried out by designing a control system to gain an eligible discharge temperature for the heater based on the gas entry conditions to the city gate station. The controller calculates the temperature of hydrate formation in terms of passing gas pressure and gives this information to the torch of the heater for regulating fuel consumption. A comprehensive study is accomplished based on energy, exergy, environment and economic analysis for different pressure reduction stations. The results indicate that employing the proposed system decreases the amount of fuel consumption and greenhouse gases emissions along with increasing system efficiency. Analyzing the results reveals that using the proposed system leads to a maximum of 28.54% relative increment in the heater efficiency compared to the conventional system (at this condition, the heater efficiency of the conventional and proposed system is η = 36.12% to η = 46.43%, respectively). Furthermore, with choosing a heater with a capacity of 100,000 SCMH, it is possible to reduce the pollutants emissions and total costs down to 142.6 tons per year and 3,671,000 $ per year, respectively.

Combined heat and power (CHP) as well as intermittent renewable energy sources (RES) are key elements in future cleaner electricity production systems. This article presents solutions which will integrate fluctuating renewable electricity supplies, such as wind power, into electricity systems using small and medium-sized combined heat and power plants (CHP). Such solutions call for a new organisational setup of partnerships and software tools. The software tools will allow the new partnerships to offer services which are currently only offered by big power plants to electricity markets. The article presents recent results of the development and implementation of such partnerships and focuses on the methodologies and computer tools necessary in order to allow the partnerships to optimise their behaviour on the market. The use of such tools and methodologies makes groups of small CHP plants able to replace large power stations and, at the same time, allows for the integration of a higher share of RES in the electricity supply, resulting in a decrease in both fossil fuels and CO2 emissions.

SUMMARY.The policy of joint implementation is emerging as a new strategy for implementing global environmental aims, especially with regard to regulating the climate change process, where emission source and sink countries agree to develop a joint program upon a mixed argument of partnership and cost-effectiveness. Pros and cons have emerged during the development of this system.Costa Rica is the first country, together with Norway, to launch such a program jointly, and Costa Rica is also the first country developing Carbon Tradable Offset bonds to be sold on the world market as a new commodity. It is hoped that this initiative will help the country and its inhabitants to create better living conditions and economic growth; however, this new institutional transformation and international acceptance of this new instrument are only just beginning to develop.This, therefore, provides a very interesting field for research from a distinct perspective. We chose to start searching for positive or negative impact...