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Brazil has an increasing production of municipal solid waste that, allied to the current waste management system, makes the search for alternatives of energy recovery essential. Thus, this work aims to study the incineration of municipal solid waste and the electricity production through steam cycles evaluating the influence of municipal solid waste composition. Several scenarios were studied, in which it was assumed that some fractions of municipal solid waste were removed previously. The municipal solid waste generated in Santo André city, São Paulo State, Brazil, was adopted for this study. Simulation results showed that the removal of organic matter and inert components impacts advantageously on the cycle performance, improving their parameters in some cases; in addition, there is the possibility of reusing the separated fractions. The separation of some recyclables, as plastic material, showed disadvantages by the reduction in the electricity generation potential owing to the high calorific value of plastics. Despite the high energy content of them, there are other possible considerations on this subject, because some plastics have a better recovery potential by recycling. [ABSTRACT FROM AUTHOR]

Abstract: A techno-economic analysis is presented, of the potential for data-centres and fibre optic networks to drive investment in geothermal resources. The concept is attractive because of data-centres’ stable demand for electricity and refrigeration at a scale of <5MW e , corresponding to the output of a single well doublet; because the cost of establishing a fibre optic link is an order of magnitude less than augmenting an electricity transmission network; and because it offers an opportunity for geothermal systems to compete with the retail price of electricity. A comparison of energy delivery outcomes was performed for both engineered geothermal systems (EGS) and hot sedimentary aquifer (HSA) reservoirs to identify the minimum conditions that could make the concept economically attractive. For the high temperature EGS, a single and dual pressure binary organic Rankine cycle (EGS-ORC, EGS-2×ORC), a single stage flash (EGS-flash) and a hybrid flash-binary system (EGS-hybrid) were studied. The HSA system investigated the direct use (HSA-DU) of the geo-fluid in an absorption chiller for refrigeration and the use of coincidental natural gas resources to deliver electricity via an internal combustion engine. The technical performance of these systems was assessed for a range of well-head pressure (EGS only) and geo-fluid flow rate scenarios. The economic performance of the combined set of investments in optical fibre and energy infrastructure was examined by estimating the expected internal rate of return (E[IRR]). The HSA-DU option yielded an E[IRR] of 14%, following the installation of energy capacity equivalent to the output of one well-doublet assuming the displacement of the Australian retail price of electricity; and 12% for the US retail price. In comparison, the EGS-hybrid was found to have an E[IRR] of 8%, if the Australian retail price were displaced and 4% if the US retail price were displaced. The EGS-flash, ORC and 2×ORC scenarios were found to be progressively less attractive than the EGS-hybrid. To identify the conditions under which the concept could satisfy commercial hurdle rates, the sensitivity of the E[IRR] was investigated for the cost of an optical fibre link; the EGS resource depth; the retail price of electricity displaced; and a data-centres’ energy consumption profile. Credits for CO2 emissions abatement at $23/ton were found to have only a marginal influence on the economic performance of the EGS and HSA scenarios examined. [Copyright &y& Elsevier]

The U.S. Department of Energy and Idaho National Laboratory are developing a next-generation nuclear plant, very high temperature gas-cooled reactor (VHTR) to serve as a demonstration of state-of-the-art nuclear technology. The purpose of the demonstration is twofold: (a) efficient low-cost energy generation and (b) hydrogen production. While hydrogen production and advanced energy cycles are still in the early stages of development, research toward coupling VHTR, electrical generation, and hydrogen production is under way. This technical note includes the coupling of a VHTR with a power conversion unit. One of the power conversion configurations in the coupled plant is a combined Brayton cycle and Rankine cycle. This configuration uses a mixture of helium and nitrogen that allows the use of modified gas-turbine technology, including the same design techniques, material, and testing facilities used for conventional air gas turbines, to be used for the VHTR electricity production application. Exhaust heat from the turbine is transferred to a heat exchanger where the transferred heat is used to generate steam for a Rankine cycle. The study was focused on the verification of the steam generator model and comparisons of results from HYSYS and RELAP5-3D. This technical note concludes that the overall results are in good agreement despite the differences in size of different flow regime lengths. The overall heat transfer behavior deviated within ~2.1%, and exit temperatures and temperature drops across the steam generator also show reasonable agreement with <5.1% difference between the two methods. [ABSTRACT FROM AUTHOR]

The article presents information on the advanced nuclear helium reactor/solid oxide fuel cell concept which can help mitigate the problems being faced by the nuclear power industry and informs that U.S. Nuclear Navy will adopt this concept for its future nuclear vessels. Utilization of helium reactor technology combined with a solid oxide fuel cell is more safer and efficient. The proposed helium reactor technology operates on the Brayton Cycle which scores over the Rankine Cycle of the current pressurized water reactor technology.