scholarly journals Municipal Solid Waste as a valuable recycled asset for small-scale electricity production in rural communities

2019 ◽  
pp. 92-106
Author(s):  
Valter Silva ◽  
João Cardoso ◽  
Paulo Brito ◽  
Luís Tarelho ◽  
José Luz

Municipal solid waste provides an opportunity for electricity production. This strategy provides the rural communities a potential waste-to-energy opportunity to manage its costly residues problem, turning them into a valuable recycled asset. To address this issue, a techno-economic study of an integrated system comprising gasification of Acacia residues and Portuguese Municipal Solid Waste (PMSW) with an Internal Combustion Engine-Generator (ICEG) for electricity generation at small-scale (100 kW) was developed. Current studies only devote attention to biomass residues and do not explore MSW potential to eschew biomass supply shortage. Conventional systems are generally part of biomass supply chains, limiting flexibility and all year operation for their operators. Experimental data was gathered at a downdraft gasifier to provide a clear assessment of particle and tar concentration in the syngas and levers conditioning a satisfactory ICE operation. Once the potential of using Acacia residues and PMSW has been proven during gasification runs testing, and validation, a set of new conditions was also explored through a high-fidelity CFD model. We find that residues blends have the highest potential to generate high-quality syngas and smallest exposure to supply disruption. Despite both substrates showing potential at specific conditions, they also present individual drawbacks which will be best mitigated by executing a hybrid supply comprising the mix of substrates. An economic model coupling the financial indicators of net present value (NPV), internal rate of return (IRR) and the payback period (PBP) considering a project lifetime of 25 years was developed. Cost factors include expenses with electricity generation, initial investment, amortizations and operation and maintenance (containing fuels costs). Revenues were estimated from electricity generated and sales to the national grid. A sensitivity analysis based on the Monte Carlo method was used to measure the economic model performance and to determine the risk in investing in such venture. The risk appraisal yielded favorable investment projections, with an NPV reaching positive values, an IRR superior to the discount rate and PBP lower than the project life span. This work allowed to confirm the positive effect of the generation of energy from downdraft gasification plants on a small-scale. Regardless of the project’s feasibility, the economic performance depended to a large extent on the electricity prices which present considerable variability and are subject to political decisions.

2019 ◽  
Vol 37 (6) ◽  
pp. 631-642 ◽  
Author(s):  
Ana Carolina Medina Jimenez ◽  
Reynaldo Palacios- Bereche ◽  
Silvia Nebra

In Brazil, in 2016, 196,050 tonnes day-1 of municipal solid waste (MSW) were collected, which means a waste generation of 1.035 kg per capita per day. Only 59.1% of the waste has adequate destination in sanitary landfills, whereas the remaining 40.9% has inadequate destination in controlled landfills and open dumps (ABRELPE, 2018). Among all the states in the country, the State of São Paulo has the biggest per capita generation: 2.290 kg. Today, the only waste destination practiced in the country is deposition in landfills, but other possibilities can be considered. Among thermal treatment routes, the gasification of MSW is an interesting alternative to be studied, because of its versatility and relatively low emissions. The aim of this work is to evaluate the potential of electricity generation through MSW gasification in Santo André city, Brazil, comparing three waste gasification technologies: TPS Termiska Processer AB, Carbogas and Energos. These alternatives have operated commercially for a few years, and data are available. Specific characteristics of each technology were taken into account, such as the reactor type and fuel properties. For the electricity production scheme, two energy conversion systems were assumed: an internal combustion engine and a steam power cycle. From the process parameters adopted, the results showed that Carbogas technology, coupled to internal combustion engines, presents the highest efficiency of electricity generation (30%) and also the lowest cost of electrical energy produced (US$65.22 MWh-1) when Santo André’s gate fee is applied.


Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3097 ◽  
Author(s):  
J. R. Copa ◽  
C. E. Tuna ◽  
J. L. Silveira ◽  
R. A. M. Boloy ◽  
P. Brito ◽  
...  

The focus of this study is to provide a comparative techno-economic analysis concerning the deployment of small-scale gasification systems in dealing with various fuels from two countries, Portugal and Brazil, for electricity generation in a 15 kWe downdraft gasifier. To quantify this, a mathematical model was implemented and validated against experimental runs gathered from the downdraft reactor. Further, a spreadsheet economic model was developed combining the net present value (NPV), internal rate of return (IRR) and the payback period (PBP) over the project’s lifetime set to 25 years. Cost factors included expenses related to electricity generation, initial investment, operation and maintenance and fuel costs. Revenues were estimated from the electricity sales to the grid. A Monte Carlo sensitivity analysis was used to measure the performance of the economic model and determine the investment risk. The analysis showed an electricity production between 11.6 to 15 kW, with a general system efficiency of approximately 13.5%. The viability of the projects was predicted for an NPV set between 18.99 to 31.65 k€, an IRR between 16.88 to 20.09% and a PBP between 8.67 to 12.61 years. The risk assessment yielded favorable investment projections with greater risk of investment loss in the NPV and the lowest for IRR. Despite the feasibility of the project, the economic performance proved to be highly reliant on the electricity sales prices subdue of energy market uncertainties. Also, regardless of the broad benefits delivered by these systems, their viability is still strikingly influenced by governmental decisions, subsidiary support and favorable electricity sales prices. Overall, this study highlights the empowering effect of small-scale gasification systems settled in decentralized communities for electric power generation.


Author(s):  
Mario Pagliaro

Sharing the same raw material, recycling and composting are in direct conflict with incineration of municipal solid waste in combined heath and power plants. Indeed, waste-to-energy plants in regions with high recycling rates import urban waste from other countries to use otherwise unused capacity, and raise revenues. Using the case of Italy’s second largest and economically most developed region, I discuss the economic viability of municipal solid waste incineration to produce electricity and heath in the context of the increasing role of electricity production from renewable energy sources as well as of the emerging mass-scale uptake of bioplastics. Four lessons and three guidelines aimed to local authorities and policy makers emerge from the present study.


2018 ◽  
Vol 67 ◽  
pp. 02044 ◽  
Author(s):  
Desti Octavianthy ◽  
Widodo Wahyu Purwanto

Smart energy system is one of the important infrastructures for building smart city. Waste to energy (WtE) is an innovative solution using municipal solid waste (MSW) as a source for electricity. This research was conducted to design WtE Plant in Depok and to asses economic viability of different business models. The technologies applied in WtE are anaerobic digestion and gas engine to generate electricity. The simulation was conducted using SuperPro Designer and UniSim Design software to evaluate the technical performances of electricity production from organic solid waste. The feasibility of project implementation of various business models are evaluated through economic analysis. The result of this study shows that the organic fraction of municipal solid waste in Depok has potential to generate electricity up to 28 MW. From economic aspect, pay off business scheme greatly affects the value of NPV and IRR. Meanwhile, the intervention scheme on fiscal incentives and low loan interest rate have slight effect on IRR values. A combination of Viability Gap Fund (VGF) and increased tipping fees intervention scheme is an optimum business scheme to build WtE plant and achieve electricity price below the offtaker’s willingness-to-pay.


Energies ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3768 ◽  
Author(s):  
Przemysław Seruga ◽  
Małgorzata Krzywonos ◽  
Anna Seruga ◽  
Łukasz Niedźwiecki ◽  
Halina Pawlak-Kruczek ◽  
...  

The replacement of fossil fuel with renewable energy sources seems as though it will be crucial in the future. On the other hand, waste generation increases year by year. Thus, waste-to-energy technologies fit in with the actual trends, such as the circular economy. The crucial type of generated waste is municipal solid waste, which is in the research area. Regarding the organic fraction of municipal solid waste (OFMSW), anaerobic digestion (AD) allows the recovery of biogas and energy. Furthermore, if it is supported by source segregation, it should allow the recovery of material as fertilizer. The AD process performance (biogas yield and stability) comparison of source-segregated OFMSW (ss-OFMWS) and mechanically sorted OFMSW (ms-OFMSW) as feedstocks was performed in full-scale conditions. The daily biogas volume and methane content were measured to assess AD efficiency. To verify the process stability, the volatile fatty acid (VFA) content, pH value, acidity, alkalinity, and dry matter were determined. The obtained biogas yield per ton was slightly higher in the case of ss-OFMSW (111.1 m3/ton), compared to ms-OFMSW (105.3 m3/ton), together with a higher methane concentration: 58–60% and 51–53%, respectively, and followed by a higher electricity production capacity of almost 700 MWh for ss-OFMSW digestion. The obtained VFA concentrations, at levels around 1.1 g/kg, pH values (slightly above 8.0), acidity, and alkalinity indicate the possibilities of the digester feeding and no-risk exploitation of either as feedstock.


2021 ◽  
Vol 145 ◽  
pp. 111080
Author(s):  
M.T. Munir ◽  
Ahmad Mohaddespour ◽  
A.T. Nasr ◽  
Susan Carter

2021 ◽  
pp. 0734242X2110115
Author(s):  
Wesley N Oehmig ◽  
Justin Roessler ◽  
Abdul Mulla Saleh ◽  
Kyle A Clavier ◽  
Christopher C Ferraro ◽  
...  

A common perception of plasma arc treatment systems for municipal solid waste incineration ash is that the resulting vitrified slag is inert from an environmental perspective. Research was conducted to examine this hypothesis and to assess whether reduced pollutant release results from pollutant depletion during the process of the ash with plasma, or encapsulation in the glassy vitrified matrix. The concentrations of four discrete municipal solid waste incineration ash samples before and after plasma arc vitrification in a bench-scale unit were compared. Slag and untreated ash samples were leached using several standardized approaches and mobility among the four metals of interest (e.g. As, Cd, Pb and Sb) varied across samples, but was generally high (as high as 100% for Cd). Comparison across methods did not indicate substantial encapsulation in the vitrified slag, which suggests that reduced pollutant release from plasma arc vitrified slag is due to pollutant depletion by volatilization, not encapsulation. This has significant implications for the management of air pollution control residues from waste-to-energy facilities using plasma arc vitrification.


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