Microgrid Viability for Small-Scale Cooling, Heating, and Power

Author(s):  
Lubomir A. Ribarov ◽  
David S. Liscinsky

Cooling, Heating, and Power (CHP) energy systems provide higher fuel efficiency than conventional systems, resulting in reduced emissions and other environmental benefits. Until recently the focus of CHP system development has been primarily on medium-scale commercial applications in a limited number of market segments where clear value propositions lead to short term payback. Small-scale integrated CHP systems that show promise of achieving economic viability through significant improvements in fuel utilization have received increased attention lately. In this paper the economic potential is quantified for small-scale (micro-grid) integrated CHP systems suitable for groups of buildings with aggregate electric loads in the 15 kW–120 kW range. Technologies are evaluated for community building groups (CBGs) consisting of aggregation of pure residential entities and combined residential and light commercial entities. Emphasis is on determination of the minimum load size (i.e. the smallest electric and thermal load for a given CBG that is supplied with electric, heating, cooling power from a CHP) for which a micro-grid CHP system is both technically and economically viable. In this paper, the operation of the CHP system is parallel with the public utility grid at all times, i.e. the grid is interconnected. Evaluations of CHP technology options using simulation studies in a “three-dimensional” space (CHP technology option, CBG load aggregation, and geographical location in the USA) were evaluated based on comparisons of net present value (NPV). The simulations indicated that as electric load increases, the viability of the CHP system (independent of the system’s size) becomes more favorable. Exceeding a system runtime (utilization) of 70% was shown to pass the break-even line in the NPV analysis. Finally, geographic location was found to have a relatively weak effect on the reported trends. These results suggest that micro grid CHP systems have the potential to be economically viable with relative independence of geographic location if adequately sized to match the load requirements.

2006 ◽  
Vol 129 (1) ◽  
pp. 71-78 ◽  
Author(s):  
Lubomir A. Ribarov ◽  
David S. Liscinsky

Cooling, heating, and power (CHP) energy systems provide higher fuel efficiency than conventional systems, resulting in reduced fuel consumption, reduced emissions, and other environmental benefits. Until recently the focus of CHP system development has been primarily on medium-scale commercial applications in a limited number of market segments where clear value propositions lead to short term payback. Small-scale integrated CHP systems that show promise of achieving economic viability through significant improvements in fuel utilization have received increased attention lately. In this paper the economic potential is quantified for small-scale (microgrid) integrated CHP systems suitable for groups of buildings with aggregate electric loads in the 15-120kW range. Technologies are evaluated for community building groups (CBGs) consisting of aggregation of pure residential entities and combined residential and light commercial entities. Emphasis is on determination of the minimum load size (i.e., the smallest electric and thermal load for a given CBG that is supplied with electric, heating, cooling power from a CHP) for which a microgrid CHP system is both technically and economically viable. In this paper, the operation of the CHP system is parallel with the public utility grid at all times, i.e., the grid is interconnected. Evaluations of CHP technology options using simulation studies in a “three-dimensional” space (CHP technology option, CBG load aggregation, and geographical location in the USA) were evaluated based on comparisons of net present value (NPV). The simulations indicated that as electric load increases, the viability of the CHP system (independent of the system’s size) becomes more favorable. Exceeding a system runtime (utilization) of 70% was shown to pass the break-even line in the NPV analysis. Finally, geographic location was found to have a relatively weak effect on the reported trends. These results suggest that microgrid CHP systems have the potential to be economically viable with relative independence of geographic location if adequately sized to match the specific load requirements.


2021 ◽  
Vol 14 (5) ◽  
pp. 44
Author(s):  
Suraya Akter ◽  
Humayun Kabir ◽  
Shamima Akhter ◽  
Md. Mehedi Hasan

The study investigated the distinct environmental impacts and economic viability of domestic biogas technology in the countryside of Bangladesh. The study was carried out by a survey through personal interviews with biogas users. Seventy households were selected purposively and interviews were conducted through semi-structured questionnaires. The study mainly highlighted the potential reduction of greenhouse gas (GHG) emission and economic benefits of biogas utilization which were evaluated considering the substitution of traditional biomass fuels, by saving Liquefied Petroleum Gas (LPG) and cost of chemical fertilizer, and carbon trading. The economic benefits are addressed using some well-known economic indicators like Net Present Value (NPV), Payback Period (PBP), and Benefit-Cost Ratio (BCR). The results of the study revealed that a small-scale household anaerobic cow dung biogas digester not only exhibited the potential to cut carbon emissions on average by about 7.8 tons of CO2 equivalents yearly, but it also demonstrated the economic feasibility of doing so as the value of NPV and BCR was positive. This study recommends that the government approach, awareness program, and continuous and proper performing of the biogas technology are needed to intensify the multiples environmental benefits of the technology.


As distributed generators and renewable energies are now becoming the fastest growing technologies in the energy industries, the technical issues and environmental aspects are to studied and examined. The large number of small scale Micro grid components with their characteristics is a vital challenge for Micro grid modelling, operation, simulation and operation. Micro-grid gives clear, economic and environmental benefits for end users, utilities, and societies. However, their implementation faces lot of challenges, such as a protection of micro-grid. Micro-grid works in two modes, grid-connected and islanded mode that operates connected with medium voltage grid or islanded from the grid with controlled coordinate manner. The major goal of this thesis is to design protection for. First, the work is done to present the detailed description of the micro grid models and lines. Then the paper will discuss the distributed generator models that have been implemented in MATLAB/Simulink including photovoltaic module, fuel cell stack system with short term storage (Li-ion battery system). Then the fault analysis is done for the whole Micro-grid, whether the micro grid is working in fault condition or not. Then Micro grid protection is done for the grid connected modes and islanding modes of Micro grid. To design the protection system for the micro grid over current relay protection scheme is used.


Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2189
Author(s):  
Cesare Caputo ◽  
Ondřej Mašek

Energy access and waste management are two of the most pressing developmental and environmental issues on a global level to help mitigate the accelerating impacts of climate change. They are particularly relevant in Sub–Saharan Africa where electrification rates are significantly below global averages and rural areas are lacking a formal waste management sector. This paper explores the potential of integrating solar energy into a biomass pyrolysis unit as a potentially synergetic solution to both issues. The full design of a slow pyrolysis batch reactor targeted at biochar production, following a strict cost minimization approach, is presented in light of the relevant considerations. SPEAR is powered using a Cassegrain optics parabolic dish system, integrated into the reactor via a manual tracking system and optically optimized with a Monte-Carlo ray tracing methodology. The design approach employed has led to the development an overall cost efficient system, with the potential to achieve optical efficiencies up 72% under a 1.5° tracking error. The outputs of the system are biochar and electricity, to be used for soil amendment and energy access purposes, respectively. There is potential to pyrolyze a number of agricultural waste streams for the region, producing at least 5 kg of biochar per unit per day depending on the feedstock employed. Financial assessment of SPEAR yields a positive Net Present Value (NPV) in nearly all scenarios evaluated and a reasonable competitiveness with small scale solar for electrification objectives. Finally, SPEAR presents important positive social and environmental externalities and should be feasibly implementable in the region in the near term.


Land ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 385
Author(s):  
Beatrice Nöldeke ◽  
Etti Winter ◽  
Yves Laumonier ◽  
Trifosa Simamora

In recent years, agroforestry has gained increasing attention as an option to simultaneously alleviate poverty, provide ecological benefits, and mitigate climate change. The present study simulates small-scale farmers’ agroforestry adoption decisions to investigate the consequences for livelihoods and the environment over time. To explore the interdependencies between agroforestry adoption, livelihoods, and the environment, an agent-based model adjusted to a case study area in rural Indonesia was implemented. Thereby, the model compares different scenarios, including a climate change scenario. The agroforestry system under investigation consists of an illipe (Shorea stenoptera) rubber (Hevea brasiliensis) mix, which are both locally valued tree species. The simulations reveal that farmers who adopt agroforestry diversify their livelihood portfolio while increasing income. Additionally, the model predicts environmental benefits: enhanced biodiversity and higher carbon sequestration in the landscape. The benefits of agroforestry for livelihoods and nature gain particular importance in the climate change scenario. The results therefore provide policy-makers and practitioners with insights into the dynamic economic and environmental advantages of promoting agroforestry.


Author(s):  
Richard L. Hack ◽  
Max R. Venaas ◽  
Vince G. McDonell ◽  
Tod M. Kaneko

Small scale Distributed Generation with waste heat recovery (<50 kW power output, micro-DG/CHP) is an expanding market supporting the widespread deployment of on-site generation to much larger numbers of facilities. The benefits of increased overall thermal efficiency, reduced pollutant emissions, and grid/microgrid support provided by DG/CHP can be maximized with greater quantities of smaller systems that better match the electric and thermal on-site loads. The 3-year CEC funded program to develop a natural gas fueled automotive based rotary engine for micro-DG/CHP, capitalizing upon the unique attributes engine configuration will be presented including initial performance results and plans for the balance of the program.


2021 ◽  
pp. 59-65
Author(s):  
SERGEY V. BRAGINETS ◽  

On-farm compound feed production from self-produced raw materials is favorable to agricultural enterprises under present-day conditions. The authors carried out a comparative technical and economic study of the conventional and modular small-scale on-farm compound feed plants with a capacity of 2 tons per hour, designed for agricultural enterprises with an average livestock population of 6…8 thousand pigs. The proposed modular plant consists of two modules – the operative storage of raw materials and the main module of grinding and mixing. Modules with installed equipment are delivered and placed on a light foundation, connected by transport equipment and with tanks for raw materials and fi nished products. The conventional factory is a technological line housed in a hangar and used for crushing, metering, and mixing raw materials. It consists of a separator, a hammer mill, weighing equipment, a mixer, containers for raw materials and fi nished products, transport, and aspiration equipment. The technical and economic analysis has shown that the erection and operation of the on-farm modular enterprise require 41% less capital investments than a traditional compound feed plant of the same capacity. The use of a small-scale modular plant will reduce operating costs by 23.8% (from 3094 to 2358 thousand rubles), increase the specifi c economic eff ect from the compound feed production by 1.6% (from 8.64 to 8.78 thousand rubles per ton) and return on margin by 4% (from 10.2 to 10.6%), reduce the payback period by 42% (from 0.8 to 0.46 years), and increase the net present value by 3% (from 66167 to 68216 thousand rubles), as compared to a conventional enterprise. The modular on-farm plants producing loose compound feed with a productivity of up to 3 tons per hour are profi table and economically sound as they can increase production effi ciency of compound feeds for farm animals.`


1999 ◽  
Vol 382 ◽  
pp. 307-329 ◽  
Author(s):  
JUDITH K. FOSS ◽  
K. B. M. Q. ZAMAN

The large- and small-scale vortical motions produced by ‘delta tabs’ in a two-stream shear layer have been studied experimentally. An increase in mixing was observed when the base of the triangular shaped tab was affixed to the trailing edge of the splitter plate and the apex was pitched at some angle with respect to the flow axis. Such an arrangement produced a pair of counter-rotating streamwise vortices. Hot-wire measurements detailed the velocity, time-averaged vorticity (Ωx) and small-scale turbulence features in the three-dimensional space downstream of the tabs. The small-scale structures, whose scale corresponds to that of the peak in the dissipation spectrum, were identified and counted using the peak-valley-counting technique. The optimal pitch angle, θ, for a single tab and the optimal spanwise spacing, S, for a multiple tab array were identified. Since the goal was to increase mixing, the optimal tab configuration was determined from two properties of the flow field: (i) the large-scale motions with the maximum Ωx, and (ii) the largest number of small-scale motions in a given time period. The peak streamwise vorticity magnitude [mid ]Ωx−max[mid ] was found to have a unique relationship with the tab pitch angle. Furthermore, for all cases examined, the overall small-scale population was found to correlate directly with [mid ]Ωx−max[mid ]. Both quantities peaked at θ≈±45°. It is interesting to note that the peak magnitude of the corresponding circulation in the cross-sectional plane occurred for θ≈±90°. For an array of tabs, the two quantities also depended on the tab spacing. An array of contiguous tabs acted as a solid deflector producing the weakest streamwise vortices and the least small-scale population. For the measurement range covered, the optimal spacing was found to be S≈1.5 tab widths.


Author(s):  
Heri Suryoatmojo

Currently the needs of electric power increased rapidly along with the development of technology. The increase in power requirements is contrary to the availability of sources of energy depletion of oil and coal. This problem affects the national electrical resistance. To meet the needs of large electric power with wide area coverage is required small scale distributed power generation. This distributed generation (DG) of renewable energy sources sought to minimize the use of energy resources such as oil and coal and connected to the micro grid and use the battery as a power balance. Because of there are many DGs and the use of batteries, therefore it is important to determine the optimal power generation of each plant as well as the use of battery based on the optimal capacity so that requirement of electric power can be met with minimal cost each time. This optimization is known as Dynamic Economic Dispatch. In this study, the methods of Quadratic Programming is required to solve the optimization problem.


2021 ◽  
Vol 9 (10) ◽  
pp. 1050
Author(s):  
Marat Eseev ◽  
Dmitry Makarov

Usually, loading and unloading of cargo ships takes place in ports that are equipped with the infrastructure necessary to carry out such operations. In the Arctic, often a helicopter is the only way to get the cargo to the right place. Finding the optimal geographic location for unloading a ship using helicopters is an important task. It is necessary to create a support system for making the right decisions in such situations. Mathematical modeling has been used to find the geographical location that ensures the most favorable and quickest delivery of cargo from a vessel to its destination, using a helicopter. A criterion has also been found in which the search for the optimum point is a more rational way of unloading the vessel compared to other discharge options. The maps of the economic benefits of loading and unloading operations in this model have been developed. Using the example of the developed model, it is shown that during the transportation of goods in Ob Bay, significant economic and temporary advantages can be obtained. The developed model can be extended to the case of cargo delivery not only in the Arctic conditions, but also where the transport infrastructure is insufficiently developed.


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