| 1. |
- Balderrama, Sergio, et al.
(författare)
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Surrogate models for rural energy planning : Application to Bolivian lowlands isolated communities
- 2021
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Ingår i: Energy. - : Elsevier BV. - 0360-5442 .- 1873-6785. ; 232
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Tidskriftsartikel (refereegranskat)abstract
- Thanks to their modularity and their capacity to adapt to different contexts, hybrid microgrids are a promising solution to decrease greenhouse gas emissions worldwide. To properly assess their impact in different settings at country or cross-country level, microgrids must be designed for each particular situation, which leads to computationally intractable problems. To tackle this issue, a methodology is proposed to create surrogate models using machine learning techniques and a database of microgrids. The selected regression model is based on Gaussian Processes and allows to drastically decrease the computation time relative to the optimal deployment of the technology. The results indicate that the proposed methodology can accurately predict key optimization variables for the design of the microgrid system. The regression models are especially well suited to estimate the net present cost and the levelized cost of electricity (R-2 = 0.99 and 0.98). Their accuracy is lower when predicting internal system variables such as installed capacities of PV and batteries (R-2 = 0.92 and 0.86). A least-cost path towards 100% electrification coverage for the Bolivian lowlands mid-size communities is finally computed, demonstrating the usability and computational efficiency of the proposed framework.
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| 2. |
- Villarroel-Schneider, Johnny, et al.
(författare)
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Open-source model applied for techno-economic optimization of a hybrid solar PV biogas-based polygeneration plant : The case of a dairy farmers’ association in central Bolivia
- 2023
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Ingår i: Energy Conversion and Management. - : Elsevier BV. - 0196-8904 .- 1879-2227. ; 291
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Tidskriftsartikel (refereegranskat)abstract
- Proper sizing of energy systems is a key aspect that allows avoiding overestimated installation costs or failures in operation and dispatch. However, most of the available sizing tools focus on systems dedicated only to electrical loads, omitting combined energy systems with simultaneous supply of various thermal demands. This study presents an adaptation of an existing open access techno-economic optimization model for broadening the design tool for small-scale energy systems supplying both, electrical and thermal needs. For this, a new typology of an energy system was proposed considering the use of biogas, solar energy and adding thermal components. This was followed by modifying the model framework, constraints equations and objective function, which is the net present cost of the system. Once the design tool was verified a model was constructed to analyse the feasibility of a polygeneration plant for an association of 30 small dairy farms. The developed model was able to optimize the sizing of the main system components for different proposed scenarios, encompassing supply of electricity, refrigeration, biogas for cooking and fertilizers. For the selected application it was found that the aggregated cost of producing electricity and heat ranges from 0.044 to 0.070 USD/kWh; the penetration of solar energy can reach up to 32%; while the annual potential savings of CO2 emissions of applying the solution ranges from 109 to 127 ton of CO2.
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| 3. |
- Villarroel-Schneider, Johnny, et al.
(författare)
-
Open-source model applied for techno-economic optimization of a hybrid solarPV biogas-based polygeneration plant: the case of a dairy farmers’ associationin central Bolivia
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Proper sizing of energy systems is a key aspect that allows avoiding overestimated installationcosts or failures in operation and dispatch. Most of the available sizing tools focus on systemsdedicated only to electrical loads, omitting combined energy systems with simultaneous supplyof various thermal demands. This study presents an adaptation of an existing techno-economicoptimization model for broadening the design tool for small-scale energy systems supplyingboth electrical and thermal needs. For this, a new typology of the energy system was proposedadding components such as a combustor and a combined heat and power generator. Thenmodifications were made to the model framework (constraints, parameters, variables andobjective function). The developed model was applied to a polygeneration plant for anassociation of 30 small dairy farmers, where biogas is proposed to be produced to cover thedemand for cooking gas and mainly for fuelling the plant that supplies electricity, refrigerationfor milk (by using absorption refrigeration technology) and heat for drying organic fertilizersthat result from biogas production. In addition, the use of solar PV panels and batteries isconsidered. Different scenarios for analysing and validating the model were proposed; thebase scenario allows the operation of all the system components, generating surpluses ofelectricity (for selling), heat (for other uses) and biogas. The aggregated cost of producingelectricity and heat ranges from 0.043 to 0.068 USD/kWh; the penetration of solar energyranges from 27 to 36%, while the potential savings of CO2 emissions of applying the proposedpolygeneration system ranges from 109 to 131 ton of CO2 per year.
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