| 1. |
- Ahlgren Ode, Kajsa, et al.
(author)
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Business model translation—The case of spreading a business model for solar energy
- 2019
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In: Renewable Energy. - : Elsevier BV. - 0960-1481. ; 133, s. 23-31
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Journal article (peer-reviewed)abstract
- Distributed solar photovoltaic systems are considered an important renewable energy source for meeting renewable energy targets and mitigating climate change. In several markets, emerging firms have established new business models to offer residential customers solar panel systems. In California, the third-party ownership business model has been successfully established during the last decade, and is currently spreading to other markets. Through a longitudinal case study, this paper explores how a startup firm in the Netherlands set up the third-party ownership business model on the Dutch market. The case shows that the process of bringing a business model to a new market is not sufficiently understood as a process of diffusion. Alternatively, it is a process of business model translation, in which the actors involved play a central role in adapting and successfully establishing the business model in a new market. The results have implications for both practitioners and policy makers, as well as the emerging literature on business models for sustainability.
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| 2. |
- Amiri, Shahnaz, et al.
(author)
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Increased cogeneration of renewable electricity through energy cooperation in a Swedish district heating system - A case study
- 2018
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In: Renewable energy. - : Elsevier BV. - 0960-1481 .- 1879-0682. ; 116, s. 866-877
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Journal article (peer-reviewed)abstract
- The present study of the district heating (DH) system in the city of Kisa, Sweden, shows how, through energy cooperation with a nearby sawmill and paper mill, a local energy company contributes to energy-efficient DH and cost-effective utilization of a new biofuel combined heat and power (CHP) plant. Cases of stand-alone and integrated energy systems are optimized with the linear program MODEST. The European power market is assumed to be fully deregulated. The results show clear advantages for the energy company to cooperate with these industries to produce heat for DH and process steam for industry. The cooperating industries gain advantages from heat and/or biofuel by-product supply as well. The opening to use a biofuel CHP plant for combined heat supply results in cogenerated electricity of almost 29 GWh/a with an increased biofuel use of 13 GWh/a, zero fuel oil use and CO2 emission reductions of 25,800 tons CO2/a with coal-condensing power plant on the margin and biofuel as limited resource. The total system cost decreases by −2.18 MEUR/a through extended cooperation and renewable electricity sales. The sensitivity analysis shows that the profitability of investing in a biofuel CHP plant increases with higher electricity and electricity certificate prices.
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| 3. |
- Ayob, Mohd Nasir, et al.
(author)
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Wave energy potential and 1-50 TWh scenarios for the Nordic synchronous grid
- 2017
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In: Renewable energy. - : Elsevier BV. - 0960-1481 .- 1879-0682. ; 101, s. 462-466
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Journal article (peer-reviewed)abstract
- This study estimates the wave energy potential along the coasts of the Nordic countries with the Nordicsynchronous grid as a chosen boundary. A model for wave farm allocation was developed and applied to achieve annual energy production targets of 1 TWh, 3 TWh, 10 TWh and 50 TWh. The study is based on 10 years of data, from 2005 to 2014, from the European Center for Medium-Range Weather Forecasts. Data from a total of 728 coordinate points along the Nordic countries, with a 0.125° x 0.125° spatial resolution, were considered. An algorithm was developed to generate the scenarios, to estimate the installed capacity of wave farms at different locations along the coasts, and to measure the physical space required by the farms. This analysis of the four energy target scenarios resulted in a required installed capacity of 337 MW, 1.02 GW, 3.42 GW and 17.09 GW, covering a stretch of the total coast of 0.4, 1.2, 3.8 and 18.9% respectively. The total annual wave energy resource for the Nordic countries is determined at 590 TWh, most of which is available along the Norwegian coast.
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| 4. |
- Azimoh, C. L., et al.
(author)
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Replicability and scalability of mini-grid solution to rural electrification programs in sub-Saharan Africa
- 2017
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In: Renewable Energy. - : Elsevier BV. - 0960-1481. ; 106, s. 222-231
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Journal article (peer-reviewed)abstract
- The assessment of off-grid electrification programs in developing countries largely based on mini-grid and solar home system (SHS) has shown that they are faced with low development imparts and sustainability challenges, which has resulted in failure of many projects. This study provides solutions on how to surmount these challenges, leaning on the experience of a hybrid solar-diesel mini-grid at Tsumkwe village in Namibia. It provides analyses of a case study based on empirical evidence from field studies, interviews of representatives of households, public institutions and energy providers. In addition, it investigates the technical challenges and economic impacts of the electrification program. HOMER™ and MATLAB™ models were used in the analysis and investigations. The findings show that despite the challenges, the system has been sustained because it keyed into an existing structure with growth potentials. The progressive tariff system adopted by the government helped to cushion costs and allow low income households in the energy matrix. Adoption of strict maintenance measures, and implementation of energy efficiency measures prior to the commissioning of the program, resulted in the reduction of costs. The success elements identified in this study could be extrapolated in other sub-Saharan African countries if the challenges are properly addressed.
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| 5. |
- Bangalore, Pramod, 1983, et al.
(author)
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Analysis of SCADA data for early fault detection with application to the maintenance management of wind turbines
- 2016
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In: CIGRE Session 46. - : CIGRE. ; , s. 1-10
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Conference paper (peer-reviewed)abstract
- During the past decade wind turbines have proven to be a promising source of renewable power. Wind turbines are generally placed in remote locations and are subject to harsh environmental conditions throughout their lifetimes. Consequently, the failures in wind turbines are expensive to repair and cause loss of revenue due to long down times. Asset management in wind turbines can aid in assessing and improving the reliability and availability of wind turbines, thereby making them more competitive. Maintenance policies play an important role in asset management and different maintenance models have been developed for wind turbine applications. Typically, mathematical models for maintenance optimization provide either an age based or a condition based preventive maintenance schedule. Age based preventive maintenance schedules provide the owner with the possibility to financially plan for maintenance activities for the entire lifetime of the wind turbine by providing the expected number of replacements for each component. However, age based preventive maintenance schedule may not consume the operating life of the wind turbine components to the maximum. Condition based maintenance scheduling has the advantage of better utilizing the operating life of the components. This paper proposes a wind turbine maintenance management framework which utilizes operation and maintenance data from different sources to combine the benefits of age based and condition based maintenance scheduling. This paper also presents an artificial neural network (ANN) based condition monitoring method which utilizes data from supervisory control and data acquisition (SCADA) system to detect failures in wind turbine components and systems. The procedures to construct ANN models for condition monitoring application are outlined. In order to demonstrate the effectiveness of the ANN based condition monitoring method it is applied to case studies from real wind turbines. Furthermore, a mathematical model called preventive maintenance schedule with interval costs (PMSPIC) is discussed and its application to a case study within the maintenance management framework is presented. The case study demonstrates the advantage of combining both the age based and condition based maintenance scheduling methods.
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| 6. |
- Berge, Axel, 1983, et al.
(author)
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Field measurements on a district heating pipe with vacuum insulation panels
- 2016
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In: Renewable Energy. - : Elsevier BV. - 0960-1481 .- 1879-0682. ; 87:3, s. 1130-1138
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Journal article (peer-reviewed)abstract
- © 2015 Elsevier Ltd. In Swedish district heating networks, around 10% of the supplied thermal energy is lost in the distribution system. One solution to decrease the losses is to use hybrid insulation district heating pipes, a concept where the innermost part of the thermal insulation consists of vacuum insulation panels, held in place by polyurethane foam. One problem with vacuum insulation panels are their sensitivity to high temperatures. This paper presents field measurements on a hybrid insulation district heating pipe where the temperatures have been measured continuously at various positions of a pipe section. The measurements show consistency and a large difference between hybrid insulation parts and reference parts without vacuum insulation panels. A superposition model has been used to calculate the temperature in a point and compare it to the measurement. The results are compared to the same calculation on the results from finite element simulations. The results show clearly that the vacuum panels in the pipes have not collapsed. A slow deterioration of the panels is harder to find with this model. Changes in the system, such as a return temperature which decreases over time, can give a larger impact, concealing the change in the panel performance.
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| 7. |
- Chopin, Pierre, et al.
(author)
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Integrating stakeholder preferences into assessment of scenarios for electricity production from locally produced biomass on a small island
- 2019
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In: Renewable Energy. - : Elsevier BV. - 0960-1481. ; 131, s. 128-136
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Journal article (peer-reviewed)abstract
- Biomass is a potential source of renewable energy that can be produced in agricultural fields. However, its introduction at regional scale should not only provide energy, but also economic, social and environmental benefits. In order to study the potential benefit of introducing energy cane cropping systems for electricity production, we developed 62 scenarios for energy cane-based biomass power plants, for which impacts were modeled with a regional bioeconomic model. Impacts were calculated and aggregated with weights on 14 issues obtained from 51 stakeholders using an analytic hierarchy process. Regression models were applied to explain the determinant of sustainability. The results showed that stakeholder preferences for local development priorities fell into four different types, while the impacts of the scenarios also differed greatly according to their attributes. The main issues appeared to be "Disruption of existing agricultural sectors", "Potential loss of biodiversity" and "Change in farmers' revenue". The factor "Output of power plant" was positively correlated with the level of contribution to local development and to "Quantity of bagasse" and "Sustainable management of energy cane". Developing energy cane biomass appears therefore to be potentially beneficial for local development, with options favoring power plants relying on different forms of biomass produced in the vicinity and managed in a sustainable way. The novel approach devised here helped to address the complex multi-dimensional development issues regarding production of biomass and to provide satisfactory compromise solutions for different stakeholders. It can also provide guidance on exploration of options to obtain the most sustainable scenario. (C) 2018 Elsevier Ltd. All rights reserved.
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| 8. |
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| 9. |
- Garcilaso, V., et al.
(author)
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Promoting effect of CeO2, ZrO2 and Ce/Zr mixed oxides on Co/Γ-Al2O3 catalyst for Fischer-Tropsch synthesis
- 2019
-
In: Renewable energy. - : Elsevier Ltd. - 0960-1481 .- 1879-0682. ; 132, s. 1141-1150
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Journal article (peer-reviewed)abstract
- A series of cobalt-based catalysts have been synthesized using as support γ-Al2O3 promoted by ceria/zirconia mixed oxides with a variable Ce/Zr molar ratio. The obtained catalysts demonstrated oxide promotion results in the protection of the major textural properties, especially for Zr-rich solids. Reducibility of cobalt species was enhanced by the presence of mixed oxides. The chemical composition of the oxide promoter influenced not only physicochemical properties of final catalysts but also determined their performance during the reaction. In this sense, Zr-rich systems presented a superior catalytic performance both in total conversion and in selectivity towards long chain hydrocarbons. The observed Zr-promotion effect could be explained by two significant contributions: firstly, the partial inhibition of Co–Al spinel compound formation by the presence of Zr-rich phases which enhances the availability of Co actives site and secondly, Zr-associate acidic sites promote higher hydrocarbons selectivity.
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| 10. |
- Gómez, Maria F, 1970-, et al.
(author)
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Exploring the effect of subsidies on small-scale renewable energy solutions in the Brazilian Amazon
- 2015
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In: Renewable energy. - : Elsevier BV. - 0960-1481 .- 1879-0682. ; 83, s. 1200-1214
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Journal article (peer-reviewed)abstract
- The Brazilian government aims at universal electricity access. The national rural electrification initiative has provided electricity services to more than 14 million people since 2003, mainly through grid extension. However, the initiative has not been able to reach remote areas in the Amazon, thus requiring a review of conditions for small scale off-grid power generation projects. As a result, new rules established under the national rural electrification program address the design and implementation of off-grid power generation projects with an installed capacity up to 100kW. The objective of this paper is to explore the effects of the new set of rules on the levelized cost of electricity for different power generation solutions in the Amazon. Our study shows that the new rules may be beneficial to isolated communities, as they reduce the levelized cost of electricity, favor renewable energy technologies and may contribute to reduce CO2 emissions. In addition, the new rules may help engage new actors to provide rural electrification of the Amazon region. To fully take advantage of the current scheme, action at local level is required to define the most appropriate model for small-scale power generation projects and establish synergies between concessionaires and local energy providers.
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