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  • 1.
    Azimoh, Chukwuma Leonard
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Klintenberg, Patrik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Wallin, Fredrik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Karlsson, Björn
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Illuminated but not electrified: An assessment of the impact of Solar Home System on rural households in South Africa2015Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 155, s. 354-364Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The introduction of the off-grid electrification program in South Africa using the Solar Home System (SHS) was a central component of the government policy aimed at bringing development to un-electrified households. An assessment of the performance of SHS in many countries provided little evidence to support the development impact of the system. The general perception is that the SHS program is wasting government funds and has no hope of achieving the set objectives. Previous scientific reports have concluded that SHS is the most viable technology for bringing about socio-economic development to rural households. Most of these conclusions have been based on one sided arguments and largely on anecdotal evidence. This study provides a pluralistic view of the subject from the perspective of the energy service companies (ESCOs) and the households using the equipment. The development impact of SHS is subjected to scientific analysis by investigating the economic and social dimensions of the program. Additionally, the sustainability of the South African SHS program is assessed by investigating the challenges facing the ESCOs and the households. The study reveals that illumination provided by SHS electricity has profound impact on the livelihoods of rural households. Due to the limited capacity of SHS for productive and thermal use, there are limited direct economic benefits to the households. The associated economic impact is peripheral to the secondary usage of SHS electricity. SHS has improved the productivity of small scale business owners who utilize the light from SHS to do business at night. Irregularities in payment of subsidy funds and energy bills, high operation cost, non-optimal use of SHS, grid encroachment, and lack of customer satisfaction contribute to make the business unsustainable for the ESCOs.

  • 2.
    Azimoh, Chukwuma Leonard
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Klintenberg, Patrik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Wallin, Fredrik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Karlsson, Björn
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    The burden of shading and location on the sustainability of South African solar home system program2015Ingår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 75, s. 308-313Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Most contributions on the issues of sustainability of rural electrification projects have focused on the technology and business models used to drive the projects. The issues of user education and environmental impact on the technology have received little attention, despite the fact that these challenges affect lives of projects after commissioning. The usage pattern of solar home systems (SHS) by most users that placed their solar panels close to obstructing objects, results in shading of the panels, and geographic location of households in the concession areas of the South African SHS program affects the performances of the system. The non-optimal use of SHS is mainly due to lack of user education. Therefore this paper reports on the impact of geographic location and shading of panels on the economics and technical performance of SHS. The study was done by investigating the performance of 75 WP solar panels operated at two sites in South Africa (Upington in Northern Cape Province and Thlatlaganya in Limpopo Province), the performance of an optimized shaded SHS and a non-shaded one was also investigated. The results show that both geographic location and shading compromise the performance of the systems, the energy output of a solar panel located at Upington is increased by 19% and the state of charge of the battery (SOC) increased by 6%, compared to the panel situated at Thlatlaganya village. Also the life span of the battery is increased by about one year. The SOC of the partially shaded SHS is reduced by 22% and loss of power to the load increased by 20%. The geographical location of the SHS concession areas in South Africa and lack of adherence to the manufacturer's installation specification affects the economics of SHS and the energy output vis-a-vis the sustainability of the program due to reduction in life cycle of the batteries. 

  • 3.
    Azimoh, Chukwuma Leonard
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Klintenberg, Patrik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Wallin, Fredrik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Karlsson, Björn
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Mbohwa, Charles
    University of Johannesburg, South Africa.
    Electricity for development:: Mini-grid solution for rural electrificationin South Africa2016Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, nr 110, s. 268-277Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The objective of most rural electrification programs in the developing world is to bring about socioeconomicdevelopment to households. Governments have put in place a number of measures to achievethis goal. Previous studies on rural electrification programs in developing countries show that solar homesystems and mini-grid systems are the dominant technologies. Assessments of a pilot hybrid mini-gridproject at Lucingweni village have concluded that mini-grid projects are not feasible due to high electricityproduction costs. As a result efforts toward rural electrification have been focused on the solar homesystem. Nevertheless, previous studies of the South African solar home system program have shown thatthe development objectives of the program are yet to be met more than a decade after commissioning.Therefore, this study investigates the viability of a hybrid mini-grid as a solution for rural developmentin South Africa. Investigations were based on Lucingweni and Thlatlaganya, two rural Villages where themini-grid and solar home system have been introduced. The mini-grid systems were designed taking intoconsideration available natural resources and existing load profiles. The results show that a village of 300households needs about 2.4 kW h/household/day of electricity to initiate and sustain income generatingactivities and that the solar home system is not capable of supporting this level of demand. We also showthat in locations with hydro resources, a hybrid mini-grid system has the most potential for meeting theenergy needs of the households in a cost effective manner. The assessment shows that with adequateplanning and optimization of available resources, the cost of electricity production can be reduced.

  • 4.
    Azimoh, Chukwuma Leonard
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Wallin, Fredrik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Klintenberg, Patrik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Karlsson, Björn
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    An assessment of unforeseen losses resulting from inappropriate use of solar home systems in South Africa2014Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 136, s. 336-346Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    One of the challenges to the sustainability of the Solar Home System (SHS) electrification program in South Africa is equipment theft. In response to this, communities susceptible to solar panel theft resort to mounting their panels flat on the ground so they can be looked after during the day and taken indoors at night for safe keeping. Other households use their security lights to illuminate their environment and provide security for pole and roof mounted solar panels at night. These actions have consequential effects on the performance of the SHS. Several studies have detected resentment from households regarding the low power quality from these systems. Most scientific contributions on the issue of low power from SHS have focused on the challenges based on the technical designs of the systems. The power losses due to the usage pattern of the system has not received much attention. This study therefore reports on the technical losses as a result of the deviation from the designed and installed specification of the system by the users in order to protect their systems. It also investigates the linkage between the technical and economic losses which affects the sustainability of SHS program. A case study was performed in Thlatlaganya village within Limpopo province in South Africa. Technical analysis using PVSYST solar software revealed that the energy output and performance of the battery is compromised as a result of these practices. Economic analysis indicates that the battery life and the economics of owning and operating SHS are affected negatively. The study recommends solutions to mitigate these losses, and proposes a cost effective way of optimizing the operation of SHS using a Bench-Rack system for mounting solar panels.

  • 5.
    Bulut, Mehmet Börühan
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Wallin, Fredrik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Karlsson, Björn
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    The role of buildings in the energy system: Intersectoral barriers to future developments2013Ingår i: The role of buildings in the energy system - intersectoral barriers to future developments, 2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    Residential energy consumption has a significant share in the final energy use in Sweden. Despite this relationship, it is hard to say that there is cooperation between the building and energy sectors for energy issues in buildings. In the grid of the future, buildings will no longer be a passive element of the electricity system; instead, they will acquire an active role in the operation of the grid. The cooperation between the building and energy sectors could play a key role for a successful development of smart grid technologies in buildings.In this paper, we describe the Swedish case and analyse the barriers to cooperation between the energy and building companies with the help of interviews with several stakeholders. This study showed that there is a demand for new business models in order to accommodate smart grid developments in buildings. Collective projects and new roles that reduce the power differences and barriers between the two sectors could contribute to the cooperation and support the development of future energy services in buildings.

  • 6.
    Campana, Pietro Elia
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Jige Quan, S.
    Georgia Institute of Technology, US.
    Robbio, F.I.
    ABB AB, Västerås, Sweden.
    Lundblad, Anders
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. KTH Royal Institute of Technology, Sweden.
    Zhang, Y.
    KTH Royal Institute of Technology, Sweden.
    Ma, Tao
    Shanghai Jiao Tong University, China.
    Karlsson, Björn
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Optimization of a residential district with special consideration on energy and water reliability2017Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 194, s. 751-764Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Many cities around the world have reached a critical situation when it comes to energy and water supply, threatening the urban sustainable development. From an engineering and architecture perspective it is mandatory to design cities taking into account energy and water issues to achieve high living and sustainability standards. The aim of this paper is to develop an optimization model for the planning of residential urban districts with special consideration of renewables and water harvesting integration. The optimization model is multi-objective which uses a genetic algorithm to minimize the system life cycle costs, and maximize renewables and water harvesting reliability through dynamic simulations. The developed model can be used for spatial optimization design of new urban districts. It can also be employed for analyzing the performances of existing urban districts under an energy-water-economic viewpoint.

    The optimization results show that the reliability of the hybrid renewables based power system can vary between 40 and 95% depending on the scenarios considered regarding the built environment area and on the cases concerning the overall electric load. The levelized cost of electricity vary between 0.096 and 0.212 $/kW h. The maximum water harvesting system reliability vary between 30% and 100% depending on the built environment area distribution. For reliabilities below 20% the levelized cost of water is kept below 1 $/m3 making competitive with the network water tariff.

  • 7.
    Chukwuma Leonard, Leonard
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Wallin, Fredrik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Nehrenheim, Emma
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Karlsson, Björn
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Chowdhury, S.P.
    University of Cape Town.
    Chowdhury, Sunetra
    University of Cape Town.
    Using Renewable Energy Paradigm as a Tool for Sustainable Village Concept (SVC) in Africa2012Konferensbidrag (Refereegranskat)
  • 8.
    Dahlquist, Erik
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Karlsson, Björn
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Lindberg, Eva
    Högskolan i Dalarna.
    Combined solar power and TPV2011Ingår i: Conference proceedings WREC 2011 in Linköping, Sweden, May 8-11, 2011 / [ed] Bahram Moshfegh, Linköping: Linköping University Press , 2011, s. 1-4240Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper design for a combined TPV and solar power system for local heat and power production is discussed. PV cells are producing electricity when there is light, while TPV cells are used when it is dark. Biomass is combusted and the heat is generating photons for the TPV system. Higher combustion temperature will give higher electric output, but also stronger deterioration of the materials in the combustor. By combining PV-cells that will generate a lot of electric power summer time with TPV-cells that can generate electric power winter time, when we also normally have a higher heat demand, we can achieve a flexible local heat and power system all year round. As both systems generate DC-power, we also can see a potential to use DC components generally, e.g for charging batteries for electrical vehicles, DC-pumps, LED-lamps etc. Design criteria for the systems are discussed in this paper for a house that is principally self sufficient on energy. Both theoretical and practical obstacles are discussed, as there are a number of issues to solve before the technique can be used in ”real life”.

  • 9.
    Dahlquist, Erik
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Wallin, Fredrik
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Karlsson, Björn
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    A fossil fuel free Europe need new incentives and a better control to balance power production and demand2011Ingår i: SAUPEC 2011 July 13-15 at Cape Town University, South Africa / [ed] SP Chowdrury, Cape Town: Cape Town University Press , 2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    In EU27 today there is a production of approximately 1000 TWh/ electric power from nuclear and 350 TWh/y from hydro power. The solar power potential is probably around 200 TWh/y. The wind power production is approximately 100 TWh/y but with a potential of at least 1000 TWh/y. The total biomass resources available are in the range 8500-12000 TWh/y. This gives a total of 10 000 – 15 000 TWh/y, from which at least 4000 TWh/y as electric power. This can be compared to the present gross energy use in EU 27 that was 16 084 TWh 2009, and 3400 TWh/y electric power. We can also see that there is a potential to save approximately 4 200 TWh/y in households, offices, transportation and industry. The energy balance thus should be possible to obtain with only non-fossil energy resources. Another matter is the power in time and by region. The demand does not always match the production locally at each moment and this demands a robust transmission and distribution network. Therefore we need new business models making it attractive for the users to reduce the load when there is a difficulty to deliver.

  • 10.
    Davidsson, H.
    et al.
    Lund University, Sweden.
    Bernardo, R.
    Lund University, Sweden.
    Gomes, J.
    Solarus AB, Älvkarleby, Sweden.
    Gentile, N.
    Lund University, Sweden.
    Gruffmanc, C.
    ÅF AB, Gävle, Sweden .
    Chea, L.
    Universidade Eduardo Mondlane, Maputo, Mozambique .
    Karlsson, Björn
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Construction of laboratories for solar energy research in developing countries2014Ingår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 57, s. 982-988Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A large number of photovoltaic systems have been installed in developing countries around the world during numerous projects. The goal is often to improve the quality of life in rural areas often lacking electricity. Many of these installations provide important services such as lighting and charging of various devices. However, when the projects are finished, there is a large risk that maintenance is not carried out properly and that malfunctions are never repaired. This situation can leave an otherwise well- functioning system unusable. A key problem is that there are not enough trained technicians that can maintain and repair the system locally. One reason for this is the lack of practical education in many developing countries. Furthermore, the availability of spare parts is essential for long term effectiveness. During 2011 a group of researchers from Lund University in Sweden built a small scale laboratory in Maputo, Mozambique, with local researchers. The project was successful and today the laboratory functions both as a teaching facility and as a measurement station for solar energy research for licentiates, masters and Ph.D. students. The main goal now is to widen the project in order to incorporate more universities in developing countries. We are now looking for new interested partners in developing countries who believe that such a laboratory could strengthen their ability to teach practical work and to perform research at a local university. Partners for planning and executing the project are also needed.

  • 11.
    Larsson, David
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Stridh, Bengt
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Karlsson, Björn
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Solar Electricity in Swedish District Heating Areas: Effective Energy Measures in Apartment Buildings to Increase the Share of Renewable Energy in Europe2014Ingår i: Proceedings from the 14th International Symposium on District Heating and Cooling / [ed] Anna Land, Stockholm: Svensk Fjärrvärme , 2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    To overcome the climate challenge is one of the greatest tasks of our time. In EU, renovating the existing building stock has been found an effective measure. In Swedish buildings with district heating, lowering heat demand could be questioned, because the energy used is mainly renewable bio energy or waste heat from industries. In addition many district heating systems cogenerate electricity, which could reduce the overall European greenhouse gas emissions.

    The aim of this article is to find effective measures for Swedish apartment buildings, in order to increase the share of renewable energy in European energy consumption. As a basis we use a previous study of energy saving potentials in apartment buildings. Added to this we study the impact of heat savings in 30 of Sweden’s largest district heating systems.

    The results show that on average heat reductions will lead to a decreased share of renewable energy, while electricity reductions will lead to an increased share of renewables. Of the investigated measures, using photovoltaics for local solar electricity generation has the largest potential.

    Our conclusion is that using the potential of solar electricity production should be considered in national energy policy and future building requirements. Heat reduction, on the other hand, could have lower priority in district heating areas, at least for existing buildings.

  • 12.
    Song, Jingjing
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Wallin, Fredrik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Karlsson, Björn
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Price models of district heating in Sweden2016Ingår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 88, s. 100-105Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Traditional pricing scheme of district heating is based on previous experience of system operation. This strategy does not work well under the circumstances of decreasing demand and shifting consumption pattern. Therefore new pricing strategies are needed. To have a comprehensive view on existing price models in Sweden, a price model survey was carried out among all members of the district heating quality system REKO. Four basic price components and multiple variants of them are detected in the survey. The result also shows that most of the district heating companies still use traditional methods and do not consider their customers’ consumption pattern while charging them.

  • 13.
    Stridh, Bengt
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yard, Stefan
    Lunds Universitet.
    Larsson, David
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Karlsson, Björn
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Production cost of PV electricity in Sweden2013Ingår i: EU PVSEC Proceedings, 2013, s. 4718-4722, artikel-id 6CV.5.13Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    The photovoltaic (PV) market in Sweden is small in comparison to most of the other PV markets in the European countries. However, the market is growing and about 8 MW was installed during 2012 that is 1/3 of the totally installed power. It is expected that the market will continue to grow during 2013.The PV levelized cost of electricity (LCOE) in Sweden was studied for grid connected PV systems to understand how competitive PV is on the Swedish market. It is concluded that PV production cost is still too high to be competitive in utility scale on the Nord Pool spot market without subsidies. However, for residential or commercial systems the production cost for PV electricity is today in some cases in the same order of magnitude as, or lower than, the running cost for bought electricity even without investment subsidy or electricity certificates, with the assumed parameters for estimation of LCOE. With investment subsidy the calculation improves substantially resulting in a LCOE lower than the running cost for bought electricity. To a much smaller extent an improvement of LCOE is also seen with electricity certificates.

  • 14.
    Stridh, Bengt
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. ABB Corp Res, SE-72178 Vasteras, Sweden.
    Yard, Stefan
    Lund Univ, Sweden..
    Larsson, David
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Solkompaniet, SE-72178 Vasteras, Sweden..
    Karlsson, Björn
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Profitability of PV electricity in Sweden2014Ingår i: 2014 IEEE 40TH PHOTOVOLTAIC SPECIALIST CONFERENCE (PVSC), IEEE , 2014, s. 1492-1497Konferensbidrag (Refereegranskat)
    Abstract [en]

    The Swedish PV market is still limited compared to many other countries in Europe. However, the growth is strong. 19 MW was installed in 2013 showing that the market more than doubled during 2013 in comparison to 2012. Hence there is of interest to more in detail study the profitability of PV electricity in Sweden for grid connected PV systems, to understand how competitive PV is on the Swedish market. LCOE and payback period are presented for a PV system that is installed to replace retail electricity with PV electricity. Both the cases of private residential systems and of non-private systems are considered.

  • 15.
    Thygesen, Richard
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Karlsson, Björn
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    An analysis on how proposed requirements for near zero energy buildings manages PV electricity in combination with two different types of heat pumps and its policy implications – A Swedish example2017Ingår i: Energy Policy, ISSN 0301-4215, E-ISSN 1873-6777, Vol. 101, s. 10-19Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents an analysis on how exhaust air- and ground source- heat pumps in combination with PV-systems affects the specific energy demand of buildings with the proposed Swedish near zero energy building definition and its policy implications. It also presents a method on how to estimate the contribution from the photovoltaic-system on the reduction of the specific energy demand of the building.

    A challenge with the proposed near zero energy building definition is that it is not clearly defined how it manages photovoltaic electricity as a mean to reduce the specific energy demand of buildings.

    The results suggest that the building with the ground source heat pump and heat recovery ventilation has the lowest specific energy demand. The proposed definition will give an advantage to system combinations comprised of heat pumps and PV-systems and this will lead to the possibility to build less insulated buildings with higher heat losses than for a building with a non-electrical heating system. A higher share of heat pumps can lead to lower electricity production in Sweden because of lost heating loads in district heating systems and a higher electricity demand.

  • 16.
    Thygesen, Richard
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Karlsson, Björn
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Economic and energy analysis of three solar assisted heat pump systems in near zero energy buildings2013Ingår i: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 66, s. 77-87Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The European Union's directive of the energy performance of buildings makes energy systems with local energy generation interesting. To support local energy generation the government has appointed a commission to investigate the possibility to implement net metering for grid connected PV-systems. In this paper three different systems are simulated and analyzed with regards to economics and energy: a PV-system and a heat pump (alternative 1), a heat pump and a solar thermal system (alternative 2) and a heat pump, a PV-system and a solar thermal system (alternative 3). System alternative 1 is profitable with daily net metering and monthly net metering and unprofitable with instantaneous net metering. The solar electrical fraction of the system is 21.5%, 43.5% and 50%, respectively. System alternative 2 is unprofitable and has a solar electricity fraction of 5.7%. System alternative 3 is unprofitable and has a solar electricity fraction of just below 50. The conclusion is that a PV system in combination with a heat pump is a superior alternative to a solar thermal system in combination with a heat pump.

  • 17.
    Thygesen, Richard
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Karlsson, Björn
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Simulation and analysis of a solar assisted heat pump system with two different storage types for high levels of PV electricity self-consumption2014Ingår i: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 103, nr May 2014, s. 19-27Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The incentives for PV-systems in Europe is being gradually lowered or ended. This makes a higher level of self-consumption interesting for owners of PV-systems.Sweden has an incentive of 35% of the investment cost for PV-systems. Unfortunately not all consumers can get this incentive. Therefore a high level of self-consumption will be necessary if the PV-systems are to be profitable in Sweden.A reference system with two different energy storage technologies is investigated in this paper. One system with 48. kW. h of batteries and one system with a hot water storage tank where the electricity is stored as heat.The research questions in this paper are:. Which storage system gives the highest level of PV electricity self-consumption?Are the storage systems profitable with the assumptions made in this paper?What are the levelized costs of electricity (LCOE) for the reference system with different storage system?The system with batteries has a self-consumption of 89% of the annual PV-electricity output and the system with a hot water storage tank has 88%.The system with batteries has a levelized cost of electricity two times higher than the system with a hot water storage tank.

  • 18.
    Thygesen, Richard
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Karlsson, Björn
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Simulation of a low energy building in Sweden with a high solar energy fraction.2012Ingår i: PassivhusNorden / [ed] Lasse Postmyr, Tapir Akademisk Forlag, 2012Konferensbidrag (Övrigt vetenskapligt)
  • 19.
    Thygesen, Richard
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Karlsson, Björn
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Simulation of a proposed novel weather forecast control for ground source heat pumps as a mean to evaluate the feasibility of forecast controls’ influence on the photovoltaic electricity self-consumption2016Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 164, s. 579-589Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The building sector in Europe and Sweden accounts for a large part of the total European electricity end use. A large fraction of Swedish buildings are equipped with heat pumps for heating and a combination of heat pumps and decentralized energy generation from photovoltaic systems is an interesting system solution for reducing the energy use. It is important that the building has a high self-consumption of the generated PV-electricity. Self-consumption can be seen as energy conservation and has a considerable higher economic value than exported electricity for the building owner.

    A ground source heat pump with a novel weather forecast controller is simulated in Trnsys and compared to a reference case in regards to self-consumption and profitability. The economic analysis is based on the annuity method and a sensitivity analysis regarding annual cost, discount rate and annual electricity price change has been performed.

    The results indicates that the increase in self-consumed photovoltaic electricity is limited to 7% with the proposed novel weather forecast controller, which means that the controller is unprofitable. Because of this the proposed novel forecast controller is not a viable way of increasing self-consumption in systems with photovoltaic systems and ground source heat pumps in Sweden.

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