Terms Of Life Cycle Cost Research Articles

Life cycle cost analysis of seismic retrofit policy at the city scale

Many early-developed cities are grappling with aging building environments, characterized by chronic deterioration of structures. The consequent rise in seismic risk and loss has spurred governments to promote relevant disaster mitigation plans. In the process of urban renewal or the retrofit of dilapidated buildings, it is crucial to consider economic feasibility and the impact of policies. To support decision-making, this study aims to develop a framework for evaluating different seismic reinforcement strategies at a city level using a life cycle cost-benefit analysis. The reduction of seismic loss by a certain reinforcement strategy was assessed through the capacity spectrum method, fragility curves, and probabilistic seismic hazard analysis. Construction costs and reinforcement costs were adapted from historical data. The Equivalent Uniform Annual Cost Method was also adopted to analyze the overall life cycle cost of the target buildings based on the chosen reinforcement strategy. The researchers of this study analyzed the private buildings in Taipei City, Taiwan, to demonstrate the proposed method. The priority for reinforcement was determined based on various vulnerability measures of the buildings. Six different reinforcement strategies were compared in the case study. The results revealed that the strategies that can properly exploit soft story reinforcement are more economically attractive in terms of life cycle cost. However, a decline in marginal utility was detected. The results also showed that the proposed method could provide an objective reference for determining the priority of reinforcement plans and effectively mitigate the impact of earthquakes on the community. The findings of this research can assist stakeholders in earthquake disaster preparedness and mitigation.

Life-cycle cost analysis of steel frames with shape-memory alloy based dampers

The shape-memory alloy (SMA) based dampers are passive dampers, with their most important feature being their memory and super elastic effect. They significantly reduce the residual response displacements of the structure subjected to earthquakes. Although the initial cost of these dampers is high, they can lower the structural expected life-cycle costs subjected to earthquakes. This study dealt with the life cycle cost analysis to calculate the expected costs of the structures equipped with shape-memory alloy-based dampers. Subsequently, two 4- and 12-story steel frame structures were investigated in controlled and uncontrolled cases in terms of life cycle costs. The results revealed that these dampers can reduce the inter-story drift ratios and the residual displacements of the 4-story structure subjected to the design level seismic acceleration by 31% and 63%, respectively. This reduction for the 12-story structure was 39% and 83%, respectively. Also, these dampers would decrease the total life-cycle cost of the 4-story and 12-story by 53%, and 90%, respectively. Finally, the result indicated that the total life-cycle cost was reduced upon increasing the capacity of the SMA-based dampers up to a specific capacity, beyond which the dampers would not play a role in reducing total life-cycle costs.

A Strategy for Determining the Decommissioning Life of Energy Equipment Based on Economic Factors and Operational Stability

LCC and EL models have been widely used in recent years to determine the decommissioning life of equipment in energy companies, with LCC (life-cycle cost) being the total “lifetime” cost of the equipment from the time it is put into operation until the end of its decommissioning and disposal; the average annual cost of the equipment can be calculated based on the LCC. The overall LCC can be calculated as the average annual LCC, while the EL is the age of the equipment at which its average annual LCC is the lowest. It is believed that the decommissioning of the equipment in the EL year will result in the lowest annual average equipment turnover, thus maximizing the economic benefits of the equipment. Recently, LCC and EL research has been gradually introduced to the energy field, but there remains a lack of research depth. In current practice, energy equipment LCCs are mainly determined by selecting a portion of inventoried equipment to serve as a sample record for all costs incurred. The intent is to derive the economic life of the equipment-year by directly seeking its average annual cost, but this method tends to downplay maintenance, overhaul, and other cost events as “random small probability events”. This method is also incomplete for evaluating the decommissioning life of equipment whose average annual cost strictly decreases year-by-year. In this study, we analyzed the use of 75,220 KV transformers that were put into service by an energy company in 1986 as a case study (costs for this type of equipment were first recorded strictly in terms of LCC in 1986), used Isolated Forest (IF) to screen the outliers of various types of data costs, and then probability-corrected the corrected dataset with a Welbull distribution (Welbull). Then, we employed a stochastic simulation (MC) to calculate the LCC of the equipment and determined its economic lifetime (EL) and compared the results of the stochastic simulation method with those of the traditional method to provide a more reasonable explanation for the “small probability” of cost occurrences. Next, we predicted the average cost of the equipment given a use-period of 38-41-years using AHA, Bi-LSTM, and other comparative algorithms, compared the MAE, MAPE, and RMES indexes, selected the most suitable prediction model, and produced a predicted cost under the chosen method to obtain the economic life of the equipment. Finally, we compared our results with the design life of the equipment (design life being the technical life expectancy of a product based on the expectations of the manufacturer), and determined its best retirement age by comprehensively studying and judging the economic and technical benefits. The retirement age analysis was guided by by a comprehensive study of economic and technical benefits. We refer to our decommissioning life determination model as Monte Carlo -artificial hummingbird algorithm–BiLSTM–lifecycle cost model (MC-AHABi-LCC). We found that the decommissioning life obtained by MC-AHABi-LCC is closer to the actual equipment decommissioning life than that given by standard LCC and EL analysis and that our model is more accurate and scientific.

Global sensitivity analysis and optimisation of design parameters for low GHG emission lifecycle of multifamily buildings in India

In India, nearly 25% of citizens live in slums, unfit for a decent living. Replacing the existing residential building stock and the rapid development of the economy will significantly increase energy consumption and related greenhouse gases (GHG) emissions in the coming decades. Consequently, there is a high need of developing low lifecycle GHG emission, affordable and comfortable multifamily building designs, which can be widely implemented in the Indian construction market.The objective of this article is first to explore the most influential design parameters of the multifamily building located in the in: warm and humid (Bhubaneswar), hot and dry (Jodhpur), and composite (New-Delhi) climate zones of India on life cycle GHG emissions and indoor thermal comfort, and secondly, to perform a multi-objective optimisation considering the life cycle GHG emissions, life cycle cost and initial material investment cost based on the set of the most sensitive design parameters. The study combines a two-step global sensitivity analysis based on the Morris and Fast method with a multi-objective genetic algorithm integrated into one framework based on the parametric multifamily building model with extensive building performance simulations.The global sensitivity analysis results indicated that for all investigated locations: the apartment’s floor area, equipment load, windows-to floor ratio, mechanical ventilation airflow, and cooling temperature setpoint were the most influential design parameters in relation to the lifecycle GHG emissions. Finally, based on the multi-objective optimization, significant reductions in the range of 62–75% in terms of life cycle GHG emissions and 40–54% in terms of life cycle cost were achieved compared to the baseline 7-storey multifamily design scenario based on the minimum requirements of the Indian energy conservation code. At the same time, the initial material investment cost was 25–34% higher. The optimal set of the design strategies, resulting in the lowest life cycle GHG emissions and life cycle cost was found to be minimisation of the apartment’s floor area and windows to floor ratio, maximisation of the on-site renewable energy use, and design of a mechanical ventilation system combined with ceiling fans thus enabling the energy-efficient and thermally comfortable operation of the multifamily building with a high cooling temperature setpoint.

An Optimal Maintenance and Replacement Strategy for Deteriorating Water Mains

Municipal water mains are built with a target service age of several decades. In such a long life, breaks can occur, even multiple times. Water mains can be maintained before or right at breaks. The former is referred to as the preventive strategy, whereas the latter is the corrective strategy. Depending on the costs of repair, replacement, and failure consequence, different strategies should typically be implemented in order to achieve the optimal watermain management in terms of life cycle costs. This study aims to investigate the optimal scenarios for the two strategies based on a two-time-scale (TTS) point process used to model the deterioration of water mains. The corrective strategy is to determine the optimal number n, where upon the n-th break, implementing a replacement for water main is justified, compared to a minimal repair. The preventive strategy is to determine the optimal replacement time in terms of pipe survival probability Ps. Monte Carlo simulations are used to investigate the optimal n and Ps considering a number of influential factors, including model parameters of the intensity function and ratios of maintenance, replacement, and consequence costs. Then, the full distributions of the life cycle costs are characterized with the mean of total life cycle costs being the target for optimization. Last, a case study is illustrated to demonstrate the application of both strategies in real water systems. An important finding is that with a typical pipe diameter of 400 mm and length of 200 m, the optimal n is typically less than five, and the optimal Ps is below 50%.

Multi-objective optimisation for building integrated photovoltaics (BIPV) roof projects in early design phase

Building-integrated photovoltaics (BIPV) is an excellent renewable energy application for building envelopes. In Australia, BIPV roofing is considered to be promising because of recent major concerns about fire risks of façades. However, the integration of PV into building envelope elements is a complicated process which, if not done properly, may lead to failure of the BIPV system. Therefore, feasible BIPV design solutions need to be examined in terms of life-cycle cost and energy performance from the early design phase of a BIPV envelope project. There have been few investigations of the identification of feasible BIPV design options in the early design phase to enable product selection and parametric tests. This study explores a multi-objective optimization method which formulates feasible BIPV envelope design options which have relatively high energy generation and low life cycle costs to informed decision making. The optimisation process has four segments: data inputs, simulator, optimizer and pareto front based optimised BIPV solutions. The proposed multi- objective optimization process is applied in a BIPV roof application using a case study in Australia with roof sheets and skylights. The results demonstrate seven optimum roof sheet BIPV design solutions and fourteen optimum skylight BIPV design solutions to enable design makers to compare and select the most appropriate. The life cycle cost, life cycle energy, CO2 emissions avoided, net present value, payback period, and levelized cost of energy of BIPV solutions vary based on the BIPV modules, tilt angles and placement locations. The proposed optimization method is a helpful guide for BIPV design professionals to identify suitable BIPV design options in the early design phase instead of relying on rule-of-thumb experience.

Techno-Economic Analysis and Feasibility Studies of Electric Vehicle Charging Station

Recent United Nations high-level dialogue on energy, which had emphasized on energy usage and environmental protection, has renewed commitments by different countries on the adoption of electric vehicle (EVs). This paper aims to analyze the economic feasibility of establishing electrical charging stations, which is an important factor for the wide adoption of EVs, using life cycle cost analysis. Although local data have been used, the method can be easily adopted to analyze economic feasibility at different markets. The findings have revealed that an electrical charging station is only feasible when the acquisition cost is kept to a minimum to return 1.47 times the initial investment in terms of life cycle cost. An acquisition cost of BND 29,725 on the electrical charging station represents the threshold below which an electrical charging station is more attractive. In order to promote these charging stations, the government needs to provide multiple incentives, including a subsidy to reduce the acquisition cost, relaxing control on the electric selling price, taxing the establishment of conventional filling stations, and minimally reducing the profit margin on the selling price of fossil fuel. It has been shown that a 40% initial subsidy on the purchase of electrical charging stations, coupled with a slight subsidy of BND 0.018/kWh on electricity, would make electrical charging stations economically competitive. To reach its target of 60% electrification of the transportation sector, Brunei would need to implement a structure program to establish between 646 and 3300 electrical charging stations by the year 2035, to cater for its expected number of EVs.

Multi-objective optimum design of nonlinear viscous dampers in steel structures based on life cycle cost

An algorithm for optimum design of nonlinear viscous dampers with the goal of achieving minimum total cost is presented. An appropriate cost model is developed to determine the initial cost of equipping structures with viscous dampers, and the expected costs of the studied structures related to the possible earthquakes over their life time are estimated using life cycle cost analysis (LCCA). The results of this analysis are used in a multi-objective optimization algorithm with the aim of achieving minimum initial and life cycle cost. To evaluate the seismic behavior of structures, the Endurance Time (ET) method is used as a dynamic response-history analysis method which requires much less computational effort in comparison with conventional time history methods. To this end, the optimum arrangement of nonlinear viscous dampers along with their damping exponent (Alpha) for two weak steel moment frames with 4 and 8 stories are acquired using multi-objective genetic algorithm. Results from the proposed method are compared with two classic methods; uniform and stiffness proportional damping methods. With the aim of proposing an optimal Alpha value, a detailed discussion is provided on its effects on the overall performance of studied structures in terms of life cycle cost.

Evaluating Double Skin Glass Façades in terms of Life Cycle Cost for High-Rise Buildings in Egypt

Evaluating Double Skin Glass Façades in terms of Life Cycle Cost for High-Rise Buildings in Egypt

Life cycle cost estimation and environmental valuation of coal mine tailings management

Sustainable mining management is increasingly seen as an important issue in achieving a social license to operate for mining companies. This study describes the life cycle cost (LCC) analysis and environmental valuation for several coal mine tailings management scenarios. The economic feasibility of six different options was assessed using the Net Present Value (NPV) and Benefit-Cost Analysis (BCA) methods. These options were belt press (OPT 1), tailings paste (OPT 2), thickened tailings (OPT 3), and OPT 1 with technology improvement and renewable energy sources (OPT 1A-C). The results revealed that OPT 1A (belt press technology with stack cell flotation) was the first preference in terms of LCC while OPT 1C (belt press technology with stack cell flotation and 10% wind energy) generated the highest benefits value (BCA) compared to the other options. The LCC and BCA components and the volume of GHG emissions were used to determine the best option. Normalization of these three elements resulted in the selection of Option 1C as being the most cost-effective option.

Comparative life-cycle cost (LCC) study of green and traditional industrial buildings in Sri Lanka

The demand for green buildings is growing, but the trend is below the expected level due to the perceived higher construction cost required by building investors. In addition, the industry or the practitioners knowledge and awareness of major operational cost savings of facilities is questionable. on that note, this study aims to establish the cost implications of green buildings via a comparative life-cycle cost analysis of two green certified industrial and one traditional building. The industrial sector is one of the largest energy consuming sectors in the world with over 50% of the world’s total delivered energy is absorbed by the sector. Energy consumption of industrial sector is likely to increase more due to the economic and population growth.The data for the analysis were extracted from construction, operation, and maintenance expenditure budget records of the selected organisations. The analysis shows that in terms of life-cycle costs, green industrial buildings are 17% cheaper than that of traditional buildings. Though the initial construction cost of a green industrial building is 29% higher, the operation and maintenance costs of green buildings result in 23% and 15% overall savings throughout the life cycle. The findings provide further empirical proof of the benefits of green buildings, especially in industrial manufacturing where it is expected to improve future uptakes and consequently the achievement of sustainable development initiatives.

Методика избыточных проектных схем и метод поконтурной минимизации систем группового водоснабжения и водоотведения

Due to the uneven distribution of water resources across the territory of Russia, many settlements and even cities do not have own sources of water supply and reservoirs, where treated wastewater could be discharged. To solve this problem, group and district water supply and sewerage systems are designed, built, and developed, hundreds and even thousands of kilometers long. The construction and operation of such facilities require significant financial investments every year. Therefore, the issues of the choice of routes, the structure of facilities, and particularly the methods of transporting water and wastewater, justifying the locations of water intakes and treat treatment facilities are relevant and require special attention and development of a comprehensive methodology for optimizing the structure and parameters of water supply and sewerage systems. The paper proposes, on the basis of a previously constructed redundant graph, the method of contour minimization of the structure of facilities and ways of supplying water to end users, transporting wastewater to treatment plants by pipelines and trucks. The redundant graph includes all kinds of connections (edges, arcs) that simulate pipelines and trucks, between vertices that simulate existing and new sources of water and wastewater discharges, sewage treatment plants, pumping stations, control tanks, and end users. The method selects the best (from the point of view of minimal life cycle costs) edges, arcs, and vertices of the graph and determines the corresponding parameters of pipeline and road sections of the network and facilities. This method is based on the procedure of traversing the contours and sequentially replacing the branches of the tree with moves, while the best option is remembered in the form of a spanning tree. Based on the results of the performed numerical experiments, it was shown that the use of combined (pipeline and truck) systems for transporting water in terms of life cycle costs is optimal.

Condition-Based Economic Assessment of Airplane Engines

A model is proposed for economic assessment of projected airplane engines, in terms of life-cycle costs. Adoption of a new strategy is recommended: management of engine life on the basis of the current state of the system (on-condition maintenance) and increase in economic efficiency at the operational stage. A conceptual approach to extending the life of promising aircraft engines is outlined, on the basis of a diagnostic system (real-time performance assessment). That permits decisions regarding the engine’s potential for continued operation.

Life cycle cost analysis on three high-performance glazing systems for an office building in New Cairo, Egypt

ABSTRACT In the hot desert climate zones, the energy consumption of fully glazed office buildings is too high due to the heavy cooling loads. This problem forced architects to use the High-Performance Glazing Systems (HPGSs) which reduce the solar heat gain and save energy. Despite the high initial cost, the HPGSs are supposed to be economically feasible in the long term. This study investigates and compares the economic feasibility of three HPGSs for an office building in New Cairo. In terms of life cycle cost (LCC), the Low-E, Electrochromic, and Photovoltaic glazing systems are compared to the Clear Double-Glazing as a conventional system. Furthermore, the three economic indicators; Net Present Value (NPV), Internal Rate of Return (IRR), and Payback Period (PBP) are analysed. In conclusion, the Low-E Glazing System has the lowest LCC because of the low disposal cost. Moreover, the Low-E glazing has the highest NPV, IRR, and the shortest PBP (15 years). Due to the high initial and maintenance costs, the Photovoltaic Glazing System has a higher LCC. The Electrochromic Glazing System is not economically feasible due to the highest LCC, the lowest NPV, the lowest IRR, and the longest PBP which exceeds 30 years.

A holistic approach to risk-based decision on inspection and design of fatigue-sensitive structures

Design and operation of large welded structural systems (e.g. ship and offshore structures) are challenging due to numerous fatigue-sensitive details, limited available budgets, uncertainties in fatigue damages, inspection & maintenance activities, etc. Traditionally, fatigue design and maintenance planning have been almost disconnected, which restricts coherent decision-making and optimum safety management. Structural design optimization, without quantitatively incorporating the effects of operational maintenance, can hardly result in a structural plan that is optimum in terms of life cycle costs. Also, if the design of a structure is not optimum, maintenance optimization alone cannot really yield a optimum maintenance plan. As operational inspections and maintenance are essential, there are merits to utilize their effects on structural design and meanwhile optimize them at the initial design stage when impacts of decisions are greater. This paper proposes a risk-based approach to holistic decision-making enveloping decisions and uncertainties affecting design, inspection and maintenance of fatigue-sensitive components. Decisions variables in structural scantling and operational maintenance are obtained holistically at the structural design stage by risk-based optimization, based on quantitative assessment of the effectiveness of both structural scantling and maintenance interventions. Optimum fatigue reliability level is also obtained, informed by the effects of uncertainties and failure consequences. The method captures combined benefits of structural scantling and operational maintenance to fatigue reliability and risk mitigation and achieves optimum resource utilization and life cycle cost reduction. Advantages of the proposed method have been demonstrated via a numerical example, in comparison to alternative methods.

Türkiye'de Rijit ve Esnek Üstyapı Kaplamalarının Yaşam Döngüsü Maliyetlerinin Karşılaştırmalı Bir Değerlendirmesi

Choosing pavement type is a challenging and much-debated issue among public authorities. It includes engineering factors such as materials, labor, and long-term performance within the scope of the initial (construction) and life-cycle costs. In recent years, given the significant public expenditure on road construction and rehabilitation processes, the trends in vehicle ownership caused by an increasing need to travel, and the decrease in local resources, concerns have been raised about the efficiency of pavement coating types. To ensure that taxpayers understand the full value of road expenditure, it is important to identify a coating type selection process that seeks to include the most appropriate construction, maintenance, and repair strategies possible. In this study, an LCCA was performed for a 2.2 km–long Roller Compacted Concrete (RCC) test track constructed in Kocaeli city. If asphalt is chosen instead of RCC as the coating preference, the economic factors that may arise at a national scale (in this case, Turkey) are discussed. During the 20-year service period, maintenance, repair, and rehabilitation planning were carried out on the basis of a 30-year analysis period. In terms of initial construction costs, an RCC road is 39.4% more economical than an asphalt road and provides maintenance and repair economies of 62% during the service period. In terms of life-cycle costs, an RCC road is a 46% more economical paving alternative than an asphalt road. Although the first serious maintenance activity was carried out in the 10th and 20th years of the asphalt road, it was significant that it only took place during the 20th year for the RCC road, and the asphalt maintenance material was more expensive than that for the RCC road.

Differential evolution - based system design optimization for net zero energy buildings under climate change

A proper system design is crucial for a net-zero energy building (NZEB) to achieve the desired performance during its lifecycle. Most conventional design methods utilize TMY (typical meteorological year) data or multi-year historical data for NZEB system sizing. Due to the climate change, future weather data may differ considerably from these utilized data. Consequently, these designs may not guarantee NZEBs to achieve the expected performance during their lifecycle. Therefore, this study proposes a differential evolution – based system design for NZEBs under climate change. Using the predicted weather data of Hong Kong (including temperature and solar radiation), the proposed system design can optimize building system sizes for minimizing its lifecycle cost with user-defined performance constraints satisfied. Three performance constraints were considered and they were thermal comfort, energy balance and grid interaction. Using the actual weather data, the proposed design has been validated by comparing with two conventional designs (i.e., TMY data-based design and multi-year historical data-based design) in an office building. The results indicated that the proposed design can achieve better performance in terms of lifecycle cost and constraints satisfaction. With improved performance, the proposed design can be used in practice for NZEB system sizing especially as climate change considered.

Evaluation of low-impact modular housing using energy optimization and life cycle analysis

This paper presents life cycle analysis of the container-based single-family housing and combines energy analysis and optimization, life cycle assessment and life cycle costing. The proposed models include the container code (CC), designed to Canadian national building code as reference model, and an improved container (IC) incorporating passive solar technologies. Utilizing passive design strategies results in approximately 79% reduction in annual operational energy consumption for the improved case. The life cycle assessment considers the total energy use and global warming potential over 60-year lifespan. Three life cycle phases are considered: pre-use, use and operation, and end of life. As a result of envelope upgrade, the IC offers 77% reduction in life cycle energy use and global warming potential (GWP) than the CC. However, the envelope upgrade requiring greater energy intensity through industrial processing of additional building materials led to higher environmental impact, approximately 65,370 kWh of embodied energy and 20 t of CO2 eq of GWP embodied carbon emissions for the improved container at pre-use phase. In terms of life cycle cost, IC shows less than 10% total cost savings as compared to CC. This study, however, proves that integrating passive solar design techniques in building not only results in reduced energy consumption but rather translates to reduction in life cycle environmental impacts and life cycle cost building systems, which is, in this case, a modular container housing.

Realistic Traffic Condition Informed Life Cycle Assessment: Interstate 495 Maintenance and Rehabilitation Case Study

As construction costs continue to rise and adequate amounts of funding continues to be a challenge, the allocation of resources is of critical importance when it comes to the maintenance and rehabilitation (M&R) of highway infrastructure. A Life Cycle Assessment (LCA) methodology is presented here that integrates realistic traffic conditions in the operational phase to compare M&R scenarios over the analysis period of a 26-km stretch of Interstate-495. Pavement International Roughness Index (IRI) were determined using American Association of State Highway and Transportation Officials (AASHTO) PavementME System. Meanwhile, vehicle fuel consumption and emission factors were calculated using a combination of Google Maps®, the United States Environmental Protection Agency (EPA) Motor Vehicle Emission Simulator, the second Strategic Highway Research Program (SHRP2) Naturalistic Driving Study, and MassDOT’s Transportation Data Management System. The evaluation of pavement performance with realistic traffic conditions, varying M&R strategies, and material characteristics was quantified in terms of Life Cycle Cost (LCC), Global Warming Potential (GWP), and Cumulative Energy Demand (CED) for both agencies and users. The inclusion of realistic traffic conditions into the use phase of the LCA resulted in a 6.4% increase in CED and GWP when compared to baseline conditions simulated for a week long operation duration. Results from this study show that optimization of M&R type, material selection, and timing may lead to a 2.72% decrease in operations cost and 47.6% decrease in construction and maintenance costs.

Computational comparison of a novel decentralized photovoltaic district heating system against three optimized solar district systems

Abstract Climate change is one of the biggest challenges at the present time, and to tackle such issue, solar energy and efficient buildings, in general, can be used. The goal is to design and optimize photovoltaic based decentralized district heating system and later compare it—economically and technically—against three different optimized typologies of solar district heating system in Nordic conditions. The photovoltaic based decentralized system consists of one centralized low temperature tank charged by photovoltaic and air-water heat pumps and a borehole thermal energy storage, while the decentralized high temperature tank charged by an individual water-water heat pump in each house. The centralized warm tank charges the borehole thermal energy storage. The other three systems are photovoltaic based centralized, roof-mounted solar thermal based centralized and roof-mounted solar thermal based decentralized district heating systems. In solar thermal based systems, collectors are used to directly charge the short-term storage tanks instead of the photovoltaics/heat pump combination. The proposed system is simulated using TRNSYS software. Lastly, purchased electricity and life cycle costs of the system are minimized using multi-objective optimization and the genetic algorithm. The results indicated that the decentralized photovoltaic based system outdoes all the other systems in terms of techno-economic performance. The purchased electricity can be reduced by 22% while at the same time life cycle cost can be reduced up to 40%, compared to the worst optimized system (solar thermal based centralized system). Moreover, the decentralized photovoltaic based energy system has a payback period of 9–27 years, compared to the solar thermal based system and the conventional single building-heat pump system, i.e. around 17–58 years and 15 years, respectively. The highest renewable energy fraction for heating can be close to 99% for this system. The decentralization and electrical based district systems are better in terms of life cycle cost, payback period and in terms of technical performance, compared to traditional single house and solar thermal based district heating systems.