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Abstract: The pulp and paper industry both uses and produces large amounts of energy and rising fuel prices bring along significant challenges to the sector. Several strategies can be applied in order to remain competitive e.g. an increase in energy efficiency, a switch in fuel and/or a novel energy conversion technology. In this study, we investigate if improved energy conversion strategies can reduce energy costs, primary energy use and CO2 emissions of paper mills within different European countries (The Netherlands, Poland and Sweden). Our results show that differences in history and availability of resources has led to different conversion strategies in the three countries. We found that a natural gas combined cycle, which is largely implemented in The Netherlands due to long term domestic availability of natural gas, has the lowest primary energy demand. Due to a long history of low electricity prices, CHP has not been common in Sweden. Many Swedish mills use biomass as an energy source and due to low CO2 emissions of the national grid the CO2 emission profile of the Swedish paper industry is very low. Our results imply that future conversion routes for the Swedish paper and board industry are again wood based; in case of increasing electricity prices these would be biomass gasification based CHP solutions. With a reduction of 800kg CO2/ton paper on average, a switch from coal to biomass would reduce CO2 emissions in the Polish pulp and paper industry with approximately 0.6Mton/year. A carbon price of 20–25€/ton would, according to our results, be enough to provoke this switch. Due to the high share of natural gas, the CO2 emission reduction potential of the Dutch paper industry (1.5Mton/year) is even larger than in Poland. Due to high biomass prices and relative low CO2 emission profile of natural gas, a carbon prices of more than 60€/ton CO2 would be needed to provoke a switch in The Netherlands. Provided with few alternatives, the most effective strategy in The Netherlands would be an increase in energy efficiency. [Copyright &y& Elsevier]

Due to the increased use of variable renewable energy sources, more capacity for reserves is required. Non-generating resources such as large industrial consumers can arbitrage energy prices and provide reserve capacity by exploiting the inherent flexibility in selected industrial processes. A large enough industrial consumer can capitalize on this flexibility through optimized bidding in electricity markets. In this work, the day-ahead cost minimization of a risk-averse pulp and paper mill is formulated as a two-stage stochastic problem, considering thermodynamic and electrical constraints. The bids in the energy and reserve markets are jointly optimized subject to price uncertainty as well as uncertainty of frequency realization. The results of a case study in Sweden display a significant economic benefit in exploiting the flexibility of integrated pulp and paper mills with electric boilers. The expected cost of the pulp and paper mill resulting from different strategies are compared and the risk-aversion of the pulp and paper mill is investigated. Reserve offers are mainly facilitated by fast-acting electric boilers and supported by flexibility in the steam network. We show that reserve offers can significantly improve the profitability of the pulp and paper mill. • Pulp and paper mills with electric boilers can supply primary frequency reserves. • Electric boilers can provide up to 50 MW flexibility of 100 MW rating. • An algorithm is developed to optimize the energy & reserve bids of the mill. • Expected cost savings range between 7.4% in summer and 2.3% in winter. [ABSTRACT FROM AUTHOR]

The energy transition towards sustainable resources is more urgent than ever given the environmental and geopolitical challenges. Being one of the major energy users, cities need to understand their energy sector to accomplish its transition, by means of data. However, data are not easily accessible and have their own challenges. This paper presents a joint effort between researchers, city representatives and industry to provide an urban system service that supports research, accelerates urban innovation, and involves the community. An energy data portal, "NRGYHUB", has been developed, where hourly data from thousands of energy meters are available. These meters were collected from neighborhoods in the city of Västerås, Sweden, and they measure electrical and heating energy. In addition, the data are complemented by geometrical and non-geometrical information of the buildings, as well as demographic statistics of the areas. The paper describes the process of data collection, preprocessing, and visualization, in addition to the main challenges and limitations of the project. This dataset can be used for energy use benchmarking, prediction, and analysis. • The creation and implementation of an energy data portal is detailed and made available on nrgyhub.mdu.se. • Legal and licensing issues in data sharing are explored, offering insights for those interested in Sweden and beyond • By showcasing real-world problems, the impact and role of this data sharing initiative are demonstrated. [ABSTRACT FROM AUTHOR]

• Proposed a two-stage optimization framework to enhance the flexibility of energy communities. • Presented a home energy management system (HEMS) incorporating solar PV, EV, heat pump, space heating, and TES. • Designed a model predictive control-based optimization algorithm for integrated energy systems. • Developed a practical algorithm to coordinate multiple HEMSs within a community energy management system. • Established a co-simulation framework to investigate energy flexibility in an energy community. Electrification of private transportation and residential heating is a potential action to decrease significantly carbon emissions. However, the lack of coordination of such emerging loads can increase stress on the power distribution grid. To this end, this paper proposes a two-stage energy management strategy, to enhance the flexibility of energy communities. First, an optimization algorithm-based model predictive control (MPC) is developed for home energy management systems (HEMS) to schedule electric vehicles (EVs) for charging and discharging in cooperation with heat pump and thermal energy storages. The objective is to reduce electricity bills and EV battery degradation costs while maintaining thermal demand. Second, the predictive coordination based on the nonlinear AC optimal power flow approach is applied to enhance the grid flexibility under a community energy management system scheme. To validate the performance of the proposed method, we develop a co-simulation framework by implementing the optimization algorithm and simulation scenarios in a Python Environment and modelling the electricity grid in the PowerFactory-DIgSILENT, which are linked together. Extensive numerical simulations are carried out under the active demand response program-based hourly electricity pricing and different weather data in Sweden. The results show that the proposed method can reduce operating costs and enhance the energy flexibility of the energy community. Moreover, it can decrease the stress on the community power grid and prevent load-shedding events compared to the non-predictive coordinated method. [ABSTRACT FROM AUTHOR]

Several studies have shown that the revenue of wind power generators on spot markets (“market value”) diminishes with increasing deployment. This “value drop” is mostly observed in power markets that are dominated by thermal power plants, such as in Germany. This paper assesses the wind market value in power systems where hydroelectric stations with large reservoirs prevail, such as in Sweden. Due to their dispatch flexibility, such hydropower compensates for wind power output variability and thereby mitigates the wind power value drop. The market value of electricity from wind declines with penetration in both types of power systems, but it tends to decline at a slower rate if hydropower is present. This paper presents empirical evidence on the relevance of this effect derived from market data and numerical model results. Our results indicate that when moving from 0% to 30% wind penetration, hydropower mitigates the value drop by a third. As a result, 1 MWh of wind energy is worth 18% more in Sweden than in Germany. Sensitivity analyses indicate high robustness despite large parameter uncertainty: in 80% of all sensitivities, wind energy is valuable 12–29% more in Sweden than in Germany. The benefits of hydropower seem to level off at around 20% wind penetration. This suggests that the hydro flexibility is “exhausted” at this level. Low wind speed wind turbines, carbon pricing, and upgrades of hydropower generation capacity can lever the added value of hydro flexibility further. Not only is wind energy more valuable in the presence of hydropower, hydroelectricity also becomes more valuable if paired with wind power. [ABSTRACT FROM AUTHOR]

Many studies have highlighted the importance of retrofitting to mitigate the energy use of building stocks. An important step in the development of renovation strategy and energy conservation advising is to gather information of the energy performance of the existing buildings. However, renovation strategies must also consider the socio-economic challenges associated with the cost of energy retrofitting. This paper describes the development of an energy atlas of the multifamily building stock in Sweden for visualizing and analyzing energy use and renovation needs. The atlas has been developed using Extract Transform and Load technology (ETL) to aggregate information on the energy performance, building ownership, renovation status, and socio-economic status of inhabitants from various data sources. The atlas can visualize the energy use and renovation status of multifamily buildings in 2D maps and 3D models, displaying data for either individual buildings or aggregated data on spatial scales ranging from 250 × 250 m squares through district and municipality to county areas. A demonstration of its use on national and city scales indicates that energy retrofits of multifamily buildings reaching a service life of 50 years can reduce the energy use of the existing building stock by up to 50% relative to 1990. However, costs associated with renovation and energy retrofits of multifamily buildings can be problematic, especially in economically weak suburbs. A good understanding of past and future renovation needs and socio-economic consequences is important in the development of a sustainable national renovation strategy. [ABSTRACT FROM AUTHOR]

The increasing population living in cities is leading to higher resource utilization, which strains the cities’ ability to focus on sustainability. Adoption of different technologies can transform cities into “smart cities” that utilize energy in a more efficiently. This paper presents results from a technology assessment tool developed together with six mid-sized European cities. The main areas of focus have been evaluated based on the cities’ priorities: transportation (both public and private) and consumers’ perspectives on the use of smart electricity meters. The use of electric vehicles in Sweden, and a techno-economic evaluation of biogas-derived biomethane and electricity use in public transportation have been analyzed. The main conclusions show an overall higher efficiency for biogas-derived electricity use in electric buses; a need for higher consumer engagement through more detailed information provision for both increasing EV market penetration and electricity savings; and a need to establish detailed technology assessments for successful technology adoption in cities. [ABSTRACT FROM AUTHOR]

Abstract: Large scale integration of wind energy poses new challenges to the European power system due to its stochastic nature and often remote location. In this paper a multivariate uncertainty analysis problem is formulated for the integration of stochastic wind energy in the European grid. By applying copula theory a synthetic set of data is generated from scarce wind speed reanalysis data in order to achieve the increased sample size for the subsequent Monte Carlo simulation. In the presented case study, European wind power samples are generated from the modeled stochastic process. Under the precondition of a modeled perfect market environment, wind power impacts dispatch decisions and therefore leads to alterations in power balances. Stochastic power balances are implemented in a detailed model of the European electricity network, based on the generated samples. Finally, a Monte Carlo method is used to determine power flows and contingencies in the system. An indicator is elaborated in order to analyze risk of overloading and to prioritize necessary grid reinforcements. Implications for the Swiss power grid are investigated in detail, revealing that the current system is significantly put at risk in certain areas by the further integration of wind power in Europe. It is the first time that the results of a probabilistic model for wind energy are further deployed within a power system analysis of the interconnected European grid. The method presented in this paper allows to account for stochastic wind energy in a load flow analysis and to evaluate deterministic indicators, such as the N −1 criterion, on a probabilistic basis. Thus, it constitutes an important extension of deterministic models. [Copyright &y& Elsevier]

Abstract: The paper focuses on Swedish homeowners’ need for and perceptions about adopting building envelop energy efficiency measures. The paper is based on a questionnaire survey of 3059 homeowners (response rate of 36%) selected by stratified random sampling during the summer of 2008. The results showed that 70–90% of the respondents had no intention of adopting such a measure over the next 10years. The main reasons for non-adoption were that homeowners were satisfied with the physical condition, thermal performance, and aesthetics of their existing building envelope components. A greater proportion of respondents perceived that improved attic insulation has more advantages than energy efficient windows and improved wall insulation, but windows were more likely to be installed than improved attic insulation. Respondents gave high priority to economic factors in deciding on an energy efficiency measure. Interpersonal sources, construction companies, installers, and energy advisers were important sources of information for homeowners as they planned to adopt building envelope energy efficiency measures. Policy measures to facilitate the rate of adoption of energy efficient building envelope measures are discussed. [Copyright &y& Elsevier]

In this paper, a municipality with district heating supplied via boilers and combined heat-and-power (CHP) plants is studied. The electricity load in the municipality is provided for by the CHP plant and electricity bought from the Nordic electricity market. It is therefore desirable to produce as much electricity as possible during periods when the price of electricity is high. The variations in the price of electricity over a 24-h period are significant. The idea presented in this paper is that heat storage can be used to maximise the amount of electricity produced in the CHP plants during peak-price periods. It can also be used to minimise the use of plants with higher operational costs. For storing heat, both a hot-water accumulator at the CHP plant and storage in the building stock are suggested. The situation is analysed using a mixed integer linear-programming model and a case study is presented for the city of Linko¨ping, a City of approximately 130,000 inhabitants, situated 200 km south of Stockholm in Sweden. A simple model for forecasting the electricity price on the Nordic electricity market is also presented. [Copyright &y& Elsevier]

The Växjö municipality sets specific energy related requirements beyond the Swedish building code (BBR) when selling land for the construction of new residential buildings. The requirement for Östra Lugnet residential area was that all buildings must be connected to the local district heating network and installation of heat pumps was prohibited in developer-built group/row houses. This paper (a) analyzed if the energy use of the buildings fulfilled the requirements of the BBR and that of Växjö municipality, and (b) compared the primary energy use and CO 2 emission from operation of the district heated buildings with hypothetical scenarios where only air-source or bedrock heat pumps were installed. Results showed that a significant proportion of the group/row houses did not fulfil the specific energy use requirements of the BBR and that of Växjö municipality. There were large variations between predicted and actual energy use. Using a marginal accounting approach, houses with district heating were found to have the lowest carbon emission. From this perspective it seems appropriate for Växjö municipality to set the requirement that new residential buildings in Östra Lugnet be connected to the local district heating network. [ABSTRACT FROM AUTHOR]

In this paper, a simulation model that forecasts electricity load profiles for a population of Swedish households living in detached houses is presented. The model is constructed of three separate modules, namely appliance usage, Domestic Hot Water (DHW) consumption and space heating. The appliance and DHW modules are based on non-homogenous Markov chains, where household members move between different states with certain probabilities over the days. The behavior of individuals is linked to various energy demanding activities at home. The space heating module is built on thermodynamical aspects of the buildings, weather dynamics, and the heat loss output from the aforementioned modules. Subsequently, a use case for a neighborhood of detached houses in Sweden is simulated using a Monte Carlo approach. For the use case, a number of justified assumptions and parameter estimations are made. The simulations results for the Swedish use case show that the model can produce realistic power demand profiles. The simulated profile coincides especially well with the measured consumption during the summer time, which confirms that the appliance and DHW modules are reliable. The deviations increase for some periods in the winter period due to, e.g. unforeseen end-user behavior during occasions of extreme electricity prices. [ABSTRACT FROM AUTHOR]

• A comprehensive analysis framework for roof-mounted solar PV systems is developed. • The estimated roof area for Västerås municipality is 5.74 km2. • Different scenarios are considered for the potential installation of PV systems. • The potential capacity is 727-956 MWp and annual yield is 626-801 GWh for Västerås. • 504 km2 usable roof area and 65-84 GWp installed capacity are estimated for Sweden. Solar photovoltaic energy, driven mostly by the residential and commercial market segments, has been growing a lot in recent years in Sweden. In response to the commitment towards sustainability goals, this paper explores the potential of roof-mounted solar photovoltaic projects. This paper focuses on: roof area estimation, potential installed capacity, and potential electricity generation, at the single municipal scale and at the national scale. The following categories of different building types have been investigated: residential buildings, industrial buildings, buildings of social function, buildings of business function, buildings of economic/agricultural function, buildings of complementary function, and buildings of other unknown functions. The analysis starts from Västerås, a typical Swedish municipality and ranking seventh among the largest cities in Sweden. An estimate of 5.74 km2 available roof area potential is calculated, by considering factors such as building purposes, roof orientations, shadows and obstacles. The total potential installed capacity is calculated, assuming the installation of commercial photovoltaic modules, and design parameters for flat roofs such as inter-row distances and tilt angles. With the inputs of meteorological parameters and geographical information, the potential yearly electricity generation is calculated. The results reveal 727, 848, and 956 MW p potential installed capacity and 626, 720, and 801 GWh annual electricity production for Västerås on pitched roofs and flat roofs with three scenarios, respectively. The extrapolation of the methodology to the entire of Sweden yields a total of 504 km2 usable roof area and 65, 75, and 84 GW p installed capacity. Finally, we reveal a new understanding of usable roof area distribution and of potential installed capacity of roof-mounted solar photovoltaic systems, which can largely help evaluate subsidy scale and solar energy policy formulation in Sweden. [ABSTRACT FROM AUTHOR]

• Energy Performance Certificates (EPCs) are being renewed across Europe. • Old and renewed EPCs for Swedish multifamily buildings are matched and compared. • A three-step method is developed to ensure that matched EPCs are comparable. • Novel quantitative, building-specific analyses of change in energy use are enabled. • Future applications of matched EPCs include evaluation of renovations and policies. Energy Performance Certificates are currently one of the most extensive data sources about the energy performance of the EUs building stock and consequently provide support for researchers and policy makers in energy regulation. As Energy Performance Certificates are being renewed, there are new possibilities to study energy performance development over time and to evaluate the building-specific effect of energy policies and measures. This paper aims to explore this possibility. In Sweden, owners of multifamily buildings had to obtain their first Energy Performance Certificate no later than the end of 2008, and with a period of validity of 10 years many owners have now obtained a second Energy Performance Certificate for their building(s). This enables unprecedented quantitative, building-specific evaluations of the change in energy performance over time. However, comparability between old and new Energy Performance Certificates must be assured. This study develops a novel three-step method to attain comparability between old and renewed Energy Performance Certificates. Results show that while many pairs of Energy Performance Certificates were considered comparable, procedural changes in methods for determining heated floor area in Swedish Energy Performance Certificates caused an overestimation of energy performance improvement of approximately 7 kWh/m2 per building which had to be corrected for. The results of this paper indicate that old and renewed Energy Performance Certificates can be utilised to successfully map development of energy performance and enable evaluation of the impact on energy performance from policies and measures that have been carried out between the two points of audit. [ABSTRACT FROM AUTHOR]

Abstract: This study presents a survey of the most important techno-economic factors for the implementation of biorefineries based on agricultural residues, in the form of straw, and biochemical conversion into ethanol and biogas, together with production of electricity and heat. The paper suggests locations where the necessary conditions can be met in Sweden. The requirements identified are regional availability of feedstock, the possibility to integrate with external heat sinks, appropriate process design and the scale of the plant. The scale of the plant should be adapted to the potential, regional, raw-material supply, but still be large enough to give economies of scale. The integration with heat sinks proved to be most important to achieve high energy-efficiency, but it was of somewhat less importance for the profitability. Development of pentose fermentation, leading to higher ethanol yields, was important to gain high profitability. Promising locations were identified in the county of Östergötland where integration with an existing 1st generation ethanol plant and district heating systems (DHSs) is possible, and in the county of Skåne where both a significant, potential straw supply and integration potential with DHSs are available. [Copyright &y& Elsevier]

Abstract: Ethanol can be produced with little impact on the environment through the use of polygeneration technology. This paper evaluates the potential of integrating a lignocellulosic ethanol plant into a district heating system by case study; the plant has an ethanol capacity of 95MW with biogas, electricity and heat as by-products. Stockholm’s district heating system is used as the case study, but the results may be relevant also for other urban areas. The system has been studied using MODEST – an optimisation model framework. The results show that introducing the plant would lead to a significant reduction in the cost of heat production. The income from the biofuels and electricity produced would be about €76million and €130million annually, respectively, which is an increase of 70% compared to the income from the electricity produced in the system today. Assuming that the electricity produced will replace marginal electricity on the European electricity market and that the biofuel produced will replace gasoline in the transport sector, the introduction of the polygeneration plant in the district heating system would lead to a reduction of global CO2 emissions of about 0.7million tonnes annually. [Copyright &y& Elsevier]

Abstract: The energy performance of buildings in cold climates, with a considerable annual heating demand, is dependent on the ventilation air change rates (ACH). Buildings utilized for commercial use often have high annual ventilation heating demand due to high ACH required from indoor air quality aspect. In order for these buildings to have a reasonable energy performance a heat recovery system is often used to recover heat from the exhaust air to the makeup air. There are different variations of these systems; one that is sometimes used in Sweden is a run around coil heat recovery system. The present paper summarizes the findings from previous studies , and presents a comparative study, for three different cases; the traditional run-around coil heat recovery system; with a three stage on/off controlled heat pump retrofitted into the system; and with a variable capacity heat pump retrofitted into the system. Annual modeling (using TRNSYS) shows that by retrofitting a well-designed 3 stage heat pump to the system the annual heat recovery rate for the Stockholm case can be increased from 47% to 65%. For a retrofitted variable speed capacity heat pump for the Stockholm case the annual heat recovery improves from 47% to 66%. The modeling also shows that a well designed variable speed heat pump can cover 81% of the total ventilation heating demand and a well designed multi stage heat pump 77% of the total ventilation heating demand. [Copyright &y& Elsevier]

Abstract: When discussing how society can decrease greenhouse gas emissions, the transport sector is often seen as posing one of the most difficult problems. In addition, the transport sector faces problems related to security of supply. The aim of this paper is to present possible strategies for a road transport system based on renewable energy sources and to illustrate how such a system could be designed to avoid dependency on imports, using Sweden as an example. The demand-side strategies considered include measures for decreasing the demand for transport, as well as various technical and non-technical means of improving vehicle fuel economy. On the supply side, biofuels and synthetic fuels produced from renewable electricity are discussed. Calculations are performed to ascertain the possible impact of these measures on the future Swedish road transport sector. The results underline the importance of powerful demand-side measures and show that although biofuels can certainly contribute significantly to an import-independent road transport sector, they are far from enough even in a biomass-rich country like Sweden. Instead, according to this study, fuels based on renewable electricity will have to cover more than half of the road transport sector’s energy demand. [Copyright &y& Elsevier]

Abstract: Concerning production and use of biofuels, mismatch between the locations of feedstock and the biofuel consumer may lead to high transportation costs and negative environmental impact. In order to minimize these consequences, it is important to locate the production plant at an appropriate location. In this paper, a case study of the county of Norrbotten in northern Sweden is presented with the purpose to illustrate how an optimization model could be used to assess a proper location for a biomass based methanol production plant. The production of lignocellulosic based methanol via gasification has been chosen, as methanol seems to be one promising alternative to replace fossil gasoline as an automotive fuel and Norrbotten has abundant resources of woody biomass. If methanol would be produced in a stand-alone production plant in the county, the cost for transportation of the feedstock as well as the produced methanol would have great impact on the final cost depending on where the methanol plant is located. Three different production plant sizes have been considered in the study, 100, 200 and 400MW (biomass fuel input), respectively. When assessing a proper location for this kind of plant, it is important to also consider the future motor fuel demand as well as to identify a heat sink for the residual heat. In this study, four different automotive fuel- and district heating demand scenarios have been created until the year 2025. The results show that methanol can be produced at a maximum cost of 0.48 €/l without heat sales. By selling the residual heat as district heating, the methanol production cost per liter fuel may decrease by up to 10% when the plant is located close to an area with high annual heat demand. [Copyright &y& Elsevier]

Abstract: This paper presents a review of the sparse district-heating research programme undertaken in Sweden between 2002 and 2006. The goal of the programme was to increase the future competitiveness for district heat in low heat density areas, e.g., suburban single-family houses and small villages. Such areas are unfavourable, since revenues from heat sold are low compared with the investment cost for the local distribution network. In Sweden, district heat has a dominant position in the heat market for residential and service-sector buildings. In order for the business to grow, it is necessary to increase the rate of expansion in the detached-house segment. This is why the programme was initiated. The extent of the programme was set at € 3.6 million with equal financing from the Swedish District-Heating Association and the Swedish Energy-Agency. The research was carried out in three phases: a state of the art survey; a development phase focused on productivity gains where new research on both technology and customer interaction was performed; and finally a demonstration phase where new methods were tested in full-scale field operation. The programme has shown that the Swedish district-heating industry needs to adjust in order to reach a higher profitability for sparse district-heating investments. Tradition from large-scale high-density district heating is hard to scale to fit sparse district-heating systems. For example, the construction becomes very labour intensive and the industry is weak when it comes to market-oriented business logic, sales and private customer interaction. Innovation seems to be a way forward and active management of innovations is a way to create increased value of the investments. Other keys to improving the profitability of sparse district-heating investments are more efficient working routines (resulting in higher productivity) and revised ways of customer communications. These seem more important than increasing efficiency in district-heating technology. [Copyright &y& Elsevier]

Over the past three decades, Swedish energy policy has evolved in three major stages—oil reduction, phase-out of nuclear energy, renewable energy—each with a different focus. Since 1977, Swedish law has required municipalities to develop an energy plan that addresses the supply, distribution, and use of energy. Whether such plans have contributed to the development of local energy-systems has been a subject for debate. This paper is based on a study of 12 municipal energy-plans that attempted to control and develop local energy-systems in southern Sweden. The analysis examines how municipalities promote oil reduction, efficient energy use, and the use of renewable energy. The plans varied in planning processes, contents, and level of ambition. The results of the study show that the contents of the plans follow the national energy-policies with respect to reduction of oil use, improved energy efficiency, and increased use of renewable energy. [Copyright &y& Elsevier]

• Strategies to facilitate biomass use in the iron & steel industry are explored. • Spatial and cost optimisation of biomass supply specific to iron & steel making. • Biomass utilisation leads to a 43% reduction in CO 2 emissions. • Energy costs increase to a maximum of 27% compared to the business-as-usual case. • Using CO 2 prices result in less CO 2 reductions compared to substitution targets. This paper considers the utilisation of forest biomass in iron and steel making by putting focus on the supply of available raw biomass assortment, biomass conversion technologies, and distribution of biomass-based products towards reduced fossil CO 2 emissions in the iron and steel industry. Biomass-based products are produced by converting biomass assortments from forestry operations and forest industries via slow pyrolysis and gasification technologies. Using a spatially explicit cost optimisation model, biomass supply is optimised to suit the corresponding demand for energy and material substitution, and the extent to which biomass can be a tool in CO 2 abatement is explored. The study findings show that maximum use of biomass-based products result in a 43% reduction in CO 2 emissions across the existing steel producing technologies. Results also show that increasing the rate of biomass utilisation via substitution targets is more effective than the use of a carbon pricing policy, since the maximum CO 2 reduction is unmet even with very high CO 2 prices. In the scenario analysis, it is found that low fossil fuel prices constitute a barrier to adopting biomass as an alternative to fossil energy use. Compared to the business-as-usual case, a maximum of 27% increase in energy-related costs was calculated for the industry. [ABSTRACT FROM AUTHOR]

• It simulates impact of COVID-19 on energy demand for a building mix at a district. • Confinement scenarios are proposed based on a new district design in Sweden. • Confinement measures increase electricity demand of buildings in the district. • Confinement measures reduce thermal energy demand of buildings in the district. The COVID-19 outbreak is exacerbating uncertainty in energy demand. This paper aims to investigate the impact of the confined measures due to COVID-19 outbreak on energy demand of a building mix in a district. Three levels of confinement for occupant schedules are proposed based on a new district design in Sweden. The Urban Modeling Interface tool is applied to simulate the energy performance of the building mix. The boundary conditions and input parameters are set up according to the Swedish building standards and statistics. The district is at early-design stage, which includes a mix of building functions, i.e. residential buildings, offices, schools and retail shops. By comparing with the base case (normal life without confinement measures), the average delivered electricity demand of the entire district increases in a range of 14.3% to 18.7% under the three confinement scenarios. However, the mean system energy demands (sum of heating, cooling, and domestic hot water) decreases in a range of 7.1% to 12.0%. These two variation nearly cancel each other out, leaving the total energy demand almost unaffected. The result also shows that the delivered electricity demands in all cases have a relatively smooth variation across a year, while the system energy demands follow the principle trends for all the cases, which have peak demands in winter and much lower demands in transit seasons and summer. This study represents a first step in the understanding of the energy performance for community buildings when they confront with this kind of shock. [ABSTRACT FROM AUTHOR]

• Develop advanced energy matching concepts to improve building cluster performance. • Present a coupled PV-exhaust air heat pump-thermal storage-electric vehicle system. • Retrofit a Swedish building cluster to be a prosumer using developed energy concepts. • Optimize capacity/position of PV modules at cluster level for difference scenarios. • Study impacts of thermal storage, electric vehicle and energy sharing on PV design. Smart grid is triggering the transformation of traditional electricity consumers into electricity prosumers. This paper reports a case study of transforming an existing residential cluster in Sweden into electricity prosumers. The main energy concepts include (1) click-and-go photovoltaics (PV) panels for building integration, (2) centralized exhaust air heat pump, (3) thermal energy storage for storing excess PV electricity by using heat pump, and (4) PV electricity sharing within the building cluster for thermal/electrical demand (including electric vehicles load) on a direct-current micro grid. For the coupled PV-heat pump-thermal storage-electric vehicle system, a fitness function based on genetic algorithm is established to optimize the capacity and positions of PV modules at cluster level, with the purpose of maximizing the self-consumed electricity under a non-negative net present value during the economic lifetime. Different techno-economic key performance indicators, including the optimal PV capacity, self-sufficiency, self-consumption and levelized cost of electricity, are analysed under impacts of thermal storage integration, electric vehicle penetration and electricity sharing possibility. Results indicate that the coupled system can effectively improve the district-level PV electricity self-consumption rate to about 77% in the baseline case. The research results reveal how electric vehicle penetrations, thermal storage, and energy sharing affect PV system sizing/positions and the performance indicators, and thus help promote the PV deployment. This study also demonstrates the feasibility for transferring the existing Swedish building clusters into smart electricity prosumers with higher self-consumption and energy efficiency and more intelligence, which benefits achieving the '32% share of renewable energy source' target in EU by 2030. [ABSTRACT FROM AUTHOR]

• A tool for calculating borehole resistance for groundwater filled boreholes. • Increased accuracy compared to estimating an effective filling conductivity. • Increased accuracy of early stage design. One of the challenges of designing ground source heat pumps systems is the calculation of the effective thermal borehole resistance which affects the heat extraction rate and thereby the required length of the borehole. Calculating effective borehole resistance is especially demanding when the boreholes are filled with groundwater. The natural convection in the groundwater affects the heat transport from the borehole heat exchanger to the borehole wall. The objective of this paper is to present the results of the modified Pygfunction software in which recently developed correlations for calculating influence of the natural convection in boreholes has been incorporated. The calculated results were validated by using results of thermal response test (TRT) from four adjacent groundwater filled borehole in the central parts of Sweden. The numerical results reveal that the original and unmodified Pygfunction can be used for accurate calculation of fluid temperatures in borehole heat exchangers by using an effective thermal conductivity of the filling material. However, that requires access to thermal response test data. The modified software calculates the effective borehole resistance with a deviation of about 15–30% compared to the effective borehole resistance from TRT. This deviation is an improvement compared with the standard assumption of neglecting natural convection in boreholes. However, for large installations with more than 4000 m of borehole heat exchangers a thermal response test is still recommended in order to ensure a more correct sizing of geothermal system. [ABSTRACT FROM AUTHOR]

• Regional combined heat and power (CHP) plants are integrated with bioethanol supply. • The influence of polygeneration on production planning of CHP plant is investigated. • Three extreme cases related to transportation system are developed and investigated. • Integration and power supply from rooftop panels affect production planning of system. • Use of hybrid cars is the optimal approach concerning fuel use, cost, CO 2 emissions. The increasing atmospheric CO 2 concentration has caused a transformative shift in global energy systems, which is contributing to an increased use of renewables. Sweden is among the countries trying to shift to a fossil-fuel-free system in all energy sectors. This paper addresses the fuel demand and supply in the transportation sector in the county of Västmanland in Sweden. A Mixed Integer Linear Programming optimization model is developed to minimize cost in the studied system. The model is further used to investigate the influence of three different scenarios on production planning of regional Combined Heat and Power (CHP) plants: (1) straw-based biofuel production integrated with existing CHP plants to fuel combustion engine vehicles, (2) use of electric vehicles, and (3) use of hybrid vehicles fueled by both electricity and bioethanol. Potential solar power generation from rooftop solar cells is also included in the model. The energy system in scenario 2 is found to have the highest overall system efficiency; however, a large amount of power needs to be imported to the system. Hybrid vehicles can potentially reduce the electricity import and CO 2 emissions compared to the current situation. Electricity production from rooftop solar collectors could provide the energy needs of the vehicles during summer, while regionally produced straw-based bioethanol integrated with CHP plants can satisfy the fuel needs of the vehicles in winter. This approach could affect the production planning of CHP plants, result in less fuel use and increase the share of renewable resources in the regional transportation system. [ABSTRACT FROM AUTHOR]