• Energy Research
• 9. Industry and infrastructure close
• SE close
• US close
• NO close
• Publikationer från KTH close

As the building and construction industry contributes considerably to global warming there isa need to increase sustainable building, especially in developing countries where the conceptis often overlooked. Even though there is a need to implement more sustainable alternatives,research shows that it comes with many challenges. The aim for this study is therefore toanalyze the barriers and motivational drivers when implementing sustainable building inGhana. Chan et al. (2018) have previously conducted a categorization of the barriers forsustainable building through a quantitative study. This categorization was used as a guidingtool in this qualitative study, which was done through a Minor Field Study (MFS). Hence,eleven interviews with green champions were held on-site in Ghana. Further, to understand themotivation of the interviewees better, self-determination theory (SDT) was used to analyze thedata. The theory divides motivation into two different levels, extrinsic and intrinsic. The formeris a more controlled form of motivation, while the latter is more autonomous. The findingsshow that the most critical barriers were lack of professional knowledge and expertise, lack ofawareness of sustainable building and its benefits, together with higher costs. Despite thesebarriers, the green champions are still highly motivated. While intrinsic motivation is dominantamongst the green champions interviewed for this study, there is still a level of extrinsicmotivation at play. When comparing the barriers to the motivational factors one suggestion isfor the private and public sector to invest in demonstration projects. This would fulfill the greenchampions’ motivation to create their own identity for African architecture combined with anincreased awareness for sustainable building. This paper contributes with a unique andcomprehensive look at sustainable building in Ghana. Additionally, the study's theoreticalframework is not often used in the field of construction management, making this a valuablecontribution as the paper can be beneficial to leaders or managers in the construction industry. Bygg- och anläggningsindustrin bidrar avsevärt till den globala uppvärmningen vilket harskapat ett behov av att öka hållbart byggande, särskilt i låg- eller medelinkomstländer därkonceptet ofta förbises. Även om det finns ett behov av att implementera mer hållbara alternativvisar forskning att det kommer med många utmaningar. Syftet med denna studie är därför attanalysera barriärerna och drivkrafterna vid implementering av hållbart byggande i Ghana.Chan et al. (2018) har tidigare kategoriserat barriärerna för hållbart byggande genom enkvantitativ studie. Kategorisering har använts som ett vägledande ramverk i denna kvalitativastudie, som gjordes genom en fältstudie. Elva intervjuer genomfördes med aktörer definieradesom “green champions” på plats i Ghana. För att bättre förstå motivationen hos de intervjuade,applicerades självbestämmandeteorin (SBT) vid analysering av data. Teorin delar in motivationi två olika nivåer, extern och intern. Extern motivation är en mer kontrollerad form avmotivation, medan intern är mer autonom. Resultatet visar att de mest kritiska barriärerna ärbrist på professionell kunskap och expertis, bristande medvetenhet om hållbart byggande ochdess fördelar, samt högre kostnader. Trots dessa hinder är de intervjuade aktörerna motiverade.Även om intern motivation är dominerande bland de intervjuade, finns en nivå av externmotivation. Efter jämförelse mellan barriärerna och motivationsfaktorerna är ett förslag att denprivata och offentliga sektorn investerar i demonstrationsprojekt. Detta skulle uppfyllaaktörernas motivation att skapa sin egen identitet för afrikansk arkitektur kombinerat med enökad medvetenhet om hållbart byggande. Den här studien bidrar med ett unikt och heltäckandeperspektiv på hållbart byggande i Ghana. Dessutom är det unikt att använda studiens teoretiskaramverk inom området byggprojektledning, vilket gör detta till ett värdefullt bidrag eftersomuppsatsen kan vara till nytta för ledare eller chefer inom byggbranschen. 

This paper presents results from a study on the impact of smart grid solutions, which includes development of a generic framework for power system analyses. The study has been performed as one of several independent studies, part of a national governmental task on smart grid in Sweden. A large amount of weather data, along with electricity consumption and wind power generation data, have been analyzed. Achieved results from these initial analyses can be used as reference material and have also been used within case studies presented. The proposed framework is flexible and numerous combinations of scenarios are possible to define. Integration of wind and solar power, analyses of transfer limits using static or dynamic rating and energy storage can be considered as well as weather effects. Results show how power systems can handle more electricity consumption and generation. The study shows that Smart Grid solutions are beneficial for resource efficient electricity grids. Moreover, different risk levels with respect to increased load can be included. Case study results show that energy storages most of the time will be unused, but that they can be used to increase the system reliability.

The electric power system is under an extensive development phase. This change is today normally expressed in the concept of Smart Grid. It captures different developments for a sustainable electric power system, e.g. including large changes at the electrical distribution level with new features for electricity customers. One move in these changes is the larger role of the regulator. In Sweden, a performance based regulatory model was introduced in 2003 as a tool to support in judging if the distribution system operators (DSOs) was charging the customers the right level of tariffs. The model was referred to as the Network Performance Assessment Model (NPAM). The NPAM was an international unique and innovative regulatory tool. The model evaluated tariffs by enter several system data to a computer program which produce a fictive network with the aim of having the same objective conditions as the real system. However, the NPAM was strongly criticized and since 2009 formally abandoned and a new regulation will be introduced 2012. Moreover, the NPAM not support climate incentives such as low losses, which will be a challenge when adopting a smart grid perspective into the regulation of distribution system tariffs in the future. The authors of this paper have followed the development of this model, and have a unique insight in the complexity behind the model. No stringent description of the NPAM is available. This paper aims to fill this gap by providing an overall picture of the NPAM including hitherto unpublished details on underlying theory. This could hopefully inspire and give a reference when developing regulations in different countries in the future by learning from its novelties as well as from its drawbacks.

Rising demand, climate change, growing fuel costs, outdated power system infrastructures, and new power generation technologies have made renewable distribution generators very attractive in recent years. Because of the increasing penetration level of renewable energy sources in addition to the growth of new electrical demand sectors, such as electrical vehicles, the power system may face serious problems and challenges in the near future. A revolutionary new power grid system, called smart grid, has been developed as a solution to these problems. The smart grid, equipped with modern communication and computation infrastructures, can coordinate different parts of the power system to enhance energy efficiency, reliability, and quality, while decreasing the energy cost. Since conventional distribution networks lack smart infrastructures, much research has been recently done in the distribution part of the smart grid, called smart distribution grid (SDG). This paper surveys contemporary literature in SDG from the perspective of the electricity market in addition to power system considerations. For this purpose, this paper reviews current demand side management methods, supply side management methods, and electrical vehicle charging and discharging techniques in SDG and also discusses their drawbacks. We also present future research directions to tackle new and existing challenges in the SDG.

With the grasp of a smart grid in sight, discussions have shifted the focus of system security measures away from generation capacity; apart from modifying the supply side, demand may also be exploited to keep the system in balance. Specifically, Demand Response (DR) is the concept of consumer load modification as a result of price signaling, generation adequacy, or state of grid reliability. Implementation of DR mechanisms is one of the solutions being investigated to improve the efficiency of electricity markets and to maintain system-wide stability. In a liberalized electricity sector, with a smart grid vision that is committed to market-based operation, end-users have now become the focal point of decision-making at every stage of the process in producing, delivering and consuming electricity. DR program implementation falls within the smart grid domain: a complex socio-technical energy system with a multiplicity of physical, economic, political and social interactions. This thesis thus employs both qualitative and quantitative research methods in order to address the ways in which residential end-users can become active DR flexibility providers in deregulated European electricity markets. The research focuses on economic incentives including dynamic pricing contracts, dynamic distribution price signals and the aggregation of load flexibility for participation in the various short-term electricity markets.

The sharing economy is an emerging niche for innovation capable of disrupting established socio-technical and economic regimes. Because of this potential to cause radical changes in a wide array of domains, research in multiple disciplines addressing various aspects entailing this phenomenon is proliferating. In this emerging body of literature, the understanding and framing of the sharing economy are often different. Without knowledge about the current state of the research related to the sharing economy, delineating research trends, gaps, and needs for directing effectively primary research are not possible. This study aimed to synthesize the state and distribution of existing publications related to the sharing economy in multiple disciplines. We used the systematic mapping technique to scope, identify, and classify the publications at a fine level of granularity. We reviewed 589 journal articles (published from 1978 to 2017), and 454 met the selection criteria. The journal articles reviewed were published in 284 different journals. Intriguingly, 15 journals published five to 13 publications each and 221 journals had a single article about the topic. Journals belonging to the subject areas “business, management and accounting” (42.1%) and “social sciences” (35.2%) published more than 70% of the reviewed publications. Accommodation (19.8%) and car and ridesharing (17.2%) were the two most prominent sectors; 50.2% of the publications addressed C2C transactions (10.6% B2C, 24.4% more than one type); 62.3% were about accessing resources, and 5.1% concerned transfer of ownership (i.e., second-hand or donation); and 19.2% covered access and transfer of ownership simultaneously. While empirical studies were the majority (53.1%, when comparing with conceptual ones), qualitative approaches were most common (51.5% against 24.9% quantitative and 17.4% mixed methods). Literature review (22.9%), survey (13.2%), case study (7.3%) and interview (7%) were the most frequently used methods. User behavior (26.4%), business models and organizational aspects (22.7%), institution and governance system (18.7%), conceptualization matters (17%), and sustainability evaluation (15.3%) are research clusters identified from a grounded approach. The link between user behavior and net environmental impacts of sharing options was the largest gap found in the research needing attention from a sustainability perspective. Accordingly, multidisciplinary investigations quantifying behavioral root causes, magnitude, and likelihood of environmental rebound effects using real-world data are strongly encouraged.

This paper considers a smart grid cyber-security problem analyzing the vulnerabilities of electric power networks to false data attacks. The analysis problem is related to a constrained cardinality minimization problem. The main result shows that an $l_1$ relaxation technique provides an exact optimal solution to this cardinality minimization problem. The proposed result is based on a polyhedral combinatorics argument. It is different from well-known results based on mutual coherence and restricted isometry property. The results are illustrated on benchmarks including the IEEE 118-bus and 300-bus systems.

Abstract Carbon emissions emanating from infrastructure construction projects are substantial and stem primarily from production of construction materials and use of energy for construction transport and site activities. In recent years, public infrastructure clients world-wide have begun to include carbon reduction goals in their procurement requirements. This is however a new and complex field where practices vary and are still developing. In this paper, we compare models for carbon reduction requirements in infrastructure construction projects based on case studies of large projects in Australia, USA, the Netherlands, Sweden and UK. We found that open, functional carbon reduction requirements were considered innovative but entailed costs for calculating baselines and risks for speculation. Also, high time pressure in projects limits contractors’ opportunities to explore reduction opportunities. Thus, specific, prescriptive requirements may play an important role in client-led, long-term innovation processes. Organizational competence and resources on the buyer side are essential, and policies for carbon reduction should aim to increase client capacity. Further, procurement practices are developed in mutual interaction between clients and suppliers over longer periods of time, which limits possibilities to transfer procurement policies and requirements between contexts.