Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2012. / Electric motors consume over 60% of the world's generated electricity. In South Africa approximately 65% of the energy generated is consumed by electric motors (Niekerk, 2009). About 95% of motors in use in South Africa are Standard-Efficient Motors (SE-motors) that operate at an average efficiency of 84% to 90%, depending on the size of the motor and the load driven by them. High-Efficient motors (HE-motor) run at an efficiency of 2% to 8% higher than that of SE-motors. In recent years, a drive to replace SE-motors with HE-motors has been promoted for the purpose of Demand Side Management (DSM). The rationale of using HE-motors as a tool of DSM is to harness a small difference in operating efficiency per motor, which can result in a huge reduction in electricity consumption, depending on the number of HE-motors that will replace SE-motors. Reducing the demand for electricity is the key driving factor for DSM in South Africa, so as to relieve the already stressed power generation capacity. Other consequential factors of DSM are to reduce the amount of pollutant gases emitted into the atmosphere. To the electricity users DSM will be a great incentive, as reduced consumption of electricity will decrease the amount of money spent on electricity. Much has been written on the ability of HE-motors to reduce electricity consumption, cost of electricity and global pollution. ESKOM has even demonstrated the faith they have in these motors by giving rebates to motor users who are willing to exchange their existing SE-motors with new HE-motors. The rebates are paid by ESKOM through a newly established DSM program. However, it must be mentioned that savings through HE-motors is not a perfect guarantee. HE-motors have inherent design limitations that may inhibit the saving of energy. To achieve higher efficiency, HE-motors are designed to operate on a smaller slip that consequently increases their speed compared to that of SE-motors (Cheek et al., 1995). Higher rotor speed impacts energy saving abilities of HE-motors when they are used to drive fans, pumps and compressors, normally referred to as centrifugal loads. An increase in speed results in a proportional increase in flow. Power consumed by a motor goes up as a cube of the speed, and the flow rate increases linearly with speed. Motor loads in the petrochemical industry are generally centrifugal, and that is why this thesis focuses on refineries.

This research aims to develop solutions to relieve system stress conditions in electric grids. The approach adopted in this research is based on a new concept in the Smart Grid, namely, demand response optimization. A number of demand response programs with energy storage systems are designed to enable a community to achieve optimal demand side energy management. The proposed models aim to improve the utilization of the demand side energy through load management programs including peak shaving, load shifting, and valley lling. First, a model is proposed to nd the optimal capacity of the battery energy storage system (BESS) to be installed in a power system. This model also aims to design optimal switchable loads programs for a community. The penetration of the switchable loads versus the size of the BESS is investigated. Another model is developed to design an optimal load operation scheduling of a residential heating ventilation and air-conditioning system (HVACs). This model investigates the ability of HVACs to provide optimal demand response. The model also proposes a comfort/cost trade-os formulation for end users. A third model is proposed to incorporate the uncertainty of the photovoltaic power in a residential model. The model would nd the optimal utilization of the PV-output to supply the residential loads. In the first part of this research, mixed integer programming (MIP) formulations are proposed to obtain the optimal capacity of the (BESS) in a power system. Two optimization problems are investigated: (i) When the BESS is owned by a utility, the operation cost of generators and cost of battery will be minimized. Generator on/o states, dispatch level and battery power dispatch level will be determined for a 24-hour period. (ii) When the BESS is owned by a community for peak shaving, the objective function will have a penalty component for the deviation of the importing power from the scheduled power. MIP problems are formulated and solved by CPLEX.The simulation results present the effect of switchable load penetration level on battery sizing parameters. In the second part, a mixed integer programming (MIP) based operation is proposed in this part for residential HVACs. The objective is to minimize the total cost of the HVAC energy consumption under varying electricity prices. A simplied model of a space cooling system considering thermal dynamics is adopted. The optimization problems consider 24-hour operation of HVAC. Comfort/cost trade-o is modeled by introducing a binary variable. The big-M technique is adopted to obtain linear constraints while considering this binary variable. The MIP problems are solved by CPLEX. Simulation results demonstrate the effectiveness of HVAC's ability to respond to varying electricity price. Then, in the final part of this research, two Benders Decomposition strategies are applied to solve a stochastic mixed integer programming (MIP) formulation to obtain the optimal sizing of a photovoltaic system (PV) and battery energy storage system (BESS) to power a residential HVACs. The uncertainty of PV output is modeled using stochastic scenarios with the probability of their occurrence. Total cost including HVAC energy consumption cost and PV/battery installation cost is to be minimized with the system at grid-connected mode over eight hours subject to a varying electricity price. The optimization problem will nd the optimal battery energy capacity, power limit, a number of PV to be installed, and expected HVAC on/o states and BESS charging/discharging states for the next eight hours. This optimization problem is a large-scale MIP problem with expensive computing cost.

In South Africa, where 75% of the worlds platinum is produced, electricity tariffs have increased significantly over recent years. This introduces challenges to the energy intensive mineral processing industry. Within the mineral processing chain, run-of-mine ore milling circuits are the most energy-intensive unit processes. Opportunities to reduce the operating costs associated with power consumption through process control are explored in this work. In order to reduce operating costs, demand side management was implemented on a milling circuit using load shifting. Time-of-use tariffs were exploited by shifting power consumption of the milling circuit from more expensive to cheaper tariff periods in order to reduce overall costs associated with electricity consumption. Reduced throughput during high tariff periods was recovered during low tariff periods in order to maintain milling circuit throughput over a week long horizon. In order to implement and evaluate demand side management through process control, a load shifting controller was developed for the non-linear Hulbert model. Implementation of the load shifting controller was achieved through a multi-layered control approach. A regulatory linear MPC controller was developed to address technical control requirements such as milling circuit stability. A supervisory real-time optimizer was developed to meet economic control requirements such as reducing electricity costs while maintaining throughput. Scenarios, designed to evaluate the sensitivities of the load shifting controller, showed interesting results. Mill power set-point optimization was found to be proportionally related to the mineral price. Set-points were not sensitive to absolute electricity costs but rather to the relationships between peak, standard, and off-peak electricity costs. The load shifting controller was most effective at controlling the milling circuit where weekly throughput was between approximately 90% and 100% of the maximum throughput capacity. From an economic point of view, it is shown that for milling circuits that are not throughput constrained, load shifting can reduce operating costs associated with electricity consumption. Simulations performed indicate that realizable cost savings are between R16.51 and R20.78 per gram of unrefined platinum processed by the milling circuit. This amounts to a potential annual cost saving of up to R1.89 m for a milling circuit that processes 90 t/h at a head grade of 3 g/t. / Dissertation (MEng)--University of Pretoria, 2015. / Electrical, Electronic and Computer Engineering / Unrestricted

Developing nations face insurmountable challenges to reliably and sustainably provide energy and water to the population. These resources are intricately entwined such that decisions on the use of one affects the other (energy-water nexus). Inadequate and ageing infrastructure, increased population and connectivity, urbanization, improved standards of living and spatially uneven rainfall are some of the reasons causing this insecurity. Expanding and developing new supply infrastructure is not sustainable due to sky high costs and negative environmental impact such as increased greenhouse gas emissions and over extraction of surface water. The exponentially increasing demand, way above the capacity of supply infrastructure in most developing countries, requires urgent mitigation strategies through demand side management (DSM). The DSM strategies seek to increase efficiency of use of available resources and reducing demand from utilities in the short, medium and long term. Renewable energy, rooftop rain water harvesting, pump-storage scheme and grey water recycling are some alternatives being used to curb the insecurity. However, renewable energy and rooftop water harvesting are spasmodic in nature hampering their adoption as the sole supply options for energy and water respectively. The built environment is one of the largest energy and water consuming sectors in the world presenting a huge potential towards conserving and increasing efficiency of these resources. For this reason, coupled with the 1970s energy challenges, the concept of green buildings seeking to, among other factors, reduce the consumption of energy and water sprung up. Conventionally, policy makers, industry players and researchers have made decisions on either resource independently, with little knowledge on the effect it would have on the other. It is therefore imperative that optimal integration of alternative sources and resource efficient technologies are implemented and analysed jointly in order to achieve maximum benefits. This is a step closer to achieving green buildings while also improving energy and water security. A multifaceted approach to save energy and water should integrate appropriate resource efficient technology, alternative source and an advanced and reliable control system to coordinate their operation. In a typical South African urban residential house, water heating is one of the most energy and water intensive end uses while lawn irrigation is the highest water intensive end use occasioned by low rainfall and high evaporation. Therefore, seamless integration of these alternative supply and most resource intensive end uses provides the highest potential towards resource conservation. This thesis introduces the first practical and economical attempt to integrate various alternative energy and water supply options with efficient devices. The multifaceted approach used in this research has proven that optimal control strategy can significantly reduce the cost of these resources, bring in revenue through renewable energy sales, reuse waste water and reduce the demand for grid energy, water and waste water services. This thesis is generally divided into cold and hot water categories; both of which energy-water nexus DSM is carried out. Open-loop optimal and closed-loop model predictive (MPC) control strategies that minimize the objective while meeting present technical and operational constraints are designed. In cold water systems, open-loop optimal and MPC strategies are designed to improve water reliability through a pump storage system. Energy efficiency (EE) of the pump is achieved through optimally shifting the load to off-peak period of the time-of-use (TOU) tariff in South Africa. Thereafter, an open-loop optimal control strategy is developed for rooftop rain water harvesting for lawn irrigation. The controller ensures water is conserved by using the stored rain water and ensuring only the required amount of water is used for irrigation. Further, EE is achieved through load shifting of the pump subject to the TOU tariff. The two control strategies are then developed to operate a grey water recycling system that is useful in meeting non-potable water demand such as toilet flushing and lawn irrigation and EE is achieved through shifting of pump's load. Finally, the two control strategies are designed for an integrated rain and grey water recycling for a residential house, whose life cycle cost (LCC) analysis is carried out. The hot water category is more energy intensive, and therefore, the open-loop optimal control strategy is developed to control a heat pump water heater (HPWH) and an instantaneous shower, both powered by grid-tied renewable energy systems. Solar and wind energy are used due to their abundance in South Africa. Thereafter, the MPC strategy is developed to power same devices with renewable energy systems. In both strategies, energy is saved through the use of renewable energy sources, that also bring in revenue through sale of excess power back to the grid. In addition, water is conserved through heating the cold water in the pipes using the instantaneous shower rather than running it down the drain while waiting for hot water to arrive. LCC analysis is also carried out for this strategy. Each of the two control strategies has its strengths. The open loop optimal control is easier and cheaper to implement but is only suitable in cases where uncertainties and disturbances affecting the system do not alter the demand pattern for water in a major way. Conversely, the closed-loop MPC strategy is more complicated and costly to implement due to additional components like sensors, but comes with great robustness against uncertainties and disturbances. Both strategies are beneficial in ensuring security and reliability of energy and water is achieved. Importantly, technology alone cannot have sustainable DSM impact. Public education and awareness on importance of energy and water savings, improved efficiency and effect on supply infrastructure and greenhouse gas emissions are essential. Awareness is also important in enabling the acceptance of these technological advancements by the society. / Thesis (PhD)--University of Pretoria, 2017. / National Hub for Energy Efficiency and Demand Side Management (EEDSM) / University of Pretoria / Electrical, Electronic and Computer Engineering / PhD / Unrestricted

The global growth in demand for transportation has been phenomenal, owing to an exponential increase in population, industrialization and urbanization. This has led to a corresponding increase in the number of motor vehicles on the roads globally which has made the transport industry one of the main contributors to environmental pollution and energy insecurity. The profile of alternative fuels has been rising as an important component of the solutions to the challenge of energy sustainability. Compressed natural gas is one of the most successful alternative fuels for motor vehicle applications because of its compatibility with the internal combustion engine, reduced engine maintenance costs, reduced criteria air pollutants, low cost, abundance and the existence of renewable sourced natural gas from biomass. The infrastructure for the delivery of compressed natural gas forms part of the primary energy supply network, which has a significant interdependence with the electricity supply network. The compressed natural gas fuelling station is one of the vital nodes of the gas delivery network, that is also reliant on the electricity supply due to the energy intensive compressors that are required to achieve the right pressure conditions for gas transfer to vehicle tanks. At the same time, the increase in human population, industrialization, urbanization and market volatility have threatened the reliability and stability of electricity supply networks. Traditional reliance on supply upgrading to meet rising demand has proven to be unsustainable due to prohibitively high costs and associated environmental impact. As a result, demand side management solutions, where better use of the existing capacity is emphasized have received increasing attention. Demand side management requires that electricity consumers also play a role in the efficient operation of the electricity grid by minimizing their electricity usage as well as shifting their flexible loads away from peak electricity demand periods, so that grid stability is sustained. In order to participate in demand side management initiatives, operators of compressed natural gas stations need technically and economically sound strategies for the operation of station compressors and system components so that energy costs are minimized and gas transfer performance is enhanced. The compressed natural gas fast-fill station, being the most used configuration for commercial fuelling service is the focus of the work carried out in this thesis, with a description of solutions to minimize energy consumption, minimize energy costs and improve gas transfer performance through reduction of filling time. For this purpose, firstly, an optimal control strategy that minimizes energy cost by shifting the compressor load optimally away from the peak electricity pricing period under a time-of-use electricity tariff, while meeting the gas demand is modelled and evaluated. The controller further minimizes the switching frequency of the compressor thereby avoiding an increase in wear and tear which would lead to higher maintenance costs. The results show the effectiveness of the optimal operation model to achieve a huge reduction in electricity cost for the compressed natural gas station, when compressor-on time is shifted to offpeak and standard electricity pricing times. Further strategies for the minimization of switching frequency are compared and the superior approach identified. Secondly, a hierarchical operation optimization model is designed and evaluated. The strategy achieves minimized electricity cost and optimal vehicle filling time by optimally controlling the gas dispenser and priority panel valve function under an optimised schedule of compressor operation. The results show that the proposed approach is effective in achieving a minimum electricity costs in the upper layer optimisation while meeting vehicle gas demand over the control horizon. Further, a reduction in filling time is achieved through a lower layer model predictive control of the pressure-ratio-dependent fuelling process. Thirdly, an evaluation of compressor optimal sizing is carried out to minimize energy consumption and cascade the benefits of optimal operation of the compressed natural gas compressor under the time-of-use tariff. A comparison of the implication of using a variable speed drive or a fixed speed drive which are optimally sized is carried out. Results show that indeed further reduction in electricity costs for the compressed natural gas station is realized when optimally sized compressor drives are used in combination with optimal operation strategies. Additionally, the four line priority panel is evaluated for gas transfer performance and found to further increase the efficiency of vehicle fuelling which is a performance indicator for consumer convenience. The outcomes of this work demonstrate the effectiveness of the approaches proposed as necessary to integrate compressed natural gas stations, which are vital nodes of the gas delivery network, with the demand side management of the electricity grid while at the same time enhancing the gas transfer performance. This increases the economic efficiency of the compressed natural gas as an alternative fuel and also advances the goals of demand side management in electricity grid reliability and stability. / Thesis (PhD)--University of Pretoria, 2019. / Electrical, Electronic and Computer Engineering / PhD / Unrestricted

Mitigating climate change lies to a large part within the Energy System. In order to make it sustainable and efficient, policies have to be framed accordingly. This study focuses on formulation of policies based on future projections of the energy demand in Oskarshamn municipality of Sweden. Oskarshamn is a former industrial municipality, whose economic activity is in decline and it requires policies that accelerates its growth. It is also stereo-typical of much of Europe, as industrial activities are transferred elsewhere and regions are left to re-invent themselves. Questions such as “how to make the existing system more efficient” and “what is the best energy saving alternative”, have to be answered. For which, Long range Energy Alternatives Planning (LEAP) tool is used to create scenarios based on different pathways and to project the energy demand in the future. The business as usual scenario is compared with mitigation scenario considering various energy efficiency measures. The measures mainly focus on Demand Side Management and improving energy lifestyle interactions. Examples include the impact of electric vehicles (EV) in the transport sector and effects of better insulation in residential buildings, etc. Nuclear is currently the main source and would possibly be phased out in the horizon and thus creating a need for alternative and sustainable sources of energy. The renewable energy scenario focuses on proposals for mixing renewable fuels in the energy supply side. These are not without costs and opportunities which are discussed in the study. The outcomes work a clear delineation of Greenhouse gas mitigation options, which in collaboration with the municipality would form the basis for a policy action plan.

The thesis aims to obtain a holistic perspective of opportunities, drivers and barriers that different grid customers experience when enabling demand side flexibility. Due to the increasing problems of capacity shortage of electricity in large cities in Sweden, solutions on the demand side of the electric power grid have become increasingly interesting. Demand side flexibility is a voluntary change of demanded electricity from the grid due to some kind of incentive, which can help support balancing the electric power grid to avoid capacity shortages. Furthermore, the energy transition towards a decentralised power system with an increasing share of variable renewable energy requires a changed demand profile. In this research, a qualitative research methodology was applied. Eleven semi-structured interviews were conducted with case companies within the industry and property company segment. Interviews were also conducted with three actors on the electric power market providing services to aggregate the potential of smaller flexibility resources, as well as with an expert from the Swedish Energy Market Inspectorate. A State of the Art review was completed in order to collect theory and draft previously identified aspects of demand side flexibility. The result shows that the concept is not unknown amongst electricity customers. However, there is a limited knowledge and interest in enabling demand side flexibility. The knowledge gap includes the awareness of potential flexibility resources as well as business opportunities of providing flexibility services. Conflicting priorities within organisations also presents an important barrier, where other easier and more profitable measures may be prioritised. There is also a fear of disrupting core business by causing loss of quality, comfort or production, which proposes a barrier. To overcome mentioned barriers and increase flexibility the financial benefits have to be distinctive and clear. Further, case companies express an ambition of contribution to the environment and sustainable development. By increasing the awareness of the benefits which increased flexibility induces, electricity consumers can become more motivated in adapting a flexible consumption. In addition, case companies express a desire of being early adopters in order to prevent future forced participation or termination of business. In order to enable demand side flexibility the knowledge and interest of the concept must increase. This should be done by providing clear, comprehensible information about the business opportunities of demand side flexibility as well as showcasing successful examples of implementation. Furthermore, it should include suggestions of easy, economical measures different grid customers could carry out to increase their flexibility. By providing this information the interest in flexibility can increase, thus increase the implementation and participation.

The real estate sector in Sweden accounts for a significant share of energy consumption andgreenhouse gas emissions in society. The increased electrification, driven by factors such asdigitalization and the use of electric cars, further contributes to the industry's climate impact.However, there are opportunities for property owners to effectively manage electricityconsumption and reduce the negative climate impact. Managing power peaks, which occurduring periods of high electricity consumption, is crucial to reduce strain on the power gridand the use of fossil fuels. It is also a key factor in achieving international sustainability goalssuch as Agenda 2030 and the Paris Agreement. Reducing peak loads can also lead to lowerelectricity costs for buildings. The purpose of this study has been to investigate the challenges and opportunities for reducingpeak power demand at KTH Campus in Östermalm, Stockholm, and to examine theenvironmental and economic benefits that can be achieved through this. Using data providedby the real estate company Akademiska Hus, an overview of the overall electricity consumptionat KTH Campus was conducted. In addition, potential measures to reduce peak power demandand finding common incentives for tenants and property owners for implementing suchinvestments were investigated through a qualitative study. The results of the study show that there are measures that property owners can take to reducepower peaks. The suggested measures include both technical investments and influencing andchanging tenants' electricity consumption. The analysis of electricity usage for the study objectrevealed that the hour that primarily should be assessed is 12:00 PM, when the highest numberof power peaks occur. Additionally, potential measures such as upgrading ventilation systemsand optimising the use of laboratory fume hoods were identified to reduce electricityconsumption and, in turn, power peaks at KTH Campus. Improved data utilisation andtransparent knowledge sharing between tenants and property owners can be key tosuccessfully reducing power peaks. Challenges in implementing the proposed measuresinvolve changing tenants' behaviour and managing split incentives between the landlord andtenant. The focus of this study was to analyse existing data on power load distribution andcomprehend it through interviews with experts within the field. Another way of conducting asimilar type of study on how to reduce power peaks could be to develop different strategiesfor analysing data or gathering alternative data. / Den svenska fastighetssektorn står för en betydande andel av energiförbrukningen ochutsläppen av växthusgaser i samhället. Ökad elektrifiering, drivet av faktorer som digitaliseringoch användning av elbilar, bidrar ytterligare till branschens klimatpåverkan. Det finnsemellertid möjligheter för fastighetsägare att effektivt hantera elförbrukningen och minskaden negativa klimatpåverkan. Att hantera effekttoppar, som uppstår under perioder med högelförbrukning, är avgörande för att minska belastningen på elnätet och användningen avfossila bränslen. Det är också en viktig faktor för att uppnå internationella hållbarhetsmål somAgenda 2030 och Parisavtalet. Minskade effekttoppar kan även leda till lägre elkostnader förbyggnader. Syftet med denna studie har varit att undersöka utmaningar och möjligheter att minskaeffekttoppar i elförbrukningen på KTH Campus på Östermalm, Stockholm, och att undersökade miljömässiga och ekonomiska fördelarna som kan uppnås genom detta. Med hjälp av datafrån fastighetsbolaget Akademiska Hus genomfördes en kartläggning av den totalaelförbrukningen vid KTH Campus. Dessutom undersöktes potentiella åtgärder för att minskaeffekttoppar och att hitta gemensamma incitament för hyresgäster och fastighetsägare attimplementera sådana investeringar genom en kvalitativ studie. Resultaten av studien visar att det finns åtgärder som fastighetsägare kan vidta för att minskaeffekttopparna. De föreslagna åtgärderna inkluderar både tekniska investeringar och påverkansamt förändring av hyresgästers elförbrukning. Analysen av elförbrukningen för studieobjektetvisade att timmen som i huvudsak bör beaktas är kl. 12:00, då flest effekttoppar förekommer.Dessutom identifierades potentiella åtgärder som uppgradering av ventilationssystem ochoptimering av användningen av dragskåp i labb för att minska elförbrukningen och därmedäven effekttopparna vid KTH Campus. Förbättrad användning av data och transparentkunskapsdelning mellan hyresgäster och fastighetsägare är också potentiella lösningar för attfrämja investeringar i energieffektivitet. Utmaningar med att implementera de föreslagnaåtgärderna innefattar att ändra hyresgästers beteende och hantera delade incitament mellanfastighetsägare och hyresgäster. Fokus för denna studie var att analysera data över effektförbrukningen på KTH och skapaförståelse genom intervjuer med kunniga inom området. Ett annat sätt att genomföra enliknande studie om hur man minskar effekttoppar skulle kunna vara att utveckla olikastrategier för att analysera data eller samla alternativ data.

District heating is considered an environmentally friendly, efficient and cost-effective way of providingheat to buildings but even so, the industry will be facing several challenges in the upcoming years. Acombination of higher operating costs, growing demand, competition from alternative heatingtechnologies, national and international climate and energy goals and the need for transparency towardscustomers places high requirements on many thermal energy suppliers. One path to try to meet many ofthe demands is to introduce heat load control in the shape of thermal inertia in buildings as a short-termthermal energy storage. Several pilot tests have been performed in the matter but no study regardinglarge scale implementation and effects on the network has been performed. Adding to this, severaldifferent thermal energy suppliers are developing similar technologies alongside each other but there iscurrently no documentation on different approaches on the matter.Stockholm Exergi, a thermal energy supplier in Stockholm, have just started a project regarding heatload control and wanted deeper understanding in the matter. The overall purpose of this thesis hastherefore been to evaluate how heat load control could be performed successfully by Stockholm Exergito continue to promote competitive and sustainable delivery of district heat. This was done throughanalysis of other heat load control projects which resulted in eight key performance indicators. Thesewere; revenue, costs, fuel mix, greenhouse gas emissions, customer satisfaction, energy demand,available capacity and peak load. The key performance indicators were used to evaluate one ongoingtest run of heat load control performed by Stockholm Exergi to determine the profitability of theapproach. The test consisted of a control period of three hours in four buildings. The base of the studyconsists of a literature study and interviews performed both internally and externally.From the data analysis it was concluded that the energy savings due to heat load control were between13-19% for the individual buildings. The average total energy saving compared the entire day was 15.8%and the average total energy saving during the control period was 57.3%. It could also be concluded thatthe average total available capacity for all four buildings due to heat load control was 410 kWhcorresponding to 20.34Wh/m2 floor area.With the current price agreements, it was found that customers could save 0.145% on their monthly billdue to this reduction. For Stockholm Exergi, cost savings took the shape of avoided fuel costs and thetotal average cost savings were during the control period 0.072% with heat pumps as marginalproduction. Due to lack of data it was not possible to calculate other costs. The avoided GHG emissionsdue to the reduction in generation was 3.4 kg CO2-equivalents. During the control, the indoortemperature was reduced by a maximum of 0.587⁰C but no residents in the test buildings complainedabout bad indoor conditions.It was concluded that the current method and process for heat load control at Stockholm Exergi showsimilar results as other heat load control projects. Even though it is too soon to know for certain, it wasalso found that it has the potential to be economically, socially and ecologically successful in large scale.The thesis also concluded a list of recommendations for the future development of the heat load controlproject within Stockholm Exergi that would contribute to increase the probability of a successfulimplementation.Lastly, it was found that Stockholm Exergi is in the forefront of the development of heat load controlon large scale and are therefore in a position of trial and error where caution is paramount. / Fjärrvärme anses vara ett miljövänligt, effektivt och ekonomiskt lönsamt sätt att tillhandahålla värmetill byggnader men fjärrvärmeindustrin kommer ändå att stå inför flera utmaningar under de kommandeåren. En kombination av högre driftskostnader, ökad efterfrågan, konkurrens från alternativauppvärmningstekniker, nationella och internationella klimat- och energimål samt behovet av öppenhetgentemot slutanvändarna ställer höga krav på många fjärrvärmeleverantörer. Ett sätt att försöka mötadessa krav är att införa värmelastkontroll i form av termisk tröghet i byggnader som en kortsiktigvärmeenergilagring i fjärrvärmenätet. Flera pilot tester har gjorts inom området men ingen studierörande storskalig implementering och effekter på nätverket har utförts. Vidare utvecklar flera olikafjärrvärmeleverantörer liknande tekniker parallellt med varandra, men det finns för närvarande ingendokumentation gällande de olika metoderna.Stockholm Exergi, en fjärrvärmeleverantör i Stockholm, har nyligen påbörjat ett projekt inomvärmelastkontroll och har önskat djupare förståelse inom ämnet. Det övergripande syftet med dennaavhandling har därför varit att utvärdera hur kontroll av värmelasten kan genomföras framgångsrikt avStockholms Exergi för att fortsätta främja konkurrenskraftig och hållbar leverans av fjärrvärme.Detta gjordes genom analys av andra projekt rörande värmelastkontroll vilket resulterade i åtta nyckeltal.Dessa var; vinster, kostnader, bränslemix, växthusgasutsläpp, kundnöjdhet, energibehov, tillgängligkapacitet och toppbelastning. Dessa användes för att utvärdera en pågående testkörning avvärmelastkontroll i Stockholms Exergis fjärrvärmenät för att bestämma lönsamheten med metoden.Testkörningen gjordes i fyra byggnader under en kontrollperiod på tre timmar. Avhandlingen hade singrund i en omfattande litteraturstudie och interna samt externa intervjuer.Från dataanalysen drogs slutsatsen att energibesparingen var mellan 13–19% för de enskildabyggnaderna. Den genomsnittliga totala energibesparingen jämfört hela dagen var 15,8% och dengenomsnittliga totala energibesparingen under kontrollperioden var 57,3%. Den genomsnittliga totalatillgängliga kapaciteten på grund av värmelastkontroll blev därigenom 410 kWh vilket motsvarade 20,34Wh/m2 golvyta.Med de nuvarande prisöverenskommelserna konstaterades det att kunderna kunde spara 0,145% på sinmånatliga faktura på grund av denna minskning. För Stockholm Exergi fanns kostnadsbesparingar iform av undvikna bränslekostnader för spetsproduktion. Den genomsnittliga besparingen för undviknabränslekostnader var under kontrollperioden 0,072% med värmepumpar som marginalproduktion. Ingaandra kostnader kunde beräknas på grund av begränsad data. De undvikna växthusgasutsläppen på grundav denna minskning var 3,4 kg CO2-ekvivalenter. Under kontrollen reducerades innertemperaturen somhögst med 0,587 °C men inga boende klagade över försämrade inomhusförhållanden.En slutsats var att den nuvarande metoden och processen för kontroll av värmelasten utförd avStockholms Exergi visar liknande resultat som andra projekt inom samma område. Det kunde ävenfastställas att det har god potential att vara ekonomiskt, socialt och ekologiskt framgångsrikt i stor skalai framtiden. Avhandlingen fastställde också en lista med rekommendationer för den framtidautvecklingen av värmelastkontroll inom Stockholms Exergi. Dessa rekommendationer ska bidra tillökad sannolikhet för en framgångsrik implementering.Slutligen konstaterades det att Stockholms Exergi ligger i spetsen för utvecklingen av värmelastkontrolli stor skala. Detta innebär att de är i en position där det gäller att försiktigt och långsamt prova sig fram.

Demand Side Management (DSM) is a term coined to describe the control of demand to optimize energy usage in a way beneficial to both users and utilities. There are different technologies and policies designed for DSM, and one of them is Direct Load Control (DLC) which refers to a utility directly controlling demand. In this thesis, an analysis of DLC for air conditioning units during summer in the Indian state of Karnataka is carried out. A new control mechanism is proposed, based on the local generation capacity, which seems to reduce until the monsoon season arrives, as the lack of rain reduces water levels in hydro power plants. The direct load control of ACs using this mechanism allows for 0.88% energy savings in a state where only around 5% of all households seem to have AC units and electricity is available for only 37% of the population. The mentioned savings could have significant economic impacts for both users and utilities, reduce the fossil-based energy consumption and/or improve issues such as blackouts and the lack of capacity to cover peak loads. Continuous improvements in both energy access and the economic conditions of the state will lead to a larger number of AC’s installed, meaning that a mechanism that reduces AC consumption could be of great utility for all stakeholders of the electricity sector. / Styrning av Efterfrågan (från Demand Side Management, DSM) är ett begrepp som myntats för att beskriva konsumtionskontroll för att optimera energianvändning på ett sätt som är fördelaktigt för både användare och samhällsservice. Det finns olika tekniker och taktiker utformade för DSM, och en av dem är Direkt Belastningskontroll (från Direct Load Control, DLC), vilket är ett verktyg för att direkt kontrollera efterfrågan. I denna avhandling genomförs en analys av DLC för luftkonditioneringsenheter under sommaren i den indiska delstaten Karnataka. En ny kontrollmekanism föreslås baserat på den lokala produktionskapaciteten, som verkar minska fram tills monsunsäsongen, eftersom bristen på regn minskar vattennivån i vattenkraftverk. Den direkta belastningskontrollen hos luftkonditioneringsenheter med denna mekanism möjliggör en energibesparing på 0,88% i ett stadium där endast cirka 5% av alla hushåll tycks ha luftkonditionering och elektricitet är tillgängligt för endast 37% av befolkningen. De nämnda besparingarna kan ha betydande ekonomiska effekter för både användare och samhällsservice, minska den fossilbaserade energiförbrukningen och/eller förbättra problem som strömavbrott och brist på kapacitet för att täcka toppbelastningar. Ständiga förbättringar av både energitillgång och de ekonomiska förhållandena i staten kommer att leda till att ett större antal luftkonditioneringsenheter installeras, vilket innebär att en mekanism som minskar konsumtionen hos luftkonditioneringsenheterna kan vara till stor nytta för alla intressenter i elsektorn.