Den 24:e oktober 2017 presenterade Energimarknadsinspektionen (Ei), som reglerar elnätsmarknaden, nya förslag gällande WACC-metoden som används för att beräkna elnätsbolagens kalkylränta. Denna uppsats har undersökt Ei:s föreslagna regeländringar gällande kalkylräntan, hur känslig metoden som används är, hur regeländringarna upplevs påverka elnätsbolagens investeringar och hur regleringen överlag upplevs fungera. Uppsatsens empiriska material är till viss del baserat på intervjuer som författarna genomfört med tre olika elnätsbolag samt en intervju med en representant från Ei. Författarna har också tagit del av ett webinarium där deltagare från ytterligare elnätsbolag, forskare och politiker delgett sina åsikter kring de nya förslagen. Känslighetsanalysen visade att den parameter som har störst inverkan på den slutliga storleken på kalkylräntan är den riskfria räntan. Studiens resultat visar också att de nya reglerna skulle, om de blev implementerade, enligt elnätsbolagen få stora inverkningar på deras verksamheter. Flera elnätsbolag skulle förändra sin investeringsstrategi och enbart genomföra de allra nödvändigaste investeringarna. Det vore fördelaktigt om regleringen fungerade på ett mer objektivt sätt.

Mälarenergi’s vision is a world where we live and operate together without climate impact. This degree project has examined which opportunities Mälarenergi Elnät has in order to work towards this vision by looking more closely at whether their bigger substations can become self-sufficient in terms of heating, cooling and battery charging. The purpose of this degree project was to investigate how heat recovery from the substations’ transformers and the installation of PV-systems could contribute to both more environmentally friendly and self-sufficient substations. In addition to that, the economics and how this would affect the Swedish power grid regulation were of interest. The thesis was based on current values and data for oil temperatures and installed power in three of Mälarenergi Elnät’s substations. In addition to this, the thesis also includes a literature study, where previous research in heat transfer from power transformers, up-to-date information about PV-installations and the power grid regulation in Sweden were studied. The results of the thesis showed that both PV-installations and heat exchange for heating the station buildings could be of great benefit for Mälarenergi Elnät. In all but one case, the energy saving measures resulted in lower life cycle costs than if no measures were taken. It shows that the measures investigated in the thesis are not only good from an environmental perspective, but also has economic profitability.

The purpose of this thesis was to examine how futureinvestments in new techniques such as solar cellsystems, electric vehicle chargers and energy storageat end costumers would affect the rural electricitygrid based on two future scenarios. The main issuepredicted with investments in this new technology atend users are over utilization of the electricitygrid if the new technique is not used in a proper wayin order to avoid high power peaks. By studying real electricity consumption as it appearstoday and adding charging of an electric vehicleaccording to the two scenarios (with our withoutenergy storage and solar cell electricity production)new usage patterns could be determined. Theseusage patterns could then be inserted insimulations of three real electricity grids for studiesof the effect on the electricity grids. The conclusion is that the electricity grids ingeneral are oversized regarding thermal loading whilstthe fuses at the end costumer need to be reinforced inorder to not get over utilized in the scenario where noenergy storage was implemented. Only one of the gridswas shown to be over utilized when all customers wasequipped with the new techniques and the grid wasdensified. Otherwise, in the other grids and scenariosonly some conductors were over utilized. However, whatwas shown to be a problem was the voltage drop at theend customer’s facilities which was higher than theallowed value of 5%.According to this the grid was shownto be over utilized. As a final conclusion it can be shown that the voltagedrop decides the design of the grids and that thepower grid companies probably should consider newpossible business strategies.