During the period 2009-2013, investments in the Swedish national grid increase by a factor of ten compared to previous years. In order to fulfil their mission to manage the national grid in a safe, efficient and environmentally sound way, Svenska Kraftnät (Swedish National Grid) needs to take all these perspectives into account while planning new investments. To compare and relate perspectives of technology, economy and environment the same yard stick must be used. That yard stick is commonly money. A problem arises however as environmental issues are difficult to price. The purpose of this master’s degree project was to develop a tool for evaluation of environmental impact related to investments in the Swedish national grid. It was initiated by and conducted at the unit for Grid development at Svenska Kraftnät. A life cycle perspective  was used and the following stages were identified: material production, construction, operation and decommissioning. The environmental impact from these stages was sorted into ten impact categories using the LCIA method ReCiPe 2008 and then two economical evaluations were performed: one at midpoint level and one at endpoint level. Also included in the evaluation were the change in power losses or in the power production mix and the visual impact coming from overhead transmission lines. The tool was implemented in Excel and offers the possibility to evaluate the environmental impact from five different power line technologies (per km), substation line bays (per bay), transformers (per piece) and reactors (per piece). The main results show that AC land cable has a significantly higher environmental impact and cost than the other power line technologies. Material production and construction are the life cycle stages that contribute the most to the environmental cost. The impact categories that affect the environmental cost the most are climate change (for midpoint evaluation) and resource depletion (for endpoint evaluation). When the investment affects the power production mix, e.g. by changing the transmission capacity to another country, the subsequent environmental impact can be very influential on the total environmental cost of the investment.

Cob can serve as an alternative building material to concrete in Nicaragua. Cob is an unbaked earth-based building technique with low global warming potential that suits the humid climate in Nicaragua. It can be constructed by hand by inexperienced people using materials such as; clay, straw, sand and water. The cob technique is relatively little studied and the exact cost of cob is unclear. The purpose of this thesis was thus to provide new information that will help assessing the economic sustainability and the environmental impact of the natural building technique cob in comparison to the conventional technique concrete. The thesis was carried out by a case study of two houses in Matagalpa, Nicaragua. The results are showing that the cob technique has cheap materials that support the Nicaraguan economy of Nicaragua but takes a lot of labour force and time in comparison to concrete. The cob technique also allows the builder to make the house personal adapted, with furniture and details, fitted to the owners need. The cob has also a great potential of a long lifespan with low needs of maintenance in comparison with concrete. Concrete also has a higher local environmental impact, more CO2-emissions and higher external costs. The conclusion is thus that cob is a more sustainable technique for building residential houses in Matagalpa. / Den naturliga byggtekniken cob kan vara ett alternativ till den mer konventionella tekniken betong i Nicaragua. Cob är en jordbaserad byggnadsteknik med låg globaluppvärmningspotential som lämpar sig i det fuktiga klimatet i Nicaragua. Cob består mestadels av; lera, halm, sand och vatten, och kan byggas för hand av oerfaren arbetskraft. Cob-tekniken är relativt lite studerad och den exakta kostnaden är osäker. Syftet med denna studie var därför att tillhandahålla ny information som ska underlätta bedömningen av den ekonomiska hållbarheten och miljöpåverkan hos den naturliga byggtekniken cob i jämförelse med den konventionella tekniken betong. Studien genomfördes med hjälp av en fallstudie av två hus i Matagalpa, Nicaragua. Resultatet visar att cob-tekniken har billiga material som stöder den lokala ekonomin, men kräver mycket arbetskraft och tid jämfört med betongtekniken. Cob-tekniken låter även byggaren att göra huset personligt anpassat, med möbler och finesser efter ägarnas behov. Den potentiella livstiden hos cob är lång, med ett lågt underhållsbehov i jämförelse med betong. Betong har också en större lokal miljöpåverkan, mer CO2-utsläpp och högre externa kostnader. Slutsatsen är således att cob är en mer hållbar teknik att använda för att bygga bostadshus i Matagalpa. / Cob puede servir como un material de construcción alternativo al concreto en Nicaragua. Cob es una técnica de construcción a base de tierra sin quemar con bajo potencial de calentamiento global que se adapta al clima húmedo en Nicaragua. Puede ser construido a mano por personas sin experiencia utilizando materiales tales como; arcilla, paja, arena y agua. La técnica de cob es relativamente poco estudiada y el coste exacto no está claro. El objetivo de esta tesis ha sido por lo tanto proporcionar nueva información que ayudará a evaluar la sostenibilidad económica y el impacto ambiental de los recursos naturales de la técnica de construcción cob en comparación con la técnica convencional de concreto. La tesis fue realizada por un estudio de caso de dos casas en Matagalpa, Nicaragua.  Los resultados muestran que la técnica de cob tiene materiales baratos que apoyan la economía local de Nicaragua, pero requiere de mucha fuerza y ​​tiempo de trabajo en comparación con el concreto. La técnica de cob también permite al constructor hacer la casa de manera más personal adaptándola con muebles y detalles, ajustada a las necesidades de los propietarios. El cob tiene también un gran potencial de larga vida con pocas necesidades de mantenimiento en comparación con el concreto. Concreto también tiene un mayor impacto ambiental local, más emisiones de CO2 y el aumento de los costos externos. La conclusión es de este estudio es que la técnica de cob es más sostenible para la construcción de viviendas residenciales en Matagalpa.