Sammendrag
This study provides an introduction to Life Cycle Assessment (LCA) in the context of energy planning, and tries to point out the major differences between emission accounting and a broader LCA perspective. LCA is a holistic approach accounting for all environmental impacts occurring from the system’s “cradle” to the “grave”, together with all related activities throughout the lifetime of the system. The study presents a broad range of different LCA studies, thus providing a starting point for further studies of LCA of energy systems. The LCA perspective is found to be useful and necessary for sound environmental planning of energy systems, aiming at socio-economic optimal energy systems.The main conclusions are as follows: For most energy system utilising a fuel, the fuel chain is of great importance. This is the case for sources such as; coal, lignite, natural gas, biomass and oil. The building/demolishing etc. from these energy systems are seldom of great importance. The total Green House Gas (GHG) emissions are for coal around 1000 g CO2 eq. / kWh, for CCGT 400 g CO2 eq. / kWh. For renewable technologies, the building phase is often more dominant, being the cause of the major environmental impact. This is the case for solar energy, wind power, hydro power etc. All renewable energies are mostly below 100 g CO2 eq. / kWh, many below 20 g CO2 eq. / kWh, with exception for Photo Voltaic (PV), which has more emissions due to energy demanding wafers, which are important components. The PV examples from this study indicates GHG emissions in the range of 100 – 280 g CO2 eq. / kWh, which is rather high from an energy source seen as renewable. This is however, totally dependent of where the PV plant is situated. Transport of biomass and other fuels is possible without severely increasing the overall environmental impact, as long as the distance is within limits, and done with proper transportation mode. Construction of electricity grids or district heating grids etc. is of