For those combined heat and power plants that was built before the Swedish green electricity certificate system was implemented, the certificates will disappear at end of year 2012. The first combined heat and power plant built in Falun (KVV1) needs to be upgraded in order to be granted renewed license for green certificates. The main objective of this work is to provide the basis for choosing an upgraded system layout. A number of different upgrade alternatives have been investigated. The study is based on calculations and simulations in the program Solvo together with district heat load data managed in MS Excel. The different alternatives for upgrading the power plant have also been evaluated economically and compared to a case where no upgrade is carried out. The most interesting alternatives have shown to be the systems that include reheat cycles and the use of two condensers. Another interesting alternative includes building a new plant beside the old one. The results show that it is possible to invest in the range of 330 – 700 Mkr for these alternatives. If the interest rate amounts to 6 %, the price for electricity is increased to 550 kr/MWh, electricity certificates to 300 kr/MWh and the payback time set to 20 years, the investment may amount to more than one billion SEK and still obtain a lower annual electricity production cost compared to the case where no upgrade is carried out.