Against the background of strongly increasing prices for primary energy carriers we examine how trends towards high energy prices could affect the development of the German energy system, the corresponding carbon dioxide emissions as well as costs. With the IKARUS bottom-up time-step model we look at a scenario with steadily increasing prices and a price shock scenario, both compared to a moderate price scenario. The results show that high prices lead to a significant reduction of the total primary energy supply and also structural changes of primary energy supply with less oil and natural gas and a noticeable increase of renewables. The corresponding cumulated CO, emission reduction for the period 2005-2030 is in the range of 830-13 10 Mt or 4.1-6.4% as compared to the reference scenario. In the high price scenario there is a continuous additional decrease of energy demand and emissions while in the price shock scenario we find a temporary minimum around 2015 and subsequently a remarkable relaxation towards the reference scenario. Due to technical measures in the model the extra system costs caused by higher prices are reduced by 65-75 billion (sic)000 for the period 2005-2030. (C) 2007 Elsevier Ltd. All rights reserved.