In this paper, we propose a systematic approach to study how the development in terms of cost and proven functionality of emerging energy technologies affects the optimal choice and timing of investment decisions at an industrial plant today. The methodology used is based on stochastic programming, and all investments are optimized under uncertain energy market conditions. The cost development of the new technology is modeled using scenario analysis where both the cost levels and the timing of the market introduction are considered. Two examples are presented to illustrate the usefulness of the proposed approach. The examples are taken from the pulp and paper industry. In addition to investments in conventional technology for heat and/or power production, the emerging technology of carbon capture is considered as a possible future investment in the first example while lignin separation is considered in the second one. It is shown that possible future technologies can be highly important to consider already in today's investment decisions. (C) 2011 Elsevier Ltd. All rights reserved.