Decisions of electricity suppliers on investments in low-carbon energy technologies like PV (photovoltaics) and CCS (carbon capture and storage) depend on the expected profits or surpluses that can be earned. For an assessment of the profitability of investments in PV (and other renewable energy technologies), additional costs caused by the fluctuation in PV power plants' productivity and by the need for backup capacities have to be taken into account. Changes in the rest of the power plant stock will via their influence on the merit-order curve also affect the return on investment. Bearing these aspects in mind, it might become more attractive to invest in alternative technologies like CCS than to channel the investments towards PV in combination with backup power plants. In our study we compare investments in CCS and PV regarding possible merit-order effects and profitability, using investments in Germany as an example. (C) 2013 Elsevier Ltd. All rights reserved.