The current European Emissions Trading Scheme (ETS) in combination with other renewable electricity (RES-E) support schemes such as a premium feed-in tariff (FIT) or tradable green certificates system (TGC) do not guarantee a carbon neutral power sector in 2050. This study shows that many plausible high carbon emissions futures exist when no substantial efficiency measures are taken in high economic growth and electrification rate futures. While the co-existence of the ETS system with other RES-E support schemes could result in high levels of carbon abatement, it does not rule out all catastrophic high carbon futures. There are potential ‘free lunches’ for policy makers to reduce carbon emissions but these will probably not suffice when ambition levels are high. Synergies between the ETS system and RES-E support schemes are possible to largely reduce carbon emissions when conditions for high penetration levels of renewables need to be fulfilled. However risks of high costs for society and producers are very real without additional measures in the co-existence of the ETS with RES-E support schemes.