A widespread use of high efficiency transformers could save the world 100 TWh/year. Under normal conditions, purchasing high efficiency transformers is both economically and environmentally sound. In the liberalized European energy market however, the regulatory and financial framework obstructs utility companies from making long term investments like purchasing high efficient transformers. National regulators put pressure on utility companies to do cost cutting and do not compensate with sufficient incentives for energy efficiency. According to this paper, there is a heterogeneous treatment between generation on renewable energy and transformer efficiency. Yet the greenest kWh is still the one that is saved, even when it is compared to a kWh derived from a renewable source.