In addition, a number of specific regulatory measures can be implemented in order to improve the functioning of both designs. However, since electricity is a non-storable good with inelastic demand, energy-only markets can lead to large price swings at moments of high (or low) production of renewable energy. For instance, the European Energy Exchange Market (EEX) in 2009 saw spot prices that reached the ceiling of EUR 3 000 per MWh imposed by the operators as well as several instances of negative spot prices.