It nevertheless provides a useful, if crude, indication of the adequacy of an electricity system. For European countries this happened in the wake of the first electricity market directive in 1996. In deregulated markets, private companies have no longer an interest in holding any spare capacity that would serve to mitigate costs and prices in the event of sudden demand peaks. On the contrary, such peaks are welcome opportunities to make additional profit and to finance the fixed costs of peak-load plants. Due to the inelasticity of electricity demand, some market power at peak time is almost inevitable and new entrants would have to tread a difficult path between profiting from high prices and causing sudden excess capacity and price decreases.