Grid balancing has become an important aspect for the power grid in matching the supply of energy to demand. In recent years, it has become more predictable with more energy being installed in the grid. This time of day, when it is windy, but there is no demand. In Scotland this has been paid off, most recently over $ 6m in the past. Constraint payments are made to other electricity suppliers as well as wind. In 2011/2012, the National Grid in the UK totaled £ 324 million of which £ 31 million went to wind. In 2012/2013, thanks to improved transmission capabilities, they were £ 130 million of which only £ 7 million were for wind. This invention could alternatively be used in the electrolysis of water to make high purity hydrogen fuel used in fuel cells. In areas with a small hydroelectricity, the pumped storage systems such as the Dinorwig Power Station can allow the energy to be used for operational reserve or at times of peak demand rather than a natural gas peaking power plant.