The transition from the traditional fossil fuels to sustainable energy solutions will take several decades. Natural gas can play an important part in this transitional phase. Of the fossil fuels, natural gas is by far the least polluting fuel. In addition to this, natural gas used in the production of electricity has a flexibility that will be increasingly necessary as our electricity production becomes more dependent on wind and solar energy. But the wind does not blow all the time and nor does the sun always shine. Fast-reacting gas-fired power plants can then step in. This is the case with large, modern gas power plants and also small decentralised electricity generators like the HEe boiler and mini-CHP installations. Fortunately there is still more than enough natural gas underground, even in the Netherlands, where the Groningen field still contains almost 1,000 billion cubic metres around fifty years after its discovery. At the international level, the already enormous supplies have increased further as a result of the emergence of unconventional gas stored in layers of stone, particularly in the US.