NWT has developed a heat storage tank ENYSTO, which with 2 000 l can store up to 160 kWh. Compared to a battery, this is a multiple of storage capacity. In combination with photovoltaics, it is the ideal solution to generate and store thermal energy yourself and to increase the degree of self-use of PV to a good 90%. ENYSTO fits through any door, is assembled on site and costs hardly more than a conventional 800 l stratified tank.