Ok, you need 4200J to rise 1kg of water by 1°C. Thus you need 420MJ to do what you need, and doing that in one hour gives you approximately 117kW.
That is a huge amount of power, but you could for example run many standard heating elements together to achieve that.
It requires 117kW, as kubeek calculated, to raise the water temperature 100°C. If the water starts out at around room temperature, then you only need to raise it about 75°C and the power drops to 87.5kW, still a huge amount of power. You'd better have a dedicated, high-voltage 3-phase line for that.