Answer: Over 120Kj of heat needed.

120,000 Joules = 33.333 Watt-hours

A 100 Watt heater would heat the water in 1/3 hour (20 minutes). Do you need faster heating?

200 Watts would take 10 minutes.

2,000 Watts would take 1 minute.

20,000 Watts would take 6 seconds.