Megawatt-hour, represented as MWh, is a unit of energy.

A Megawatt-hour (MWh) is equal to thousand kilowatt-hours. 1 KWh is the one unit of electricity. So, 1 MWh is thousand units of electricity or a million watt-hours.

A 1 MW power plant, if it operates at full capacity for one hour, will generate 1 MWh of energy, and 24 MWh in a day. However, most power plants do not operate at 100% capacity utilization. Solar PV power plants for instance operate at capacity utilization factors of less than 20%. Thus, a 1 MW solar power plant generates much less than 24 MWh per day; in fact, it is only about 4 MWh.

For detailed information on Megawatt-hour, please refer the following link:
http://www.solarmango.com/suncyclopedia/en/mwh-megawatt-hour-thousand-units-of-electricity/