The unit for solar panels is MWp, which means megawatt.
For example, 50 MWp means that the maximum output power under standard conditions is 50 W.
Under normal circumstances, it can simply be considered to have the same meaning than W.
Photovoltaics refers to the production of solar energy. Grid connected means that the electricity produced is fed into the national grid. The 50 MWp grid-connected photovoltaic is a solar power plant with a capacity of 50 MWp (5,000 kW).