Solar Power plant design Considerations

Design of Solar Power plant entails considering the following factors:

• An estimated total load consumption and load characteristics (DC and Ac load, variable load, alternate supply to grid or standalone).
• Sizing of the inverter (this should be 1.6 times the estimated load to allow for future growth)
• The PV panel sizes is dependent on the level of insolation level in your region. The PV size should typically be 3 times the estimated load to allow for inefficiencies. However, the use of Solar trackers can actually improve PV panel efficiency.
• Then the batteries are sized based on duty cycle and rated ampere hour. (Allow for 1.8 times the actual load to accommodate inefficiencies and future growth).

Latitude is going to have a major effect for you on seasonal variation of power production. For me, my peak sun hours (measuring energy production) right now (near the winter solstice) are about 2 times the instantaneous power of the system. In other words, 2 panels with 250W each will give me 500W of instantaneous power (with perfect conditions at solar noon) and about 1000 Wh (watt-hours) each day. In the summer I get around three times that, say 3000 Wh (or 3 kWh). Average sun hours for me are around 3.8 annually. So no one on here can give you a good answer without location information.

If you goal is grid feeding this power (in other words you put power into the grid when you produce and pull power out when you consume) then raw power production will usually be your main consideration. The rough efficiency you can expect is around 75% end to end. So on average, at my location, 2 panels of 250W is a system of 500W, which on average will produce 3.8 (average peak sun hours) x 365 (days of year) x 500W (system power rating) x .75 giving a total of 520,000 Wh or 520 kWh per year. You can get data on peak sun hours for many cities in the world off of NREL. Cairo gets 5.7 peak sun hours a day on average, and is closer to the equator than I am in NY state, so the seasonal change is much less.

We'd also need to know total energy consumption, not peak power. Unless you are doing a battery system off-grid, or you have special responsibilities for grid stability or interconnecting, the energy consumption on a monthly basis is probably fine. If this is an off-grid system I'd say you need to learn a great deal more before attempting it, or you need to build a small system that will scale so you can learn more by direct experience of how things will work in your area. A lot of the advice we could give you in a vacuum of data might not be helpful... for example I spend a lot of time and effort on keeping batteries from taking cold damage, where you might only be concerned about overheating.