When we discuss Solar Energy or any other Energy for that matter, while the Mega Watt number is important, what is more significant is the Mega Watt Hour (meaning how long the rated Mega Watt of Power is available in a day). If it is Solar Energy, then the panels generate power only when the sun is shining. Therefore Solar Energy is most efficient in places where the sun shines brightly, un-interrupted by clouds. Likewise when we talk about Wind Energy, power is being generated only when there is wind.
The Solar Energy Industry Assocation (SEIA) in a detailed document illustrates why Mega Watt Hour matters. Likewise in the SREC(Solar Renewable Energy Consortium) trade markets which covers several states in the United States, the credits are based on how many Watt Hours an entity can produce.
This begs the bigger question: Can Renewable Energy supply 100% of our power needs? Solar energy is the most abundant natural source available on the planet and this excellent article by Clean Technica suggests how we can achieve that. The key is rechargeable batteries and other energy storage mechanisms which can kick in when needed.
Electric car maker Tesla has invested in a new Lithium Ion based battery Gigafactory in Nevada. This factory is expected to start producing 30GWh (note the hours!) of energy by 2020. Elon Musk has already announced that through his SolarCity company he plans on bundling Solar panels with Battery storage. If successful, this could be a game changer.
In 2014, the US generated 36% of its new Electrical energy from Solar. Some studies suggest that 100% of US’s energy needs can be addressed by Renewable Energy resources by 2030. Let us wait and see!