A mandatory renewable energy target is a government legislated requirement on electricity retailers to source specific proportions of total electricity sales from renewable energy sources according to a fixed time frame.
With this, many countries and states now have target that may be short time or long time.
From findings and documentations, 66 countries have target for energy from renewable energy sources.
For example, Brazil has 5% power production from renewable energy, but has no future target, which means, Brazil will either sustain the 5% or waste it because of lack of future target.

Egypt has 10% production currently, and is expected to double it in 2020, that is move renewable power generation to 20%.

India has 4% power generation from various renewable energy method, 1% from solar which amount to 1.3gigawatts and 211gigawwatts from all other sources.

Nigeria has a Zero share currently and is targeting 7% in 2025.
Question-
What are the state and national government policy that will make this target achievable.
Before talking of target, you must first know what you have.
For further reading, please check Wikipedia and wall street journal of February 27, 2013.

Nigeria has a renewable energy master plan. Check online, its free