It is Distributed Power Generation system.Small Cells or non-conventional energy sources like bio-mass plants etc. needs to mitigate the system requirements can be taken as a DPGS system.
I think you mean Distribution Generation (DG), don't you?
DG units are small-scale generators which can be installed by end-users or private investors in the distribution network in order to meet their own demand.
The size of DGs are defined by different regulators in different countries and thus we cannot say exactly what their capacity are.
Meanwhile, in my opinion, 20MW is much larger than a typical house demand!
Normally the generators we use for our personal use come under backup category with a changeover switch to provide power in case of power failures. I think if there is an MOU with DISCOM it may be used as DG.