Roof top solar, small wind generator in your back yard.
Would anyone build a substation for each of these?
They would be on a customer property, which is fed from a distribution line.
@NickParker,
Distributed Generation is any generated power tapped to the distribution lines of the power network, POCCs not on the transmission line points of the grid.
Not that cranky108's description is wrong per se, but in my view it is a bit narrow; Parchie's answer to my way of thinking gets at it better, suggesting generation of whatever kind distributed like pixie dust within the electricity distribution system.
For sure the itty-bitty stuff that cranky108 mentions falls into the category even if the output barely even mentions a net metering agreement; but my utility also has non-utility distribution-connected generators that get well into two significant digits' worth of megawatt output. These latter have much more detailed connection and power sale agreements, "technical interface requirements," and other burdens imposed on them that the wee ones don't merit.
Hope this helps.
CR
"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]
For folks in North America, NERC has just proposed that Distributed Energy Resource (DER) be defined as "Generators and energy storage technologies connected to the Distribution Provider’s system that are capable of providing active power in non-isolated parallel operation with the Bulk Electric System."
