Explanation:

All four.

• Distributed energy resources (DER) refers to often smaller generation units that are located on the consumer’s side of the meter.
• Examples of distributed energy resources that can be installed include:
• roof top solar photovoltaic units
• wind generating units
• battery storage
• batteries in electric vehicles used to export power back to the grid
• combined heat and power units, or tri-generation units that also utilise waste heat to provide cooling
• biomass generators, which are fuelled with waste gas or industrial and agricultural by-products.
• open and closed cycle gas turbines
• reciprocating engines (diesel, oil)
• hydro and mini-hydro schemes
• fuel cells.