What is DE?

WADE Canada defines ‘Decentralized Energy’ (DE) as:

DE is heating, cooling and/or electrical power that is produced, managed and stored at the point of consumption.

The three main supply streams for DE are renewable energy, recycled energy or waste to energy. DE offsets centralised energy demands for residential, commercial and industrial consumers by:

Integrating energy generation into buildings
Attaching on-site energy generation to energy intensive processes and equipment
Building district energy and micro-grids (thermal and/or electric output) for a cluster of consumers or entire communities

The term 'DE' may be relatively new, but the concept is as old as commercial electricity. The very first power plant in the world, in New York City in 1882, provided both electricity and useful heat to the neighbouring buildings.

	Pearl Street Station was the first DE plant, providing both useful heat and electricity.

What determines whether energy generation is DE is not so much how it is generated rather where it is generated. DE technologies generate energy where it is needed. Centralized generation on the other hand generates electricity in large remote plants and power must then be transported over long distances at high voltage before it can be put to use. Regardless of technology, whether it is used in connection with an existing grid or in a remote village, or whether the energy comes from a clean renewable source or from burning fossil fuel: if the generator is 'on-site' it is DE. This means that, strictly speaking, DE could imply technologies that are not necessarily cleaner for the environment such as diesel generators without heat recovery. More often that not, however, DE is synonymous with cleaner electricity- indeed that is one of DE's main benefits.

There are many different terms used in the context of DE and it can get confusing. Below is a table that lists many of the terms, defines them and explains how they are related to DE:

Term	Acronym	Notes
Decentralized Energy	DE	Electricity production at or near the point of use, irrespective of size, technology or fuel used - both off-grid and on-grid. DE includes high efficiency cogeneration (CHP), on-site renewable energy and industrial energy recycling and on-site power.
Renewables/ Renewable Energy	RE	Energy sources that are naturally replensihed in the short term, including non-carbon technologies such as solar energy, hydropower and wind as well as carbon-neutral technologies such as biomass. There is considerable overlap between renewables and DE. When renewables are used to generate power where it is required renewables can be said to fall within the DE definition. On the other hand large wind farms, that are built remotely from where the electricity is used, do not fall under the DE definition.
Distributed Generation	DG	Often used interchangeably with DE although sometimes DG refers to power only whereas DE includes thermal energy and electrical power.
Microgeneration		Very small scale applications of DE- usually at the scale of an individual home.
District Energy (District Heating/Cooling)	DE/DH/DC	Production of steam, hot water or chilled water, or a combination of the three, at a single central plant for distribution to other buildings through a network of pipes. The term is closely related to DE. It often, but not always, overlaps with DE. When district energy systems employ waste heat from electricity generation to supply heating/cooling networks they can be considered DE. In some cases, however, district energy plants are used in heat only applications in which case they are not considered DE.
Combined Heat and Power	CHP	The simultaneous production of both electricity and useful heat. CHP can be on any scale from very large applications in refineries to tiny machines in individual homes. CHP is one type of DE.
Cogeneration		Term used interchangeable with 'combined heat and power'. Cogeneration is the simultaneous production of both electricity and useful heat. Cogeneration can be on any scale from very large applications in refineries to tiny machines in individual homes.
Combined Cooling Heating and Power/Cooling Heating and Power	CCHP/ CHP	CCHP is the simultaneous production of electricity and useful heat and cooling (usually by a heat powered chiller). CCHP is one type of DE.
Trigeneration		Term used interchangeably with CCHP. Trigeneration is the simultaneous production of electricity and useful heat and cooling.
Uninterupted Power Supply	UPS	Term often used to describe on-site power, especially in the context of emergenecy power for computers. The term is usually associated with fossil-fired generators and implies power only applications, however it can also refer to applications where waste heat is recovered in which case greater environmental benefits would be realized.
Backup Generator		Usually associated with fossil-fired generators and implies power only applications, however it can also refer to applications where waste heat is recovered in which case greater environmental benefits would be realized. Renewable technologoiges are also increasingly being employed to provide backup power.
Captive Power		Term closely related to DE often used to describe on-site power. The term can imply either power only or cogeneration applications.
Embedded Generation		Closely related term often used to describe on-site power. The term can imply either power only or cogeneration applications.
Micro grid		A collection of DE technologies grouped together in a specific area and often connected at a single point to the larger grid.
Distributed Resource	DR	Often used interchangeably with 'Decentralized Energy' or 'Distributed Generation' but because a resource can also be either supply or demand side DR also includes conservation measures at the point of consumption.