Microgeneration seems to be called different things by different people so I thought I’d start with some definitions. These are mainly from UK sources so if the terminology is different in your part of the world, please leave a comment.
There are three terms floating around:
- Embedded generation is defined by Ofgem, the UK’s electricity and gas regulator:
Embedded generation is electricity generation which is connected to the Distribution network rather than to the high voltage National Grid. Embedded generation is typically smaller generation such as Combined Heat and Power (CHP) or renewable generation: small hydro, wind or solar power.
- Distribued generation is synonymous with embedded generational; e.g. Ofgem’s Distributed Generation Coordination Group says:
Distributed generation, sometimes called embedded generation, is electricity generation, which is connected to the distribution network rather than the high voltage transmission network. It is typically smaller generation such as renewable, including small hydro, wind and solar power and small Combined Heat and Power.
Pretty much the same then. A quick Google suggests that the only difference is the country you are in: in the UK, embedded generation is popular, but in the US, it’s distributed generation.
- Microgeneration means any type of small generator but the exact definition can be tricky. Ofgem for example, uses the definition from Engineering Recommendation G83 courtesy of the Energy Networks Association:
“…a source of electrical energy rated up to and including 16 Amperes per phase, single or multiphase, 230/400V a.c.”
The Energy Act 2004 defines microgeneration more broadly as generating plant with a capacity of less than 50 kW. More than enough for households, whose winter demand peak is about 20kW.
However these definitions focus on the generation of electricity. The DTI’s Microgeneration Strategy states that microgen can be the production of electricity and/or heat and, more importantly, that it should be from a low-carbon source.
The key points of these definitions then are that microgeneration occurs at a local scale, it can include the generation of heat and/or electricity, it generates small amounts of electricity compared to centralized plant, and preferably it should be environmentally friendly. Seems sensible to me!
Domestic microgeneration is defined as less than 10 kWp (electricity) in the Electricity (Microgeneration) Bill