generation

System Listings

Base Power Generation

System Overview
Most of the electricity (approx. 98%) used by the UK populace is generated by some form of public generation.
However there is a place for private generation in the industry. It may be used for a number of reasons for supply security or financial reasons .
Private Generation can incorporate forms of renewable energy. However at present, most schemes utilise some form of fuel burning engine or turbine as the prime mover.

Currently private generation is employed mainly for financial or operational reasons rather than for environmental considerations - although this is changing with the advent of changes required as a result of the Kioto Summit and carbon taxes. Whatever the type of private scheme, it usually still produces electricity at a relatively low efficiency (typically 70% for a CHP scheme).

Systems Available and Applications

Private generation can be divided into various types.

Base load generation - Where electricity is generated on a private site and used by the owner to serve equipment and plant on site. There is often some facility to export surplus electricity to public supply companies. Such generation is normally due to the commercial and financial reasons. However, remote users may resort to such generation if public supplies are not available.

Standby Generation - Where generators are provided to ensure continuity of supply if the public supplies fail. Such systems are normally employed in critical situations such as hospitals or commercial installations where supply failure could endanger life or profits.

Temporary Generation - In remote situations where cost or distance may preclude availability of public supplies, self contained generating plant can be installed to serve the required load. Such systems are rarely installed within the building.

Combined Heat & Power - Where heat is required as well as electricity, it can prove effective and economic to operate gas or oil fired engines and recover both high & low grade heat from these for use in heating, hot water generation or other industrial processes. The engines are also used to drive generators which supply some or even all of the installation's electrical requirements. CHP is used in both large and small scale applications.

Generation systems, whatever their form are commonly incorporated into the electrical distribution system near to or at the mains intake. Hence the LV switchgear is designed to accommodate any control or changeover equipment that may be required.

Space should be made available depending upon the type of system utilised. Adequate ventilation, access and noise reduction measures should be provided.

Legislation & Guidelines
Further information on types generating set may obtained from the CIBSE Application Manual AM8:1992 "Private & Standby generation"

British Standards.

Also refer to The British Standards Institution

BS 7671:2001 "Requirements for electrical installations". IEE Wiring Regulations. Sixteenth edition. This is the all encompassing "Bible" in relation to the design, installation and use of electrical installations and equipment in buildings.
BS 4752:1977 "Circuit Breakers". This covers the manufacture and application of Circuit Breakers for use with voltages up to and including 1000V a.c and 1200V d.c. (Supersedes BS862:1939 & BS936:1960)
BS 5486:1989 "Low-voltage switchgear and controlgear assemblies". Specification for particular requirements of consumer units.
BS 4999: "General requirements for rotating electrical machines". Covers both motors and generator sets.
BS 5000: Pt 3. " Generators to be driven by reciprocating internal combustion engines" Specific constructional and operational requirements for engine driven generators.
BS 7698: "Reciprocating internal combustion engine driven alternating current generating sets". Complete

International Standards