The Connection Minefield
Abstract
One alternative approach for deferring investment on the transmission network is to install distributed generation. This can take many forms. This paper describes typical issues that need to be addressed when installing such generators in the electrical network, focussing on a particular project that was implemented at Auckland Hospital.
The installation of cogeneration plant at the Auckland Hospital was mooted as early as 1995. The reasons for not installing the plant where numerous and included both technical and commercial issues. Despite the many issues involved with the project, in 2002 Meridian Solutions (a business unit of Meridian Energy) negotiated an agreement with the Auckland District Health Board to install a 5.4MW cogeneration and standby plant located on the hospital site. The Plant comprises 2 x 1.9MW gas powered cogeneration units and 1 x 1.8 MW diesel generator. Some pictures of the Plant during and after installation are shown in Appendix A.
The final cogeneration technology used is that of reciprocating gas engines. This technology is mature and well understood, as is the connection of the plant to an islanded load. However the physical connection of the plant to Hospital network whilst at the same time connecting to the local distribution network (and in turn the national grid) proved to be a significant challenge. This paper discusses the technical and commercial issues associated with the connection of a cogeneration plant into an existing electrical consumers premises, whilst at the same time considering the fine balance between economics and the requirements of the local distribution company.
SKM worked as technical advisor and owners representative to Meridian Solutions on the project. Acknowledgement is given to Meridian for allowing this information on the project to be published.
Authors
Richard Fairbairn, Lindsay Stanfield, Frank Lewis, Kelvin Yee, Kenny Dunn
Sinclair Knight Merz