Recognition of Embedded Generation within Distributed Power Systems in the USA: The New Centre at the NREL

Abstract

INTRODUCTION Electricity generated from wind power, as from most other renewable energy resources, is generated at dispersed locations and is of variable output. This contrasts with conventional power, usually of much larger scale and generated centrally. Both types of system require grid distribution sy stems to service consumers, however the control and power flow within each type is clearly different. A s renewables develop, the power enters grids designed for central distribution and there can be incompatibility. Such ‘embedded generation’ is often significant and so reconsideration of the grid is necessary. The challenge concerning the compatibility of renewables supplying electricity power grids and gas distribution networks has been recognised recently in the USA by the establishment of a special centre at the US National Renewable Energy Laboratory (NREL) at Golden. This is an important recognition of the changes taking place in energy delivery and will have favourable implications for the increase use of wind power and other renewable sources in main market power generation. The normal expectation is for wind power to be electricity generation and immediate dispersal in a power grid. However the policy of the Center to include the distribution of hy drogen and other gases, gives the possibility for wind power to be dispersed in this form also, thereby allowing the power to be stored and dispersed. NREL is a United States Department of Energy national laboratory managed by Midwest Research Institute, Battelle and Bechtel. Beyond its w ork on distributed power, the lab is a leading centre for research into photovoltaics, wind energy, plantand waste-derived fuels, chemicals, and electric power, energy -ef ficient buildings, advanced vehicle design and hydrogen fuel cells.