Short-term storage and wind power availability

Abstract

IN a discussion on the economics of alternative energy sources, Ryle¹ suggested that wind power in conjunction with short-term thermal storage can provide a viable and attractive source of energy in the UK. Leicester, Newman and Wright² have recently analysed wind data and empirically derived heating demand over a six-month period. On the basis of these data they suggest that short-term (∼150 h) storage is inadequate to provide a reasonably reliable supply from wind generators for heating purposes. This conclusion has been criticised by Diesendorf and Westcott³ and, in view of the limited data sample used it is clear that a more extensive analysis is required. Here we use hourly wind and temperature measurements over a 17-yr period (data obtained from the Meteorological Office, Bracknell) to investigate the performance of a simple system in which wind power is used in conjunction with 150-h thermal storage to provide domestic space heating. The results are promising, even for this basic system, and confirm that, with some modifications, such a system can provide adequate reliability. A significant result of this analysis has been to indicate the importance of selecting an appropriate value for the wind speed at which the wind turbine is to produce its peak output (the ‘rated’ wind speed). It is shown that the use of too high a rated speed not only greatly exaggerates the fluctuations in available power but could also result in a more expensive design of turbine for a given annual energy output.