Presentation Details
| Impact of Long-Term Average Soiling and Temporal Resolution on Energy Yield Analysis Mark A.Mikofski, Umay Akkoseoglu, Javier Lopez Lorente, Usgal Zandanbal. DNV Energy USA, Oakland, CA, USA |
Abstract
Soiling losses from dust and snow are important in forecasting long-term average (LTA) energy production of photovoltaic (PV) systems. Monthly soiling profiles of dust or snow are often derived from the LTA of individual years in the historical weather data. However, irradiance and other inputs differ each year and within each year. Contradictions both in inter-annual and intra-annual weather may cause errors in predictions of LTA performance. This study investigates the magnitude of these errors from dust soiling only (not snow) by comparing annual energy production between daily versus monthly and between LTA versus individual-year monthly soiling profiles. We found a negligible delta in annual energy between monthly versus daily soiling profiles. However, we observed a bias between LTA versus individual-year monthly profiles. On average monthly LTA was 2% to 4% greater than individual-year monthly profiles for both a tracker and fixed tilt system at two test sites studied in the western United States. In future work, we will broaden the study to more geographical regions and compare energy predicted using historical weather versus typical meteorological year (TMY).
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No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the author.