Using Electric Water Heaters (EWHs) for Power Balancing and Frequency Control in PV-Diesel Hybrid Mini-Grids

K. Elamari
Department of Electrical and Computer Engineering, Concordia University, Montreal, Canada

L. A. C. Lopes
Department of Electrical and Computer Engineering, Concordia University, Montreal, Canada

R. Tonkoski
Department of Electrical and Computer Engineering, Concordia University, Montreal, Canada

Ladda ner artikelhttp://dx.doi.org/10.3384/ecp11057842

Ingår i: World Renewable Energy Congress - Sweden; 8-13 May; 2011; Linköping; Sweden

Linköping Electronic Conference Proceedings 57:13, s. 842-850

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Publicerad: 2011-11-03

ISBN: 978-91-7393-070-3

ISSN: 1650-3686 (tryckt), 1650-3740 (online)


Electricity is usually supplied by diesel generators in remote communities at costs that can reach up to $1.50 per kWh in northern Canada. At these costs; several renewable energy sources (RESs) such as wind and photovoltaic (PV) can be cost effective to meet part of the energy needs. Their main drawback; being fluctuating and intermittent; can be compensated with either storage units; which are costly; and/or by adapting the electrical power consumption (load) to the availability of RESs. Electric water heaters (EWHs) are good candidates for demand side management (DMS) because of their relatively high power ratings and intrinsic thermal energy storage capabilities. The average power consumed by an EWH is strongly related to the set point temperature (Td) and to the hot water draw (Wd). A 5.5 kW; 50 gallon EWH is modeled in MATLAB-Simulink and a typical 24-hour water draw profile is used to estimate the potential range of power variation offered by an EWH for power balancing purposes. Besides; a strategy for controlling the power consumed by the EWH; by means of Td; using a grid frequency versus temperature/power droop characteristic is proposed. In this way; the EWH can be used for power balancing and for assisting with the mini-grid frequency control.


Diesel hybrid system; electric water heater; power balancing; frequency regulation


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