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SRP Demand Charge


May 10, 2018
Queen Creek, AZ
The biggest concern with solar in AZ with SRP is the demand charge. Enter the PW! Been over a week now with 0 demand and actually a negative demand! This is all while the AC is on and my house is nice and cool. Bill has dropped $5-$10 a day since turning on our system.
Dec 2, 2017
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Jan 12, 2018
Phoenix, Az
I’ll bet SRP won’t give you a negative demand charge for negative peak demand, though. ;)

Yes, unfortunately, demand by definition can't be negative. To make it even worse, demand is not net metered over the 30 minute demand period. So if in a given half hour, you send 6kW net surplus power to the grid for 15 minutes and then consume 2 kW net for 15 minutes, your demand penalty will be (0 + 2kW)/2 = 1 kW for the 30 minute period, despite producing a net (-6kW + 2kw)/2 = -2 kW power surplus to the grid for that same 30 minute period.

This is one of many things that kills me about SRP's demand plans. In this example, you get charged a 1 kW demand fee, despite having provided 2kW of energy to the grid over a 30 minute period during peak demand hours. SRP charges you a demand fee despite having helped them with their demand problem, pays you only 6 cents per kW for you excess power, and then turns around and sells that excess power to your neighbor for 22 cents/kW.

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