[RE-wrenches] Demand savings from PV FYI

[Peter Parrish]

Darryl,

I'm sure what you say is generally true, but unless your utility has an
enlightened tariff, I still think we have a problem.

Since the demand charges are based on the highest demand recorded on a
trailing 12 month basis, what happens on that one sunny hot day when a cloud
passes in front of the sun for 15 minutes and the recorded demand for that
time period is recorded and the demand then snaps back to historical values.

In SCE territory, I believe, the demand charge gets pegged at that value for
the next 12 months, regardless.

Please explain to me anything I'm missing.

- Peter

                                                     
 Peter T. Parrish, Ph.D., President
California Solar Engineering, Inc.
820 Cynthia Ave., Los Angeles, CA 90065
CA Lic. 854779, NABCEP Cert. 031806-26
peter.parrish at calsolareng.com  
Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885

 

-----Original Message-----
From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Darryl
Thayer
Sent: Saturday, June 26, 2010 7:21 AM
To: RE-wrenches
Subject: Re: [RE-wrenches] Demand savings from PV FYI

Hi all
A while back we had a thread going on demand savings from PV.  I reciently
viewed a 1 year data set.  The PV Savings were $36/ month on energy and
almost $100 a month on Demand.  The company is a small business with lots of
computers and of course air conditioning  We are blessed with a diurnal temp
swing.  so morning are cool, and economizers are effective.  The builoding
does not have building automation system.

The summer demand is by far the highest, Every monthly peak occured in the
afternoon, The highest peaks were on sunny days in the afternoon, the solar
reduced all the highest demand peaks.  The Demand fee structure is both a
monthly charge and a ratchet that follows the highest peak for 11 months.
The system is 12 Outback inverters. 

BTW the smud program with Silent Power should reduce both utility and
customer demand charges.   


      
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