Thoughts on Solar

UPDATE - We heard back from BWP - details at the end of the post…

The wizards at Burbank Water and Power have announced their solar rebate program will resume, but only for the lucky few who happen to be facing West.  Here’s our take.

Having a stable, predictable solar rebate program is the key to making a solar program successful. Municipal utilities like Pasadena Water & Power, and investor-owned utilities (like SCE) participating in the California Solar Initiative, have had great success with their programs. 

Then there are other munis, like Burbank Water & Power (BWP), that just can’t seem to get it right.  BWP, like its similarly misguided neighbor, Glendale Water & Power, has had an on-again, off-again rebate program that baffles all who attempt to make use of it.  Now, for a brief moment, BWP’s solar rebate program is on-again, sort of.  During the month of August, potential Burbank solar customers are allowed to submit rebate applications (submission deadline is August 29 at 5:00 p.m.) for a lottery to be held on September 8th.  The lucky 60 residential and 15 small commercial (<30 kW) customers who make the grade (no details on how the auction will actually be conducted have been released) will be advised of their good fortune by September 12th.  Rebate amounts are $0.96/CEC AC Watt for residential and $0.73 for small commercial.

But wait, there’s more.

For the first time in our experience, a utility is limiting rebates for solar systems to only those which face in a generally westerly direction.  In fact, systems facing true south are completely ineligible for rebates (as shown in the  image to the left), even though such systems are the most productive! 

BWP is essentially precluding the overwhelming majority of building owners from even having a chance at a rebate in their lottery system.

This continues a trend we have seen with other muni utilities (GWP we are talking about you) where solar programs are designed to be unsuccessful.  It will be interesting to see if we can extract any data from BWP about the results of their lottery.

BWP’s Stated Rationale for Restricting System Azimuth

But why the restriction in the first place?

According to BWP, it is to insure that the power produced comes closest to overlapping with BWP’s peak afternoon demand from 4-7 p.m.  Thus to qualify, systems have to be oriented between 200 and 270 degrees and have a minimum tilt of 5 degrees.

That seemed pretty arbitrary to us. 

While we could understand a utility wanting to limit providing rate payer money to systems that yield the maximum benefit to those rate payers, there is certainly nothing magical about a limit of 200-270 degrees.  In fact, somewhere around 270 should be the sweet spot for afternoon production, with a fall-off on either side.  So why cutoff systems beyond 270 degrees?

We decided to run some models using NREL’s PVWATTS tool.  We assumed a 10 kW system at a 10 degree pitch (a common residential roof pitch) and accepted the other defaults for the model.  We then calculated the hour-by-hour output for systems with azimuths ranging from 200 to 330 degrees.  Here are the results for the critical hours from 4 to 7 p.m.

All of the azimuth angles in the green box are acceptable to BWP, whereas all of the azimuth values in the red box are deemed unacceptable for a rebate from BWP.

But here’s the thing… see that green horizontal line?  That represents the 4-7 p.m. output for our hypothetical array with an approved azimuth of 200 degrees.  Yet five out of six azimuth values modeled here that are rejected by BWP, actually produce more power during the critical period than does our approved system at 200 degrees!

So what exactly is going on here?  BWP’s asserted rationale does not hold up to scrutiny.  Which begs the question, why, really, is BWP so seriously limiting who can participate in their lottery?  It certainly is not justified by their desire to maximize 4-7 p.m. production.  If that were truly the case, they should include azimuth angles all the way to 320 degrees.  They would get more timely power production while opening their rebate lottery to many more potential customers.

How about it, BWP, what is going on here? 

If you are a potential BWP customer who falls outside of the “accepted” azimuth band, you might want to contact the Solar Support program managers:

John Joyce: jjoyce@burbankca.gov or

Alfred Antoun: aantoun@burbankca.gov

If you get a response, please add it to the comments.

UPDATE - We heard back from John Joyce, Solar Support Program Manager at BWP, about the outcome of the lottery process.  According to Mr. Joyce:

105 lottery entries have been submitted and the budget is sufficient to allow each of these applicants to participate, therefore no lottery will be held.

We have a further inquiry in to Mr. Joyce to see if there is still budget left over to allow more applications going forward.  We will update this again if we hear back.