Trying to wrap my brain around exactly what this entails. Specifically in Colorado, as that's where I still do most of my design work, but also in other places if it's different/better/worse/etc....
This is the actual text of the Colorado bill
From reading it... it appears that it's limited to 1920 watts AC output, and limited to one system per address. Systems under 391 watts AC output are exempt from a number of other requirements (which seem to pertain mostly to NABCEP certified supervisors and licensed electricians), but still have to be UL listed. Does that imply that licensed electricians or NABCEP certified installers must install ones between 391 watts and 1920 watts?
It appears that utilities cannot require approval, a fee, or any modifications to the house electrical system (4a) but can require being notified of the installation and size (4b)
I am wondering how this works with ratcheted meters, which is the norm nowadays in Colorado. I have asked Xcel for their guidance on this.
In general... the idea of balcony solar seems very problematic. While I'm totally in support of more solar on the grid, and making smaller systems more doable, I have lots of questions on how this will work in reality.
1) Structural issues: Most homeowners do not know how to properly mount solar panels against the winds that we have in Colorado. It's normal for cars and neighbors to be assulted by wandering trash cans during every windstorm... adding errant solar modules to this doesn't seem like a good idea. Most temporary solar racking I've seen from manfucturers (from RV solar sellers mostly) is completely inadequate to withstand 100+mph winds as well. How will proper securing of the solar modules be enforced?
2) Electrical integration: 1920 watts is a fully loaded 20A 120 volt output (16A continuous). If it is a new, high quality outlet, it should be good for that, but what if it is a old outlet on the deck that's gotten all loose from 30 years of power tools and christmas lights being plugged and unplugged? What if it's the $1.99 consumer version of the outlet, not the $8.99 commercial version? I've seen the cheaper ones, and many old loose ones, burn up when used with electric space heaters, which is a similar amperage and time span load to a full size balcony solar system.
3) Metering: Since most all utilities in Colorado now use ratcheted meters, it will be a problem if the system exports without somehow getting a bidirectional meter. If it is a lightly loaded apartment, where a 1920 watt system would really make a different in energy use, then it's likely the baseload will be below 1920 watts midday, and it needs to export. If it's a larger house where the baseload midday is over 1920 watts, then export isn't the issue, but the problem is that people will install a 1920 watt system when they really need a 5 or 8 or 12kW system to affect their bill much -- and then they'll just decide that "solar doesn't work" and it will give solar a bad name for more people. Given that most people don't understand kWh and energy use, and marketing always seems to overpromise what equipment can do, I don't expect that a majority of consumers will understand that a 1920 watt system is not sufficient to make a significant impact for a majority of houses out there. I've even had customers install 10kW systems, and not understand that by adding a hot tub and electric water heater and heat pump and electric range at the same time, they overwhelmed the production of the system, and that's why their bill actually went up.
4) Licensure and permits: This could solve some of the issues above... but Colorado allows homeowners to pull permits so licensure and training of the installer is still no guaranteed. And most building departments have a permitting process that's aimed at larger systems... a large system requiring 10 pages of documentation and an engineers stamp and a $500 permit fee is not unreasonable. But for a $2000 balcony kit... how can permitting enforce some basic standards, without becoming a insurmountable hurdle. Also, as a professional installer, I found that fixed costs were a large portion of the cost of installing a system. My cost to do drawings, get a PE stamp for the roof/racking, file for a permit, file for interconnection agreement, and roll a truck were pretty much the same for a 3kW system or a 10kW system. There was more onsite labor for the 10kW system doing racking and modules, but even electrical wiring was about the same onsite labor for both sizes. Onsite labor should be much less for a balcony solar system, especially if plugging into a deck outlet (replacing it with a brand new commercial quality 20A outlet maybe). But costs for drawings, permitting, interconnection won't be different unless a different system is made. Materials are obviously more for the larger systems, but labor made the overall total cost quite a bit higher per watt for the smaller systems, and going to a one or two panel system could be even more share for the off-site labor portion of the total cost. If building departments and utilities put the balcony solar systems through the same paperwork as larger systems, I can easily see that costing more than the materials or onsite labor.
-- Zeke Yewdall
PV Engineer
NABCEP #031508-89
303-523-3592
