The Moore’s of Hamilton, Montana completed installation this Fall 2010 of a 10 module photovoltaic system which will provide 40% of the electrical power used in their home. The pole mount solar array is mounted on a tracking system which follows the sun from East to West through the day. The electricity is run into their home where it powers any electrical appliances that are currently in use.
If more power is available from the array than can be used by the home, this excess power will then turn the electrical meter backwards creating a financial credit with the utility. This credit can then be used at night or this winter when the power draw of the home exceeds the solar power production. So you can see that a system can easily be designed to provide any portion of you power bill that a homeowner determines.
This PV system(short for photovoltaic’s) is one of several in downtown Hamilton that Dan Brandborg , a native Bitterrooter has been involved with since he started working with PV in the early 80’s. He has worked with Sustainable Building Systems out of Missoula, since 2009.
We finished the off-the-grid system in Maui in June of 2010 and it seems to be working wonderfully all summer.
All in all, we installed a 5.6 kW solar array, battery bank and inverter system on the island of Maui for an off grid facility. The system powers a main house, two guest houses and a pool house.
We had fun with this project as it is located in such a beautiful part of the world and the local Hawaiians where integrally involved in the installation work. Because the system is beyond the power lines we employed a large battery bank and backup generator fired by propane. This system design varies greatly from grid connected systems where batteries are seldom employed as the power grid serves as “financial” power storage.
Cloud cover and precipitation vary extremely from 12 to 360 inches per year depending upon the microclimate which made the system sizing a bit more challenging. To compensate for this variable we included a 30 kW generator and four inverter/battery chargers which can recharge the batteries in several hours time.
Here is our photo show of the final install, inverter and battery bank, etc… If you want captions, please click on the image below and then on the icon in the lower right w /the four-arrows for full-screen mode.
We just finished installing a 3450 watt solar PV system in the Rattlesnake where we employed 16 Enphase micro inverters. Micro inverters offer several advantages over more conventional string inverters.
Racking system in, Panel get ready!
Each solar module power production is optimized individually so little module mismatching occurs. As well, if one module is shaded from a nearby tree, this one module will have reduced output, not the entire series string of modules as with the larger string inverters. This advantage alone makes a huge difference but the pluses don’t end here.
Josh setting the first panel. Check out the lines on those racks and micro-inverters.
The Enphase engineers designed one of the coolest monitoring programs found in the PV world. Each individual module reports its power output over the existing AC output wiring to your in home computer or with internet service, this data is directed to the company’s website where current and cumulative data is displayed and stored.
After five weeks of designing, ordering and coordinating over sea shipments, we are about to depart for the final installation phase of our Maui PV system. As things move a bit slower in this part of the world we have needed every day to bring the pieces and people together to be at this point.
Several hundred feet of buried conduit are being set this week in advance of the final week push of installation. A new concrete pad has been poured for the 500 gallon propane tank which will fuel the backup generator. Project objectives have grown which is typical yet always different. As we found a place for this tank it was decided to pull the old above ground diesel tanks which died long ago. It is amazing to see what this rainforest climate can do to steel. The top portion of the tanks have literally rotted away. Don’t stand in one place to long or a vine will start growing up your leg.
We will be installing 27 Sharp 235 watt modules, three of which will operate the swimming pool circulation and filtering pump directly. An Outback power panel including 4 outback inverter/ chargers will be placed in the equipment room along with 24 -2 volt cells to give us a large battery storage system.
Check out the video clips of our initial inspection.
Missoula to Maui – two trips – 6-weeks – off the grid – this is awesome!
We completed our in depth site analysis of the Maui, Hawaii facility earlier in April. We shot three video clips of the existing 20 year old PV system which we will soon have on our site. The clips detail the review of this system which is at the end of its useful life, and our suggestions of what to replace it with.
In brief we will be installing a 5.6 kW solar array and expanding the existing mount structure. The two Trace inverters will be replaced with four Outback inverters and a Outback power panel. A stationary generator will be installed to maximize the battery charging ability of the above mentioned inverter/chargers and minimize the generator run time.
As the pool filtration pump was found to be consuming one third of the entire facilities electrical power, this AC pump will be replaced with a DC pump powered from its own three module solar array. This will maximize overall efficiency and greatly reduce the man hours spent in cleaning the pool.
We are scheduled to install this system in the first half of June so we will keep posting as we go.
I think a pretty cool subject is the BIPV systems, short for Built in PV. When it comes to installing a new roof or building a structure from scratch we have the opportunity to integrate the array into the building itself.
One great company that has been doing this successfully for over a decade is Uni-Solar. They make a thin film(amorphous) module which is 15.5” wide and comes off the assembly line in one mile long sheets. Being constructed of amorphous silicon instead of the more main-stream crystalline modules, has a number of differences. First amorphous modules are flexible, the modules actually come in a roll. Because the individual cells are long and narrow they are more tolerant to shading. Amorphous products are roughly half as efficient per square area as crystalline. Yet if applicable roof area is abundant, this is not an issue as the cost per watt of generating capacity is similar to crystalline.
The modules are built to be laminated to metal roofing panels that are roughly 16” in width. The “pan” of the standing seem type roofing must not have any corrugations in the pan, but a smooth flat surface.
SIDE NOTE: Besides having a cool product the company’s founder Stanford Ovshinsky is one hell of a guy. He personally holds hundreds of patents. He never sold out to the big petroleum companies when most of his contemporaries had and developed the battery for GM’s Chevy Volt electric car which was later murdered by GM. http://en.wikipedia.org/wiki/Stanford_R._Ovshinsky.