source: Wahila Minshall Akeena Solar 2003.08 - seen in issue #98 (Dec03-Jan04 HomePower magzine)

On a clear, sunny day in March, a group of women were outside a California environmental science school talking shop - and that isn't short for shopping. Discussing everything from conduit bending to system voltage, these 23 women were at Walden West Center in Saratoga, California installing a 1.5 KW solar photovoltaic system.

Instructor Justine Sanchez, bottom right, and the array installation crew line up
behind the finished array as the sun sets.

Walden West is an outdoor environmental science school in the Saratoga hills that hosts weeklong science programs for 5000 to 7000 students each year. The women - who came from everywhere from New York to San Jose - had just finished four days of classroom labs in Santa Cruz, California as part of a "Women Only" PV Design and Installation class offered by Solar Energy International (SEI). Each SEI course culminates in an actual installation providing students with the hands-on training needed to truly understand PV system operation and installation. This PV system will begin its lifetime by educating future renewable energy workers and advocates and, since it is installed as part of an environmental education program, it will go on to teach tens of thousands of children about the benefits and practicality of solar electric energy.

Collaborative Effort
The installation was accomplished through a collaborative effort among Walden West Center, Solar Energy International, Rahus Institute and Akeena Solar. Walden West received a Flex Your Power grant from Pacific Gas and Electric (PG&E) for the project, but that money didn't cover the full $13,000 cost of the system and installation. Tor Allen, Director of Solar Schoolhouse, a program of the Rahus Institute brought the funding situation to my attention. Meanwhile, we at Akeena Solar, having two SEI graduates on staff, had already agreed to guarantee a local installation for the hands on portion of the March 3-8 SEI class. Akeena President, Barry Cinnamon, then offered to donate the remaining funds and set up the labor via the SEI class attendants. Everyone involved was thrilled with this solution. Most of all we were happy to be installing a system that will educate future power buyers and decision makers.

"As a parent I want to do everything I can to help break our country's dependence on fossil fuel energy sources, both foreign and domestic. My kids go here in the summer, and they have a terrific outdoor education program." said Cinnamon. "By helping fund the installation at Walden West Center, we will be able to communicate the clean energy benefits of solar to the thousands of students and promote the transition from fossil fuels to clean renewable energy. Akeena Solar's philosophy is simple: we believe that producing clean electricity directly from the sun is the right thing to do for our environment and economy."

The Walden West site was an ideal installation for the SEI students for a variety of reasons. The site offered plenty of space for this large group of women to work. The installation offered some unique challenges - including a black widow spider (the female of the species) - in the service panel closet, but was small enough to be completed in the two days allotted. To top it off Walden West offered to feed and house the SEI students during the class, helping to defray their expenses. "Akeena Solar helped make this whole project happen on our limited budget." said Richard Reid, Walden West's Supervisor of Business Operations. "We appreciate this so much," says Anita Parsons, Walden West co-director. "We wouldn't be able to do it without SEI and Akeena organizing and donating the time and money.

Educating Women PV Installers
Colorado based Solar Energy International (SEI) is one of the nations foremost educators for Renewable Energy Installers and Green Builders. They offer classroom and laboratory work, complemented by case studies, field tours and professional installations with real equipment in real settings. Six years ago SEI began to offer some courses for "Women Only" to support and encourage more women to enter this traditionally male dominated field by providing a less intimidating atmosphere for learning. The "Women Only" courses have been extremely successful, greatly increasing the number of women taking these courses and drawing in women from all walks of life and all ages. Some come because they are thinking of installing their own systems, some because they are looking to make a career in the field and others to further their knowledge of the field in which they are already employed.

Jennifer Seguin, a participant in the 2003 SEI class and the environmental project coordinator for the city of San Jose, says the city is looking to coordinate its energy policy to address statewide needs. She was sent to the class to learn and report back to the city in hopes of creating a coordinated energy plan. "I had learned all the theory, but I wanted the hands-on experience," Seguin said. "It has been great. I am definitely getting a clear understanding of solar power and installation."

Carol Weis, an SEI instructor, says the classes are "a lot of fun" and believes there is "something special" about the women's-only class. "The women are all talking within 30 minutes; there is a deep level of conversation and camaraderie. These classes talk much more and get hands-on for everything," Weis said. These classes allow women to talk about this very technical subject in language that we are comfortable with. As a result a lot more questions are asked and an inspiring amount of networking goes on.

I was a class participant in the first SEI Women Only course in to be offered in Santa Cruz. I was pursuing a career in the solar electric field and felt that the hands on aspect of the SEI course and SEI's good reputation for training renewable energy workers would make me ultimately more employable. This proved to be true when I interviewed with Akeena Solar. The fact that I could work as an auxiliary installer when needed tipped the scales in my favor and I was hired as the marketing manager.

Educating Power Consumers/Children
Walden West Center, which is owned and operated by the Santa Clara County Office of Education, provides residential outdoor science programs with a strong environmental emphasis for 5th and 6th grade students throughout the school year. During the summer they run day camps with an environmental focus for children of all ages. Using energy efficiently and having alternative energy systems on site is a priority for this school both to decrease operating costs and for educational purposes.

Walden West recognizes how critical it is to teach children about renewable energy. Richard Reid said, "Our children will experience a huge transition in how power is produced in their lifetimes. An important goal of this school is to educate these students so that they will understand, embrace and encourage this change." With this installation the school will develop and implement a new curriculum unit on solar electricity to add to the solar thermal unit they already have. The students will conduct a weekly study on how much power is generated. They will then quantify that to the number of 100 watt bulbs that could be powered for an hour. Rahus' Solar Schoolhouse program has provided portable solar labs that allow the students to experiment with operating motors, lights and water pumps from solar cells. They will experiment with the effects of shading and orientation. Rahus has conducted staff training workshops and complimentary hands-on activities with the Walden West staff over the last six months. Lessons are being piloted this school year. "It is exciting because the kids will actually be able to see the electric meter backing up. It is a great place for them to learn, and we'll save energy but also show them how we are saving energy for California," Parsons said.

Other Energy Efficiency Upgrades
To reduce its power needs the school has upgraded all the lighting systems. They are using a combination of fluorescents with electronic T-8 ballasts and high pressure sodium lamps. In addition they have a large solar thermal system for heating the swimming pool and plan to install a solar domestic hot water system to supply the shower rooms. The new PV system will provide Walden West over 2,000 kilowatt hours of clean electricity per year. By installing this system Walden West will eliminate the release of 60 tons of CO2 over the 30+-year life of the equipment and save $600 per year on their PG&E bill.

System
The system consists of an SMA 2500 watt 208-volt SunnyBoy inverter with display, and 9 Sharp NE-Q5E2U 165 watt modules. When more funds become available this system can expand to 16 modules. Since the building's electrical service was 208 volts we were not able to use the standard 240 volt model of the SunnyBoy. Note that the lower output voltage of the 208 inverter means that the maximum AC output power is less than the standard 2500 watts, and the maximum DC input power can only handle 16 (instead of 18) modules.

Because the system was installed in an accessible, outdoor classroom area the wiring was a bit tricky to prevent vandalism and accidents. It was important to install the inverter and external AC display meter in a place that was visible to the students; it was also important to install the DC disconnect in a secure location inside a locked electrical closet. The solution was to construct a complicated junction box - affectionately dubbed the "artificial heart" - so that conduit could securely pass through a concrete block wall.

In terms of actual wiring, the DC run from the array went to the "artificial heart", through the wall to the DC disconnect inside the electrical closet, then back out through the wall through the "artificial heart" and into the inverter. The AC line went out of the inverter through the artificial heart and to the AC display meter, back through the "artificial heart", and through the wall to the 208volt service panel. The inverter was installed about seven feet above ground level to minimize the likelihood of tampering by "playful" students or others.

EMT conduit was used on all exposed wiring. There was a fairly long conduit run down the roof angle and across the face of the building under the eaves. This required some complicated bends and thus gave plenty of opportunity for learning the "art" of conduit bending. A rooftop terminal box was used for the transition from USE-2 wire from the modules to the to THWN wire used inside the conduit

The modules were mounted in a three by three array on UniRac rails using top mount clips. The rails were then secured to the composition shingle roof using aluminum L-brackets and stainless steel lag bolts attached to the underlying 4-foot on center rafters. The women carried the modules up an A-frame ladder one at a time instead of panelizing the modules on the ground as this technique was easier and safer in this location.

By about 4:30 PM on the last day of the class, most of the pieces of the system were in place. But the sun was about to set beyond the western hills, so we had to pick up the pace. We worked madly to get all the modules aligned and finally secured, wiring completed, junction boxes closed and final safety checks made. Just before the sun went down we began to commission the inverter. After about ten minutes of system initialization, the system fired up with minutes to spare. A cheer went up as the AC meter started to spin slowly and the inverter's display indicated that we were producing several hundred watts of power. The class was delighted to see that they had accurately applied the principles they had learned in class.

Costs and Savings
Total system costs were $13,984, broken down as follows:

9 Sharp NE-Q5E2U PV Modules $6,156
SMA 2500U SBD 208v Inverter $2,569
Balance of System components $3,744
Design & Engineering $ 1,516
Total $ 13,984

Out of this total, Walden West will receive a $4,921 rebate from the California Energy Commission. Of the balance, Walden West paid about $5,000 and Akeena Solar contributed the balance of system costs of about $4,000.

In terms of real-world system output and savings, Akeena Solar relies on a fairly conservative model of system performance. Total DC output of 1,485 watts (9 modules, each producing 165 watts DC) is reduced by 11% for PVUSA rating factors, 4% for low irradiance conditions, 7% for annualized panel soiling, 14% for inverter efficiency/MPPT and wire losses, and 3% for orientation/tilt factors. The end result of these factors is that we expect the actual AC power output to be about 66% of the full irradiance DC input. When we multiply this output by 5.5 hours of peak sun per day and 365 days per year, annual energy output is about 2000 kwh per year.

In actuality, the vast majority of our customers see real outputs that exceed our conservative initial estimates. In the 120 days that the system has been running at Walden West it has already produced 1,275 kwh, which is about 30% ahead of what our modeled performance predicted.

Conclusion
Due to tight budgets Walden West was only able to install this small system even with the help of SEI and Akeena. Reid has hopes of adding to the system size, perhaps as soon as this fall. Walden West also has a new main building in the planning stage and have included in the specs a PV system sized to provide for all the energy needs of this new structure.
Nevertheless, Wallden West remains committed to demonstrating and educating students on the viability of renewable energy sources. One of the best ways we can ensure the long-term success of our industry is to help educate future generations on the benefits of solar energy - and teach the other half of population how much fun it is to be on top!

About Akeena Solar
Akeena Solar provides customers with an unsurpassed combination of solar design expertise, financial analysis and quality installation. Their growing list of satisfied commercial and residential customers is a reflection of the care and attention they pay to every project. Akeena Solar's philosophy is simple: we believe that producing clean electricity directly from the sun is the right thing to do for our environment and economy.