Case Stories

Michael’s Backup System
Michael contacted me in the winter of 1998. At that time, there was much talk of public services breaking down or malfunctioning as a result of Y2K. Michael had a few concerns regarding Y2K, but primarily he doubted the reliability of the utility company in general. He had had a few problems in the past with power outages. This was a big concern since his water comes from a well that is powered by submersible electric water pump. So, if there were a power outage, he would be left with no water. Finally, the idea of doing something that would be good for the environment was appealing to him.

Michael lives in an average-sized suburban house, and what he wanted was a system that would give him enough power during utility company outages to live comfortably. So, what he needed was a backup system. Also, while the utility was fully available, he would be generating enough power from his system to reduce his electric bill by a small amount. One of the hardest things for people who have only a financial interest in renewable energy to accept is that it is simply not worth the cost. If you want to install a renewable energy system simply to save money, you should look for another way of saving money!

Michael came to me initially with the idea of installing a system that would combine both wind and solar power. But we had to abandon the idea of wind energy because of 100-foot trees in his back yard that would make an extremely high tower necessary for the wind generator. Thus, it was not feasible to include a wind generator in the system. Solar power was the only option. The house had a pitched roof facing south, but there was also a big yard that could accommodate a couple of solar trackers. Trackers are devices that follow the sun to an accuracy of about 1 degree. Since these would increase efficiency by 40% over an immobile roof system, we decided to go ahead with two double axis trackers. Michael is a typical suburban consumer of electricity, consuming about 60 kW/h per day (this is typical for a large suburban house, with central heating and cooling). So, we needed to squeeze as much power out of the solar panels as possible.

Because the submersible water pump was in a 240 V AC configuration, we used two 120 V AC inverters, connected in series. On the two tracker poles were installed a total of 32 solar panels producing 2.88 kW of electricity. Since Michael did not mind a little maintenance and wanted to cut costs, wet lead acid batteries were used. The client chose dedicated circuits to be powered by the system, such as certain lights in each room, and one receptacle outlet in each room, plus a refrigerator. Another refrigerator and the central heating system were placed on a manual transfer switch, so the client could choose which system to run it on, depending on the state of battery charge. We did this because the consumption for these appliances is too large to be powered by the alternative system all the time. The total energy saving was about 40% --that is 40% of the total electric bill was saved each month. We designed the system so that in the future, if the client decides to enlarge it and to power more circuits through renewable energy, we can add more to it.

Michael’s system has been working since spring 1999. Except for a lightening strike that damaged the controller of one of the tracking devices, the system is working flawlessly. Much to everyone’s surprise lightening struck while the controller was still under warranty, and so it was promptly replaced, and everything is functioning smoothly.

Marjie’s Stand-alone System
Marjie lives in the city, in a densely populated neighborhood 5 minutes from downtown. In her free time, she’s an environmental and community activist. Having a solar system had been her dream for a long time. When she heard of the incentives that the Department of Commerce and Community Affairs was offering, she decided to invest in a full fledged stand alone system that would make her independent of the grid. Her rationale for spending a significant amount of savings was: "Hey, some people spend as much money or more on a fancy SUV to be driving it around city streets! So why shouldn’t I invest in something that is good for the environment?" It’s funny how people balk at someone spending most of their savings on a renewable energy system but don’t think twice about buying a fancy sports car. As someone once said, "The implication is that anyone choosing to pay for PV electricity is foolish, while anyone choosing to pay a Lexus is discerning."

Marjie has the perfect setting for a renewable energy system in a city house. She owns a two-story building with a full basement. The building has a 41° pitched-roof facing south, which matches the latitude of the location perfectly. It also has an unobstructed view to the south. Marjie wanted to be independent of the grid, and so we needed to route all her electric consumption through the system.

In order to save on installation costs, we decided to install the biggest solar panels available on the market. Twelve 300watt ASE solar panels were installed on the roof. The power generated feeds a battery bank of AGM lead acid batteries. These are maintenance-free batteries, which was convenient for the client. A 120 V AC 4000watt inverter was enough to cover all her electrical consumption needs. So, Marjie’s system was designed to replace the utility grid. For the first six months that the system began to function, the utility meter has essentially not moved (yet, the utility company kept charging her the average estimate, which of course upsets her to no end!) The beauty of Marjie’s system is that all the excess power, if any, is diverted to preheating water. Thus, when the batteries are full, all the excess power goes to an electric water heater which is connected in series with her own gas powered water heater, saving in gas expenses.

Since the beginning of 2000, the system has been working smoothly, and Marjie is proud to live off of what the environment offers without in turn causing any damage to it. 

Jeff's Utility-Connected System