Approximately 30 minutes.
Take a closer look, however, and there are some underlying differences that create the magic of freedom from utility bills. Out behind the house, mounted on a thirty plus foot steel pole are an array of photovoltaic solar panels that generate electricity. This solar array is actually mounted on an automatic “tracking” system that directs the panels as close to directly at the sun as possible all day. In the morning the panels point east, by mid-day they are pointed almost straight up into the sky, and finally by evening they end up facing west, constantly optimizing their transformation of sunlight into electricity.
Beyond these solar panels you would never know that this family lives off-the-grid. There are no other unusual features of the actual home, garden, or windows that would indicate that this home works a little differently. To be sure the house is wonderfully bright with light because of the many windows. If you look closely the fridge, elegantly designed into the beautiful kitchen, is a SunFrost (reportedly the most efficient fridge in the world). If you look a little closer you’ll also notice that the lights are all compact florescent of a wide variety of shapes, sizes and types.
Leonard bought the property in 1987 before having a family. He made a decision not to get electricity from the grid during initial construction. He was able to run many small power tools for construction using an initial set of four solar photovoltaic panels, an inverter to convert the DC current to AC, and a small set of batteries to store excess power. The SunFrost refrigerator was ordered early on as the only means of significantly reducing the load typically required by a fridge. It was touted to be the most efficient in the world at the time. Since Leonard was the only one living in the house he was able to limit his use to 400 watts of solar power generation. Everything worked well. The garage was added and since it faced south he put an additional 300 watts of solar panels on the roof. The security systems business Leonard ran moved towards more and more solar powered systems and in fact has turned into primarily a renewable energy systems provider today. The original system was fine for about five years. The battery storage system has been expanded several times in order to allow the home to operate for longer periods of time without as much sunlight. This is especially important during the winter.
The original 900 watt solar system, including the original battery system was then sold. That old system is still operating well for the people that Leonard sold the system to. He had no trouble selling the system as demand for solar is high. The battery system was expanded to three times the original size and is now able to store 50-60 Kilowatt-hours of electricity. This is enough to supply the home for the darker periods in the winter. There is a backup generator in case this is not enough.
With the larger solar array and battery system a larger inverter was required. The new solar panels were put on a tower and tracker system, and mounted on a pole. The tracker automatically adjusts for variations in the sun’s position during summer and winter, as well as throughout each day. The steep angle of the panels in the winter ensures that the snow does not accumulate on the panels (a problem when the panels were fix mounted on the garage). The current battery system is about ten years old. It should last another three years. The array is now up to 1500 watts and is on a higher pole than in the early days. The shading from trees required that they get it up even higher. They have more power than they need in the summer and the charger shuts down sometimes. There is still a deficiency in the winter. November in southern Ontario has many fewer daylight hours and may have no direct sun for days on end. The solar array could be bigger to make up the difference in the winter. In fact, engine-driven generators have been the biggest problem. They have been unreliable in general. They are strictly for backup power and aren’t designed for long term usage.
The generator runs about 150 hours a year. The cost for gas on this is about $150. This is a stop gap for now, says Leonard. Eventually he is hoping to store the summer excess power for later usage in the winter. Eventually he hopes to run on a fuel cell energy storage system when these units come down in price. This should be in two to three years. Leonard expects to be one of the first off-the-grid users of fuel cells in the country. The fuel cell unit would then be sized to store the annual requirement for kilowatts needed. The array would probably need to be about 20% greater than expected requirement, and then the fuel cells could be used to store excess for use during the winter.
The home has lots of natural daylight so that electric lights don’t need to be turned on during the day. During the recent renovations the changes to the overhangs on windows have significantly improved cooling in the summer. The home was originally a forced air gas furnace. During the most recent renovation an in-floor hydronic heating system was put in on the 1200 sq.ft ground floor. Now no blowers, which were gobbling up lots of power with the old system, are required. The in-floor heating system is supplied with hot water by a propane in-line water heater. This same unit supplies all of the in-floor and domestic hot water required. By turning up the hot water temperature while the dish washer runs Leonard is able to ensure that the electric water heater in the dish washer doesn’t turn on, significantly reducing the load on the electrical energy systems. The dishwasher needs to see at least 140°C to not need the energy boost. Before, the dishwasher was using about 1000 watts of power.
Propane is used for water heating, cooking and the clothes dryer. They get a 1000 liter propane tank filled three times a year. They spend about $1,200 per year on propane. To some extent the extensive windows require this high level of heating. The wood stove also is used to supply an additional 20% of heating and only when it is especially cold outside. The cost of wood is about $300 per year. Triple glazed windows are something Leonard would do next time. Another idea Leonard has is using the wood stove for heating water used in the in-floor system.
Being off-the-grid you must be cognizant of your energy usage. You may undergo an adjustment period initially. People are, in general, unconscious of their energy usage. When it is finite, in off-the-gird homes, it may take a few months, if not a year or two, to become familiar with how efficient and careful you can be with this resource.
Despite this, there is zero maintenance on the system now that everything has been optimized and tuned. There are some monitors for viewing the percentage of power available on the batteries. This becomes useful for unusual events more than day-to-day operations. For something like parties where additional power will be required it is possible to generate supplemental power with the generator. Basically, after the first year you understand what each system will provide. Each year will be about the same once the system has been tuned.
For Leonard the system has been working well as is for a few years now. Each solar panel is 85 watts and costs about $600. He has 18 panels on the tracker. The skylights also provide lots of good day lighting. The garage has skylights for additional light. The solar array is about 75 feet from the house with an underground cable in PVC pipe. There are six pairs of conductors. The six pairs of wires come into a 60 amp circuit breaker and then into a charge regulator. The charge regulator is able to take the increased voltage that solar panels generate in the winter and improve charging current by 25%-30%. The charge regulator also displays a great deal of useful information about the amount of energy being generated. The power flows into a 250 amp breaker that is connected to the battery bank. The warmer the batteries are kept the better their capacity. So maintaining them in a warmer environment is better. The second breaker protects the DC systems from the AC inverter. There is a meter that monitors the level of charge in the batteries. The sine wave inverter converts the DC current generated by the solar panels to clean sine-wave AC for conventional appliances. The inverter is sized to convert 120 V AC sufficient for having all of the loads including all lights being turned on – 40 amps AC - 5,000-6,000 watts. It takes a few days of sunny weather to charge the batteries to capacity again. However, with a properly designed system, the batteries should never get to the point of being totally depleted. It takes about a day and a half of sunny weather to charge the batteries to capacity again. For 240 volt appliances an additional inverter can be included. The Allen’s 240 volt inverter unit is no longer used. Amazingly, since the recent renovations and system expansions, the generator hasn’t been used since March and won’t go on again until November.
The water system starts with a 13 year old 1/3 horsepower pump. It is sized to be just enough for what they need. An ultra-violet sterilizer cleans the water and is DC based using less power than other units. The SunFrost fridge and water cleaner run on DC (12-48 volts) rather than AC. The preheat tank will eventually be fed by a solar thermal heating array (panels). Currently the Rinnai Model 2532 Continuum in-line water heater provides all the hot water required for both in-floor and domestic needs. The unit is efficient at adjusting the flame to optimize for high and low BTU usage. Small pumps push warmed water through the floors for heating. The four small pumps are 12 volt DC circulation pumps each drawing just 3.1 watts as compared to 40-60 watt AC pumps used normally. Again, the off-the-grid aspect dictates ultra-efficiency wherever possible. The whole system only uses as much as a 60 watt light bulb, which is uncommonly low. The old forced air furnace was a major electricity load that drained the batteries. The in-floor or radiator based systems are the “only way to go” according to Leonard when compared to big fans blowing hot air around.
The appliances, washer and dryer are very efficient. The dryer is propane to reduce loads on the electrical systems. The washing machine has a high capacity for double loads. The theme of maximum efficiency, wherever possible, is the key. Other appliances are standard. The stove is propane.
Leonard gave us a Kill A Watt™ device that lets you measure the electricity usage characteristics. This device showed Leonard that his satellite Internet connection and television system combined were constantly draining 60 watts even while turned off. By adding a power bar to these systems Leonard has been able to shut off this constant drain on his system. Killing all the phantom loads is essential when you live off-the-grid.
Leonard Allen is the President of Solera Energies, a major supplier of solar and renewable energy systems in Ontario. For more information about renewable energy systems products, installation and operation see www.soleraenergies.com .
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