Northern Lights
This 5.28 kW grid tie system under construction in the photo, is on the roof of the owner of Northern Lights Energy. Its built with 22 Suniva 240W panels and a 4000W SMA Sunnyboy inverter. Suniva panels are made in the USA. There are a number of US manufacturers and foreign based companies manufacturing panels in the US today.
This system will provide all of our electrical needs and a bit more. Our goal is to make as much of our energy use as solar based as possible. As part of that effort we switched to an electric lawnmower last summer. We also installed an electrically driven heat pump water heater to replace an on demand propane water heater. So now we can make our hot water using solar energy during the day, and from wind power we buy off the grid at night. Our only propane use, as of this writing, is for cooking and some heating (we primarily heat with wood). Cooking can be done most efficiently with a microwave oven powered by solar. Heating a home with solar electricity will take a bit more thought.
Heating a home with a solar electric system could be done in conjunction with heat pump technology, either air source or ground source. Heat pumps take heat out of the surrounding air, water, or ground, and transfer it to heat a building or domestic hot water. Heat pumps are essentially refrigerators run in reverse. In our climate, it would likely take a very large solar electric system to heat an average home with a heat pump. The trick to heating with solar is to build a super-efficient home with levels of insulation not generally installed in most homes today. Size matters also. Big homes generally use more energy of all kinds no matter how many people live in them. A modest size home will have a much better chance to get all its energy from solar. Our home has insulation levels higher than typical homes, and is generally much more efficient, but we don't have a heat pump based heating system to see yet just how much solar we would need to power it. Yet.
The accompanying photos show how snow melts off of a system without assistance. Customers often ask if they should clean snow off their systems. If the system is close to the ground and it is safe to do so, by all means clean them off. A broom or snow rake can both work well. If the system is high up on a roof and you need a ladder to clean them off, don't bother. There really is not much power coming from the sun during extended snow periods. The loss is minimal so any extra power you may get will be quickly offset by the damage you do to yourself if you fall off the ladder. The rate at which the snow melts will depend on the air temperature, the amount of sunlight, and the pitch of the roof. Sometimes it can be a lesson in patience. But who couldn't use one of those? There was about three inches of snow on the panels when the sun came up. It took about 2 days of sun and partly sunny weather with temperatures around freezing to melt the snow. This was December when days are short. The system produces power unless there is a lot of snow on the panels. The snow shades the panels like a cloudy day. Unless it is very deep it does not completely shut the system down.
