How many solar panels to replace 850 kw per month?

Question

I work nights. Use about 850 kw a month. what would it cost to get mostly off grid? I know solar ot as dependable as the hydro dam down the road, but I'm trying to lower my foot print not eliminate it.

Answer 1

Take the rated maximum output of panels and assume that a  pannel rated to produce 15 watts will produce between 50 and 120 Watt hours of electricity per day times 30 days per month.

When our panels face the sun most of the time you get close to the 120 Watt hours.

With snow cover you may get well below 50.

However, if you use a lot of series connections to provide higher voltage, any panel in series that is in shade will define the output of all the panels in series with it.

Answer 2

That question is difficult to answer. It completely depends on the orrientation of your roof, and physical location of your property. I am in the process of getting PV panels, I got quotes from 3 companies and the size and quantity of panels varied depending on the manufacturer.

The system I'm getting is estimated 4KWDC and it has 18 panels. Of course I'll get more electricity in the summer than I will in the winter, but it should cut my electricity by 1/3 to 1/2 for the year.

Answer 3

First, I suppose you mean 850 kiloWatt *hours* per month.  This would make about 28 per day.  For a 12-hour day, you need to *average* over 2 kW.  For sunlight at 1KW/sq. meter, and cells 10% efficient, 20 square meters (about 9 x 21 feet).  The sun would need to per *perpendicular* to the cells the whole time.