In an area that has a "net metering" plan, the utility company acts just like a huge storage battery in practice.

Let’s say you had some actual batteries in your house, and the solar array generated 1 kWh more than you need during the day. You would charge those batteries, then draw the 1 kWh out at night. Net charge from the utility company: zero. But you would still have to buy the batteries and charger, and deal with the hassle of maintaining the batteries.

With net zero metering, if the array generates 1 kWh excess during the day, you drive your meter backwards, effectively selling to the electric company. At night, when you draw out the 1 kWh, the meter advances again, showing a net advance of zero. Net charge from the utility company: zero. Financially the same, except no batteries.

The example above is just an approximation, though. Some utility companies have various ways of charging you even though your net usage is zero.

#2. Hail won’t be a problem.

#3. Wind won’t be a problem. They’ll only come off if your roof was going to come off anyway.

#4 & #5 – Battery storage technology has advanced a lot, you won’t have a problem unless you live in the polar winter.

In most cases, solar panel efficiency is not a concern. A good example of this is our home. We produce about 80% of our own electricity using a solar array and a small wind turbine. The array is 1.4 kw, or 1,400 watts peak power. There are 12 panels, each is about 2 feet wide and 5 feet long, and rated at 120 watts. That entire array fits very nicely on the roof of our single car carport, with some room to spare. If the panels were 25% efficient instead of 12, they would take up half the space, and cost about 20% more money. This would accomplish nothing more than expose more of our garage roof to the sun, and reduce the size of our bank account.

Some new companies are touting their solar panels as being the most efficient. One company claims to have reached 18% efficiency. That’s great, but for most users, it’s of no concern, because the space on the roof of their home is way more than they need for even the most inefficient panels today, and generally they cost less per unit power in the first place. All of this applies to solar electric panels, or photovoltiacs. In the case of thermal panels, the ones that heat water or air, they run much higher, in the 50 – 60 % range, but it is a little hard to quantify because they are also affected by ambient temperatures more dramatically. If you’re interested in learning more, check out some websites below. Take care, Rudydoo

Roughly solar panels will supply electrical power costing about 3-10 times more than what you can purchase from your local electrical company when averaged over the 20-25 year life of any solar panels.

Go look at how much you spend for your electricity in a single year. Then go look at how many solar panels you can purchase for this amount of cash (In my case I spend about $1000 each year for power).

This means that economic "sense" must be tempered with some other desire for the solar panels.

Thermal: The energy in the sunlight can heat water.
PV- Photovoltaic: Photons from the light of the sun are absorbed by the solar cells. Their energy is converted into an electrical charge. This electrical charge is gathered and put to use in powering devices.

Thanks!

I think someone may have been confused and been talking about solar water heating panels, which can give a lot more in a hot area, simply because the air temperature is already warm, and the average sun-hours per day is higher. My brother’s house in Hawaii can get away with a smaller panel for his water heater than would be needed in (say) Michigan.

Solar electric panels are more efficient at colder temperatures. But even at cold, there isn’t even a 2x output compared to the hottest day.

I also have another question. How much energy can a small solar panel produce?

A small panel will not produce much power. When people put solar electric panels on their house with the goal of saving money, they generally put up a lot of large panels – 200 or 500 square feet worth. Its hard to save money with just one panel.

The only way to get close on how much it will cost and whether that represents a savings is to get out your electric bills for the past year, and call a local solar installer for a quote. The system on our house cost $20,000 and we got back $8,000 in incentives, so $12,000 net. It can save money, but that will be over many, many years.