solar resource and performance

Before you buy and install a photovoltaic (PV) solar system (for electricity generation) or a solar hot water heater or other solar thermal system you should take a look to your site's solar resource. The design, the solar panel area or the solar performance depends largely on the number of hours of sunlight.

Number of sunny days

Obviously, if you live in a climate with very few sunny days, you are in a disadvantage. An average of less than 3 hours of sunlight per day can undermine solar performance.

In the case of a solar photovoltaic solutions, you will get electricity at virtually any location and place, but the latitude and cloudy weather will have a strong impact on the performance of the system. Similarly, in solar thermal solutions like water heating, you will not get enough hot water and sufficiently high temperatures with low levels of sunlight.

Solar maps

Below, we show the world solar map. For other more detailed maps, see:
US Solar Maps
Europe Solar Maps
Australia Solar Map

These solar maps are an important preliminary tool for the assessment of a site’s solar resource…

Note: The smoother the color, the lower the solar resource of the region…

World Solar Resource Map

Un-Shaded locations

To get a better solar performance locate your solar panels in an unobstructed view of the sky, that is, with no trees or walls or other physical elements obstructing them (or obstructing them as little as possible).

You may need to make adjustments according to the situation of your site. If you have trees to the west but not to the east, it may be better to locate solar panels slightly to the east to maximize solar performance...

solar patterns and local climate variations

There are regions with many cloudy afternoons, or cloudy mornings, or with dusty periods, or persistent haze... and all these elements affect the solar performance and should be considered...

If, for example, you have in your region many cloudy afternoons and few cloudy mornings, you may have advantages in pointing the panels slightly to the east...

Orientation and tilt

For a better solar performance, solar panels should face true south (if you live in the northern hemisphere; or true north, in the southern hemisphere).

Besides, to maximize the potential solar resource, solar panels should also be tilted properly, at an angle equal to your latitude plus/minus 15º in winter/summer .

See on these issues: Solar panels location and tilt

Temperatures and solar performance

The most important, in what concerns solar power performance, isn't the temperatures but the the number of hours of sunlight that the panels receive in good conditions. Obviously, that doesn't mean that temperatures never matter. If you have very low temperatures, and snow or other negative atmospheric phenomena, that may well negatively impact on the solar performance...