Design, installation and performance
Solar radiation
Also known as: solar irradiation, solar resource, insolation.
Definition
Solar radiation is the energy arriving from the sun at a surface. In Colombia, because of its equatorial location, it is relatively stable throughout the year. IDEAM's Solar Radiation Atlas is the official reference for this data.
Sources: Solar Radiation Atlas of Colombia (opens in a new tab)
It is measured in kilowatt-hours per square metre per day (kWh/m²·day), a figure that numerically coincides with peak sun hours. It is made up of direct radiation, arriving in a straight line from the sun, and diffuse radiation, arriving scattered by the atmosphere and the clouds. Photovoltaic panels make use of both, which is why they keep producing on cloudy days, albeit at a lower rate.
Colombia's advantage is stability rather than the absolute maximum. Sitting on the equator, day length barely changes between January and July and there is none of the seasonal drop in output typical of high latitudes. That makes annual generation more predictable and simplifies sizing: there is no need to oversize in order to survive a winter.
The relevant variation in the country is geographic, not seasonal: between regions there are significant differences due to cloud cover, altitude and rainfall patterns. That is why an output estimate has to start from data for the specific location, not a national average.
The essentials of Solar radiation
- It is measured in kWh/m² per day; numerically it is equivalent to peak sun hours.
- It is made up of direct and diffuse radiation: panels use both.
- The equatorial position means there is barely any seasonal variation.
- The relevant differences in Colombia are between regions, not between months.
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Related terms
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Frequently asked questions about Solar radiation
Is there enough solar radiation in Colombia?
Yes. The country has a usable solar resource across practically its whole territory, with the added advantage of being stable through the year. Regional differences are real and affect sizing, but they do not invalidate a project: they change the number of panels needed.
Where do I look up the radiation for my city?
IDEAM's Solar Radiation Atlas is the official Colombian source and publishes values by area. It is the figure any installer should use to estimate your output; if a quote does not explain where its radiation assumptions come from, it is worth asking.
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