Average dni for solar power

What is direct normal irradiation (DNI)?

Direct Normal Irradiation (DNI) is the amount of solar radiation received per unit area by a surface that is always held perpendicular (or normal) to the rays that come in a straight line from the direction of the sun at its current position in the sky. You might find these chapters and articles relevant to this topic.

What is the annual DNI for solar thermal power generation?

Threshold values of annual DNI for solar thermal power generation as suggested by some researchers are presented in Table 1. As an example, out of 23 solar thermal power plants of cumulative installed capacity 1086 MW in Spain and USA, at most of the locations, the annual DNI is more than 2000 kW h/m 2.

What is the difference between GHI and DNI in solar irradiation?

In the Global Solar Atlas, we provide three magnitudes related to solar irradiation. GHI and DIF are referred to a surface horizontal to the ground, while DNI is referred to a surface perpendicular to the Sun.

How does a pyrheliometer measure DNI?

Direct normal irradiance represents the quantity of radiation received per unit area on a surface perpendicular to the sun. Consequently, the pyrheliometer measures DNI. Using a sun tracker that can be SOLYS2, a pyrheliometer can track and point directly at the sun at all times. The pyrheliometer does not measure diffuse radiation.

How many kWh m 2 is a DNI?

The annual DNI values ranged from 1585 kWh m −2 to 2217 kWh m −2. The DNI measurements in Burns have been extensively analyzed showing seasonal differences in DNI trends (Riihimaki and Vignola, 2005).

What is the difference between a typical year and a DNI?

In the case of typical DNI only the month of December has changed from the original typical year with the whole database resulting in a slightly higher annual value of 2019 kWh m −2. The same holds in the case of Andasol 1 reference plant for November month.