EME 810
Solar Resource Assessment and Economics

4.1 Learning Outcomes


By the end of this lesson, you should be able to:

  • explain why the human eye is a poor solar detector and creates bias in decision making;
  • describe the equipment used to measure irradiance and irradiation in the field and from space;
  • contrast collecting data for horizontal irradiance and DNI with (Plane of Array) POA measurements;
  • describe the meaning of a component of light, and list the components for anisotropic skies on a tilted surface;
  • explain scenarios where direct POA (Plane of Array) measurement is not available and one must use empirical correlations (via clearness indices) to estimate irradiation on a horizontal surface;
  • understand and be able to apply typical meteorologic year (tmy) data to energy system simulations.

What is due for Lesson 4?

This lesson will take us one week to complete. Please refer to the Course Syllabus for specific time frames and due dates. Specific directions for the assignment below can be found within this lesson.

Lesson 4 Assignments
Required Reading:

J.R. Brownson, Solar Energy Conversion Systems (SECS), Chapter 8 - Measure and Estimation of the Solar Resource.

D. T. Reindl, W. A. Beckman, J. A. Duffie (1990) Diffuse Fraction Correlations. Solar Energy. 45(1) 1-7.

C. A. Gueymard (2008) From Global Horizontal to Global Tilted Irradiance: How accurate are solar energy engineering predictions in practice? Solar 2008 Conference, San Diego, CA, American Solar Energy Society

Sengupta et al. (2015) Best Practices Handbook for the Collection and Use of Solar Resource Data for Solar Energy Applications. NREL/TP-5D00-63112 (selected sections)

S. Kalogirou (2011), Solar Energy Engineering, Chapter 2, pp 106 - 117 (section on Typical Meteorological Year).

C. A. Gueymard (2012) Solar Resource Assessment and Forecasting: Recent Achievements, Bankability Pressures, and Current Challenges. 2012 World Renewable Energy Forum, Denver, CO May 12-17.

Read Lesson 4. This lesson will show the relationships of broad regions of the sky contributing to the total budget of down welling shortwave irradiance.

Optional Reading (not required): Liu and Jordan (1960) The Interrelationship and Characteristic Distribution of Direct, Diffuse, and Total Solar Radiation. Solar Energy J. 4(3), 1–19.

S. Wilcox and W. Marion (2008) Users Manual for TMY3 Data Sets. NREL/TP-581-43156

S. Wilcox (2012) National solar radiation database 1991- 2010 update: User’s manual. NREL/TP- 5500-54824

Perez, Ineichen, and Seals (1990) Modeling Daylight Availability and Irradiance Components from Direct and Global Irradiance. Solar Energy J. 44(5), 271-289.
To Do

Learning Activity: Clearness Index calculation

Discussion: Typical Meteorological Year

Quiz Assignment: Components of Light (see Canvas)

Engage in all Try-This and Self-check activities (not graded).

Topic(s) Irradiance/irradiation measurement (ground vs. satellite)

Horizontal Surfaces: Day/Month/Hourly Clearness Indices

Typical Metrological Year (TMY)

Tilted surfaces: Isotropic/Anisotropic sky models and POA

Direct Normal Irradiance


If you have any questions, please post them to the Lesson 4 General Questions and Comments Discussion Forum in Canvas. I will check the forum regularly to respond. While you are in a discussion, feel free to post your own responses if you, too, are able to help out a classmate.