Global Solar Resources: The Future Is Here

A recent report from the World Economic Forum documents that the future that many of us have been talking about has arrived: across the globe, the levellized cost of electricity (LCOE) of renewable technologies, wind and solar, has fallen to parity with coal ([3], p. 8). In many places, solar power is considerably cheaper than coal for new electric utility plants. It sounds like the great “conspiracy” is winning the war on coal!

Clearly, any sensible investors will want to build new solar power plants, and there will be a lot of new solar installations constructed in the coming years.

One of the keys to effective solar power generation is to know the solar resources actually available, and placing generation in favored locations. For some locations, there may be records, possibly extending back decades. But available sunlight may be quite localized, so it isn’t easy to extrapolate to other locations. Furthermore, the sunlight varies from day to day, and year to year, and we’d like to know what the long term potential is for a solar generator.

In a recent article resented at the Solar 2016 conference, a team from NASA, NOAA, NREL, and SUNY, Albany, report on the development a new global map of solar energy resources, to be updated several times daily as additional data arrives [1]. The data comes from several satellites is combined with a model of the physics of the atmosphere and surface (land, water, and ice), to estimate the irradiance at a scale of 10 km per pixel.

One thing that interested me is that the team also incorporates information about clouds from the CERES (Clouds and Earth’s Radiant Energy System) project, which has been measuring and modeling clouds and storms for two decades now [2]. (Spoiler alert: cloud cover has a dramatic effect on solar energy potential!)

The article contains many technical details about combining these data sets, as well as validation they have done to confirm that the results are accurate based on comparisons to other measurements on the surface. They also show that the spatial and temporal resolution is useful for determining estimates for daily and monthly available sunlight, which is a key factor for locating solar arrays.

These satellite studies have been and continue to be extremely important basic scientific research. As the CERES project says, “The sun’s radiant energy is the fuel that drives Earth’s climate engine.

The comprehensive global solar map is also quite valuable for the growing solar energy industry, which can use this data to quickly identify potential sites for new plants. Narrowing a search to a handful of promising 10km x 10 km locations could potentially shave months off the time required for initial planning.

  1. Paul W. Stackhouse, Patrick Minnis, Richard Perez, Manajit Sengupta, Kenneth Knapp, J. Colleen Mikovitz, James Schlemmer, Benjamin Scarino, Taiping Zhang, and Stephen J. Cox, An Assessment of New Satellite Data Products for the Development of a Long-term Global Solar Resource at 10-100 km in Solar 2016. 2016, American Solar Energy Society: San Francisco. p. 121-125.
  2. Bruce A. Wielicki, Bruce R. Barkstrom, Edwin F. Harrison, Robert B. Lee, G. Louis Smith, and John E. Cooper, Clouds and the Earth’s Radiant Energy System (CERES): An Earth Observing System Experiment. Bulletin of the American Meteorological Society, 77 (5):853-868, 1996/05/01 1996.;2
  3. World Economic Forum, Renewable Infrastructure Investment Handbook: A Guide for Institutional Investors Geneva, 2016.

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