EME 810
Solar Resource Assessment and Economics

4.9 Measurement vs Estimation


Reading Assignment

Review the linked presentation from solar expert Dr. Chris Gueymard. It provides a historical context of where we came from in solar resource assessment, the current pressures associated with bankability, and the new challenges that we expect in the field in the near future. Now, compare the presentation to your earlier reading of Sengupta et al. (2015). In particular, scan the Chapter 6: Applying Solar Resource Data to Concentrating Solar Power Projects (p. 97).

Finally, go back to your Ch 8 SECS reading, and review the section "When Empirical Correlations are not Appropriate." You may begin to realize where the old empirical methods are useful, and the occasions when they are not useful to project implementation for our stakeholders.

I want you to think about the need for estimation in preparing a new project design using a software like SAM. When does the estimation process give way to more detailed measurements in a SECS project?

Think about where estimated data sets like TMY fit in the process of applying solar resource data detailed below.

  1. Pre-feasibility
  2. Feasibility
  3. Due Diligence
  4. Project Acceptance and Systems Operation

When do we need to work as a larger design team with solar resource specialists who can monitor a site actively and maintain the equipment? When is the investment in measurement equipment appropriate for the planned project? For solar incorporations on the facade of a building (roof, windows, walls), do we need to measure the solar resource at the site?

As the world looks for low-carbon sources of energy, solar power stands out as the most abundant energy resource. Harnessing this energy is the challenge for this century. Photovoltaics and concentrating solar power (CSP) are two primary forms of electricity generation using sunlight. These use different technologies, collect different fractions of the solar resource, and have different siting and production capabilities. Although PV systems are most often deployed as distributed generation sources, CSP systems favor large, centrally located systems. Accordingly, large CSP systems require a substantial investment, sometimes exceeding $1 billion in construction costs. Before such a project is undertaken, the best possible information about the quality and reliability of the fuel source must be made available. That is, project developers need to have reliable data about the solar resource available at specific locations to predict the daily and annual performance of a proposed CSP plant. Without these data, no financial analysis is possible. This handbook presents detailed information about solar resource data and the resulting data products needed for each stage of the project."

--Tom Stoffel, Dave Renné, Daryl Myers, Steve Wilcox, Manajit Sengupta, Ray George, Craig Turchi; NREL/TP-550-47465