Summary: I personally interviewed Frank Vignola, a University of Oregon Physics professor and the Director of the UO Solar Radiation Monitoring Laboratory. He provided a wealth of information in response to my questions about a national RPS.
Topic: Renewable Electricity Policy
Category: Citizen (Expert)
What is it? An interview with the Director of the University of Oregon Solar Radiation Monitoring Laboratory
Title: Interview with Frank Vignola
Publication Information: N/A
Location: N/A
Date of Interview: March 3, 2009 at 3:00 PM
Support: N/A
Audience and Agenda: Frank Vignola has been a UO faculty member since 1977. He is currently a Senior Research Associate at the UO. Vignola is also Director of the University of Oregon Solar Radiation Laboratory. Furthermore, he is the founder and a current editor of Solar Spectrum, a publication of the Resource Assessment Division of ASES. Thus, Frank Vignola has a wealth of knowledge concerning solar energy policy, including renewable portfolio standards and energy mandates. 
Usefulness: This interview was extraordinarily helpful and useful. Frank Vignola provided a great deal of information concerning national RPSs. He said that a national RPS of 20 to 25 is certainly achievable. But he also said that both a national RPS and individual state RPSs are needed.
Works Cited:
http://solardat.uoregon.edu/FV.html
[...] and experts agree (including the three experts I interviewed; Eric Hiaasen, Greg Bothun, and Frank Vignola) that a national RPS of 25% by 2025 is realistic and achievable. Greg Bothun, a Professor at the [...]