Solar energy education at the University level is sparse, but student interest is driving new classes to be developed and taught. Solar energy is a calculation-intense, multiparameter systems field that relies on numerical tools. In the scaling up solar energy education to meet large numbers of interested students in science, engineering, and economics, we choose to develop numerical tools in the Python language to supplement courses for the new generation of young professionals. We demonstrate the fundamentals of assessing radiative transfer from the Sun, spherical trigonometry, and energy economics using open source software. We find that the core tools in solar energy project development can be explored in the classroom or remotely online using the Sage (System for Algebra and Geometry Experimentation) math suite available as an online server. The Sage mathematical software has capabilities to solve multiparameter problems, interactive plotting, and allows students to develop formalized notebooks to demonstrate a flow of work towards a final set of solutions. Integrated with Python, it can also be extended with additional mathematical libraries as needed. The Sage server can be installed on a University server and notebooks can be shared among students and faculty. Additionally, working in Sage allows students to develop basic programming skills that will be essential to future solar software development. The use of an online tool allows students to work on home computer devices or in computer labs on campus, makes the problem solving independent of major operating systems, and removes the barrier of purchasing proprietary software.