The NREL PVWatts Python SDK by Miguel Paolino supports the development of apps on the National Renewable Energy Laboratory (NREL) platform using Python. The SDK communicates with the NREL PVWatts API. You can use it with Python 2 or 3.
The PVOutput API allows solar panel owners to plug their data into the PVOutput website so that they and others can track and compare their results. The data also get compiled into regional and international rankings, as the donut graph illustrates below.
Genability was founded in 2010 with a simple goal: "to empower consumers and producers to choose cleaner, cheaper power." To reach its goal, Genability created and utilizes tools to gain insight into electricity usage. Genability now looks to focus its tools specifically at solar energy after becoming a SunShot Awardee. The Department of Energy (DOE)'s SunShot Initiative "aims to drive solar to cost-competition with other energy sources by 2020." The $500,000 award allows Genability to develop the Genability API as well as "Data tools to instantly and accurately calculate and optimize the savings of implementing solar PV."
It seems that the API cleaning has not yet ended at Google. Awhile back, Google announced its decision to shut down its popular translation API, a decision that did not go down favourably with the users. Now Google Health API has been given a negative prognosis and Google PowerMeter API will soon run out of juice.