An effective way to reduce carbon emissions is to increase sourcing of renewable electricity. Traditionally, while the majority of the renewable electricity is sourced by utility firms in the USA, consumers are also increasingly sourcing renewable electricity by investing in rooftop solar panels. An emerging trend is corporate sourcing of renewable energy: Several corporations, including Apple, Google, IKEA, and Walmart, have committed to source 100% of their electricity from renewable sources by 2050. In this chapter, we survey the extant academic literature on sourcing of renewable energy by utility firms and consumers. We also discuss the advantages and disadvantages of different mechanisms used by corporations to source renewable energy.