Power Purchase Agreements (PPAs) are one of the main instruments to finance the deployment of new renewable projects and are critical to decarbonizing the energy sector worldwide. These contracts provide some predictability of revenue for energy producers, thereby enhancing the bankability of projects. Moreover, large corporations pursue these contracts to reduce their greenhouse gas emissions while securing a certain level of price stability. Recognizing the increasing significance of PPAs, this chapter examines the main concepts that underpin their arrangements, including delivery mechanisms and pricing structures. We underline the factors related to risk allocation between the parties in various PPA formats and securities that ensure contract effectiveness. Further, the chapter explains the mechanics of multiple types of PPA with the roles of the entities involved. By offering insights into PPAs, we aim to equip decision-makers with a clearer understanding of related risks and mitigation strategies, enabling corporations to reduce their environmental impacts and contribute to global climate change goals.