A Power Purchase Agreement (PPA) is an often long-term electricity purchase agreement, usually between a current purchaser (buyer) and a plant operator (seller) of renewable energies. This contract regulates all the necessary conditions, such as the amount of electricity, the prices negotiated, the balance sheet processing or the contract duration. Since a PPA is a bilateral contract, it can take many different forms that are tailored to the contracting parties. PPAs are found primarily with large electricity consumers (e.g. industrial companies), traders, energy suppliers and operators of renewable energy systems without government subsidy systems. The advantages of a power purchase agreement for players in the energy market include: long-term price security, opportunities to finance investments in new electricity generation capacities or the reduction of risks in the sale and purchase of electricity.