ESCO
An Energy Service Company (ESCO) is a legal entity that provides energy services and implements measures to improve energy efficiency in end-users’ facilities, sites, and operations, while assuming a certain level of financial risk. (According to the Global ESCO Network: https://unepccc.org/wp-content/uploads/2023/06/esco-perspectives-2023-web.pdf, page 25)
EPC
According to the Hungarian Energy and Public Utility Regulatory Authority, an Energy Service Company (ESCO) conducts its activities under an Energy Performance Contract (EPC). This contract is established between the energy consumer and the energy efficiency service provider. The essence of this contract lies in the remuneration for energy efficiency services being contingent upon achieving the agreed-upon level of energy efficiency improvement or meeting other energy efficiency criteria specified in the contract.
https://www.enhat.mekh.hu/esco