35 Assistance and consultancy services with regard to business management of companies that provide energy produced through renewable and non-renewable sources installations; cost analysis related to energy commodities; billing services in the nature of tracking and monitoring energy consumption for others; organization of trade fairs for commercial or advertising purposes in the fields of energy efficiency and energy production from renewable sources; intermediary business services relating to financing interventions in the energy service company [ESCo] formula and the production of energy from renewable sources, and in the fields of the sale of electricity to end customers; commercial intermediation services, namely, mediation and conclusion of commercial transactions for others in the fields of energy production from renewable and non-renewable sources; retail and purchasing agency services relating to electric energy, wind energy, photovoltaic energy, thermal and water energy, gas, fuels and combustibles, namely, retail energy provider services that allow customers to purchase electric energy, wind energy, photovoltaic energy, thermal and water energy, gas, fuels and combustibles as part of a competitive retail energy market; purchasing agents in the field of electric energy, wind energy, photovoltaic energy, thermal and water energy, gas, fuels and combustibles; business administrative management of power plants engaged in the production and distribution of electric energy and gas; business management services and business administrative services for companies engaged in the installation, maintenance and management of machinery and equipment used in the production, storage and distribution of electric energy; purchasing of photovoltaic plants, wind turbines or other energy production installations, for others; business consulting services in the fields of energy measurement to improve energy efficiency within residential, commercial, industrial and institutional facilities; marketplaces services, namely providing online virtual environments in which users can trade virtual goods, namely biofuel and energy from renewable sources; retail services relating to energy, namely providing online virtual environments in which users can sell virtual goods, namely biofuel and energy from renewable sources.