About Environment-Friendly Energies and Applications (EFEA)

Environment-Friendly Energies and Applications (EFEA) is a forum for bringing academics, scientists, engineers and industry together to discuss the recent developments in environment friendly energies and their applications. The main theme of this symposium is on renewable and sustainable energy systems, hybrid transportation systems and energy security. The 5th Edition of EFEA will be held in Sofia, Bulgariay, on March 24-26, 2021. The hosting institution will be the Technical University of Sofia, in close collaboration with Polytechnic University of Hauts-de-France (Fr), University of Northumbria (UK), and the University of Aberdeen (UK).

EFEA 2021 is the sixth event in the EFEA series, following EFEA 2010 in Ghardaia, EFEA 2012 in Newcastle, EFEA 2014 in Paris, EFEA 2016 in Belgrade, and EFEA 2018 in Rome.

Conference Topics

EFEA 2021 conference topics include but are not limited to


Renewable Energy Technology Roadmap; R & D; Finance; Supply Chain; Marketing

Low Energy Building and Architecture

Green Building; Bioclimatic Architecture; Comfort and Indoor Climates; New Materials; Smart HVAC systems

Advanced Power Systems

Distributed Energy Resources; Smart Grid; Micro-grid; Power Electronic Convertors

Electric and Hybrid Vehicles

Electric Cars; Hybrid Engines; Regenerative Brake Systems; Power/Electric Transmission Systems; Battery, Energy Management


Smart Electrical Energy Metering; Fault Tolerated Control Systems; Demand/Power Control

Wind and Hybrid Renewable Energy Systems

Wind Turbine Aerodynamics and Structure; Wind Turbine Load and Power Control; On-grid and standalone Hybrid System; Power/Demand Management Systems; Resource Modelling; Condition monitoring of Wind Apparatus

Solar Thermal and Geothermal

Solar thermal collectors; Solar Heat Pump; Combined Heat/ Power; Geothermal Heat Pump; Geothermal Direct Use

Hydrogen & Fuel Cell

Fuel Cell Power Plants; Hydrogen Production

Hydropower and Marine Energy

Micro & Pico Hydro System; Ocean Thermal Energy; Wave Energy

Energy Storage

High voltage batteries; Battery charge balancing and cooling; Charge/energy management; Ultra-batteries; Thermal, unconventional, Hybrid energy storage systems and Flywheel systems


Biofuel; Biomaterials; Biomass Gasification; Biomass heating systems

Materials in Renewable Energy Technologies

Composite materials; Smart materials; Shape memory alloys

Education and Career

Higher education; Life-long learning; Prospects in green job opportunities

Eco design

Methods and design tools for renewable energy; Eco-design

Energy System Sustainability and Integration

Eco-Sustainable Energy Development; Conventional and Green Power Sources Integration; Special Focus on the Euro-Med Region


Delegates will receive a copy of the proceedings at the registration desk. The conference is technically co-sponsorized by the IEEE Industrial Electronics Society. Registered and presented papers will be published in the proceedings that will be indexed on IEEE Xplore.