Classification
EMA - Hydroelectric, tidal energy
21
EHA - Renewable energy sources
4
EBA - Energy production, energy technology
1
EIA - Solar energy - general
1
EIS - Solar cells
1
EKA - Wind energy
1
ELA - Geothermal energy
1
ENA - Energy from biomass and waste
1
ETA - Energy storage
1
GHM - Sedimentary rocks
1
TKF - Power plants
1
UHCH - Urban areas
1
UKA - Environmental damage and energy production
1
UKB - Environmental effects and energy
1
UPK - Water resources, water supply
1
UPN - Water protection, water quality, clean water
1
UPVF - Surface waters - streams, rivers, lakes
1