At the start of the 20th century, energy costs were only a fraction of the total expense of operating homes, offices, and factories. Coal and petroleum were abundant and relatively inexpensive. Low energy prices contributed to the emergence of the United States as the leading industrialized nation as well as the world's largest energy consumer.
Because petroleum was inexpensive and could easily produce heat, steam, electricity, and fuel, it displaced coal for many purposes. As a result, the nation's coal mining industry declined, and the United States became dependent on foreign oil for half of its energy supply.
In 1973, when many foreign oil-producing nations stopped shipments of oil to the United States and other Western countries, fuel costs increased dramatically. In the 2000s, political instability in the Middle East—where many of the top oil-producing countries are located—caused fuel prices to once again rise significantly. Although the U.S. has become more energy independent in recent years as a result of hydraulic fracturing (the extraction of natural gas from shale rock deep below the earth), continuing uncertainty about foreign energy supplies and a growing awareness about environmental pollution have fueled the development of energy conservation techniques in the United States. The emphasis on discovering new sources of energy, developing more efficient methods and equipment to use energy, and reducing the amount of wasted energy has created demand for energy conservation technicians.
- Agricultural Scientists
- Air Quality Engineers
- Aquarists
- Arborists
- Biochemists
- Bioenergy/Biofuels Workers
- Biofuels Processing Technicians
- Biofuels Production Managers
- Biofuels/Biodiesel Technology and Product Development Managers
- Biologists
- Biomass Plant Technicians
- Biomass Power Plant Managers
- Boilermakers and Mechanics
- Botanists
- Brownfield Redevelopment Specialists and Site Managers
- Chemical Engineers
- Chemical Technicians
- Chemists
- Chief Sustainability Officers
- Civil Engineers
- Climate Scientists
- Coal Miners
- Corporate Climate Strategists
- Divers and Diving Technicians
- Ecologists
- Electricians
- Energy Brokers
- Energy Consultants
- Energy Efficiency Engineers
- Energy Transmission and Distribution Workers
- Engineers
- Environmental Economists
- Environmental Education Program Directors
- Environmental Engineers
- Environmental Lawyers
- Environmental Lobbyists
- Environmental Planners
- Environmental Restoration Planners
- Environmental Scientists
- Environmental Technicians
- EPA Special Agents
- Fish and Game Wardens
- Forensic Meteorologists
- Foresters
- Forestry Technicians
- Fuel Cell Engineers
- Fuel Cell Technicians
- Fuel Cell Technology Workers
- Futurists
- Geodetic Surveyors
- Geological Technicians
- Geologists
- Geophysicists
- Geotechnical Engineers
- Geothermal Energy Industry Workers
- Geothermal Production Managers
- Geothermal Technicians
- Green Builders
- Green Hotel/Resort Ecomanagers
- Green Products Manufacturers
- Green Transportation Careers
- Groundwater Professionals
- Hazardous Waste Management Specialists
- Hazardous Waste Management Technicians
- Horticultural Inspectors
- Horticultural Technicians
- Hydroelectric Plant Technicians
- Hydroelectric Production Managers
- Hydropower and Marine Energy Industry Workers
- Indoor Environmental Health Specialists
- Industrial Ecologists
- Industrial Engineering Technicians
- Land Acquisition Professionals
- Land Trust or Preserve Managers
- Landmen
- Landscape Architects
- Line Installers and Cable Splicers
- Marine Biologists
- Materials Engineers
- Meter Readers, Utilities
- Methane/Landfill Gas Collection System Operators
- Methane/Landfill Gas Generation System Technicians
- Microbiologists
- Mining Engineers
- Molecular and Cellular Biologists
- National Park Service Employees
- Naturalists
- Non-Destructive Testing Specialists
- Nuclear Engineers
- Nuclear Reactor Operators and Technicians
- Oceanographers
- Park Rangers
- Petroleum Engineers
- Petroleum Technicians
- Plumbers and Pipefitters
- Power Plant Workers
- Radiation Protection Technicians
- Range Managers
- Recycling and Reclamation Workers
- Recycling Coordinators
- Renewable Energy Careers
- Renewable Energy Engineers
- Renewable Energy Site Assessors
- Rewilders
- Roustabouts
- Soil Conservationists and Technicians
- Soil Scientists
- Solar Energy Industry Workers
- Solar Energy Installation Managers
- Solar Energy Sales Representatives
- Solar Engineers
- Solar Thermal Installers and Technicians
- Surveying and Mapping Technicians
- Surveyors
- Telephone and PBX Installers and Repairers
- Traffic Engineers
- Wastewater Treatment Plant Operators and Technicians
- Water/Wastewater Engineers
- Wind Energy Engineers
- Wind Energy Industry Workers
- Wind Energy Operations Managers
- Wind Energy Project Managers
- Zoo and Aquarium Curators and Directors
- Zoologists