What Does Energy Get Used For?

Energy is the ability to do work and can come in many different forms. Broadly speaking, energy is what makes the modern world function. Energy powers transportation, creates materials, provides heating and cooling, enables communication, and is used in countless other applications. Without energy, life as we know it would not be possible.

On a basic level, energy comes from the sun or from the release of heat inside the earth. This energy is harnessed in various ways and converted into forms of energy that can provide light, generate electricity, move vehicles, or enable some other useful application. Energy is essential to society’s needs, but there are also environmental impacts based on how it is produced, distributed, and consumed. Exploring energy flows and use patterns provides important insights into the economy, environment, lifestyle, and many issues that shape the world.

Table of Contents

Transportation

The transportation sector accounts for a significant portion of global energy consumption. This sector includes transportation methods like cars, trucks, trains, planes, ships, and public transit. Transportation is vital for moving people and goods domestically and globally, enabling economic activity and growth.

Road transportation like passenger vehicles and freight trucks comprise the largest share of transportation energy use. Cars, SUVs, and other light-duty vehicles consume substantial gasoline and diesel through internal combustion engines. Energy is lost through engine heat and friction. Electrifying vehicles can increase efficiency over traditional combustion engines.

Air travel via jet fuel is one of the most energy-intensive transportation modes per passenger mile. Commercial aviation enables global mobility and commerce but emits greenhouse gases. Improving airplane design and using biofuels can reduce emissions.

Rail transportation like subways, commuter trains, and freight rail is generally more efficient than road or air travel and can be further decarbonized by transitioning to electricity. Shipping via barges and container ships is very efficient per ton-mile and enables substantial global trade. Making ships larger and optimizing logistics can further improve efficiency.

In summary, the transportation sector utilizes substantial energy, especially from oil. But new technologies and optimization can help reduce energy use and emissions over time while maintaining mobility.

Industry

Industrial facilities require significant amounts of energy to manufacture goods and operate equipment. The industrial sector is one of the largest consumers of energy worldwide. In the United States, industry accounts for about 30% of total energy consumption.

The manufacturing industry uses energy for a wide range of purposes, such as operating machines and industrial processes, space heating and cooling, and lighting facilities. Major energy-intensive industries include petroleum refining, chemical, iron and steel, mining, and cement production. These industries rely heavily on fossil fuels like natural gas, coal, and petroleum to power equipment and heat processes.

Increasing efficiency has helped reduce the energy intensity of industrial processes over time. Cogeneration systems, which produce both heat and electricity from a single fuel source, provide an efficient way to meet manufacturing facilities’ energy needs. Switching to renewable energy sources like wind, solar, hydropower, and biomass can also help decrease the industrial sector’s carbon footprint and reliance on fossil fuels.

As manufacturing output continues to grow worldwide, particularly in developing nations, industrial energy consumption is projected to rise. More efficient systems, emerging technologies, and conservation efforts will be needed to curb energy demand and the related environmental impacts.

Commercial Buildings

Energy consumption in commercial buildings accounts for a significant portion of overall energy use worldwide. Commercial real estate, including office buildings, hospitals, schools, restaurants, hotels, warehouses, and retail stores, requires substantial energy to power lighting, heating, cooling, appliances, electronics, and other equipment. Several key factors drive energy demand in the commercial sector:

Lighting – Producing high quality, flicker-free lighting represents the largest share of electricity consumption in commercial buildings. Office lighting alone can account for 25-50% of total energy use.
HVAC Systems – Heating, ventilation, and air conditioning systems require major energy inputs for climate control, air circulation, and maintaining indoor air quality.

Plug Loads – Commercial equipment like computers, monitors, copiers, printers, refrigerators, elevators, and machinery can consume significant energy even while idle.
Water Heating – Restaurants, hotels, hospitals, and other facilities need hot water for restrooms, kitchens, laundries and sterilization.

Intelligent building design, upgraded equipment, occupancy sensors, and energy management systems can help optimize energy use. But the sheer scale of commercial real estate means this sector will continue driving electricity demand. Strategic energy policies are critical for cost-effective and sustainable operations.

Residential Buildings

Residential buildings, including single-family homes and multi-family apartment buildings, consume over 20% of total energy used in the United States. The main uses of energy in homes are space heating and cooling, water heating, lighting, appliances, and electronics. Energy usage varies significantly based on factors like climate, home size, age of home, and energy efficiency measures in place.

Space heating and cooling accounts for over half of energy use in homes. Colder regions require more heating during winter months, while warmer regions require more air conditioning in summer. Improving insulation, sealing air leaks, upgrading to efficient HVAC systems, and installing programmable thermostats can help reduce energy waste for climate control. Replacing old windows with new double or triple pane models also improves efficiency.

Water heating is the second largest energy use, as significant amounts of energy are needed to heat water for bathing, cooking, cleaning, etc. Installing an efficient water heater and adding insulation to hot water pipes helps reduce water heating costs. Low-flow showerheads and faucets can also conserve hot water usage.

Appliances and electronics continue to consume greater amounts of home energy as modern gadgets proliferate. Choosing ENERGY STAR certified appliances saves energy and money over time. Turning off lights and electronics when not in use also trims unnecessary energy waste.

Implementing energy efficiency measures and conserving energy in daily habits can lead to substantial energy and cost savings for residential buildings over time. Home energy use per square foot has declined in recent decades due to greater efficiency awareness.

Agriculture

A significant amount of energy is used in agriculture for food production and farming. This includes energy for operating farm equipment and machinery, heating and cooling livestock facilities, and powering irrigation pumps. According to the USDA, agriculture accounted for approximately 2% of total U.S. energy consumption in 2019.

The largest share of energy use on farms is for operating machinery and equipment needed for planting, harvesting, and transporting crops. Tractors, combines, balers, and other mechanized equipment run on gasoline, diesel, and other petroleum fuels. Additionally, energy is needed for heating, cooling, and ventilating livestock facilities such as dairy and poultry barns. Proper temperature control helps maintain animal health and productivity.

Water pumping for irrigation is another major agricultural energy use, especially in drier regions. Center pivot systems and other irrigation pumps run on electricity or diesel. Farmers also use energy for lighting, cooling and refrigeration, and administrative operations. Looking ahead, precision agriculture techniques and “smart farming” technologies may help optimize energy efficiency in the agriculture sector.

Public Services

Public services such as street lighting, public transportation, water supply, sewage, and waste management require significant amounts of energy. Street lighting alone accounts for a major portion of energy use by municipalities. Electrically powered street lights, traffic signals, illuminated signage and other outdoor lighting amount to 20-40% of the total electricity bill in typical cities worldwide. Public transportation like subways, buses and trains also consume considerable electricity for powering the vehicles and stations.

Operating water supply and sewage systems is also energy intensive, as pumping and treating water requires power. Similarly, the collection, processing and disposal of solid waste uses energy for powering garbage trucks and the equipment at treatment facilities. As populations grow, more investment and energy is needed to develop water, sanitation and waste management infrastructure. Hence public service energy use is projected to rise globally.

Trends & Projections

Energy demand is expected to continue rising globally in the coming decades. According to the International Energy Agency (IEA), energy demand could grow by as much as 30% by 2040 under current policies.

Much of this demand growth is expected to come from developing nations as they industrialize and increase access to energy services. For example, energy demand in India is projected to more than double by 2040 as the population grows and becomes more affluent. China is also expected to see strong energy demand growth despite efforts to transition to a more service-based economy.

Fossil fuels like oil, coal and natural gas are projected to continue meeting much of the world’s energy needs. However, renewable energy sources are the fastest growing part of the mix. The share of renewables like solar, wind and hydropower is forecast to increase from around 15% today to over 20% by 2040.

Improving energy efficiency will also play a major role in shaping future demand. With strong efficiency policies, global energy needs could grow more slowly despite population and economic expansion. This underscores the importance of initiatives to reduce energy waste and adopt green building designs worldwide.

Energy Efficiency

There are several ways we can optimize and reduce energy consumption in our daily lives.

Using energy efficient appliances and electronics certified by Energy Star can significantly cut electricity usage in homes and offices. Simple habits like turning off lights when not in use, using natural daylight, and lowering thermostats a few degrees in winter can also make a difference.

Improving insulation, weatherization, and upgrading to energy efficient windows help minimize energy waste from heating and cooling. Programmable and smart thermostats allow HVAC systems to operate more efficiently as well.

Transitioning to LED lighting, installing occupancy sensors, and using timers or daylight sensors for outdoor lighting slashes electricity usage while still providing quality illumination.

Purchasing energy efficient vehicles, maintaining them properly, and driving mindfully improves transportation fuel economy. Walking, biking, public transit, carpooling and telecommuting also reduce fuel needs whenever possible.

Industry can employ advanced technologies like waste heat recovery, cogeneration, and more efficient motors and processes to significantly cut energy requirements.

With some thoughtful changes, we can work towards optimizing energy utilization across all sectors while still enjoying modern comforts and conveniences.

Conclusion

In summary, society today requires a vast amount of energy to power the infrastructure and activities that we all rely on. From transportation and agriculture to industry, commercial buildings and our homes, energy consumption drives modern life. While most of our energy still comes from fossil fuels, renewable sources like solar and wind are making inroads and hold promise for a more sustainable energy system. Projects to improve energy efficiency across sectors are also crucial for reducing overall demand. Even as new technologies emerge, thoughtful use of energy remains vital. The choices we make about energy production and usage will shape our collective future. With smart policies and individual actions, we can work towards an energy system that sustains economic prosperity while protecting the planet.