Learning more on energy

Is energy used economically?

Transportation sector

Buses, taxis, trucks, railroads, ships, and airplanes are included as well as passenger cars owned at home in the transportation sector.
In Japan, passenger cars consume energy most in the transportation sector. Energy consumption has continued to rise along with the development of industry, increase of passenger car ownership, and increase in the size of passenger cars.
However the development of cars is remarkable these days. There is energy diversity, a variety of motor vehicles that are friendly to the environment are available, and also mileage has been greatly improved.

Gasoline car

Gasoline cars are mainly driven by engine. The mixture of air and gasoline is fed into the engine, then compressed in the engine. The compressed gas is ignited with electricity to explode. The explosion pushes the piston, which in turn moves a car.

Parallel hybrid car

Parallel hybrid cars combine an internal combustion engine with an electric motor to assist the main engine. The engine works mainly during driving, while the motor activates and assists the driving force when the engine is under load such as starting or accelerating. Releasing the accelerator or slowing down changes the driving force motor into the generator to charge the battery.

Series parallel hybrid car

Series hybrid cars are driven either by engine or motor, or by both with the best balance. The motor works when the speed is low such as starting. The motor and engine work together when accelerating and power is required. In addition, at the constant speed driving, the combustion engine drives a generator to simultaneously generate electricity to recharge the battery.

Plug-in hybrid car

Plug-in hybrid cars can be charged with the household power supply. Larger capacity of battery than a regular hybrid's makes it possible to drive longer distance by motor. The engine and motor work when we drive long-distance and at high speed.

Electric car

Electric cars are propelled by an electric motor (or motors) powered by electricity stored in the battery. Electricity can be charged with the household power supply.

Industrial sector

The future energy technologies

Residential and commercial sector

  • 01 Where is energy from?
  • 02 What do we use energy for?
  • 03 Is energy used economically?
  • 04 The future energy technologies


  • Fossil-fuel Energy
  • Non-energy use
  • Watt (W) vs. Watt-hour (Wh)