The primary purpose of these alternative propulsion systems is to reduce the amount of carbon emissions released into the atmosphere while continuing to power as many or more vehicles as have been propelled in the past, with a key side benefit of being able to make the world’s fuel supply less dependent on only one source of energy.

Which alternative fuel systems are most popular for propulsion?

Propulsion systems that run on alternative fuels are in high demand worldwide today, in part due to the obvious need to find fossil fuel replacements, but also because huge advances in alternative energy technologies have resulted in viable, real world alternative propulsion systems being available – right now, here, today – that perform as well or better than traditional systems. Some include:

  • Full Battery Electric systems produce zero emissions, so it is a popular choice for municipal buses, tour buses, boats, motorized bicycles, scooters, locomotives, trucks, unmanned vehicles, and more. Some of these vehicles have on-board battery recharging through brake energy recapture, solar, flywheel, and other charging systems. Plug-in electrics use as much as the battery will hold, then recharge at a charging station. Many have a primary charging source backed by a second source to extend use.
  • Hybrid Electric systems, which were among the most popular alternative fuel system at first because they combine serious environmental benefits while using only their electric motors with the confidence of having a diesel or gas internal combustion engine (ICE) onboard to recharge batteries and to assure a back-up system if the battery power runs out.
  • Hydrogen Fuel Cell, a technology that is growing in popularity for its zero emissions and long range when powering and propelling municipal buses, tour buses, heavy duty work trucks, delivery vans, boats and ships of many sizes and types, automobiles, and more. Adoption is expanding as the availability of hydrogen filling/refilling facilities grows.
  • Nuclear Reactors have been widely used in submarines worldwide for many years, but today also power some space vehicles, including the Voyage spacecraft and Perseverance rover. Experimental cars and trucks powered by nuclear energy have also been explored.
  • Solar Electric systems have shown a lot of promise, especially as solar collectors and converters have become more efficient and lighter. Most today are used as a secondary – not primary – power source, but as the technology continues to evolve, so will its importance in everyday lives.
  • Compressed Natural Gas (CNG) cars and trucks gained popularity several years ago, as cleaner alternatives to gasoline or diesel engines, but have since lost market share to electric vehicles (EVs) as their performance and charging access improved.

What type of vehicles are alternative propulsion systems used in?

The number of uses continues to grow, but today most alternative propulsion systems are for:

  • Aircraft, including new experimental planes, all-electric propulsion, solar powered, and more.
  • Automobiles ranging from personal cars and taxis to corporate fleets, race cars, and limousines. Most today are full battery electric vehicles (BEVs) or hybrid electric vehicles (HEVs), although hydrogen fuel cell cars have gained in popularity.
  • Boats & Ships, from tugs, trawlers, barges, and cruise ships to ferries, cargo ships, yachts, and unmanned underwater vehicles (UUVs). Even U.S. Navy ships and submarines use alternative fuels.
  • Buses serving city transit systems, tourist boards, theme parks, airports, and more in several configurations, not only to cut down emissions, but also to reduce both noise pollution and fuel costs.
  • Space Vehicles, especially those used on other planets and in orbit around earth right now.
  • Trucks of every kind, including local delivery vans, municipal service vehicles, long-haul semis,
    tow trucks, fire and rescue trucks, personal use pick-ups, specialty applications, and more.
  • 1- and 2-Person Transports, from adult bicycles, tricycles, and motorcycles to scooters, mopeds, and skateboards, the switch to rechargeable battery electric power systems in small transport vehicles is already substantial and growing, especially in crowded urban areas.

Recent advances made in alternative power systems have been significant, and the need to continue developing more and better alternative propulsion systems only grows as both environmental damage caused by fossil fuels and shortages of those very same fuels both become more evident. Next generation development in this category requires commitment, insight, and focus, as well as development partners that provide a culture of innovation, a breadth of relevant experience, and worldwide resources.


This information page is provided as a service to our readers by BAE Systems, Inc., a U.S.-based world leader in aerospace, defense, power, and intelligence solutions. Learn more about us here.

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