How Fuel Cells Compare

Understanding the primary technology powering vehicles is the first step to evaluating different vehicle types. Battery electric, hydrogen fuel cell electric, and internal combustion vehicles are each powered by a fundamentally different technology: 

• Battery electric vehicles are powered by rechargeable batteries

• Fuel cell electric vehicles rely primarily on fuel cells

• Internal combustion vehicles burn fuel
   

Rechargeable batteries, fuel cells, and combustion engines are distinct technologies, yet they share some common attributes. Here is how fuel cells are similar to and different from rechargeable batteries and combustion engines:

Fuel Cell Versus Rechargeable Batteries

A fuel cell operates similar to a rechargeable battery. Fuel cells and batteries are devices that transform chemical energy from a substance or compound into electricity through electrochemistry. The electrochemical reactions in batteries and fuel cells are controlled and produce virtually zero pollutants. The difference between the two technologies lies in the storage of fuel. A battery converts a finite amount of a chemical compound stored internally into electricity. The chemical substance consumed in the battery to produce electricity is regenerated when the battery is recharged. A fuel cell, on the other hand, converts a chemical compound stored externally into electricity. That chemical compound is hydrogen stored in a tank onboard the FCEV. 

Fuel Cell Versus Combustion Engines

Fuel cells and combustion engines both consume fuel that is stored externally in a tank onboard the vehicle. Unlike the controlled chemical reactions in batteries and fuel cells, gasoline combustion is marked by a series of uncontrolled chemical reactions that produce many undesired compounds. NOx, SOx, and particulate emissions are all undesired products of combustion that negatively affect air quality. 

The uncontrolled combustion of gasoline also reduces how efficiently engines transform chemical energy into power. A conventional combustion engine uses less than 20 percent of the chemical energy in gasoline, which means more than 80 percent of the fuel is “wasted.” In contrast, a fuel cell converts up to 60 percent of the chemical energy in hydrogen to drive the vehicle. Therefore, a fuel cell electric vehicle is potentially 3 times as efficient as traditional combustion vehicle and virtually pollution-free. 

Fuel cell electric vehicles achieve the beneficial characteristics of both conventional and battery electric vehicles. The combination of these desirable characteristics makes fuel cell electric vehicles an attractive advanced vehicle option for drivers that value long range, fast refueling, and zero-emissions. The similarities and differences between conventional, battery electric, and fuel cell electric vehicles are summarized the figure below.

DriveClean. (n.d.). Hydrogen Fuel Cell. Retrieved 9th August 2018 from https://www.driveclean.ca.gov/Search_and_Explore/Technologies_and_Fuel_Types/Hydrogen_Fuel_Cell.php

Hydrogen technology is being applied to address the impact of petrol emissions in motor vehicles. How is hydrogen used to solve the problem of replacing petrol in motor vehicles?   The United States is committed to reducing its dependence on petroleum fuels as a result of increasing focus on environmental, public health, and energy security issues.  California is taking a leadership role in deploying new fuel and vehicle technologies that can benefit its constituents across these areas. As a fuel capable of being produced from domestic, conceivably renewable, feedstocks and carbon-free, hydrogen has the potential to become a substantial portion of our sustainable transportation fuel portfolio. Fuel cell electric vehicles are highly-efficient, have zero tailpipe emissions, and can be powered by domestically-produced hydrogen fuel. Consequently, hydrogen fuel cell electric vehicle adoption in California will help the state achieve its environmental, public health, and energy security goals.

Hydrogen Fuel Cell. (n.d.). Drive Clean. Retrieved 10th August from https://www.driveclean.ca.gov/Search_and_Explore/Technologies_and_Fuel_Types/Hydrogen_Fuel_Cell.php

CIBSE Journal. (n.D.). Fig 2 Comparison of hydrogen and electricity approximate carbon emissions. Retrieved 13th August 2018 from https://www.cibsejournal.com/general/power-of-good-future-of-uk-heat/

Like electric vehicles, FCVs are zero-emission vehicles – they have no smog-related or greenhouse gas tailpipe emissions. Emissions are created in the process of producing and transporting hydrogen fuel.

While hydrogen is abundant in the universe, it must be separated from other compounds to be used as fuel. This process can be energy intensive. The amount of emissions associated with producing hydrogen fuels depends on the source of hydrogen and production method. Currently, the majority of hydrogen that is made for use as a fuel comes from natural gas, but hydrogen fuel also can be made from water, oil, coal, and plant material. Hydrogen can even be produced from your trash! Pilot projects have used landfill gas and wastewater to make hydrogen fuel.

Retrieved 14th August 2018 from https://www.epa.gov/greenvehicles/hydrogen-fuel-cell-vehicles