When Is Hydrogen Fuel Cell Power More Economical Than Battery-Powered Solutions?

The shift towards cleaner, more sustainable forms of transportation is an ongoing global effort. Among the various technologies in play, hydrogen fuel cells and battery-powered vehicles are at the forefront. This article explores the conditions under which using hydrogen fuel cells might be more economical than battery-powered solutions, focusing on round-trip efficiency, stationary applications, and automotive uses.

Round-Trip Efficiency: A Critical Comparison

The efficiency of the process from electricity to hydrogen back to electricity poses a significant challenge. The round-trip efficiency for this conversion is around 40%, whereas electricity to batteries to electricity has an efficiency of 85%.

This means that for every 100 units of energy input, a hydrogen fuel cell system recovers only 40 units after the round-trip conversion, while a battery system recovers 85 units. This is a stark difference, making hydrogen fuel cells much less energy-efficient in this respect. The additional cost of specialized and expensive materials for the transmission, distribution, and storage of hydrogen further compounds this inefficiency, leading to a more expensive overall solution.

More Economical Than What?

When considering stationary applications, hydrogen fuel cells can be more efficient. They work well in providing electricity and home heating, more efficiently than simply burning the gas or using a Stirling engine. However, these systems come with a much higher installation cost, making them uncompetitive with simpler solutions like a Stirling engine setup.

For automotive use, the challenges multiply. The need to transport hydrogen along with the vehicle, stored under high pressure, introduces new difficulties. Steam reformation of natural gas is inefficient, and compressed natural gas (CNG) comes with its own set of problems, such as metal embrittlement and exploding tanks due to pressure cycling issues. The use of low-pressure liquid petroleum gas (LPG) would improve efficiency but introduces size and mass issues that are not ideal for automotive applications. Additionally, the warmup and cooldown times for LPG systems are not compatible with automotive operations.

The conclusion is that hydrogen fuelled vehicles are not the most economical or safe option on the road. High-pressure tank systems are even more dangerous than CNG installations. Liquid hydrogen is impractical, and gaseous hydrogen will escape over time, even in a stationary setting. In both cases, the gas will permeate through most metals, and the storage tanks become disproportionately expensive. This situation invites the question: why not simply use batteries, which are both more efficient and much safer?

Conclusion and Future Prospects

The economics of hydrogen fuel cells in transportation are currently less favorable compared to battery-powered solutions. While hydrogen fuel cells may hold promise in specific niche applications, such as spacecraft, where weight and energy density are critical factors, the necessity for a comprehensive overhaul in materials and processes to make them economical for cars is necessary. For the time being, batteries remain the more cost-effective and practical choice for both stationary and mobile energy storage.