What is the role of hydrogen in our energy future?

Compared to other forms of energy storage, such as electrochemical batteries or pumped hydro storage, the physics of manufacturing, storing, disrupting, and utilizing hydrogen make it inherently inefficient.

Hydrogen is not a source of chemical energy that we can extract from natural deposits like fossil fuels, but rather it is an energy storage medium that is “charged” in its manufacturing process. When used to power a vehicle, for example, hydrogen is at best about one-third as efficient as a lithium-ion battery. This inefficiency alone translates into an unsurmountable barrier to cost-competitiveness. On top of this unavoidable inefficiency, hydrogen also requires new supporting infrastructure for manufacturing, storage, and distribution that is far more costly to build and maintain than standard electricity infrastructure.

Despite its economic uncompetitiveness, hydrogen is still being considered in conventional analyses for several reasons:

• Hydrogen provides relatively high energy density

  • In cryogenically liquified form, hydrogen stores about 2600 watt-hours per liter, which is about 6 times better than the energy density of today’s standard lithium-ion batteries, but only one-quarter the volumetric density of gasoline.

  • In pressurized form at 150 bar, hydrogen stores about 400 watt-hours per liter, which is about the same as today’s standard lithium-ion batteries, but roughly 1/25 the volumetric density of gasoline.

  • Hydrogen can be stored in other forms and mediums, such as within metal hydrides, but performance claims are unreliable as these are not yet commercially proven technologies.

• Hydrogen energy storage is relatively durable, meaning that it can be stockpiled for weeks or months with modest loss/leakage (<20%).

• Hydrogen energy storage is scalable

The two major use-cases for hydrogen are in fuel cell vehicles that benefit from a longer range that batteries can currently provide (such as aircraft and long-haul trucking) and in large-scale long-duration “seasonal” energy storage. However, our research has shown that seasonal energy storage is not required for an SWB-based energy system, but rather that less than one week of battery energy storage is required to meet all energy needs in virtually every populated region.

It is worth noting that interest in hydrogen remains high at least in part because it offers a way to preserve existing business models and assets from the fossil fuel industry.