IEEE Electrification Magazine - March 2018 - 15

This project
combines modeling,
simulation, and
hardware to validate
system performance
and quantify the
economic benefit.

maintenance cost of hydrogen stations in california. in turn, the cec
mandates that all hydrogen stations
funded by the commission must provide 33% of their hydrogen from
renewables. the cec has also funded
100% renewable hydrogen stations as
part of the same initiative; these 100%
renewable stations typically produce
hydrogen from electrolysis, purchasing renewable electricity credits to
power the system. in practice, a
majority of the stations simply pay a
small renewable gas credit fee and do
not actually produce the renewable hydrogen themselves.
For this reason, the california air resources Board established a low-carbon fuel standard to help offset the cost of
producing hydrogen from renewable sources. this 2015
standard has the goal of reducing the carbon intensity pool
of the transportation sector by 10% by 2020.
california is not the only state with hydrogen stations in development. in the northeast, air Liquide,
United States, plans to build 12 stations as a first step
in establishing a station network in that area. air Liquide is committed to generating renewable hydrogen,
with a goal of having 50% of its hydrogen energy be
co2-free by 2020. in addition, BMW has demonstrated a

landfill-gas-to-hydrogen project in
South carolina, leaving the door
open for a mix of technologies in
the future of hydrogen production.

Advances in Renewable Hydrogen
Production Systems

out of all of the renewable hydrogen
production technologies, electrolysis
has the highest system readiness
level because of advancements made
by small business electrolyzer companies, advancements in the fuel-cell
field that have been applied to electrolyzers, and research in the direct coupling and operation of electrolyzers at nreL. in the near- (e.g., less than
five years) and midterm (e.g., five-to-ten years), low-temperature electrolysis is a viable solution for renewable
hydrogen production. in the long-term (e.g., more than ten
years), technologies like high-temperature electrolysis,
photoelectrochemical water splitting, or others may
become the mainstream technology. there have been significant technology advancements in long-term solutions. For instance, nreL demonstrated a new world
record for photoelectrochemical solar-to-hydrogen conversion of more than 16% in 2017. Figure 6 illustrates the
status of current technologies and what the near-, mid-, and

Central

Established
Industrial Process

Natural Gas
Reforming

Biomass
Gasification

Distributed

Near Term

Natural Gas
Reforming

High-Temp
Electrolysis

Coal Gasification
with CCS
Electrolysis
(Wind)

STCH

Electrolysis
(Solar)

Midterm

Electrolysis
(Grid)

PEC

PhotoBiological

Long Term

Bio-Derived
Liquids

Microbial Biomass
Conversion

Biomass Pathways

Solar Pathways

P&D Subprogram R&D Efforts
Successfully Concluded
Estimated Plant
Capacity (kg/day)

Up to
1,500

50,000

≥ 500,000

100,000

Figure 6. The near-, mid-, and long-term hydrogen production pathways. CCS: carbon capture sequestration; STCH: solar thermochemical hydrogen production; PEC: photoelectrochemical; P&D: production and delivery. (Image courtesy of the DOE Fuel-Cell Technologies Office.)

IEEE Electrific ation Magazine / Ma r c h 201 8

Table of Contents for the Digital Edition of IEEE Electrification Magazine - March 2018