Sandia is in the process of developing liquid hydrogen fueling stations that offer the same safety quotient as conventional gas stations.
The research laboratory has signed a Cooperative Research and Development Agreement with U.S. hydrogen retailer, First Element Fuel, to build more of these cutting-edge liquid hydrogen stations.
The agreement will also help modernize the National Fire Protection Association (NFPA) safety codes dealing with liquid hydrogen safety distances.
These updated codes will in turn benefit hydrogen retailers and fire marshals in designing and permitting new, safer stations.
The Sandia team is using an indigenous software to quantify the effect of hydrogen leaks from various system designs and the safety measures used to detect and protect against the effects of leaks.
Cars powered by hydrogen refill as quickly as those powered by gasoline and drive just as far. In addition, the only emission from their tailpipes is pure water.
Nevertheless, one of the biggest obstacles hindering the growth of hydrogen-fueled transportation is building enough fueling stations.
“We need more stations and larger, faster, better equipment because we have more customers and more demand than we’d ever dreamed,” said Tim Brown, COO of First Element Fuel.
Liquid hydrogen carries its own set of unique benefits and challenges. It can be stored at significantly lower pressure than gas, which lowers the risk of a leak.
However, liquid hydrogen is also cryogenic – meaning it must be kept very cold.
“When released, liquid hydrogen can actually freeze the air around it,” said Sandia risk analyst Brian Ehrhart. “This presents a challenge for calculating the concentration of hydrogen in the air.”
The team negotiated this challenge by assuming an initial ‘zone’ of hydrogen/air mixing that warms the mixture to a point at which Sandia’s gas dispersion models can predict behavior.
This simplification allowed the team to predict how far away from the leak the flammable concentration exists, rather than focusing on the mixture right next to the release and using more expensive fluid dynamics models.
First Element Fuel/Sandia