EnerG2, a manufacturer of advanced carbon materials for next-generation energy storage (generally for batteries and ultracapacitors), has leveraged its polymer chemistry technologies to develop materials for adsorbed natural gas (ANG) applications. The ultra-high surface area carbon adsorbent material, which packs at optimal density and has been produced at scale, is compatible with any and all tank geometries and systems, the company says.
Currently, natural gas vehicles are fitted with on-board fuel tanks that are too large, cumbersome, and expensive to properly facilitate the widespread adoption of natural gas vehicles in the US and globally. Additionally, the low volumetric density of natural gas (~30% less energy by volume than gasoline) limits range, and makes cost-effective storage solutions a significant challenge. One possible solution is adsorbed storage; the interest is so keen, that ARPA-E awarded a combined $10.875 million in 2012 to four different projects (led by Ford, GTI, Texas A&M and SRI) to develop new sorbent materials for on-board natural gas storage. (Earlier post.)
Among the issues that need to be addressed for adsorbent materials are (1) sorbent lifetimes, (2) deactivation rates/processes, and (3) plans to deal with compaction, ARPA-E noted in its funding notice.
In terms of raw storage capability, EnerG2 says that its material allows similar volumes of gas to be stored at lower pressure levels of 500-800 psi (34-55 bar), as opposed to the more standard pressure levels of 3,000-3,600 psi (207-248 bar). The new adsorbent material for natural gas tanks on vehicles has a number of advantages:
Design efficiency and no wasted space, because a tank at 500-800 psi can store as much natural gas as a tank at 3,000-3,600 psi, but its flexible form factor will allow it to fit in a space on board a vehicle that’s about half the size.
Lower pressure tanks also mean a much simpler and cheaper transition to home refueling. This would help alleviate another key obstacle to natural gas vehicle adoption: availability of refueling infrastructure. Low-pressure compressors are a fraction of the cost of high compression systems.
Lower-pressure tanks are also safer, and they hold more fuel longer if there’s a puncture. In addition, they require less energy to compress the gas.
The lower pressure tanks also lower the cost of compression, as well as the capital investment required for a compressor itself.
This material represents a real breakthrough because we’re ready to go at scale with a material that totally changes the dynamics of natural gas tanks on board a wide variety of vehicles.—Dr. Aaron Feaver, Co-Founder and CTO at EnerG2
What EnerG2 is doing can radically change the availability of natural gas vehicles in our country and around the world.—Garret Alpers, Founder and CEO of World CNG, a converter of light- to medium-duty vehicles
There are approximately 135,000 natural gas vehicles on US roads today, and more than 15.2 million operating worldwide, according to Natural Gas Vehicles for America. About one-fifth of all transit buses were run by compressed natural gas or liquid natural gas in 2012; almost 50% of the trash trucks purchased in 2012 are powered by natural gas; and more than 35 airports in the US have natural gas vehicles in their own fleets or encourage natural gas use by private fleets operating on their premises.
EnerG2 materials would enhance performance for these fleets and infrastructure already in place using high pressure storage. Using their polymer chemistry approach to materials engineering, EnerG2 can tune the adsorbent’s nanostructure to improve the storage capacity of high-pressure storage systems by up to 30%.
Regardless of the ultimate outcome, EnerG2 said it is committed to enabling natural gas as a transportation fuel.
Natural gas has huge benefits. It’s still a fossil fuel, but now it’s far cheaper than gasoline, it’s domestically produced, and it generates lower emissions than gasoline. That’s one of the key reasons why we’re actively seeking natural gas system development partners for our new material.—Rick Luebbe, Co-Founder and CEO of EnerG2