The Fuse

Three Key Transportation Innovations Supported in ARPA-E’s First Seven Years

by Leslie Hayward | August 26, 2016

A number of ARPA-E projects are also dedicated to enabling transportation without oil, such as better batteries for electric vehicles, supportive technologies for natural gas vehicles, and more advanced biofuels.

ARPA-E, the Advanced Research Projects Agency-Energy, is a United States government agency tasked with promoting and funding high-risk, high-reward projects in energy that are too early-stage for private investment. The agency, modeled after the Department of Defense’s legendary DARPA program which helped develop innovations including GPS, radar, and the internet, is now seven years old, and has been pioneering new technologies across the energy spectrum, with everything from high powered drills for geothermal energy to advanced window coatings in its portfolio. A number of ARPA-E projects are also dedicated to enabling transportation without oil, such as better batteries for electric vehicles, supportive technologies for natural gas vehicles, and more advanced biofuels. When it comes to batteries, ARPA-E wants to improve the monitoring of existing battery technologies, as well as develop new battery chemistries. With natural gas vehicles, the agency has focused on reducing the cost of compressing natural gas for vehicles, as well as improving storage tanks. ARPA-E is also trying to develop energy-rich feedstocks for biofuels that will produce more energy per acre with less processing to convert them into biofuels.

Below are three of the most interesting transportation technologies from ARPA-E’s early portfolio.

  • Silicon Anodes for Lithium-Ion Batteries

Improved battery technology is one of the key components of making electric vehicles more viable as a petroleum alternative. Of major concern is the cost of battery packs, which drive a cost premium on electric vehicles, and reduce range. ARPA-E supported a research partnership between the Georgia Institute of Technology and Sila Nanotechnologies which promised a new battery chemistry using silicon instead of graphite as the anode in lithium-ion batteries. Silicon anodes can improve the energy density of lithium-ion batteries by up to 40 percent, and reduce the cell price from current levels around $200 per kWh to $100 per kWh—but the challenge lies in the fact that silicone and lithium are highly reactive together. Therefore, new technologies such as those developed by Sila are necessary to create a stable barrier between the two. ARPA-E funded Sila’s ongoing silicon anode project by $3 million, as it sought to make the first batteries with stable silicon anodes that can cycle hundreds of times while staying within industry durability, performance, and cost specifications. The company plans to deploy the new battery technology in personal electronics next year, with automotive applications expected as early as 2020.

  • Conformable Natural Gas Tanks

natural gas tankDespite surging domestic production of natural gas which have pushed prices to historic lows, there remain significant barriers to natural gas as a transportation fuel, one of which is the nature of tanks in natural gas vehicles (NGVs). According to ARPA-E, “the large, cumbersome, and expensive on-board fuel tanks presently used in NGVs create a major barrier to increased utilization of natural gas as a transportation fuel. Additionally, the low volumetric density of compressed natural gas—26.9 percent of the volumetric energy density of gasoline—limits the driving range of NGVs and makes cost-effective storage solutions an even more important challenge.”

Current natural gas tanks are cylindrical. The ability to adjust the shape of the tanks would significantly improve their versatility and create options for automotive engineers. Accordingly, ARPA-E allocated $5 million to help develop a new type of tank which has an internal lattice that enables the tank to be molded into arbitrary shapes. The company is hoping to apply this new tank in pickup trucks.

  • Low-Input, High-Energy Beets

Beets? Yes. Beets. Even with the alternatives presented by electric and natural-gas vehicles, ARPA-E and others expect liquid fuels to remain a predominant energy source in transportation. While biofuels can replace petroleum in many applications, they remain hampered by three main things. Per ARPA-E, “1) Crops intended for biofuel production require large tracts of arable land that may compete with food crops; 2) Biomass is not easily digested and requires an expensive or inefficient process to break down into its components; and 3) Oil-rich crops do not provide enough energy yield per unit area to be a cost-effective alternative for production of transportation fuel at scale.”

Boosting the potential for high-sugar beets is the fact that certain citrus crops in Florida have been damaged by Citrus Greening disease.

Thankfully, beet technology offers a promising alternative. Scientists have identified that the amino acid gamma-aminobutyric acid (GABA) which regulates plant growth can also increase sugar content in certain crops, and also manage the crop’s nitrogen consumption, which impacts how much fertilizer is needed to grow the crops. A company called Plant Sensory Systems, funded by ARPA-E for $2 million, engineered a method to increase GABA production in sugar beets, boosting sugar yield by up to 40 percent while reducing the need for nitrogen-based fertilizers. At present, nearly one million barrels per day of corn-based ethanol is blended into gasoline to offset crude oil demand. But corn is a relatively poor feedstock for ethanol production compared to high-sugar beets, which produce 60 percent more ethanol per acre than corn crops. Thanks to promising early field trials and economic modeling, grower-investors are slated to begin installing beet ethanol fermentation facilities in 2017.

Boosting the potential for high-sugar beets is the fact that certain citrus crops in Florida have been damaged by Citrus Greening disease. Florida’s citrus industry generates $10 billion dollars per year and employs over 70,000 people, but the disease has tripled expenses for growers and led to the smallest citrus crop in more than 50 years. Plant Sensory Systems has created a spinoff called Just Beets which is working with growers to use citrus fields for beet cultivation in the very near future, benefiting local farmers while boosting energy security.

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