A team lead by assistant professor Vaibhav Bahadur (VB) in the Department of Mechanical Engineering is developing a novel technology to utilize excess natural gas (that is flared) from fracking sites, for harvesting atmospheric moisture. His article on the topic of ‘flared gas-based atmospheric water harvesting’ is featured on the cover of this month’s American Society of Mechanical Engineers magazine.
With his solution, Bahadur addresses the increasing cost of water for hydraulic fracturing, as well as the energy waste and environmental issues due to flaring at fracking sites. Water is a critical bottleneck to extracting shale reserves, with frack jobs requiring 1-10 million gallons water. Challenges include the high costs associated with freshwater sourcing and transportation (which can exceed 10 cents per gallon), and truck traffic (about 450 water trucks are needed per frack job).
At the same time, fracking sites waste a lot of energy in the form of natural gas that surges out during the initial weeks and months after fracking. Lower value of gas compared to oil and infrastructure challenges associated with gas handling make flaring a preferred operation. Flaring is a global issue; about 4 % of gas produced worldwide is flared, which can be valued to the tune of USD 50 billion annually. The US is the fifth largest flarer and has jumped up 10 places in this list over the past five years, largely due to the surge in fracking.
The technology proposed by Bahadur utilizes the energy of natural gas to produce onsite water for oilfield operations. The third aspect of this story (in addition to water issues and flaring) is the enormous amount of atmospheric moisture. The researchers (including graduate student Enakshi Wikramanayake) propose tapping this limitless water reservoir by running a refrigeration cycle, powered by excess natural gas. The year-round hot-humid conditions in many oil producing regions like Texas, the Middle East, Africa, etc., and the abundance of natural gas, makes this technology attractive for large scale onsite water production.
