What if there was an energy source that was larger than all conventional gas, oil, and coal deposits combined, created less greenhouse gas effect and potentially produced fresh water? This dream-like scenario could actually be reality. Think fire and ice – not the famous poem by Robert Frost – but what lies beneath permafrost.
Beyond providing solutions for how to enhance recovery of our current energy sources, UT PGE also takes a forward-thinking approach to its research on other viable energy options that exist in large volumes. UT PGE’s Dr. Steve Bryant is currently conducting research on methane hydrates to gauge whether it could serve as the next big source of natural gas.
According to the U.S. Department of Energy, who provides the funding for the project, “Methane hydrate is a cage-like lattice of ice which inside is trapped molecules of methane, the chief constituent of natural gas.”
Methane hydrate deposits are plentiful and are located all over the globe.
“The wealth of methane hydrates are dispersed among many countries’ coastlines, including Russia, Canada, the U.S. and Japan, just to name a few and some authorities believe up to 200,000 trillion cubic feet (tcf) of methane is in hydrates in the U.S. Exclusive Economic Zone,” said Bryant.
In nature, the hydrates can be found either in ocean sediments or beneath Arctic permafrost. There is an awareness of methane hydrates because of flow assurance in offshore oil and gas wells. Another professor in the department, Dr. Kishore Mohanty, is working on the project conducting research on various production methods of methane hydrates.
“There are three ways to produce methane from the hydrate deposits,” said Mohanty. “The first method is depressurization which releases gas and water; it can be done only in confined reservoirs. The second method is warm water injection. If warm water can be pumped from an underlying aquifer or a nearby conventional oil reservoir, this process is energy efficient. The third method is to inject CO2 to form CO2 hydrate and release the methane.”
Several challenges are associated with methane hydrates, including best practices for production in order to protect the environment.
“I’m looking overall at how natural accumulations form, because this has a lot to do with whether we can produce methane from them in a way that is safe and economic,” said Bryant. “Drilling through hydrates to produce gas can be detrimental if methane is released into the air, so it’s important to assess the method and have a strong understanding of the hydrates’ characteristics.”
Another challenge or question is simply whether it’s recoverable.
“For the methane hydrates that are in ocean sediments, it’s difficult to capture the energy since there is no trapping structure,” said Bryant. “The research will require strong blue-sky thinking.”
Although there are a handful of roadblocks, strong benefits exist as well.
“Since most of the mass of methane hydrates is water, when we melt it to obtain the gas, we are left with large amounts of pure water – no other form of energy has that capability,” said Bryant. Dr. Mohanty also shared another positive aspect. “One of the production processes of methane hydrates solves two problems at the same time - it produces methane for energy and sequesters the greenhouse gas, CO2 for a better environment,” said Mohanty.
Commercial production of this energy source likely won’t occur anytime soon, if proven fruitful, but there is a good amount of research taking place.
“Field production experiments are currently being conducted in the North Slope, so we can learn more about the geology and phase behavior,” said Bryant. “Methane hydrates won’t start heating our homes over the next year, but with its sheer mass, it’s not one to rule out.”