Heidi Vella: How long has research into gas hydrates as an energy source been going on for?
Martin Scherwath: Gas hydrates research first started over three decades ago, which is not very long for fundamental science. The original estimates back then for how much was in the ground was based on the belief that because the conditions below the sea floor were stable for gas hydrates, there was a good chance for all of it to be gas hydrates. From drilling, that was found to not be the case, so from 100% we are down to 3%.
Initially the hype was really big, even in Canada, to go for it and develop a harvesting program until it was found that off the coast of Vancouver Island, where we are, a lot of the sea floor is mud, which is not good to drill in. Ideally you want to be in sand, so that lowered the chances of doing anything commercial here. Canada is now more focused on the tar sands than gas hydrates.
HV: What work is Ocean Networks Canada doing on gas hydrates?
MS: There are two known locations where we have gas hydrates at present. Those are Barkley Canyon and Clayoquot Slope. Both of those are on the continental slope, which is important for gas hydrates as they need to have the right stability conditions to form and be stable. Those two locations are ideal settings off our coast. Over the last years, we've installed and maintained these experiments in those two locations specifically for gas hydrates. The main purpose of most of these experiments is around the long term variability of gas hydrates.
It's a very dynamic system on the sea floor and in the past, when people went there with a ship, they only got an instance in time view of what is happening down there, maybe a few days if they had the time to spare. That meant you could only find out what was happening throughout your cruise season. What we really want to find out now, is what the variability is over a long period of time and especially in the bad weather season, when we couldn't go there with a ship, so that we can find what's happening in the winter. We'll be looking at how storms effect gas hydrates on the sea floor.
HV: What have you discovered through the experiments on gas hydrates?
MS: We have an experiment at Clayoquot Slope that uses a bubble sonar to scan through the water column and bubbles from the sea floor. We now have about a year's worth of good data from the bubble sonar scanning around and looking at the bubbles and have found that when the winter storms came in 2012 there was actually much higher activity. You need more than one season to be confident with it being a real result, rather than a coincidence, but there is some indication that maybe it is more dynamic at the times when we haven't been looking in the past.
HV: Where are the gas hydrates located?
MS: The gas hydrates are in the seafloor and are stable, but there are pockets of free gas, and those are dynamic, filling up with gas that is probably from a deeper part. Gas hydrates are a bit like ice, in that they are relatively stable but the free gas is in between. Free gas likes to come out abruptly, and that is the bubbles that we see. It could also be found below the stability field.
HV: How do you extract the gas?
MS: You have to melt it or change the surrounding conditions so that it becomes unstable. Increasing temperatures takes a lot of energy, which is not very good, but you can also reduce the pressure if you bring down your gear and transfer low atmospheric pressure to the sea floor. Then the gas hydrates will disassociate as well. Another way is changing their chemistry, even just adding salt to it in the same way you melt ice on the road, will eventually melt it away.
HV: What are the environmental concerns around exploiting gas hydrates as an energy source?
MS: Methane is quite a greenhouse gas, with much more potential than CO2 but only in the short term. Methane in the atmosphere breaks down and disappears basically within [a] few decades, whereas CO2 can be around for much longer, so over the long term CO2 is actually worse for climate change, but if you have a lot of methane released in a very short time, it definitely has a stronger impact on climate change.
As far as production of methane hydrates is concerned, that is slightly different, because when you produce it you try to capture as much of the methane as you can as a fuel, so nothing should really reach the atmosphere. That is even more the case when you extract it from the sea floor, which is in the hydrates stability field, because when the gas bubbles out and you drill in there because if it goes through a km of water, what little is released and not captured, is dissolved.
HV: Is there any other way that the methane might be released into the atmosphere?
MS: In the Arctic and Antarctic you can have very shallow gas hydrates, which means that if you have global warming and melting gas hydrates then those regions will have methane reach the atmosphere because there is not too much ocean water between where it melts and where it comes out to where the atmosphere starts. Those are the regions where we have to be very, very careful and monitor to see what's going on.
HV: Gas hydrates have been touted as the next big thing in energy, with some suggesting that it could have a similar impact to shale gas. Do you agree with that?
MS: I can't see it happening for a while but because of climate change and the research into alternatives like ocean wave power and wind power, we may not need fossil fuels in the future. That's my personal opinion so I could be wrong but that's my impression right now. I see a lot of groups trying to get away from fossil fuels and gas hydrates would be one, so it wouldn't be such a hot topic. But for a while it will definitely help countries like Japan, India and Korea. So maybe for a few decades they will exploit gas hydrates and make it commercially usable to become a little more independent.
HV: How are you looking to develop the work at your observatories in relation to gas hydrates?
MS: I am keen to work ever more closely with the principal investigators, especially the new ones, to understand how we can help them as an observatory because this dynamic environment has not been as available in the past, especially for gas hydrates. We can now look at gas hydrates all year round at our Canadian observatory and our US observatory just down the coast is hopefully coming online this year and there is a growing interest in understanding the dynamics of gas hydrates on the sea floor, so how stable are they, how explosive are the releases gas and things like that. If we do that for many years, we may even see trends, so for example if climate change does have an impact on gas hydrates we can observe that over many years, hopefully decades.