The current draft ordinance for the City of Denton follows existing TAC requirements allowing any "facility" (defined as a device, such as a storage tank) to emit up to 25 tons per year of VOCs.
To me, that is unacceptable.
Well, it turns out the EPA agrees. There is a new source performance standard that went into effect five days ago. Operators have a year to get into compliance. Here is the key part:
"Storage vessels. Individual storage vessels in the oil and natural gas production segment and the natural gas processing, transmission and storage segments with emissions equal to or greater than 6 tons per year (tpy) must achieve at least 95.0 percent reduction in VOC emissions."
Now, most operators will try to come into compliance with this rule by flaring. But we are not going to allow flaring in Denton. At least, I hope City Council prohibits it...
So, they will have to find another path to reduce their emissions. Now one way - and it is complex (there is no magic bullet here) - is vapor recovery units.
I have been doing some digging around on VRUs - here are some things I have been told by engineers who design and manufacture such systems. They can work on tanks with very low pressures. There are a variety of types of systems - including Ejector Vapor Recovery Units. When done right, then need not entail any safety hazards. We need to make sure any units that are installed are not just hood ornaments but are actually doing their job.
And check out the requirements made by the Colorado Department of Public Health and the Environment for the Front Range Ozone Non-Attainment Area:
"90 percent Volatile Organic Compound (VOC) control requirement for the summertime ozone season beginning May 1 2011 (May 1 - September 30). 70 percent Volatile Organic Compound (VOC) control requirement for the remainder of the year."
That is regardless of total emissions - no matter what the level, when it is summertime, you have to control 90% of your emissions. Now, why can't we get protection like that?
So, I was asking myself: Do we have to live with 25 tons per year? Is that the best we can do?
I wondered: Is this an economic constraint (too expensive to recover gasses at lower pressures)? A technological constraint (just not possible to recover such gasses)? Or is it a political constraint (there are no rules in place to force industry to do it)?
Turns out it is not a technological constraint - we can do it. It is not a political constraint - EPA is mandating it. And Colorado also shows ways to do it. So, it may come down to economics - but if it is too expensive with the new rules, then so be it. That just means we have been getting cheap gas by offloading or externalizing those costs into the lungs of the people living on the shale patch. It's time to stop doing that.
We had "experts" take 6 months to write our draft ordinance. Why is there no mention of this new EPA requirement? Why no mention of alternative VRU technologies?
I am glad that the EPA is on our side. Let's make sure our ordinance echoes this new requirement and incentivizes clean technologies and best practices. If we have to live with gas, let's make it compatible with breathing clean air.
Additional note: The Gas Well Inspection Division in Denton says it is tracking 455 active wells in Denton. IF we assume only one tank per well (which is probably low) and we assume 25 tons per year per tank (which is probably high), then that gives us: 11,375 tons of VOCs per year. Now, I don't think anyone knows how much is actually being emitted (which is a big part of the problem - we run a social/environmental/health experiment and don't monitor it). But the point is that that outrageous number is perfectly legal under our current rules.