Last night I went to check on the natural gas meter. I heard a hiss and found a leak in the junction from the supply line to the meter. I called the gas company and they sent someone out to fix it. The repairman told me that the o-rings fail - he was able to tighten the junction and stop the leak, though often the fitting bottoms out and one can't tighten it further (the fittings are designed so you can't crush the o-ring). If an o-ring needs replacement, another specialized crew comes and replaces it on the fly, i.e. with the natural gas not shut off they undo the junction, replace the o-ring and replace the junction. To replace a meter they dig up part of the line and crimp it closed. Incredibly crude - there is no shut-off valve on the line to my house, unlike a water line.
Since the leak was on the supply side of the meter, I haven't been paying for the gas that has been wasted. That's the least of my worries - my primary concern is the safety of my family and house around the #$%^%$3 stuff! Thankfully, the meter is in an open area at the side of the house away from the entrances, though it is close to a fresh air intake. The fitting had turned black - the repairman told me it indicated it had been leaking for some time.
This incident begs a few questions:
1) How safe are all these home natural gas systems? What if the meter had been in a more enclosed space between houses in a city environment (i.e. close-packed housing)? Apparently these leaks are not uncommon, and are often caused by ground heavage in the winter. Or people hitting the lines with lawnmowers in the summer. Why aren't the meters better protected against damage?
2) Methane is the primary constituent of natural gas. Methane has a greenhouse gas factor over 10 times that of CO2 (as much as 20 times?). Aside from the safety aspect, what is the impact of leaking natural gas systems? What are the losses in Canada's nat gas systems? I recall a claim that in the UK the leaks counteracted any environmental benefit from burning natural gas instead of coal (the CO2 production in a nat gas fired power plant is in the order of 55% of that from an equivalent output coal plant, I recall). Note that the UK distribution infrastructure is older and therefore in (probably) worse shape than Canada's.