Why are these empty?

The blue frame in the photo to the left is a gas holder, or "Gasometer". Note the filled one to the right in the background, which is very much the exception to the rule these days - normally, it appears that they're both empty. You can tell, by the way, which one if the newer of the two. It's the blue framed one. The grey, filthy-looking one, dates back to before the Second World War; the blue one is much more recent.


Anyhow, there was a time, a few years ago, when all these things were almost always full, maintaining reserves of gas under pressure for people in local areas, thus ensuring a ready supply of gas on demand for cooking, heating, and so on. Gas was the first properly clean, cheap, and affordable energy source in the home; prior to gas, coal and wood was used, both of which being both messy and occasionally somewhat smelly; in my youth (like before I was twenty), people swore by gas for cooking - not much of a surprise that, as electric cookers, while lacking the danger of leaking gas, were notorious for taking ages to get to working temperature, and for using the actual temperature as a gauge for oven heat (which confused all manner of folk - including me!), rather than the existing 'Regulo' or 'Gas mark' system.

Granted, gas is a fossil fuel and a greenhouse gas, all rolled into one, but the vast majority of homes in Great Britain use the stuff. I still do, for both main purposes, heating and cooking. I also use elecricity for all those (can you say "Microwave Oven" and "Immersion Heater"?), and much more besides. But you don't see massive capacitors dotted about the landscape, storing electrical energy to tide over high demand periods, instead, all you see are zillions of pylons and thousands of miles of cables.

So, with all this said and done, here're the burning questions of the moment: Why, given that a great number of us still use gas at home, are do the gasometers all seem to be empty these days? Are the gas companies not storing the gas locally any more? If this is the case, are they instead relying on pipelines from far-flung lands to supply a constant supply of gas to us, without managing a national gas reserve? We've seen what happens in those cases over the last few years - and if I recall correctly, wasn't it Germany that was one of the pigs-in-the-middle of the Russia/Ukraine gas dispute in 2009?

The idea of National Energy Reserves is not a new one; during the Cold War, we maintained strategic emergency stores of various types of fuel oils and gas; the USA does the same to this very day, as do most sensible nations - especially in these extremist terrorist-infested and troubled times. So I'll ask again: Why are the gasometers empty?

Anyone?