Why is LNG so bad?
Many commentators in Ireland recently defended LNG (and specifically the proposed project at Ballylongford) as just natural gas and therefore much cleaner than coal. At a molecular level it is indeed the very same as natural gas. It is the same gas used for cooking and heating in many Irish households. It's used to generate electricity in many of our power stations. It is the same gas that livestock belch out. So, LNG is natural gas. It is methane. It is CH4. At the molecular level there's no difference.
However, the fact that it is molecularly the same as natural gas is often used to obfuscate and confuse matters and ultimately present LNG as a necessary, even benign solution to our energy needs. You'll hear and read lines such as:
"It's cleaner than coal"
"It's just natural gas"
"It's a transition fuel"
It's crucially important to understand what the big deal is when it comes to this particular gas and why it is so damaging when converted to its liquid form.
Fundamentally, when natural gas is burned (in a power station or in a domestic boiler or cooker, for example) it is much less of a problem than when it leaks into the atmosphere. In this situation, i.e. when it is burned, it produces energy, which is what we want and need, but also carbon dioxide as an unwanted byproduct. While the carbon dioxide is a very potent greenhouse gas, natural gas itself when it escapes directly into the atmosphere (i.e. when it is not burned in some form of combustion process) is anything between 25 and 85 times more harmful than carbon dioxide as a greenhouse gas. It is hugely damaging. (As an aside, this is the reason that there is so much focus on agriculture in our efforts to mitigate climate change).
LNG (Liquified Natural Gas) is what it says it is. It is simply natural gas that has been cooled down so much that it is now in liquid form. It is cooled to around -163C. This makes it easier to transport across oceans using big bulk shipping tankers than building a network of undersea pipes. But keeping it so cool requires a lot of energy. So, a proportion of the energy in the gas that you might want for generating electricity or heating your home or cooking your dinner is lost in the process of cooling and transporting it. That means that you're getting less useful energy from natural gas that has been converted to LNG than natural gas that has not been. Yet the unwanted carbon dioxide byproduct is the same. That's the first problem. If natural gas has at some stage been converted (i.e. cooled) to LNG then it has a higher carbon dioxide output that natural gas that has not been.
The next problem is that it leaks, and it leaks a lot, and however much the engineering profession has tried to limit leakage there is still plenty of it. So, not only are you losing energy through cooling and transportation you're losing it to the atmosphere as well. And when it goes up into the atmosphere it is 25 - 85 times worse than CO2.
When all of this is considered, LNG isn't only worse than conventional natural gas, it's actually worse, from a climate change point of view, than coal or oil. At best, according to a new study, it's 24% worse than coal, but depending on how far it's being transported it could be ten times worse than that.
Here's a recent New Yorker article on the new research.