Distinction between security and reliability: 

Energy Security – is about the physical provision of energy, fossil fuels, uranium, or even some of the fancy hardware that goes into the electrical grid, which is manufactured abroad. We saw a dramatic example of disrupted energy security in the Arab oil embargo in the 1970s, when it was very difficult to get enough oil. Up until recently, the U.S. has been producing more oil than it actually consumes, and so we’ve become, in that sense, energy self-sufficient. These days this is certainly true for natural gas, which is also a current example of energy insecurity in terms of what’s going on in Europe, where natural gas is needed for heating, for industry, and for electricity generation. The problem is that availability of this fuel in Europe relies on imports, which used to come predominantly from Russia. Geopolitically, that’s not a very comfortable place to be. In a nutshell, that’s what we mean by energy security.

Energy Reliability – is a different story. It’s mostly whether the fuel is capable of being delivered continuously. For example, is the refining supply chain stable? But more importantly, is the electrical grid able to deliver energy 99.9 percent of the time? We have recently seen dramatic instances of when the electricity supply fails, which leads to all kinds of chaos. Then there’s another aspect of the electrical utility business: these are regulated utilities, which means they cannot freely tend to the problems that they see.