These people have "a highly reversible, gas cycle machine that works as both an engine and a heat pump": Our PHES Technology
I'd like the views of only competent people, who have studied and have more than a passing knowledge of, engineering.
Even if you are a 100% climate denier, you can still perceive the need for non-imported energy in a world of economic uncertainties such as this.
The very survival of the Euro is in doubt. The smaller countries of the Eurozone could very easily find themselves being forced to undergo an overnight transition to a worthless currency with which it is impossible to obtain cheap oil.
Therefore, it behooves them to find ways to be less dependent on their energy sources. Most countries, after all, strive to produce all of their vital medicines, their penicillin and aspirin, at home rather than depend on the international markets. Because there is a non-zero chance of an international market failure similar to 2008 endangering the arrival of medicines, countries have decided not to take a gamble for short-term price savings.
It's a bit like the difference between a torch and the lights in your house. If you measure the hours of illumination, the extent of illumination, then the ESB is vastly more cost-effective than the torch. But you have the torch for those moments when for whatever reason, the ESB is unable to help you.
Anyway, these guys have a very interesting system of electricity storage. I presume they have patented it, but patents run out eventually, or maybe their patent can be circumvented by using similar but not identical methods.
So for those in the know: can this actually be done in Ireland for a reasonable cost?
It basically takes an energy source, turns it into heat, then transfers that heat between two containers filled with gravel. It's been implemented and works great, it produces energy reliably whenever it's needed.