.....There is only one producer of electricity in the country- ESB Networks (I am leaving out the minimal amount sold into the national grid), who then sell it on to ESB or Bord Gais.....
Incorrect. ESB Networks do not generate electricity.They distribute it around the country via overhead lines in rural areas and underground cables in urban centres. They also maintain the networks and provide meter reading services to all suppliers. So, for instance, if you switch to Bord Gais or Airtricity, ESB Networks will still be reading your meter and will still call out to you to fix the fault if your lights go out. Problems with lots of estimated bills? Whatever the reason may be, switching supplier will not fix it. My advice to anyone with frequent estimates is to read your meter on a regular basis and advise your supplier be it ESB, Bord Gais or Airtricity. They will all be happy to amend your bill.
ESB Power Generation used to have a monopoly of power generation but those days are long gone. They now have less than 50% of the total market share of electricity generation. The rest is made up of independent power producers of which there are many, big and small. Have a look at the Eirgrid website if you want details of who they are (www.eirgrid.com). One of them is obviously Airtricity with their significant number of windfarms. Airtricity is both a generator and a supplier. Bord Gais will also have this dual role when they complete the building of their electricity generating plant in Whitegate, County Cork.
All electricity generated goes into one virtual "pool" from which the various suppliers on the island, north and south, but their electricity to sell on to their customers. (This is the Single Electricity Market and it is a world first in that it spans two separate political jurisdictions).
By all means go to Airtricity if you like their green offering. It will help I'm sure in developing their wind generation portfolio. But don't think that because you are an Airtricity customer the electricity that comes down the wires to your house is generated purely from wind. Like for every other customer it's generated from a mix of sources. You are getting the very same mix of generated electricity as your non-green neighbour.
Regards,
Fnergg