Simply, it is now more economical to USE the electricity generated by a home turbine rather than export it to the grid. You will be paying 18.36c per unit for the energy you buy from the ESB (or thereabouts) and so every unit your microgenerator produces will displace a unit at this cost. So the effect of this change in tariffs is un-noticeable in a house that has a relatively high usage, say above 7000 units, but will detrimentally effect customers who want to install a turbine in a holiday home for example. Some customers wanted to put a turbine in their holiday home because there is often better wind; they would offset their costs at their city residence by getting an export payment HIGHER than their unit cost to import and would consequently make a profit. Their electricity usage in this case would be low as the holiday property is only occupied occasionally and most of the electricity would be exported, this is now not so attractive with a lower rate of 9c per unit, although having a turbine will still save money and create a profit, just not as quickly.