I am informed by the Irish Prison Service that the statistics being sought are not readily available. The information is currently being collated and I will respond to the Deputy as soon as the information is to hand.
The following deferred reply was received under Standing Order 42A
There are considerable difficulties in carrying out the calculations sought on the basis of the information you provide in your Question, given the variables involved. For example, while maintenance of buildings, staff pay costs, utilities and so on are fixed costs and would remain the same regardless of the length of sentence being served by prisoners, in relation to variable cost factors such as catering, healthcare, gratuities and so on, any calculation would have to be based on the average sentence for a person in custody (which itself varies from year to year), and also take into account “life” sentence prisoners who are not entitled to remission, as well as “fines” committals who are entitled to remission but are generally released within a short timeframe. Given the considerable variables involved in such forecasting, any calculation may give an incorrect expectation of the savings that could be achieved, and in the absence of any intention at present to change the remission regime along the lines suggested in your question, it would not therefore be helpful to engage in speculative forecasting of this type.