Eco Home on Agri land - planning permission???

Looking for some advice here...…. Thinking of putting a log cabin onto family agricultural land with a compostable toilet, solar power etc. The main aim is to live off grid in so far as possible. Any advice on if planning permission is required for a non-permanent structure that will be a residential dwelling for the foreseeable future. It based in Co. Kerry so it's Kerry County Council's remit we would fall under. Has one gone down this route before or any advice on where to start? Loopholes / pitfalls / recommendations of people in the area that could help advise even?