Mr. Declan Murray:

I will start with the question on how we deal with feedstocks. Anaerobic digestors are a bit like humans or cows because they are like a stomach and digestion is done in a sealed environment at a particular temperature but that does not mean the same thing is eaten every day. In fact, our digestors do not like getting the same single feedstock every single day of the week. We co-mingle our feedstock. For example, in County Roscommon we could get 30 tonnes of dairy byproduct from Aurivo and then we might not have anything for four days. In the grand scheme of things over an average period, where the amount of time we keep stuff in the tanks is 42 days, it generally is a uniform product. We will always have an ability to swap out products. We keep an eye on the markets so we know what is coming in and out of season. The Senator is quite right that summertime is not a good time of the year for slurry because all of the cattle are back in the fields and nobody is looking to get rid of too much slurry. However, summertime is our busiest time for other feedstocks. There is seasonality throughout with the way feedstocks are fed into the plant. We will probably have six or seven feedstocks coming into our AD plant, which vary in consistency. The final output is the digestate.

The next question that the Senator asked was what is the make up of the digestate. We put something through our tanks where it is digested and that then goes into a storage tank. We have about 7,000 or 8,000 tonnes of storage on our site in County Roscommon. The product in the tanks is tested every week, bi-monthly, six-monthly and on annual basis for nutrients. We then do a nutrient management plan based on what is in the tanks. We have not seen any real difference in the last four years of annual testing of biosolids, which may be 1% down in nitrogen this year and 2% up next year but within normal parameters. Each year, a nutrient management plan is updated for farmers.

I shall skip the Senator's question about giving carbon credits to farmers. On improvements in AD technology, the major improvements in the last ten years have been in front-end processing, that is the way you deal with raw materials coming into plants. For example, the brown bin was mentioned in one of our discussions earlier today. Historically, a brown bin would have been put through what is called a hammer mill, which is a high-speed hammer and is very basic technology. That process has now been changed entirely into a dry cleaning process with less plastics and all of that sort of thing. When we originally started in 2008 gas upgrading was primarily done using technology from the USA, which, I think, was created in the early 1970s and it was oxygen washing, which is taking carbon dioxide out of biomethane. That process was fun and games as it was 15 m high towers where you literally drizzled gas down through water, and the water became carbonated so it turned into soda water. The process was inefficient to say the least. That process has now changed into membrane upgraders and there is a whole different way of doing things so there is much less kit. The type of materials used moves on all the time. Our roofs and tanks will now last for between 15 and 20 years whereas before they had to be changed every four years. New materials come online and things get improved all the time. There have been major steps forward in gas upgrading and in feed-in technology. I think that carbon capture will probably be the next to experience a big technological jump.