This is EPA's reason for withholding the requested information.
"The information you have requested is subject to an obligation of confidentiality imposed on the Environmental Protection Authority (EPA) by section 99 of the Climate Change Response Act 2002 (CCRA). Section 52(3)(b) of the OIA provides that the EPA's obligation of confidence is not overruled by any provision within the OIA. As such, the EPA is unable to release the information that you have requested unless one of the exceptions specified in section 99(2)(b) of the CCRA applies... the information relevant to your request is withheld pursuant to section 99 of the CCRA. "
I have lodged a complaint with the Office of the Ombudsmen.

After a year's delay, the Deputy Ombudsman Leo Donnelly advised that he agreed with the EPA view that they did not have to provide the information on units surrendered. This is a quote from his letter dated 8 April 2014.
"I am not persuaded that the OIA is an Act that provides for the disclosure of information in s 99(2)(a) of the Climate Change Response Act. The OIA confers a right to request official information and requires that such requests be processed in accordance with its provisions, but those provisions do not provide for the disclosure of information under the CCRA (or any other Act that imposes restrictions on the availability of official information). Instead, section 52(3)(b)(i) of the OIA provides that nothing in that Act derogates from any provision which is contained in any other Act which imposes a prohibition or restriction in relation to the availability of official information. Section 99 is such a section.
Accordingly, the OIA does not override the restrictions imposed by section 99 of the CCRA and it would be contrary to that section for the requested information to be made available to you. Consequently, section 18(c)(1) of the OIA provides a reason to refuse your request on that basis."

Here is the Ombudsman's letter of 9 April 2014.
https://drive.google.com/file/d/0B8LhMBA...