The GRI reporting guideline is intended to serve as a generally accepted framework for reporting on an organisation’s economic, environmental and social performance. It is designed for use by organisations of any size, sector or location. The GRI reporting guideline contains both general and sector-specific content that has been agreed by a wide range of stakeholders around the world. The guideline for the electric utility sector, Sustainability Reporting Guidelines & Electric Utility Sector Supplement was issued in spring 2009.

Initially the guideline defines a set of reporting principles. Four of these deal with establishing the scope and contents of the report, while the remaining six address the quality of the information presented.

Thereafter the guideline specifies the base content that should appear in a sustainability report. The content is divided into three types of disclosures:
• Strategy and profile: disclosures that set the overall context for understanding the organisation’s performance
• Management approach: disclosures on management approach within the different reporting areas
• Performance indicators: indicators that elicit comparable information on the economic, environmental, and social performance of the organisation

GRI has identified three reporting levels, A, B and C, where A is the highest level. The reporting organisation is supposed to self-declare its reporting level based on self assessment against the criteria in the GRI Application Levels.
Link to www.globalreporting.org