The Association of Power Producers of Ontario (abbreviated APPrO) is a trade and professional body representing commercial electricity generators in Ontario, and the largest organization of its type in Canada. APPrO was established in 1986 as the Independent Power Producers' Society of Ontario (IPPSO) and changed its name to APPrO in 2003. It projects a unified voice of advocacy for Ontario-based generators of all types, addressing a range of public policy and regulatory issues of concern to the power industry. The organization also operates industry conferences and produces a number of publications, both hardcopy and electronic. The APPrO conference is the largest annual event of its type in Canada, and its magazine, IPPSO FACTO, is considered by many in the industry to be one of the most authoritative periodicals on electricity business and policy issues in Canada. APPrO currently has about 100 corporate members including some of the most well-known names in the Canadian power business such as TransCanada Corporation, Bruce Power and Brookfield Renewable Power, along with many lesser-known companies. APPrO members produce electricity from a range of sources including natural gas, hydroelectricity (waterpower), cogeneration, windpower, solar energy, biomass (wood waste), biogas, nuclear energy, and other sources. The organization has been a leading advocate for public policies and regulatory treatments that it believes would facilitate the development of power generation in the province and assist in the development of a more open and competitive market for power. APPrO's mission statement cites the following as its top objective: The achievement of an economically and environmentally sustainable electricity sector in Ontario that supports the business interests of electricity generators including a reasonable rate of return. APPrO's current advocacy work is focused on regulatory and policy issues affecting generators in Ontario including electricity market rules, power procurement processes, the regulation of the natural gas market, both provincially and federally, climate change rules and compliance mechanisms, approval requirements, transmission development, distributed generation, and a number of other issues.