Best Available Retrofit Technology (BART)
In January 2013, the Environmental Protection Agency (EPA) issued a proposed Best Available Retrofit Technology (BART) rule for NGS.
As part of the Clean Air Act (CAA), Congress established a goal of returning visibility in national parks and wilderness areas to natural background conditions by 2064. To implement this CAA requirement, the EPA established the Regional Haze Rule. The haze rule is structured to make progress towards the long-term goal over 10-year planning periods and is specifically designed to improve visibility on the haziest days and prevent visibility deterioration on the clearest days.
In the first 10-year planning period of the rule (2008-2018), BART analyses are required for certain older stationary sources, like power plants, to determine whether these sources can be cost-effectively retrofitted with pollution controls that reduce haze in designated areas. The EPA determined that NGS is a BART-eligible source.
Companies are required to follow a procedure that is prescribed by the EPA to establish retrofit technology for power plants that are subject to the rule. BART is determined by evaluating five factors, including the cost of controls, current controls installed, degree of visibility improvement associated with controls, remaining useful life of the facility, and non-air quality environmental impacts. The regulatory agency then reviews the company's proposal and determines whether it is acceptable, or whether additional controls are needed.