Best available technology (or just BAT) is a term applied with regulations on limiting pollutant discharges with regard to the abatement strategy. Similar terms are best available techniques , best practicable means or best practicable environmental option. The term constitutes a moving targets on practices, since developing societal values and advancing techniques may change what is currently regarded as "reasonably achievable", "best practicable" and "best available".
A literal understanding will connect it with a "spare no expense" doctrine which prescribes the acquisition of the best state of the art technology available, without regard for traditional cost-benefit analysis. In practical use the cost aspect is also taken into account.
Best practicable means was used for the first time in UK national primary legislation in section 5 of the Salmon Fishery Act 1861 and another early use was found in the Alkali Act Amendment Act 1874, but before that appeared in the Leeds Act of 1848.
The BAT concept was first time used in the 1992 OSPAR Convention for protection of marine environment of North-East Atlantic for all types of industrial installations.
Some doctrine deem it already acquired the status of customary law.
In the United States, BAT or similar terminology is used in the Clean Air Act and Clean Water Act.
European Union directives
Best available techniques not entailing excessive costs (BATNEEC), sometimes referred to as best available technology, was introduced with the 1984 Air Framework Directive (AFD) and applies to air pollution emissions from large industrial installations.
In 1996 the AFD was superseded by the Integrated pollution prevention and control directive (IPPC), 96/61/EC, which applies the framework concept of Best Available Techniques (BAT) to the integrated control of pollution to the three media air, water and soil.
In the European Union directive 96/61/EC emission limit values were to be based on the best available techniques, as described in item #17: "Whereas emission limit values, parameters or equivalent technical measures should be based on the best available techniques, without prescribing the use of one specific technique or technology and taking into consideration the technical characteristics of the installation concerned, its geographical location and local environmental conditions; whereas in all cases the authorization conditions will lay down provisions on minimizing long-distance or transfrontier pollution and ensure a high level of protection for the environment as a whole.
The directive includes a definition of best available techniques in article 2.11:
"best available techniques" shall mean the most effective and advanced stage in the development of activities and their methods of operation which indicate the practical suitability of particular techniques for providing in principle the basis for emission limit values designed to prevent and, where that is not practicable, generally to reduce emissions and the impact on the environment as a whole:
- "techniques" shall include both the technology used and the way in which the installation is designed, built, maintained, operated and decommissioned,
- "available" techniques shall mean those developed on a scale which allows implementation in the relevant industrial sector, under economically and technically viable conditions, taking into consideration the costs and advantages, whether or not the techniques are used or produced inside the Member State in question, as long as they are reasonably accessible to the operator,
- "best" shall mean most effective in achieving a high general level of protection of the environment as a whole.
United States environmental law
The Clean Air Act requires that certain facilities employ Best Available Control Technology to control emissions.
...an emission limitation based on the maximum degree of reduction of each pollutant subject to regulation under this Act emitted from or which results from any major emitting facility, which the permitting authority, on a case-by-case basis, taking into account energy, environmental, and economic impacts and other costs, determines is achievable for such facility through application of production processes and available methods, systems, and techniques, including fuel cleaning, clean fuels, or treatment or innovative fuel combustion techniques for control of each such pollutant.
The Clean Water Act (CWA) requires issuance of national industrial wastewater discharge regulations (called "effluent guidelines"), which are based on BAT and several related standards.
...effluent limitations for categories and classes of point sources,... which (i) shall require application of the best available technology economically achievable for such category or class, which will result in reasonable further progress toward the national goal of eliminating the discharge of all pollutants. ...Factors relating to the assessment of best available technology shall take into account the age of equipment and facilities involved, the process employed, the engineering aspects of the application of various types of control techniques, process changes, the cost of achieving such effluent reduction, non-water quality environmental impact (including energy requirements), and such other factors as the Administrator deems appropriate.
A related CWA provision for cooling water intake structures requires standards based on "best technology available."
...the location, design, construction, and capacity of cooling water intake structures reflect the best technology available for minimizing adverse environmental impact.