I don't know what you mean by transmitter.

I know of one factory that has their own coal power plant. The boiler is from the 1880s, the generator installed in the 1920s. It is horribly inefficient by any reasonable standard and takes hours to turn on. However because they keep it operational the power company gives them a massive discount on electric. About ever 5 years there is a major event and the power company has them turn it on for a few days and they power the entire town.

That's a really cool story! I live near a couple of industrial sites like that which have a power plant on site, that were shut down quite a long time ago due to environmental concerns they don't burn cleanly at all as you said!

A transmitter is a sensor in a power plant that very precisely measures the air flow within the combustion chamber, so the fuel burns as clean/efficiently as possible. Relatively new transmitters can read with more precision, so you can dial down the airflow/fuel and the corresponding power output.