Reverse osmosis and electrodialysis membrane technologies of water conditioning which have not yet received much attention are the most promising in modification of water conditioning plants operating at thermal power stations. Using electrodialysis membrane devices in the schemes of water conditioning plants for water softening and desalting allows not only the reduction of current operating costs for water treatment but also to attain a higher level of automation of the manufacturing processes of water conditioning as well as to improve ecological indices of thermal power stations. Investments in ED make it possible not only to reduce the costs of TPS for water conditioning but also to significantly improve the chemical conditions of the operation of equipment and to reduce costs for repair of boilers and heating systems by increasing the period of overhaul campaigns.