Final answer:
The statement is false. Capturing waste heat in a thermal-electric plant does not increase efficiency to 80 or 90 percent.
Step-by-step explanation:
The statement that capturing waste heat in a thermal-electric plant can increase efficiency from 30 percent to 80 or 90 percent is false.
According to the information provided, the efficiency value for coal-burning power stations is typically around 42 percent. The remaining energy, about 59.2 percent, is transferred as heat to the environment. This waste heat can be used for heating homes or industrial processes, but it does not significantly improve the overall efficiency of the plant.