CPS Energy's coal-fired Deely One power station is being restarted Saturday, after an investigation revealed the cause of an explosion and fire that forced the closing of the facility last month, 1200 WOAI news reports.
The utility says computerized sensors in the part of the plant that stores coal gave plant operators faulty readings about how much coal was in the storage facility. After the sensor indicated that the coal bin was half full, two veteran CPS Energy engineers made the decision to open a valve which had been automatically closed because there was no coal in the bin.
Since the silo was empty, heating the bin led to a rapid increase in temperature, leading to a fire. It is similar to how an empty pan will burn if it is placed on a hot stove burner, because there is no water in the pan to diffuse the heat.
The overheated steam ignited coal dust, leading to the explosion.
CPS Energy has instituted changes in its processes to avoid the problem from arising again, and the computer sensors have been repaired.
The plant, which is mockingly called 'Dirty Deely' by environmentalists, is set to be decommissioned later this decade.