Where can a Relief Operator (Control Room and Station Operator combined) from a coal fired electric generation station fit into serving companies during this current energy transition?

Your fundamentals are sound (safety, understanding process, ability to read P&ID's, follow operational orders, regulatory mandates, etc..). Applying them to any of the "new" energy generation technologies should be a quick learning curve for you. Moving forward, the ability to learn and work with new platforms is going to be more and more appreciated as a skill set within itself. Change is not constant; it's accelerating. As the others have said, you're a valuable asset, and will continue to be in demand. Good luck!!! 

You are an operator, you know the jargon, you understand safety, you have a gut feel for what will happen if you do "X", and whether that is good or bad.

Any utility would love to have that experience in a control center - generation, transmission, or distribution (which is going from zero in 2000 to thousands of jobs by 2030). Most control center are union if the field workforce is union. If you are union, you have seniority based on how long you work - check the IBEW website for questions if that is your union - If you have not been exposed to how transmission or distribution work, check with people you know and find someone to sit down with for a couple of hours to get the basics, maybe ask your employer if you can work some days in the transmission control center or ride with some of the substation qualified people to see what they are doing. 

There are plenty of jobs in the industry, if you are interested in staying in the industry. While the jobs are rare, most Nuclear plants are seeing a wave or retirement and looking for operators. You may have to take a step back for a year or two to learn the plant and get qualified, but that is another option. 

Some utilities will pay for a summer course at the UofW Madison that can bring your understanding on aspects of the industry that you may want to learn.

Not knowing your other degrees, if they are technical you would have additional choices.  There is a tremendous amount of focus on all aspects of energy usage beyond electricity, this includes transportation fuels, chemicals and other fossil fuel displacements.  This effort is leading to many regional/local processing facilities for bio-materials (corn, soybean, wood, etc..), a demand for recycling of many materials - plastics is a leading one and also the re-purposing of plastics into other products.  These segments are requiring the same 24/7 operations similar to the utility segment.  The key challenge is that the entry level salaries are not going to be the same as a regulated utility, but I would suspect that the opportunity to grow into larger roles at a rapid rate may offset this initial loss of pay and benefits.  Recommend you search for bio-fuels, plastics recycling, bio-materials and see what is available in your region.