Central Station Generation
Over the next several years we are likely to see small scale distributed generation acquire an increased share of electric generation in this country. See Post entitled Distributed Generation – and Old Idea Reconsidered. However, notwithstanding the growth of distributed generation, we are still going to rely primarily upon the historic system of large central station generators interconnected by a complex high voltage transmission grid.
The following chart shows electricity generation by fuel source in the United States:
As depicted above, the vast majority of our electricity comes from large coal, natural gas and nuclear plants. These are the types of central station generators promoted by George Westinghouse more than 100 years ago.
The following video explains how electricity is produced at one of those central station power plants:
No matter how much distributed generation is added, the historic reliance upon central station generators plants is not going to disappear any time soon. Instead, central station generation is likely to be made cleaner with natural gas plants replacing coal plants and utility scale renewables being added to the mix.
High Voltage Transmission
All of the central station generators interconnect to the electric transmission grid. For the most part all of that generation stands ready to provide electricity when needed. However, not all of the plants are needed all of the time.
In states that remain highly regulated utilities own their own generating plants. They dispatch those plants strategically to meet their customer load requirements at the lowest overall operating costs.
In states where Independent System Operators (ISO) manage the grid generating plants operate at the direction of the ISO usually as a result of participation in a competitive auction.
Transformers located on the site of each generator boost the voltage of the generated electricity so that it can be transmitted at high voltage levels over long distances on the grid. After transmission the voltage is reduced at local substations so that it can be transported the final distance to the points of usage.
The following video explains how the electric transmission system delivers electricity from a central station generator to a local distribution system for final delivery to customers:
I. David Rosenstein worked as a consulting engineer and attorney in the electric industry for 40 years. At various times during his career he worked for utility customers, Rural Electric Cooperatives, traditional investor owned regulated utilities and deregulated power generation companies. Each of his posts in this blog describes a different aspect of the past, present or future of the electric industry.