Electric Grid Control: Is it Time to Look Carefully at How the Grid is Managed?
Utility people for more than 100 years have supplied electrical power to users and have achieved this with good reliability. The principle is simple. Loads may do as they wish, but generation, the supply, MUST be both dispatchable and monitorable. An operator can, at the touch of a button, start or stop a generator or change capacity. Generator activities are carefully monitored and controlled.
The loads, that use the electric power can be intermittent, unmonitored and subject to starting and stopping at what the grid operator would see as near random times. The utilities have become adept at managing the generation capacity to maintain a continuous balance between supply and demand. Some of the random load events fit patterns that follow a general daily path up and down.
Suddenly, the world is faced with a need to reduce or even eliminate emissions. Most electricity in the US is generated by burning fossil fuel, so change to the electricity supply system will be needed as well as many changes to the direct methods of using fossil fuel, like natural gas heating and gasoline powered vehicles. Renewable resources with their intermittency operate much like a “negative” load. They can be very random, but in general, they can also follow a pattern that provides elements of predictability for their available capacity.
There is little or no solar energy available through the night, but as the sun rises and sets, solar energy may become plentiful and then disappear again as the sun sets. Many utilities seem terrified at the need to change their approach to manage intermittent generating sources. Storage is seen as a means of making intermittent resources into firm resources. But with battery technology advancing, and prices falling, the concept of storing summer energy to carry one through a cold month in winter remains a costly challenge. A typical electrically powered house, with an EV for transportation may need batteries valued at more than $300-400k at current prices.
Perhaps there is a better solution that is right in front of us, but not considered. For more than 100 years, the utilities have balanced their operation by adjusting the supply side of the equation. Perhaps it is time to switch the system to adjust the load side and let the generation run at its most efficient level at all times when it has capability. Intermittent generators can come and go as available, much like loads have done in the past. Contolled loads would provide the required balance between supply and demand.
There are many loads that have inherent storage, such as electric water heaters and EV chargers, but this may only be the tip of the iceberg. New communications technology can enable us to manage many of these loads that were never feasible in the past. Load owners may see the opportunity to get some revenue in return for providing load flexibility. Essentially, we would turn the power grid upside down and balance from the bottom; the load side of the equation.
In looking carefully at this concept there may be significant advantages that can be captured. Distributed loads, distributed storage, and distributed generation, all at the grid edge may be easily controlled and the remaining central sources can be run at maximum efficiency. Local response to local changes is always more efficient at reducing delivery losses than remote generation changes to provide the same service. Most of the central fossil fuel powered generation will need to be eliminated or replaced, but this too may create opportunities.
Natural gas, as an example, will generate electricity at a very low efficiency if a simple cycle gas turbine used for providing flexibility and it is located with other generation at a central location. But if the unit is replaced with a Combined Heat and Power system that is located at the grid edge near where the changes occur, and where it delivers heating, cooling and electricity for local loads, significant gains in efficiency can be captured.
There appear to be many opportunities to optimize operations, maximizing efficiency, minimizing losses, and hopefully keeping costs at acceptably low levels.
This process will require detailed thought and planning. The concept may cause real concern for utility people with a long history of central generation dispatch and control. But surely it may offer many advantages that can help us to get through this difficult and expensive transition to a clean energy system without damaging our way of life.
Photo Credit: Chris Hunkeler via Flickr