Enbala Blog

Energy – A Philosophical Look at Change

Posted by Malcolm Metcalfe on May 9, 2018 10:29:00 AM

For more than 100 years utilities have supplied electrical power to their customers 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 must be able to start or stop a generator or to change capacity at the touch of a button to maintain a continuous balance between supply and demand.  On the other hand, the loads that use the electric power can be intermittent, unmonitored and subject to starting and stopping at what the system operator would see as near random times. 

Suddenly, the world is faced with a need to reduce or even eliminate emissions.

Most electricity in the United States is generated by burning fossil fuel, so eliminating emissions will require change to the
supply system along with many changes to the direct methods of using fossil fuel, for example, heating and gas-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.

MetcalfeHRThere 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 to fear the need to change their approach to managing intermittent generating sources. Storage is seen as a means of making intermittent resources into firm resources.

But even with battery technology advancing, and prices falling, the concept of storing summer energy to carry us through a cold month in winter is very costly. A typical electrically powered house with an EV for transportation may need batteries valued at more than $300k at current prices.

Turning the Power System Upside Down: From Adjusting Supply to Adjusting Load

Perhaps there is a better solution right in front of us. For more than 100 years, utilities have balanced their operation by adjusting the supply side of the equation. Maybe it is time to switch the system to adjust the load side and let generation run at its most efficient level all the time when it can. Intermittent generators can come and go as available, much like loads have done in the past. 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, reducing delivery losses.

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 is used for providing flexibility and 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, 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, maximize efficiency, minimize losses and hopefully keep 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 negatively impacting our quality of life.


Topics: renewable energy, utility future, carbon emissions, Distibuted energy resources

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