Utility operating people have been creating demand curves for decades. A demand curve shows the use of electricity over the course of each day. As you would expect, demand rises with the sun. As people wake up and factories gear up, the electricity usage increases until it reaches a peak late in the afternoon. As the first shift shuts down and people leave their jobs, the demand gradually falls off. As people arrive home, they crank up their air-conditioners, turn on their lights, and flick on the TV. Demand shoots up again. Â
In the past utilities would schedule power supply to mirror customer behavior. As demand for power increased over the day, the utility would add more power. As demand decreased, utilities would shut plants down.Â
Before solar.
The Duck Curve - California’s One Day Demand Curve
(Source – California Independent System Operator)
The fastest growing segment of new energy is solar. In some regions (California, Hawaii and Germany) solar supplies nearly all the electricity to customers for part of the day. That’s the good news. The bad news is that they are variable and can’t be turned on whenever we want. That’s unlike regular power plants. Utilities can turn them on and off. It is difficult and very expensive to turn on and off some large plants. And utilities hate to do this.
In areas with lots of solar, utilities can’t mirror their supplies to meet the customer.  Instead the utility supply curve looks like a duck. It follows customer demand in the mornings, but as the sun gets stronger, solar takes over. The utility supply drops quickly. But just as fast as the sun goes down, the utilities must quickly ramp up their supply with conventional generation.
This situation is shown the picture created by California Independent System Operation (CAISO) - the famous duck curve.
If there is too much solar and utilities don’t want to shut down their big plants, that creates a big problem. It’s called over generation. So far, the solution is to turn off the free, clean and cheap solar.
The National Energy Renewable Lab (NREL) suggested two approaches. Fatten the duck. Flatten the duck. Fattening the duck means making the duck’s belly even fatter. Utilities do this by figuring out how to make it easer and cheaper to turn on and off large power plants that normally run all the time. I won’t cover that here. The other approach is to flatten the curve by moving demand from the head of the duck to the belly. That’s where GIS comes in.
Five ways to flatten the duck:
Crush the duck’s head – energy efficiency
Mapping energy efficiency by location boosts utilities incentive programs to willing customers. Â Utilities have been using GIS to do this for years. GIS provides insight into the greatest opportunities for conservation and energy management programs. Â They gain insight into where they get the best return for the incentives.
Put the duck on a diet – demand response
In the old days, utilities put practices in place to encourage customers to stop using electricity during peak times. That used to happen during hot sunny summer middays. Now they must do the reverse. They must encourage customers to move usage from the late afternoon/early evening hours during the rapid rise in usage to the mid-day, during the peak of solar. Using spatial technology, utilities can map where to best apply demand response. Esri’s Tapestry data set can pinpoint where to establish incentives to control all kinds of loads, from air-conditioning to pool pumps to refrigeration units.
Pad the duck’s belly- storage
Storing electricity during the periods of excess generation is one of the best ways to use every ounce of clean, free electricity. Spatial technologies find ways to locate and design storage systems that are compatible with network operations. ArcGIS’s new Utility Network has advanced tracing capabilities to facilitate the rapid and widespread use of storage into the network. Storage can take many forms from batteries to air conditioning with built in ice-like storage facilities. Here again, utilities can leverage demographic data to target the right customers.
Go west young duck - transmission
Horace Greeley was credited with the expression of “Go West Young Man”. As we move from one region to another, the duck curve shifts in time. By adding more interconnections, utilities can expand solar generation time. GIS can model solar resources. It can determine the best location for transmission ties. It can even help utilities build real time market pricing into highly valuable solar resources that flatten the late afternoon ramp time.
Break the duck’s back – diversity
The duck’s back is a problem. The steeper the back, the faster that utilities must convert from solar to some other form of generation. One way to ease that transition is to apply other generation resources during that critical time. These can distributed energy resources that are relatively clean but not all renewable, such as natural gas micro-turbines, small scale wind energy resources and electric vehicle to grid resources. GIS can be used to site, plan, and discover the best location to optimize the breaking of the duck’s back.
It’s hard to think about anything but Covid-19 these days. As we move into a new world of increased residential and decreased commercial electrical demand, we may find additional opportunities to reshape the way we respond to the duck. The conventional wisdom about customer electric demand will be different. As customer behavior changes, GIS will be there to model it.
For more information on how GIS can add value to electric utilities, download our free e-book.
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