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Basically, it looks like the first 3 hours from 16:00 to 19:00 uses about 20 GWhr of electricity above what a flat curve would get you. I haven't seen any definite cost, but Telsa's 129 MWh Australian battery was about $50 million, or $390,000/MWh. So (and I realize that scale up and Telsa in the same sentence is a bit iffy) that would make 20 GWhr of storage cost $7.8 billion dollars. In terms of gigawatt power plant costs, that is a possible fix.
Two thoughts: We should be investing heavily in energy storage research. That could be batteries, pumped storage, flywheels, etc. When these technologies become available they will flatten the head of the duck.
Fossil fuel plants are not going away, they are the only commercially available technology that can ramp up relatively quickly to supply power when the wind is not blowing, it is night or cloudy. In my state of California, regulators are refusing plans for natural gas power plants, preferring to permit renewable power instead. This is short sighted, for the foreseeable future we are going to need 24/7 capable power generation.
The cost of net metering is transferred from those with large enough rooftops to provide a total energy output for their home to those living in small houses and apartments. This is a regressive taxation, favoring the rich over the poor. And when utilities propose to distribute costs more fairly the solar energy industry screams that it is a plot to put them out of business.
It would have been good to see the equivalent chart for 1 August to gainan indication if there is seasonal aspect to this issue.
We have the technology to address these challenges.
The real question is - Who's paying for the upgrades?
Many states in the US use the billing method known as "Net Metering". This means that the customer can sell and buy power at the same price. This, however, isn't fair. When buying power the cost is split into two types: Generation Cost and Delivery Cost. The Delivery Cost goes to the Utility so that they can build and maintain the power grid.
In short, the utility is required by law to pay the solar generator for the work that the utility does! Imagine working 8 hours a day and then paying your customer for the amount of time you worked. Net metering also means there's no incentive for the customer to buy battery banks to help stabilize the grid.
Utilities aren't going to accept a model where they go out of business. And the government isn't going to let a utility go out of business either. So they both agreed to make everyone who buys electricity pay for the lost revenue (translates to increase in electricity cost).
If the cost of infrastructure upgrades were charged to the solar generators, and if they were only paid for the generation cost, then solar generators would get paid less than half of what they are currently getting.
I prefer to call the evening ramp-up „Peaking Duck“
Of course adapting the pricing to the realities of the day can be useful. But shifting energy demand can only work if there are alternatives. When people return from work in the evening after a hot day, it's likely they won't want to turn off the AC. Yet little solar power is available at this time. The truth is that the value of solar power decreases after a certain installed capacity is added on the network, because human activity is not in sync with the sun's height in the sky, especially in modern times. The costs of electricity storage are incredibly high compared to classical production by power plants, so it's not really a viable alternative.
Another interesting development is that network costs are recouped today proportionally to the electricity consumption. But now that many people have installed solar panels, they draw power when there's no sun while they offload excess production when it's sunny. So they are using the service provided by the grid, but don't pay for the costs. The consequence is that grid operators would have an incentive to move a flat pricing for grid access with no link with actual power consumption. But as internet users know, when flat pricing is introduced, the consumer's incentive is to use more of the service, which runs counter to the energy savings mantra often heard today.
Rate optimization is just hugely important to flattening the duck. One huge problem in California is that the time-of-use rates are still highest between noon and 6 PM, where they were set in the '80s and still the basis for the production schedules of large industrial customers for whom energy is their principal input--even though the first half of that window is the part of the day when wholesale electricity is now cheapest. The California Public Utilities Commission is only just now getting around to moving the peak period to 4-9 PM, the neck and head of the duck. Once this happens, industrial customers (electric arc furnaces for melting scrap steel, industrial gas producers, cement kilns, etc.), water and sewage treatment plants, etc. will be able to shift their production back to the daytime from the evening.
(Full disclosure: I'm an employee of one of the major California utilities in demand response and energy storage. I deal with this stuff 8 hours a day and was pleasantly surprised to see an article about the Duck Curve.)
The demand for heat in a well insulated house with a thermostat timer, and residents away at work during the day, would look similar.
Once enough solar power is adopted, it will become clear when energy is scarce. Not on a hot summer day with AC running, as is the case today. When less sunlight is available.