TECHNOLOGY

The grid is not ready for a renewable revolution


You can almost The electrical grid hears cracking and wailing under the weight of the future, as the two forces come together to push each other – often literally – to its breaking point.

One force is climate change, which could exacerbate disasters that have hit parts of the grid, as Hurricane Ida did this summer, pushing New Orleans offline as a heat wave settles. Or extreme weather can suddenly increase energy demand when the grid is at least able to supply it, such as during last winter’s Texas freeze and subsequent power system failures.

The other energy, ironically enough, is the massive deployment of renewable energy – the best way to deal with climate change and avoid such disasters. But it will demand a fundamental rethink of how the grid works. Gas and coal power plants generate electricity continuously by burning fuel and it is possible to measure how much they burn based on the demand for electricity. But the production of solar and wind energy fluctuates. The sun does not shine at night, and the turbines do not rotate without wind.

This can create a discrepancy between supply and demand. Imagine there is a heat wave. You come home from work in the evening and your house is freezing, so you crank the AC. The problem is everyone else is doing the same. This is the day when people use the most energy, when they come back from work and start cooling their house, cooking and washing clothes and running dryers.

Yet by sunset the sun is setting, and the solar panels are not producing much electricity. And can stop air flow at any time, leaving a gap between demand and production. (Utilities currently have very limited capacity to load giant batteries with solar power in the morning and save it when customers need more power.)

This puts tremendous pressure on the grid, which has to exist in a steady balance. Utilities have sophisticated systems to predict when demand will rise and when it will go down, so most days it is not a problem. If necessary, they can buy additional electricity from neighboring utilities. Or, they could hit that balance by burning more fossil fuels – but it certainly emits more carbon. But if unexpected demand increases and a utility does not have the required power, it needs to restore balance by reducing demand, including blackouts.

While renewable sources take up the mix of energy, utilities will not be able to provide a fast supply by burning fossil fuels. So future grids that run from renewable to often uninterrupted power supplies need to be much more flexible to compensate.

Kelly Sanders, an environmental engineer at the University of Southern California who studies how the grid is evolving, is researching a technique called precooling, where home users will turn on the AC early in the day when the grid is buzzing with clean solar energy. Basically, they will remove the highest demand from the crowd returning home. “You can use a lot more electricity when the sun goes out, and then reduce that use when the sun goes down, so you can improve our behavior with wind and solar availability,” Sanders said.

The same principle will apply to heating. In some cooler areas of the United States, demand increases at 6 or 8 a.m. during the winter, when people stay awake in frozen rooms. Here people can start heating their house at dawn. Sanders suggests that local authorities could also change the work of critical infrastructure in line with the availability of renewable energy – perhaps giving an area time to treat its drinking water when there is plenty of solar power.



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