Who shall lay out those constraints, clearly, credibly?
Steve Mitnick is Editor-in-Chief of Public Utilities Fortnightly and author of the book “Lines Down: How We Pay, Use, Value Grid Electricity Amid the Storm.”
Once, electricity was the exclusive province of utilities and regulators, and their vendors and experts. The public’s limited understanding of electricity’s cold hard truths wasn’t problematic.
That all changed in the seventies. Since then, third parties have increasingly demanded and been granted a role in plotting electricity’s path. This trend accelerated in the nineties, with deregulation. And accelerated to warp speed in the last ten years, propelled by the push for a low-carbon future.
Millions of Americans have developed a real interest in electricity’s future. Particularly younger Americans, many of whom aspire to be activists and disruptors.
No longer an exclusive province, the public’s limited understanding of electricity’s truths is now problematic. Notions that defy basic scientific and economic constraints too often catch on.
Who shall lay out those constraints, clearly, credibly? And what are the coldest hardest truths that a much more involved public must grasp? Here’s one, an especially cold and hard truth.
Electricity is instantaneous. It can be switched on, and off, in an instant. When the sun peeks through the clouds, solar panels make electricity that instant. And when the clouds drift back, the panels stop that instant.
But our lights, air conditioners, televisions, etc. are on for minutes or hours at a time. If the electricity supplying them varied like cloud cover, they’d erratically switch on and off.
So, what matters is not the maximum amount of electricity the panels can make. But how much electricity they do make over the course of a day, a week, a year. And how much electricity they make consistently.
Which is why things that make electricity, from solar panels to wind turbines to power plants, have two basic numbers. There’s “capacity,” the maximum amount of electricity that the thing can make under perfect conditions. And there’s “energy,” the amount of electricity that the thing makes over the course of time, through thick and thin.
A solar-paneled roof of a house typically has a capacity of around seven kilowatts. It can make seven kilowatts of electricity under perfect conditions, more than enough juice to power the house’s machines, appliances and devices.
But those perfect conditions, mid-day sun and completely clear skies, may be present for no more than a couple of hours daily. That’s why that solar-paneled roof, with a capacity of around seven kilowatts, only makes as much energy over the course of time as if its capacity is around one kilowatt.
Here’s another cold hard truth. The storage of electricity for later use has inherent limitations.
Before the invention of electric generators, and the development of power plants, the electric storage battery ruled. Nineteenth century generators, through the end of the Civil War, generally trickled electricity and did so discontinuously.
Zenobe Gramme changed that in 1869. Obsessively neat, he hated the messes of chemical-based batteries. So, he invented the electric generator, that is, the first one that made a usable amount of electricity, and did so continuously.
This began the age of the electric generator we’re still in. Electric batteries were relegated to powering mobile and low-power uses.
Electric batteries and other things that store electricity for later use do have some advantages over electric generators.
Generate electricity with solar panels, or wind turbines, or power plants. You must use that electricity, to power machines, appliances and devices, in that instant in time. Generation is instantaneous. Store electricity with batteries, or pumping water up and into a reservoir, or pumping air into an enclosed space. You can use that electricity later. Storage isn’t instantaneous.
But anything that stores electricity stores a maximum amount of it. Use that amount up, and you’re stuck. Hence the range anxiety of electric car owners. When electric car batteries run low on juice, a generator (the charging station) may not be right there right then.
In the future, we may rely on storage much more to power cities, assuming we can restore the storage anytime by running generators. But what if there aren’t generators right there right then?
What if the generators are predominantly solar panels? What if heavy cloud cover from a storm obscures the sun for a couple of days? When the stored electricity is used up, we’re stuck.
And that’s why the goal of a hundred percent renewables for electric generators is so daunting. To pull this off, the country would need to construct a truly incredible amount of storage. David Roberts of Vox estimates the country’s maximum storage capacity would need to grow by 2,687 times the storage we have presently. (“Is 100% Renewable Energy Realistic? Here’s What We Know,” April 7, 2017.)
Here’s another cold hard truth. Our country’s electricity, how much juice we make and how much we use, is ginormous. So, the scale of changes really matters.
Nuclear has been in the news these days. One nuke makes around nine million megawatt-hours a year. If it shuts down, or if a new one isn’t built, that’s another four and a half million tons of climate change gas into the atmosphere. Every year. (Assuming the power is instead made by the cleanest natural gas power plants.) And three hundred and sixty million tons over the nuke’s operating life. Not good.
Wind and solar power need a whole lot of real estate to make a meaningful amount of electricity. And prime real estate, real windy in the case of wind power, and real sunny in the case of solar power.
That lone wind turbine the town erected at the beach, and those twenty solar panels your neighbor erected on his roof, is making a negligible amount of electricity, in the grand scheme of things. All the home solar roofs in America, combined, made around ten and a half million megawatt-hours in 2016. That’s a bit more juice than that one nuke.