There once was a a time when people believed the world was flat and if you sailed too far out into the ocean, your ship would go right over the edte and disappear forever. Today, most people (excluding Donald Trump supporters) know that isn’t true. There is another myth in existence today that says the utility grid can only handle a certain amount of electricity from renewable sources. Now some people think if more than 10% to 15% of all electrical power comes from renewable sources, the grid will become unstable and any number of calamities will befall mankind as a result.
This myth is no more valid than the idea that the world is flat, but that doesn’t stop if from being promoted by lots of folks, especially utility companies and fossil fuel corporations. Why? Mostly because utility companies have enjoyed a government sponsored monopoly for more than 100 years. The whole idea that someone other than them should be able to make and distribute electricity disrupts their entire world view.
The people with vested interests in electricity like to point out that renewable energy is not as stable as electricity that comes from nuclear power or from burning fossil fuels. And they are right. Renewable energy fluctuates with the amount of sunshine falling on solar panels of the amount or wind that strikes the turbine blades. But the issue is not that renewable power is variable or intermittent. The issue is that the electrical grid is not constructed to handle that kind of power efficiently.
There are two keys to integrating renewable power into the utility grid successfully. One is constructing a grid that can adapt moment by moment to changes in supply and demand. A smart grid can turn off electric car chargers or lower the output of air conditioning equipment by a small amount when demand spikes. Second is energy storage. Whether it is pumped hydro, batteries, molten salt, or a train loaded with rocks that climbs and descends a mountain every day, energy storage is the secret weapon that makes renewables suitable for grid applications.