As utilities across the grid seek to get move into renewable energy and away from fossil fuels, one of the key aspects holding renewables back are their inherent intermittency. Intermittency means that they can not be relied upon to generate electricity whenever you want, because solar power needs to have sun and wind energy requires the wind to be blowing. When either of these factors, which are out of our control, are not cooperating, you cannot generate energy from them. Contrast this with baseload energy sources, such as coal, natural gas, and nuclear energy, which can be determined to be turned on whenever the grid needs them, regardless of extraneous factors. This intermittency is one of the main characteristics holding renewable energy back from really taking over the grid, but luckily there’s another energy technology that’s being developed in tandem that can help start to solve that problem: energy storage.
Energy storage is exactly what it sounds like—a type of technology that can take energy that’s generated and utilize it at a later time when it’s needed. As such, the connection with intermittent renewable energy is quite clear. When the sun is shining or the wind is blowing, these renewable energy sources can be used to create extra energy to save for later via energy storage.
This combination of energy storage with renewable energy is particular a good fit because the prime hours of generating wind and solar energy come during the middle of the day, when energy consumption is not peaked and so total power generation tends to outpace consumption on the grid. In scenarios without energy storage, this would result in extra energy being generated going to waste, being taken by neighboring grids for a negative price (i.e., one grid operator paying another grid to take it’s excess generation), or the uneconomical practice of curtailing energy generation and turning off perfectly good resources.
Given how inefficient a market is when the excess supply goes to waste, energy storage provides a market-based solution. Energy storage is often available as a grid resource where a utility or grid operator can simply take the cheap and available energy that’s being generated from renewable energy sources and store it in giant batteries on the grid, such as Megapack stationary storage solutions being built by Tesla. Similarly, energy can be stored on a small scale, via battery packs installed in homes (especially those who have on-site generation from solar rooftop panels) or even by mobile storage solutions that you may known as electric cars!
Wherever they are on the grid, energy storage is able to draw further value out of renewable energy resources.
You’re likely familiar with a basic form of energy storage littered throughout your house in the form of batteries. Batteries are an electrochemical solution that converts electricity to chemical energy to be stored and dispatched at a later time when it’s needed. However, that’s just one type of energy storage.
Another common form of energy storage is pumped hydropower. Using this technique, energy is used to increase the potential energy of water—either through pumping it up to a higher distance and/or by increasing it’s pressure so it’s ready to be released at a high velocity—and then releasing that water when the energy is required so it goes through a typical hydropower plant.
An emerging form of energy storage is thermal energy storage. The principal can be implemented in a number of techniques, such as through solar energy storage or molten-salt thermal storage, but the implementation is essentially to collect and store excess energy generation and use it at later times. For a micro-example, an HVAC system may take extra energy to make ice and then use that ice as a means to create cold air to cool a building later the next day when it’s warm out.
Given the possibility of energy storage solutions, what’s the real-life outlook look like? The best way to look at energy storage is that we’re looking at a tipping point, but we’re still a few years away from reaching it. One energy storage expert at Duke Energy noted:
If you are wanting to run your home just on solar and batteries, from where the technology is today, it’s going to be tough. It’s something we are keeping an eye on, but at this point it’s pretty overstated.
At the same time, though, the market, the technology, and the public policy surrounding energy storage are all moving in the right direction. Respected energy analysts at Wood Mackenzie see energy storage markets doubling from 2018 to 2019 and then tripling from 2019 to 2020. That’s massive growth, underscored by the continual bipartisan support that energy storage solutions get and the increasing R&D that’s being poured into the solutions.
Especially as energy storage becomes a part of an increasingly flexible, demand responding, and versatile grid, batteries and all other energy storage technologies are going to see the type of growth in the next ten years that solar power has experienced over the previous decade. Get ready for it!