Powering the Future with Energy Storage ☀️🔋
How Energy Storage is Making Renewables Reliable
Welcome to Fostering Our Earth, a space for untangling the complex systems needed for a sustainable future, from infrastructure and policies to lifestyles and cultures.
This post has an accompanying case study exploring EVs as a form of energy storage, which can be viewed here.
Let's start with a question to get our juices flowing: How can a solar-powered home function at night?
A sustainable energy system of the future must be secure, meaning that it is reliable in times of high usage, resilient in the face of disruptions, and renewable in its energy sources. This week, we're exploring energy storage's important role in creating this future.
The Gist 🎯
The energy that powers our lives comes from a primary energy source (whether renewable or non-renewable), is managed by power plants, and is distributed by the electric grid.
There are two primary reasons energy storage is essential to a sustainable energy system:
Storing excess renewables
Improving reliability and resilience of the grid
Storing Excess Renewables
Energy storage enables more significant use of renewable energy sources while integrating them into our energy system. Renewable sources such as solar and wind power are known as variable renewable energy (VRE), meaning they have an intermittent output since they rely on natural phenomena like the sun's position and wind patterns. This means their output varies daily or seasonally, making it difficult to predict and plan for the amount of energy produced at a given time. Therefore, energy storage becomes essential for us to harness the full power of VRE sources by storing excess energy for cloudy or still days (I think we just answered our question at the top). We can take a step closer to moving away from traditional fossil fuels by using storage to deal with the unpredictability issue.
Grid Reliability and Resilience
Energy storage can provide backup power during outages caused by high usage or external disruptions. Utility companies control the power supply, but when we all demand power simultaneously, like on extremely hot days or during the winter, it can cause power outages. We can manage this dynamic with practices like flex alerts in California, which call for consumers to voluntarily conserve energy (minimizing large appliance uses like laundry). Energy storage enables more flexibility in case these dynamics are out of control, meaning we can keep powering our homes.
External disruptions, such as climate hazards, extreme heat or cold, hurricanes and earthquakes, or geopolitics, can physically harm power generation and transmission. In times like these, it is prudent to have energy storage systems capable of providing power to people. Providing backup power can make a life-or-death difference, whether by powering hospitals, community centers, or homes in the middle of hot summers or winter storms.
How Do We Actually Store Energy?
There are several ways to store energy for future use; below are some of the most popular systems:
Pumped hydroelectric storage (pumped hydro for short) is a form of mechanical storage. Water is pumped from a lower reservoir to an upper one when energy is abundant and released to generate energy when needed. This method is widely used in globally and is relatively low-cost and long-lasting. One example of this is the Bath County Pumped Storage Station in Virginia, which has a capacity of 3,000MW, enough to power about 750,000 homes.
Batteries and hydrogen fuel cells are a form of chemical storage. Batteries are everywhere, from electric cars and smartphones, while hydrogen fuel cells are used in large-scale applications, such as power plants and vehicles. Lithium-ion batteries are the most common type used in energy storage, with iron-air batteries on the rise. California currently has over 3,000MW of battery storage.
Thermal storage: We can store energy in materials such as molten salt, which can be used to generate electricity or heat. Thermal storage is widely used in concentrated solar power plants, as it allows for storing energy generated during the day for use during the evening or night. An example of this is the super cool Crescent Dunes Solar Energy Facility in Nevada, which uses a combination of thermal storage to generate 110MW of electricity.
Compressed Air Energy Storage (CAES) is a form of mechanical energy storage. The air is compressed during off-peak hours and stored in underground caverns or depleted natural gas reservoirs. When energy is needed, the compressed air is heated and expanded through a turbine to generate electricity. One example is the Huntorf CAES Plant in Germany, which has a capacity of 290MW.
Flywheel energy storage is another form of mechanical storage that uses spinning flywheels to store energy. When energy is surplus, electric power is used to spin the flywheels up to high speeds. When energy is needed, the flywheels are used to generate electricity through a generator. An example of this is Beacon Power's 20MW flywheel energy storage plant in New York.
Electric Vehicles—yes, EVs can be used for energy storage because they run on batteries (chemical storage). For more on this, check out this case study exploring how EVs can help build energy resilience.
There are different methods of energy storage to suit different needs, and the technology is still advancing and improving, making energy storage more efficient, reliable, and cost-effective.
Questions You Should Be Asking 💭
Here are a few questions you should be asking when thinking about energy storage in your city:
How does my city plan to use energy storage to support emergency preparedness and response?
What types of energy storage systems does my city currently use?
What kind of metrics does my city use to track and communicate energy storage performance? Check out the CAISO App, for example.
How does my city plan to integrate energy storage with other forms of renewable energy, such as solar and wind power?
Are there any opportunities for local job creation and/or workforce development through energy storage projects?
TL;DR + What's Next 🧭
Energy storage is critically important to our future sustainable energy system as it enables security and reliability, especially in the face of increasing climate hazards. Expanding energy storage is also critical in our transition to renewable energy sources. In the last few weeks of our "Sustainable Energy Systems" series, we'll be exploring renewable energy and the grid.