Energy Storage: The Peanut Butter to Solar’s Jelly

As the world shifts away from fossil fuels, renewable generation can’t get us there alone. From transportation to the electric grid, energy storage, paired with abundant renewable energy sources, will prove an essential technology in reaching global decarbonization goals.

In 2017, this 30 MW 4-hour battery storage project in Escondido, CA held the title of the world’s largest. As of 2021, a project ten times the size now holds the record. Source: San Diego Gas and Electric

Did you know that 50% of the US’s greenhouse gas emissions result from transportation and electricity generation? To limit the worst impacts of climate change, experts tell us the fastest, most cost-effective pathway to decarbonize is through electrification. That is, replacing systems that combust fossil fuels with cleaner, electric-powered alternatives.

Two landmark pieces of California legislation further support demand for decarbonization through electrification:

  1. Senate Bill (SB) 100 sets targets for the golden state to strip 100% of carbon emissions from electricity generation by 2045.
  2. An executive order calls for 5 million zero-emission vehicles on California roads by 2030.

In response, the adoption of energy storage to support intermittent renewables, like solar, is accelerating. In 2019, the golden state’s electric grid reached 31.7% renewable penetration. But critics are quick to point out an obstacle with solar called intermittency. That is, PV generation is weather-dependent, falling at the mercy of mother nature.

I Wanna Soak Up the Sun

Many familiar with renewables have heard the horror stories of electric grids with high solar PV penetrations being brought to their knees by an errant cloud. Nor infamous Californian ducks casting their curves!

Fortunately, such scenarios haven’t materialized at the scale one feared thanks in part to the energy storage industry. But energy storage and electric transport are underpinned by a single technology.

Batteries. And lots of them.

Why Does the Grid Need Storage?

Operating the electric grid is tricky. For a variety of reasons, we designed our grid to provide electricity instantaneously. In other words, when we turn on our lights, grid operators must generate the exact amount of electricity immediately – Right now!

We all are aware of what results when the electricity supply doesn’t meet demand. It’s called a blackout.

But not all utilities operate with the level of immediacy. Water utility operators built buffers into their systems as safeguards to decouple volatility from daily spikes in demand. Depending on where you live in the US, you know these buffers in the form of reservoirs or water towers. As long as the water tower isn’t empty, customers can draw from the reservoir. Utilities can replenish stocks throughout the day at their convenience.

Lithium-ion batteries (LIB) are quickly becoming our electric grid’s “water towers”.

How Does Energy Storage Work?

Like a water reservoir, batteries store electricity for a time when you or I need it. Storage can soak up excess daytime renewable energy, and discharge when the sun isn’t shining. LIBs can only store electricity in the form of direct current (DC).

To power our home appliances and electric grid which operate on alternating current (AC), we require equipment about the size of a kitchen cabinet called “inverters”. Inverters convert electricity from AC to DC when charging, and vice versa when discharging. They can also be paired with solar PV as depicted below.

Batteries store energy in the form of DC. Inverters convert DC to usable AC energy for compatibility with our electric grid. Source: CleanEnergyReviews

The scale and versatility of LIBs are virtually endless. We can design energy storage systems for single homes or businesses – what energy nerds refer to as “distributed generation”. Battery storage technologies can scale up to serve utility-scale transmission-level projects (really big!). They can also offer resilience across a regional grid, or down to the building level.

We Got Your Back(Up)

During a grid outage, a residential or commercial energy storage system can supply backup power to customers. When paired with onsite solar PV, customers can theoretically operate indefinitely.

Such attributes make energy storage an attractive option to utilities, grid operators, policy regulators, business owners, and residential customers. As a result, analysts expect global energy storage capacity to grow by 31% per year through 2030. And that’s only for electricity generation.

Ready, Set, Green

To meet the primary driver for lithium-ion batteries, let’s turn to the global automotive electric vehicle market. It’s taking off like a Model S on a dragstrip.

Fueled by the EV industry, battery costs have fallen dramatically over the last five years, marking trends analysts anticipate will accelerate. Some expect the EV battery market to approach a trillion dollars by 2030.

As the global transportation industry embraces all-electric options, cost reductions will continue to drive demand for more LIBs. These trends spell good news for both the EV and energy storage markets.

Back to the Future

Solar PV paired with energy storage is already cost-competitive with open-cycle gas turbines. In some areas such as California, combined-cycle gas generators (de facto natural gas turbines) are struggling to maintain their status as the lowest-cost generation asset. Experts expect that solar and storage could one day represent 70-80% of generation in most markets.

There’s also the possibility that electric vehicles could one day provide stationary energy storage for our grid.

The climate crisis calls for rapid decarbonization. As the world shifts away from fossil fuels, renewable energy can’t get us there alone. From transportation to the electric grid, energy storage, paired with abundant renewable energy sources, will prove a pivotal technology to reaching our global decarbonization goals.

About the Author

Alex Kaufman is a science communicator, clean energy specialist, sustainability nerd, professional engineer, travel enthusiast, and resident of San Diego, California. When not helping clients, you can usually find him cycling, hiking, reading, spending time with loved ones, or planning the next big adventure. He is open to speaking engagements. Contact him at

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