All Commercially Available Long Duration Energy Storage Technologies, in One Chart

Long duration energy storage (LDES) technologies can store electricity for 10+ hours, complementing intermittent renewables, boosting grid resiliency, and reducing fossil fuel dependency. 

Created in partnership with the National Public Utilities Council, this chart lists the characteristics of LDES technologies that have commercial or pre-commercial readiness, using data from the LDES Council’s Net-Zero Power report and 2023 deployment update. 

The Four Primary Types of LDES

Before getting into the details, let’s cover the four primary types of LDES. 

1. Mechanical: Stores potential energy (by tension or position) 
2. Thermal: Stores energy as heat
3. Chemical: Stores energy found within chemical bonds
4. Electrochemical (batteries): Stores energy of chemical reactions, where electrical energy is converted to chemical energy and vice versa 

Currently, mechanical storage systems are the most common around the world. Aboveground pumped hydropower, for instance, currently accounts for 96% of all utility-scale energy storage in the United States. 

How Do LDES Technologies Measure Up?

Below, we list the storage capacity, storage duration, and average round-trip efficiency (RTE) of LDES technologies that have commercial or pre-commercial readiness on a global scale. 

For context, RTE measures the effectiveness of a storage system by measuring the ratio of energy output to energy input during a full charge-discharge cycle. Or briefly, the higher the RTE, the lower the losses and therefore higher the efficiency. 

The table above shows that a mechanical, gravity-based LDES system can provide the highest storage capacity while presenting an impressive 70–90% average RTE. 

On the other hand, a chemical power-to-gas-to-power system, which typically converts electricity to hydrogen gas and back to electricity, provides the highest storage duration of up to 1,000 hours. 

With that said, there are different storage needs and siting considerations across electrical grids. Given the diverse range of options available, suitable solutions can be found to complement renewables and aid decarbonization. 

2024 U.S. Clean Electricity Outlook

As the world urgently seeks sustainable energy solutions, the U.S. has the opportunity to lead the charge in the shift toward clean electricity.

But what kind of progress can the country expect in the upcoming year? 

To find out, we partnered with the National Public Utilities Council to visualize the projected 2024 electricity generation capacity of clean energy technologies in the U.S., using data from the U.S. Energy Information Administration (EIA). 

The Rise of Battery Storage and Solar Power

Looking ahead to 2024, U.S. generation capacity projections unveil a promising trajectory for battery storage and solar power. Battery storage is projected to grow by 82% compared to 2023 estimates, while solar is projected to grow by 40%.

Wind power is also growing, albeit at a slower rate (5%) due to higher costs and permitting challenges, especially for offshore projects. 

As illustrated in the table above, the EIA projects a modest year for the rest of the major clean electricity sources in the nation, with nuclear expected to eke out a lackluster 1% growth, while hydro and geothermal remain unchanged. 

Overall, these projections underscore a diversification of the U.S. energy portfolio, with a pronounced emphasis on renewables and energy storage. The growth in battery storage capacity, specifically, underscores efforts to overcome the intermittency challenges of renewables, ultimately ensuring a reliable and emission-free power supply in the country.

The Broader U.S. Power Sector in 2024

Beyond capacity projections, let’s also take a look at some projected trends related to the broader U.S. power sector in 2024. 

• U.S. daily electricity generation is projected to grow by 3% between 2023 and 2024, reflecting an increasing demand for power in the country. 
• Renewables are set to claim an even larger slice of the U.S. electricity mix in 2024, rising from 22% in 2023 to 24%. 
• Electricity production from coal is projected to decline by 9% as the country continues its move away from this emission-intensive energy source. 
• Despite the country’s projected growth in clean electricity capacity, total U.S. energy-related emissions are projected to drop by 0.1% in 2024. 

All in all, the 2024 landscape of the U.S. power sector signifies progress with increased renewables and heightened electricity generation. However, the marginal dip in emissions emphasizes the need to ramp-up country-wide efforts to meet the goal of a net-zero future.