Towards a 100% renewable electricity system: The dawn of megabatteries

The examination of sediments at the Dhra' site in Jordan in 2009 uncovered barley hulls, initially unremarkable. Yet, the carbon-14 dating of a charred beam within the same ruins established a definitive date of 9913 BC, with a margin of error of 59 years. This discovery signified the earliest known granary of mankind, evidencing storage structures for sustenance a millennium before the domestication of cereals, setting the stage for agricultural societies and the onset of civilizations.

Today, the challenge is not so much about taming nature as it is about protecting it and moving towards a more sustainable world. However, we do share something in common with those distant Neolithic ancestors: the need to manage valuable resources to ensure our future as a species. And one of the most critical resources of our era is renewable energy.

Transitioning to a low-carbon economy by 2050 entails adopting an almost entirely renewable electricity system, a critical albeit insufficient step for achieving climate neutrality and averting severe global warming impacts.

Energy storage technology plays a pivotal role in this transition, designed to conserve energy when excess is available and deploy it when needed to ensure supply stability and maintain essential grid parameters like voltage and frequency, preventing blackouts or other disturbances when wind or sunlight are insufficient.

At ACCIONA, our longstanding commitment to clean energy production is now advancing towards closing the sustainability loop. This article delves into one of the most potent tools for this purpose and a landmark project in its application.

The dawn of megabatteries

Achieving 100% renewable energy transcends merely replacing coal and gas with wind and solar farms; it necessitates reconfiguring the electricity system to accommodate a vast influx of clean, albeit variable, energy sources. Wind and solar energy's reliability, unmarred by international conflicts or supply crises, relies on weather conditions, which naturally do not guarantee constant availability. Thus, the focus intensifies on energy storage solutions.

Among various technologies, pumped-storage hydroelectric power plants are prevalent, leveraging off-peak electricity to elevate water for later energy generation. This article, however, centers on a nascent yet rapidly expanding technology: large stationary batteries (BESS, Battery Energy Storage System) connected to the grid, capable of alternately consuming or supplying energy based on systemic demands.

Forecasting by S&P Global indicates a 57% surge in grid-connected battery storage capacity to 40 gigawatts (GW) in 2024, with projections of reaching around 70 GW by 2030. Bloomberg NEF's outlook suggests an even more dramatic escalation, anticipating global energy storage installations to ascend to 1,091 GW/2,850 GWh by 2040, a monumental leap from 9 GW/17 GWh in 2018.

What are megabatteries for?

Electricity storage is pivotal for integrating variable renewable energies like wind and solar into the grid, given their aptitude for rapid energy absorption from the grid, subsequent storage, and re-injection.

Modern megabatteries connected to the electricity system offer multifaceted services and functionalities, enhancing grid efficiency and economic viability. Highlighted below are six key functionalities facilitating the extensive integration of renewable energies into electricity systems [Source: Electricity Storage Valuation Framework, IRENA, 2020].

Beyond these six key functions, megabatteries prove invaluable in various other scenarios, including off-grid locations, islands, or small networks, ensuring reliable system management without reliance on fossil fuel-based solutions.

The largest battery in Texas

ACCIONA Energía recent acquisition of the largest battery in Texas, alongside a portfolio of six developmental projects totaling 1.23 gigawatts—a capacity akin to a mid-sized nuclear plant—exemplifies the vast potential of large battery technology for grid services.

The Cunningham project, situated 21 miles from Dallas and operational since July 2023, stands as the largest grid-connected battery in Texas, boasting a 190 MW capacity and 380 MWh energy storage across approximately six hectares. The anticipated commissioning of the remaining projects over the next three years aims to fulfill the ambitious global forecasts outlined earlier, marking significant strides towards a renewable energy future.