The Cube Pro energy storage system / Credit: BYD

BYD Energy Storage has landed a contract to supply 11.275 GWh of battery storage for Masdar’s Round the Clock (RTC) project in Abu Dhabi — one of the single largest energy storage procurements ever signed.

The RTC project pairs a 5.2 GW solar array with a 19 GWh battery system, making it the world’s largest combined solar-plus-storage plant. BYD’s award covers the majority of that storage.

The biggest solar+storage project on Earth

Masdar and the Emirates Water and Electricity Company (EWEC) are building the RTC plant to do something solar has never reliably done at gigawatt scale: deliver clean power 24 hours a day.

We first covered the project in January 2025, when Masdar announced plans for a 5.2 GW solar PV plant coupled with a 19 GWh battery energy storage system (BESS) capable of dispatching 1 GW of continuous baseload. Masdar chairman Dr. Sultan Al Jaber framed it as solving renewable energy’s oldest problem — intermittency.

According to BYD, its share of the project is a single battery station rated at 1,644 MW / 11,275 MWh, using the company’s Haohan storage system. That one station holds more energy than most countries’ entire grid-storage fleets.

Chinese suppliers now own the entire 19 GWh

Here’s the detail worth noting. When Masdar unveiled the RTC project in early 2025, it named CATL as its preferred battery supplier.

The actual contracts tell a different story. BYD secured 11.275 GWh, and Sungrow signed for the remaining 7.5 GWh in an earlier phase. Combined, the two Chinese firms have locked up the full 19 GWh — leaving no room for Western battery makers on the world’s flagship storage project.

It’s a clean illustration of how thoroughly Chinese manufacturers dominate grid-scale storage. The same LFP cell scale that made BYD and CATL the world’s largest EV battery producers is now being turned directly on the utility market.

Bigger cells, simpler systems

The Haohan system leans on BYD’s 2,710 Ah Blade Battery — a cell with more than 300% higher capacity than legacy grid-storage cells, according to the company.

The logic is straightforward: fewer, bigger cells mean fewer connections. BYD says that cuts battery management system complexity by 70% to 80% and packs 10 MWh into a standard 20-foot container. The system is rated IP66 for dust and sand and built to run from -30°C to 55°C — necessary in the Abu Dhabi desert.

BYD says the accompanying GC Master energy management system can manage up to 15 GWh in a single station.

Part of a Middle East storage surge

The Masdar deal isn’t a one-off. BYD recently landed a 12.5 GWh grid-storage contract in Saudi Arabia, and Chinese suppliers have been sweeping up Gulf storage projects as prices collapse.

The economics are moving fast. BYD is pushing sodium-ion storage toward costs as low as $0.04 per watt-hour, while CATL has pushed its Tener platform toward multi-decade durability. The competition is now over who can build the cheapest, longest-lived cells at the largest scale.

Electrek’s Take

The numbers are just insane here. BYD and CATL have a massive advantage over the energy storage competition, such as Tesla, because they produce all their battery cells and therefore own the full production process, from battery cells to packs to deployment.

It’s unsurprising to see them land the biggest contracts, even though the size of the contracts is surprising.

If you’re powering your home in a sunny climate, the RTC project is a reminder that solar-plus-storage is now the cheapest way to deliver round-the-clock clean power — at any scale. With electricity rates climbing nearly 10% last year, home solar protects you against future rate increases. And with lease and PPA options, you can go solar with zero upfront cost and start saving immediately. If you want to find the best deal, check out EnergySage. It’s a free service with hundreds of pre-vetted installers competing for your business, so you save 20 to 30% compared to going it alone. No sales calls until you pick an installer. Get your free quotes here.