Tesla & BYD: Why are EV Manufacturers Making Solar Storage?
Solar photovoltaic (PV) and wind have constituted the majority of new global power capacity for several years according to the United Nations 2025 Energy Transition Report.
“Despite this, renewable energy is not replacing fossil fuels in energy systems at the pace and scale needed,” the report says.
Some EV manufacturers are making batteries and energy storage to be used outside vehicles, aiming to support the grid during the energy transition.
“The electricity and transport sectors are two key pillars for bringing down emissions quickly enough to meet the targets agreed at COP28 and keep open the possibility of limiting global warming to 1.5 °C,” said IEA Executive Director Fatih Birol on the release of the 2024 Batteries and Secure Energy Transitions report.
“Batteries will provide the foundations in both areas, playing an invaluable role in scaling up renewables and electrifying transport while delivering secure and sustainable energy for businesses and households.
“The combination of solar PV and batteries is today competitive with new coal plants in India. And just in the next few years, it will be cheaper than new coal in China and gas-fired power in the United States. Batteries are changing the game before our eyes.”
Costs and growth of solar and storage
In 2025 there was just 2 GW of battery storage capacity installed, but by 2023 this grew to 89 GW – an increase of 4,350%, the UN report says.
The global average cost of electricity generation for utility-scale solar PV decreased by 68% over the same period.
In 2024, 91% of new renewable projects offered cheaper electricity than the lowest-cost, new-build fossil fuel alternative.
The cost of battery energy storage systems for grid applications also fell by 93%, supported by an abundance of renewable energy technology manufacturing capacity in China.
Tesla’s solar energy storage
While primarily known for its EVs, Tesla entered the solar installation market in 2016 with its acquisition of SolarCity.
The company offers solar panels, the Tesla Solar Roof and the Tesla Solar Inverter.
Complementary to these are Tesla’s energy storage solutions, including the Powerwall and Megapack.
Megapack, a utility-scale battery, launched in 2019 and has surpassed 10 GWh in installations.
The Powerwall is designed for homes, enabling solar electricity storage for self-consumption, demand shifting and backup power.
Batteries and solar from BYD
Like Tesla, EV manufacturer BYD looks to cover energy and storage as a whole beyond mobility.
It produces solar panels for both commercial and industrial situations alongside residential rooftop solar.
Electricity can then be stored in a BYD battery, such as the residential Battery-Box HVE.
BYD Energy Storage and Saudi Electricity Company signed a deal in February 2025 for the world’s largest grid-scale battery storage projects of 12.5 GWh.
BYD described the signing as “a solid and crucial step forward in their collaboration in the renewable energy sector, injecting strong momentum into the development of Saudi Arabia's renewable energy industry”.
CATL’s energy storage solutions
Chinese battery manufacturer CATL was founded in 2011 and is the biggest EV and energy storage battery manufacturer in the world.
Alongside EV batteries, the company produces large-scale, stationary energy storage systems designed to support renewable energy integration, power grid stability, power transmission and distribution and power consumption management.
For example, CATL's EnerOne is a modular outdoor liquid-cooling battery energy storage system with high energy density, and a compact footprint.
The TENER energy storage system features high-energy-density cells with zero capacity degradation for the first five years.
