BESS supplier bankability: CATL to AAA, Wärtsilä to BB

Antony TopunovCo-founder, SOLTECH

Solar Media's Q2 bankability update lifts CATL to AAA and cuts Wärtsilä to BB. The top five BESS suppliers hold about 39% of shipments. What it means.

BESS supplier bankability has been reshuffled. In its Q2 2026 update, published on 9 September, Solar Media Market Research upgraded CATL to AAA on the strength of its energy storage revenue growth and downgraded Wärtsilä from BBB to BB on persistently low storage orders. The scale runs from AAA to C and measures company risk, not product performance.

What changed in the Q2 2026 ratings

Cell prices reversed, and the ratings followed

The single change driving this update is that battery costs stopped going down. Lithium carbonate prices climbed in the second quarter of 2026 and LFP cell prices followed, reversing the steady decline of the preceding years. That turned vertical integration from a nice-to-have into a balance-sheet advantage: a supplier that makes its own cells absorbs the input cost swing, while a pure integrator has to pass it on or eat it.

The pressure is compounding from a second direction. Chinese cell makers began raising list prices from 1 September 2026, when a 2% consumption tax on lithium-ion batteries took effect - CATL, for one, lifted its 314Ah storage cell from RMB 0.414/Wh to RMB 0.423/Wh. Anyone still budgeting a battery on 2024 or 2025 price curves is working from a stale number.

Where the growth is going

Chinese suppliers are pushing outward. Overseas revenue rose an average of 51% in the first half of 2026 and gained three percentage points as a share of total revenue, as domestic margin pressure made export markets more attractive. RelyEZ is a clean illustration: over 95% of its 2024 and 2025 shipment volume went to domestic sites, and in 2026 it delivered into Poland and Hungary.

The new demand is arriving in places that were not on the map two years ago. Romania approved a EUR 150 million (US$174 million) support scheme, Bulgaria's RESTORE programme backs more than 4 GWh of battery storage projects, Argentina has been running storage tenders since 2025 and Brazil holds its first battery storage auction this year. India commissioned its largest BESS to date, at 3.37 GWh, and has proposed mandatory co-location for new solar and wind.

At the top the market is not fragmenting. The combined share of the five largest suppliers was around 39%, barely moved from 40% a year earlier, while the mid-tier stays crowded and price-driven. Meanwhile more than RMB 120 billion of new Chinese battery manufacturing projects were announced in the first half of 2026 alone - capacity being added into a market that is already competing hard on margin.

The SOLTECH view

Storage is no longer an optional line in Gulf procurement. Abu Dhabi's round-the-clock project pairs 5.2 GW of solar with 19 GWh of batteries, Saudi Arabia has signed 8 GWh of storage contracts, and rooftop-scale storage is starting to appear in C&I tenders. That makes supplier selection a fifteen-to-twenty-year credit decision, and this report is a useful input to it. It is also frequently misused, so three cautions.

For a villa owner in the UAE: none of this argues for buying a home battery yet. Under Shams Dubai net metering the grid already acts as your store at no capital cost, and we have written before about how DEWA tariffs shape that maths. A battery earns its place when you have genuine outage exposure, a load profile the grid cannot absorb, or an off-grid site - not because the storage market is booming. If someone quotes you one anyway, ask which entity signs the performance guarantee and what happens to it if that entity is sold.

For EPC contractors: the useful discipline is separating the cell rating from the integrator rating. A AAA cell maker inside a container assembled and warranted by a thinly capitalised integrator gives you a AAA sticker and an unrated obligation. Get cell-level traceability, the integrator's own financials, and a warranty that names a legal entity you could actually pursue. The Wärtsilä downgrade is the case in point: the corporate parent is large and solvent, and the ESS obligations have been moved into a joint venture expected to lose money this year.

For investors: we would not lean on a single ratings agency, and we say that about this report as much as any other. It is a model with disclosed inputs - financial health, manufacturing, shipments - and its Q2 methodology change explicitly rewarded companies that own cell plants, which mechanically favours CATL and its Chinese peers. That may well be the right call given where input costs went. It is still a judgement, not a measurement. Read it alongside the supplier's own filings and your own site data before it sets your procurement shortlist. Our approach to underwriting is set out on the investor page, and our equipment position on products.

Related reading: China's battery consumption tax and rising cell prices, Saudi Arabia's first 2 GW / 8 GWh storage deals, and storage for commercial and industrial sites.

Sources

• Energy-Storage.News - CATL upgraded to AAA, Wärtsilä downgraded to BB in Bankability Report Q2 update, 9 September 2026
• Solar Media Market Research - Battery StorageTech Bankability Ratings Report
• Energy-Storage.News - CATL, EVE Energy lead Chinese manufacturers' battery storage cell price hikes, 9 September 2026
• Energy-Storage.News - China's half-year energy storage deployments post first-ever decline, 4 September 2026