FAQ
Your questions, our answers.
BESS, peak shaving, aFRR / mFRR, spot arbitrage, 5,000-cycle warranty, ROI — answers to every question businesses ask when considering stationary storage.
FAQ
General
A second-life battery comes from an electric vehicle. While it no longer meets the demanding requirements of automotive traction (range), it still holds 80 to 90 % of its initial capacity — which is ideal for stationary storage. Reusing an EV battery cuts the embodied carbon footprint by a factor of four versus a brand-new battery, while also generating significant savings on the upfront investment.
On a typical professional site, our customers see a 30 to 60 % reduction in their electricity bill. This comes from maximising solar self-consumption (up to 90 % valorised), peak shaving, time-of-use shifting, spot-market arbitrage, participation in aFRR/mFRR grid services, etc. Typical payback (ROI) is 4 to 7 years, depending on the site profile.
Yes. Our stationary storage solutions are technology-agnostic and integrate via AC coupling on existing or new solar installations. They are also compatible with EV charging infrastructure (EVCI) and back-up generators.
Typical lead time is 8 to 14 weeks. The turnkey process includes the technical & economic study, custom manufacturing in our workshop, on-site installation, grid connection, and commissioning with Consuel compliance.
FAQ
Solution & use cases
A BESS is a battery energy storage system that captures electricity (from solar or the grid) and releases it at the most valuable moment. For a business, it maximises self-consumption, reduces subscribed power via peak shaving, and generates revenue on the energy markets.
The TURPE (the French regulated tariff for public electricity networks) is partly driven by your subscribed power. Peak shaving uses the battery to absorb the site's consumption peaks. By smoothing those peaks, you can lower the subscribed power and remove overshoot penalties, durably reducing your bill.
RTE remunerates owners of storage solutions that make their capacity available to stabilise grid frequency. aFRR (automatic Frequency Restoration Reserve, secondary reserve) and mFRR (manual Frequency Restoration Reserve, tertiary reserve) are flexibility mechanisms that generate complementary passive income. The valorisation depends on volumes offered and on the clearing prices set by RTE's reserve markets.
Off-peak/peak shifting exploits fixed tariffs (night vs. day). Spot-market arbitrage on EPEX day-ahead is more dynamic: you charge the battery when prices are low (e.g. strong wind or solar generation on the grid) and discharge when prices spike.
Yes — our BESS units include a backup function with Blackstart mode. On grid fault, the system transfers in under 20 milliseconds to supply your critical loads (servers, cold rooms, industrial processes). Blackstart mode can also restart a fully islanded site with no human intervention.
An undersized system will not cover your needs; an oversized one weighs on profitability. We analyse your 10-minute load curves to design the unit that maximises cumulative gains across the six optimisation levers. Across our projects we observe a typical ROI between 4 and 7 years — every site is a specific case, this is not a contractual guarantee.
FAQ
Expertise & product
We source modules from European automotive manufacturers. Each battery undergoes a double diagnostic — first at our suppliers, then in our workshop — following a protocol validated by the independent VDE laboratory. We precisely measure the SoH (State of Health), voltage balancing, and internal resistance to retain only the modules certified as fit.
Battwoo is a French cleantech headquartered in Paris. Manufacturing and integration of our stationary cabinets take place at our workshop in Spain. This European footprint lets us control the full value chain — from module sourcing to on-site delivery — and remain highly responsive.
Safety is at the core of our engineering. Our systems carry the CE marking, comply with REGULATION (EU) 2023/1542 and are validated by the independent VDE laboratory. Each unit is fitted with a custom-configured Battwoo BMS plus fire detection and suppression — included as standard.
We contractually warrant 5,000 cycles — 15 to 30 years of service depending on your usage profile. Stationary use is far less demanding than automotive (lower discharge currents, steadier cycles): by keeping every cell inside a strict Safe Operating Area (SOA) via our control software, we stay well below accelerated-degradation thresholds.
After the warranted cycles, the battery does not stop abruptly: it enters a phase of degraded but still usable capacity for less demanding applications. We then route customers to the certified European recycling chain, which recovers up to 95 % of critical materials (lithium, cobalt, nickel) to make new cells. Battwoo keeps full traceability on every module, from purchase to end of life.
Interested?
Personalised technical and economic study in under 7 days.
Custom battery sizing to maximise gains based on your consumption profile. Free and no-obligation.
Reply within 48 business hours — Confidential