SOLAR THE WORLD GmbH & Co. KG

What SOLAR THE WORLD GmbH & Co. KG does

STW Group GmbH & Co. KG (trading as STW Group) is a Soest-based German operator that develops, constructs, and operates front-of-the-meter (FTM) battery storage systems and commercial photovoltaic (PV) systems across Germany. The company was founded in 2019, with roots in a family-office PV project business dating to 2016, and is led by managing shareholder David Holdenried. Its installed base includes 306 commercial PV systems in operation and management out of more than 1,300 PV systems developed within the group since 2019, alongside a 32-site, 5.8 MW battery storage pipeline launched in 2026.

The technical platform centers on lithium iron phosphate (LFP) battery cells in outdoor-rated containers with German-developed cybersecure control and energy management software, German-made inverters, and continuous cell-level battery management. Storage systems are integrated into Redispatch 2.0 with staffed EIV and BTR roles, and AI-supported trading algorithms execute arbitrage on EPEX Spot Day-Ahead and Intraday markets and bid into FCR and aFRR balancing energy. The systems are designed for a 20-year operating life with a 15-year performance warranty when operated with the trading software and more than 10,000 guaranteed charge cycles.

STW Group operates three commercial motions: (1) zero-capex energy supply for landowners, who lease approximately two parking spaces near a substation for 750 € per storage unit per year; (2) commercial PV for industrial, logistics, retail, and agricultural customers via purchase, free rental (Pachtmodell), or roof-rental (Dachpacht) models; and (3) flexibility services for distribution grid operators and Stadtwerke under §11b EnWG. Revenue streams combine EPEX Spot arbitrage, FCR/aFRR capacity and energy payments, fixed flexibility fees from grid operators, PV system sales and recurring electricity supply, and direct-investor or subordinated-loan financing of storage assets. Go-to-market is sales-led via direct B2B engagement and a commission-based network of independent Handelsvertreter across Germany, supported by an inbound content-marketing funnel through the company's knowledge blog and newsletter.

Name

SOLAR THE WORLD GmbH & Co. KG

Legal name

STW Group GmbH & Co. KG

Website

https://solartheworld.de

Company type

Private

Founded year

2019

Operating status

Operating

Headcount range

1–10 employees

Short description

STW Group GmbH & Co. KG develops, constructs, and operates front-of-the-meter battery storage systems and commercial photovoltaic installations across Germany, serving landowners, commercial and industrial businesses, and distribution grid operators with arbitrage trading, balancing services, and flexible PV deployment models.

Ownership category

akta.pro rank

Product category

Battery Energy Storage & Commercial Photovoltaic Services

NAICS

Battery Manufacturing (33591), Solar Electric Power Generation (221114)

SIC

Cogeneration Services & Small Power Producers (4991)

akta.pro primary industry

Battery Modules & Packs (Industrial/Commercial pack assembly) (IMAGAHAB)

akta.pro secondary industry

Battery Containerization, Enclosures & HVAC / Thermal Management Integration (EUAEAEAH)

Keywords

• Battery storage systems
• Commercial photovoltaic
• Grid balancing services
• Electricity market trading
• Rooftop solar leasing

Headquarters

HQ city

Soest

HQ country

Germany

HQ region

Europe

Offices1 record

Markets served

GTM type

B2B

Offering type

Services

Cost components

Infrastructure, Technology or R&D, Operations, Personnel, Marketing or Sales, Supply Chain

Revenue model

1. Battery Storage Electricity Trading (Arbitrage): Trading batteries earn revenue by buying electricity at low prices when wind and solar generation is high (often negative prices at midday), and selling at high prices during peak demand (evenings). This arbitrage is executed fully automatically through AI algorithms on EPEX Spot Day-Ahead and Intraday markets. 96 price windows per day since the switch to 15-minute intervals.
2. Grid Balancing Services (Regelenergie): Revenue from providing FCR (Frequency Containment Reserve) and aFRR (automatic Frequency Restoration Reserve) to transmission system operators. Batteries can respond in fractions of a second, making them ideal for these services. Paid via capacity price (for holding) and energy price (for actual delivery).
3. Flexibility Services for Distribution Grid Operators: Distribution grid operators book storage capacity for limited periods and define the operating schedule. Grid operators pay a fixed fee for the flexibility service while STW Group retains ownership and operational responsibility. Based on §11b EnWG.
4. Capacity Provision (Kapazitätsvorhaltung): Revenue from making storage capacity available and maintaining operational hours in the portfolio, independent of actual energy throughput.
5. Commercial PV Systems - Purchase Model: Commercial PV systems sold as turnkey solutions to commercial and industrial businesses. Revenue from the sale of complete PV installations including planning, grid connection, and commissioning.
6. Commercial PV - Free Rental Model (Pachtmodell): PV systems installed at no cost to the customer. Revenue generated by selling the solar electricity to the commercial customer at a price contractually guaranteed to be lower than their utility provider. After 20 years, the customer takes ownership at no additional cost.
7. Roof Rental (Dachpacht) for PV: Property owners rent out their roof space for PV installations. STW Group installs and operates the system at its own cost and risk, paying the property owner ongoing rental income.
8. Land Lease for Battery Storage: Property owners with suitable substations receive 750 € per storage unit per year for approximately two parking spaces. Revenue is paid annually in advance from commissioning date. 10-year term with two 5-year extension options.
9. Direct Investment in Battery Storage: Investors purchase trading battery storage units as assets. STW Group handles site selection, grid connection, construction, insurance, and automated market trading. Investment returns come from trading revenues minus operating costs.
10. Subordinated Loan (Nachrangdarlehen): Capital provided to STW Group for specific storage projects with fixed interest rates over agreed terms. Higher interest rates due to subordination risk compared to traditional savings products.

Pricing tiers

Go-to-market motion2 records

Distribution channels4 records

Marketing channels4 records

Core offering

STW Group develops, constructs, and operates front-of-the-meter battery storage systems (LFP chemistry, German-made) and commercial photovoltaic installations across Germany. Battery storage units are monetized through AI-driven trading on EPEX Spot (Day-Ahead/Intraday) and by providing FCR/aFRR grid balancing services under Redispatch 2.0. Commercial PV systems are delivered via three commercial models: outright purchase, free rental (PV-Pachtmodell), or roof rental (Dachpacht). Property owners without capital outlay can lease land or roof space at €750/unit/year for battery deployment.

Product overview

STW Group offers a integrated portfolio of battery storage and photovoltaic solutions for commercial and industrial applications across Germany. The core offerings consist of Trading-Batteriespeicher (front-of-the-meter battery storage trading on electricity markets) and Netzdienlicher Batteriespeicher (grid-serving storage for distribution network relief), complemented by Gewerbliche PV-Anlagen (commercial PV systems) available through purchase, leasing, or roof-pacht models. Services include Fläche verpachten (land leasing for storage deployment) and investment models. The company operates from Soest, Germany, with 306 commercial PV systems in operation and 32 battery storage locations (5.8 MW) in the pipeline.

Differentiator

Problem solved

Functional benefit

Products and services

• Trading Battery Storage (Trading-Batteriespeicher)

Quantifiable outcome

• 1,300+ PV systems developed in group since 2019
• +7 more outcomes

Segments4 records

Ideal customer profiles4 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature6 records

Scale indicators11 records

Recent moves8 records

Expansion highlights5 records

Direct peers

• Solarwatt GmbH: Dresden-based PV and battery storage provider serving residential and commercial German customers. Comparable product overlap in commercial PV leasing models and integrated storage offerings.
• Next Kraftwerke GmbH: Cologne-based virtual power plant operator aggregating distributed storage, biogas, and renewable assets to trade EPEX Spot and provide balancing energy. Direct competitor on the same German EPEX/FCR/aFRR revenue stack.
• E3/DC GmbH: German manufacturer of residential and commercial battery storage and PV-coupled systems (Hager Group). Comparable on integrated PV-plus-storage commercial offerings in Germany using LFP technology.
• Sonnen GmbH: Germany-based battery storage manufacturer and operator (now a Shell subsidiary) serving residential and commercial customers. Direct peer on LFP-based storage hardware and German data-sovereignty positioning, though focused more on behind-the-meter than STW's front-of-the-meter trading model.
• SENEC GmbH: EnBW-owned German home and commercial battery storage provider. Comparable in LFP-based storage deployment for German C&I customers and in operating storage assets under the same German regulatory and balancing-energy framework.
• Fluence Energy: Global grid-scale battery storage IPP and software provider operating utility-scale BESS projects across Europe. Closest functional peer on front-of-the-meter trading-storage arbitrage and ancillary services, though at materially larger scale.

Broad incumbents

• BYD Energy Storage: Vertically integrated battery manufacturer and storage IPP deploying C&I and grid-scale LFP systems globally. Comparable on LFP supply and European storage deployment, but at much greater scale and with direct cell manufacturing.
• Tesla Energy: Global grid-scale storage operator (Megapack) with major European projects. Larger-scale competitor in front-of-the-meter storage and AI-driven trading, but with much broader portfolio and customer base.
• Wärtsilä Energy Storage: Global grid-scale storage and balancing-energy provider active across European TSOs. Comparable on FCR/aFRR market participation and EPC delivery, but operating from a much larger industrial base.

Others

• SMA Solar Technology AG: German inverter and storage-system integrator headquartered in Kassel. Ecosystem enabler rather than direct competitor — STW specifies German-made inverters and competes in the same PV-plus-storage C&I segment that SMA serves.

Market position

Strengths4 records

Weaknesses5 records

Competitive moat4 records

Key risks6 records

Key highlights6 records

Customer concentration

• LinkedInlinkedin.com/company/solar-the-world-gmbh-&-co.-kg

Revenue estimate

Valuation estimate

Number of profiles

Profiles1 record

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about SOLAR THE WORLD GmbH & Co. KG