On a warehouse roof outside Stuttgart, a few hundred photovoltaic panels are quietly doing something the German grid was not really designed for: selling their electrons directly to the company unloading pallets one floor below. The metering, the contracts, the per-tenant billing, the regulatory paperwork that makes a landlord nervous about becoming an accidental utility, all of that runs on software from a local company called Solarize.
This is the wedge. Solarize, founded in 2015 and headquartered in Stuttgart, sells a SaaS platform for energy production, distribution, and billing inside commercial microgrids [Crunchbase]. The customer is the awkward middle of the European energy transition: the building owner who has installed solar but does not want to wholesale the power back into the grid at miserable feed-in tariffs, the utility that wants to offer on-site power-purchase agreements without building bespoke IT for every site, and the microgrid operator juggling generation, storage, and a stack of tenants with different meters. Solarize's pitch is that an app with automation and monitoring can handle the lot, so the electricity gets sold on-site without detours [Crunchbase].
The company describes itself as a microgrid operating system, and in October 2022 it raised €4.3 million (about $4.73 million) in seed funding to keep building it out [pv magazine Deutschland, Oct 2022] [EU-Startups, Oct 2022]. That round was explicitly earmarked for scaling solar implementations on commercial rooftops across Europe [EU-Startups, Oct 2022], which is a polite way of saying: the product works, now go find more landlords.
The bet
The interesting thing about Solarize is what it is not trying to do. It is not manufacturing panels. It is not financing projects. It is not chasing residential homeowners, where customer acquisition costs eat solar installers alive. It is selling the boring connective tissue, the billing engine and tenant-facing app, that turns a rooftop array into a small revenue-generating utility. Software margins on hardware-driven decarbonization is a thesis that has worked elsewhere (think of what Auxio or GridX are attempting in adjacent corners of the German energy stack), and Solarize is one of the cleaner expressions of it on commercial real estate.
The company frames its product as helping owners "upgrade real estate to a decentralized electricity future" [PitchBook]. Strip the marketing and what remains is genuinely useful: a single piece of software that lets a building owner bill ten different tenants for ten different consumption profiles from one shared solar array, and stay on the right side of German energy law while doing it. That last part is not trivial. Germany's Mieterstrom (tenant electricity) framework is famously paperwork-heavy, and the regulatory complexity is precisely why a SaaS layer can charge for itself.
Why it could be big
The tailwinds are unusually favorable. EU member states are pushing rooftop solar mandates on new commercial construction. German industrial electricity prices remain among the highest in the OECD, which makes self-consumption the most valuable kilowatt-hour a building owner can produce. And the underlying physical asset, a commercial PV system, has collapsed in cost over the past decade while the software around it has barely moved.
Back of envelope: a mid-sized German logistics warehouse with 30,000 square meters of roof can host roughly 3 MW of PV, generating about 3 GWh per year. At a self-consumption price of €0.20/kWh versus a feed-in tariff closer to €0.08/kWh, the on-site sale is worth an extra €360,000 per year per building compared to dumping the power to the grid. If Solarize captures even 1 to 2 percent of that uplift as a SaaS fee, that is €3,600 to €7,200 per building per year in recurring revenue, on infrastructure the customer already owns. Multiply by the tens of thousands of suitable commercial roofs in the DACH region and the addressable market is not small. It is also not glamorous, which is usually a good sign.
| Round | Date | Amount | Use of funds |
|---|---|---|---|
| Seed | Oct 2022 | €4.3M (~$4.73M) | Scale commercial rooftop deployments across Europe [EU-Startups, Oct 2022] |
The team and traction
Solarize operates as Solarize Energy Solutions GmbH out of Stuttgart [Startbase], with team members including Andi Weiß listed publicly on LinkedIn [LinkedIn]. The company has been building since 2015, which means it spent roughly seven years on product and early customers before taking institutional money, an unusually patient arc for a venture-backed software business. The 2022 round was reported by both German trade press [pv magazine Deutschland, Oct 2022] and the broader European startup press [EU-Startups, Oct 2022] [TheSaaSNews], and the company is actively hiring through its careers page at solarize.de/karriere.
The honest counterfactual
The bear case is straightforward: energy management software for commercial PV is a crowded category in Europe, with incumbents and well-funded peers building adjacent products that could, in principle, extend into Mieterstrom billing. The bull answer, supported by the company's own positioning [Crunchbase] and the trade press coverage of its microgrid operating system [pv magazine Deutschland, Oct 2022], is that Solarize has spent the better part of a decade specifically on the billing-and-tenant-relationship layer that general energy management platforms tend to treat as an afterthought. In a regulatory regime as specific as Germany's, depth often beats breadth.
What to watch
The next twelve months should reveal whether Solarize can convert a respectable seed round into a Series A story. The questions are concrete: how many commercial sites are live on the platform, what is the gross retention on landlord accounts, and does the product travel cleanly into Austria, Switzerland, and the Netherlands where the regulatory shape is similar but not identical. A second round, likely in 2025 or 2026, would be the cleanest signal that the unit economics on the rooftop are translating into the unit economics of the SaaS contract.
The incumbent to beat is the local utility itself, specifically the Stadtwerke and regional players who already have billing relationships with tenants and could, if motivated, build or buy their way into on-site PPAs. Solarize's wager is that they will not move fast enough, and that landlords would rather not hand their tenant relationships to the utility anyway. If that bet holds, the boring software on the warehouse roof becomes the interesting business underneath it.