PV and BESS Operator Models: Overview for Commercial & Industrial

Brief overview:

• For PV systems, companies essentially have two options: Purchase/Direct operation (full control, full investment risk) or Contracting/PPA (no equity investment, electricity is purchased at a fixed price)
• The same basic logic applies to battery storage systems, supplemented by a third model: Purchase, Contracting or CPFS (combined amortization via grid connection and flexibility revenues)
• From 100 kWp of PV capacity, the direct marketing obligation applies; in the case of BESS, the chosen model determines who bears the revenues from flexibility marketing
• When PV and BESS are implemented together, combined models such as CPFS open up, which amortize the investment costs of both assets jointly.

Choice of operator model as a strategic decision

The decision regarding an operating model is one of the most important strategic milestones for a PV or BESS project. It determines who invests, who bears the technical and financial responsibility, and how the project impacts the balance sheet.

For companies considering both technologies, there is an additional layer: PV systems and battery storage can be operated independently of one another – or financed together via combined models such as CPFS, which can noticeably shorten the payback period of the entire project. Against the backdrop of the 2027 EEG reform and the associated shifts in remuneration rates and market obligations, choosing the right model is becoming increasingly complex – but also more economically relevant.

This article provides a structured overview of the most common PV and BESS operator models for commercial and industrial applications, outlines their respective advantages and disadvantages, and assesses when which model – or a combination thereof – is most worthwhile.

PV Operator Models

Purchase/Direct operation

In the case of a purchase or direct operation, the company itself invests in the PV system and assumes all areas of responsibility. This includes planning, financing, construction, grid connection, operation, and maintenance—all under the operator’s sole responsibility. If a turnkey solar system is purchased from CUBE, these time-consuming key areas are eliminated. In return, the operator retains the full control regarding revenue and electricity consumption—and bears the entire financial and technical risk itself.

Within direct operation, there are two basic approaches, which are determined by the company's actual electricity needs:

Self-Sufficiency with Surplus Power Feed-In

For most commercial and industrial facilities, this is the most economically viable option. Since purchasing electricity from the public grid is usually significantly more expensive than the feed-in tariff, every kilowatt-hour generated and consumed directly reduces energy costs immediately. Added to this is an often underestimated effect: On self-generated and locally consumed solar power, no grid fees and no electricity tax For energy-intensive businesses with a high proportion of fixed costs in their electricity bill, this has a noticeable impact on calculation certainty.

Full Feed-in – No Longer as Attractive

With full feed-in, all of the electricity generated is fed into the grid at the rates specified in the EEG. Due to the declining market values for solar power however, this model has noticeably in recent years lost some of its economic appeal – especially for small and medium-sized rooftop systems in a commercial context, the sole route via the statutory feed-in tariff is often no longer worthwhile.

If a company has large roof areas with low internal demand, other approaches are therefore often more economical in practice than the traditional full feed-in:

• Direct Wiring to Neighboring Companies: The operator sells the surplus electricity directly to nearby businesses—without routing it through the public grid. This model generally yields higher prices than the full feed-in tariff, since there is no direct marketer involved and the electricity is usually cheaper for the customer than the regular grid supply.
• Marketing via the balancing group: Alternatively, the surplus electricity is resold to a customer through a balancing group. In this case, the operator tends to generate higher revenues than with pure full feed-in. Prices are freely negotiable rather than fixed by law.

Full feed-in, however, remains a relevant option for large open-space systems, especially when no off-taker is available in the immediate vicinity or the amount of electricity generated significantly exceeds local demand. In practice, however, an off-site PPA is often the more economically attractive route for projects of this size.

Mandatory direct marketing from 100 kWp

The statutory direct marketing requirement applies to systems with an installed capacity of 100 kWp or more. Under this requirement, the solar power fed into the grid is no longer sold at a fixed feed-in tariff but is instead sold on the electricity exchange through a direct marketer. The revenue consists of the market value achieved and a market premium that compensates for the difference between that value and the statutory reference value. PV electricity consumed on-site is exempt from this requirement—so it applies only to the portion fed into the grid.

In addition, for systems of 100 kWp or more, there is a technical requirement for remote control under Section 9 of the EEG: The grid operator must be able to remotely control and curtail the system in the event of an impending grid overload, which requires appropriate telecontrol technology (e.g.,. EZA Rules) is required.

Note: The direct sales requirement itself will not fundamentally change as a result of the 2027 EEG reform. However, the new CfD model will replace the existing EEG subsidies and feed-in tariffs. For more on this, see the article on EEG 2027 and Grid Package.

PV-Contracting (PPA)

In a Contracting arrangement, it is not the company itself but an energy service provider (contractor) that invests in the PV system. The contractor handles all aspects of financing, construction, operation, and maintenance—the company simply provides the roof space and purchases the electricity generated on-site at a contractually fixed price. The key advantage: There are no upfront investments, and the technical and financial operational risks are borne by the contractor.

CUBE Contracting is known as Power Purchase Agreement (PPA) structured—a long-term electricity supply agreement between the plant operator and the customer. Depending on the plant’s location relative to the consumer, a distinction is made between two basic forms:

On-Site PPA

The PV system will be installed directly on the company's premises, for example on the hall roof. Since generation and consumption take place at the same location, grid fees and electricity tax are eliminated—an immediate cost advantage compared to drawing electricity from the grid. Surpluses exceeding self-consumption are fed into the public grid. If the solar power is insufficient during peak times, the existing residual electricity contract automatically takes over.

Off-Site PPA

Generation plant and consumer are located at different sites – for example, when a company has no suitable land of its own, but still wants to benefit from green electricity at a fixed price. The allocation is done balance-wise via balance groups; physically, the electricity continues to flow via the regular grid, which is why grid fees apply here. Since no physical delivery takes place, the transmission of Guarantees of Origin (GoO) a central role in the sustainability balance of the customer.

NoteHere you will find a more detailed description of Designing off-site PPAs.

Which PPA variant a company chooses depends primarily on the available space and its own load profile: If the roof area is sufficient for self-consumption, on-site is usually the more economical choice. If suitable areas are lacking or a large-scale project such as a solar park is to be marketed, off-site moves into focus – as shown in the previous section using the example of the solar park in southern Germany.

Excursion: Joint Building Supply (GGV) & Tenant Electricity

In addition to purchase/direct operation and Contracting/PPA, there are two other PV operating models that are particularly relevant in multi-party scenarios—such as commercial properties with multiple tenants or mixed-use properties.

Communal building supply

The one with the Solar package I The GGV, introduced in May 2024, makes it possible to distribute locally generated solar power directly to multiple parties in the same building without routing it through the public grid. If on-site generation is not sufficient, the remaining demand is automatically covered by the individual tenants' existing residual electricity contracts—unlike the tenant electricity model (Mieterstrommodell), there is no full-supply obligation for the operator.

Tenant electricity

Under the tenant electricity model, the system operator receives a government tenant electricity surcharge in addition to the electricity sales revenue. In return, they must ensure a full supply of electricity to the participating tenants—even when the PV system is not currently generating power. This higher administrative and technical effort makes the model particularly attractive for larger residential or commercial complexes with many parties.

For the classic commercial or industrial single user, both models are generally not the first choice, as they are tailored to multi-party configurations. However, as soon as multiple tenants or units are to be supplied on a property or in a building, a closer look is worthwhile.

A detailed classification of actors, contract components, and allocation keys can be found in our expert articles on collective building supply and to Tenant electricity model.

BESS operator models

The same logic generally applies to battery storage systems as to PV. Here, too, the basic models to choose from are “Purchase” and “Contracting.” In addition, however, a third, combined model—CPFS—has become established for BESS, which is specifically tailored to the economic characteristics of storage projects.

Purchase/In-house operation

When purchasing, the company invests in the battery storage system itself and operates it under its own responsibility. As with direct PV operation, this means: full control over the system and all generated revenue – but in return, also full capital commitment as well as the technical and economic operational risk.

For the economic viability of a self-operated storage system, how the operator uses the system is crucial: purely behind-the-meter (BTM) for self-consumption optimization and peak shaving, or additionally in the electricity market for the active marketing of flexibility (front-of-the-meter, FTM). Anyone who decides on self-operation and wants to tap into FTM revenues generally needs a flexibility aggregator.

Since companies bear the full risk when making a purchase, a reliable revenue forecast is important—especially for debt-financed projects and particularly in conjunction with the chosen marketing model.

Contracting

For the BESS-Contracting project, CUBE CONCEPTS, as the contractor, is responsible for the investment, operation, and marketing of the storage facility. The company provides the site and the grid connection point and receives a contractually agreed share of the revenue. This is done without any investment on the company’s part and without any technical operational risk.

This model is particularly suitable for companies that want to benefit from the economic advantages of a storage system without tying up capital or building their own expertise in storage operation and flexibility marketing.

CPFS (CUBE Profit Flex Solution®)

CPFS is a model developed by CUBE CONCEPTS that is specifically designed to amortize the grid connection. The core idea: The revenues from the flexibility marketing of the storage system are used specifically for refinancing. This improves the economic attractiveness of the overall project – especially in the case of scarce or capacity-limited grid connections.

Unlike the traditional Contracting model, CPFS focuses on a combination of grid connection amortization and Flex revenue. For companies, this means they benefit from the revenue starting on the very first day of operation without having to make any investments themselves.

The Revenue Level: Flexibility Trading

Regardless of whether a storage system is purchased, operated under the Contracting model, or via CPFS: As soon as the system is FTM-capable and actively participates in the electricity market, it needs a partner to market this flexibility. This revenue stream is not a standalone operating model, but rather a marketing layer that is structured differently depending on the chosen model—in the case of self-operation, the company selects and commissions the marketer, while for Contracting and CPFS, CUBE CONCEPTS handles this as part of its partner collaborations.

You can learn in detail how flexibility marketing works, what contract models (profit-share, floor-price) exist, and what to look for when choosing a partner in our article on Flexibility trading for BESS operators.

Combined PV+BESS operator models

With Co-Location BESS (Battery storage in combination with a PV system), both assets can generally be operated independently of each other. Strategically, however, it often makes more sense to operate them as an overall project to be considered. As soon as both assets use the same grid connection, the revenue strategy must be coordinated.

Co-Location as an economic booster

A grid connection with sufficient capacity is often the limiting and most costly factor of a project – regardless of whether it is used for PV, BESS, or both. When combined, the PV system and storage share this infrastructure. On-site power generation and flexibility revenues complement each other, resulting in significantly shorter payback periods overall.

In addition, there are further operational benefits. For example, a storage system absorbs PV generation peaks and feeds them back into the grid with a time delay. This increases self-consumption and relieves the grid connection. For systems with feed-in limitations or restricted grid connection capacity, this creates additional financial headroom. With peak shaving, the storage system pursues the exact opposite approach: it reduces peak load demand, thus ensuring lower grid fees.  

PV operator models ≠ combined operator models

If you plan both PV and BESS from a single provider, you benefit from a coordinated design of both assets. This starts with sizing, extends to grid connection planning, and goes all the way to the marketing strategy. Providers that focus exclusively on PV operator models naturally cannot capture these synergies, as the combination with a storage system is outside their range of services.

For companies, this means that anyone considering both PV and BESS for the future should not make the decision for an operator model separately for each asset, but rather check from the outset whether a combined solution makes more economic sense.

Comprehensive comparison table of operator models

Which operating models are suitable for your company?

• Companies with high equity and an interest in full ownership: acquisition/direct operation – for both PV and BESS, provided capacities for operation and marketing are available
• Companies without an investment budget, focused on cost reduction: PV-Contracting/PPA or BESS-Contracting—no capital outlay, predictable revenues or costs
• Companies with limited grid connection capacity for storage: BESS-CPFS – Amortization via flexibility revenues also makes storage projects with tight grid connections economically viable
• Companies planning to install PV and BESS together at the same location: PV and BESS can be implemented at the same grid connection point—the storage system can be financed through CPFS, while the PV system is financed separately through purchase or Contracting; a joint technical design from a single source still makes sense
• Commercial real estate with multiple tenants: Evaluate GGV or tenant electricity as special models

Frequently Asked Questions