(Updated April 2026) Today, a commercial photovoltaic system alone is no longer sufficient to meet the requirements for economic viability, grid integration, CO₂ reduction, and energy efficiency. The Combination of PV and Battery Storage (BESS – Battery Energy Storage System) has long since become the norm—not only for large industrial plants, but also for companies with moderate energy needs.
In this post, we'll show you why PV + BESS is the modern standard duo, which BTM and FTM applications optimize solar power plants, and how companies can maximize their benefits from solar energy.
Why PV alone is no longer enough today
A solar system without BESS has clear limitations:
- Daytime PV power surplus → cheap feed-in or unused.
- High grid electricity consumption in the evening/at night leads to expensive electricity bills.
- Peak loads result in high grid fees (accounting for up to 25–50% of costs).
BESS solves this: It stores solar power during the day, supplies it when needed, reduces peak loads, and optimizes rates.
What are the benefits of a battery storage system for a company's PV installation?
A BESS (Battery Energy Storage System) is now the heart of modern commercial solar systems. It stores electrical energy and releases it when needed. This is essential in trade and industry in order to:
- Storing surplus solar power and using it yourself later.Increase in PV self-consumption)
- To cap peak loads (Peak Shaving).
- To optimize electricity consumptionLoad shifting to the atypical network use).
- to ensure a backup power supply (USV unit)
- Network and Market IntegrationControl energy and Power trading)
BESS solutions are considered Container Systems, Modular Plants or integrated large-scale systems deployed and are scalable.
BTM vs. FTM: When does a battery storage system with a solar array come into play?
FTM (Front-of-the-Meter) and BTM (Behind-the-Meter) are the central application areas of BESS. If the battery storage is coupled with a solar system, the BTM use cases usually come into play to further reduce electricity costs.
Classic BTM Usage of BESS for Cost Reduction
- Application of BESS in your own company network
- Self-consumption optimizationStore solar power, use later.
- Peak Shaving: Reduce peak loads, save grid fees.
- Load Shifting: Shift consumption to favorable times.
This approach is used in approximately 90% of all combinations of solar systems with battery storage. However, FTM applications are also possible.
FTM applications of BESS for additional revenue
BESS in combination with solar systems connected to the public grid are considered Co-location Gray current storage. You can also use FTM applications:
- Arbitrage in the electricity market: Buy low, sell high
- Ancillary Services Deployment (FCR, aFRR, mFRR)
However, only BESS with a certain performance and capacity can participate. For ancillary services, 1 MW / 2 MWh applies, and for electricity trading, at least similar values are recommended.
Hybrid Models: Maximum Benefit Through Solar System with Battery Storage
The combination of FTM + BTM ensures maximum yields from a BESS with an attached solar system in the commercial sector. Prerequisites include a sophisticated measurement concept and an intelligent energy management system (EMS), as well as individually optimized BESS dimensioning.
- Value Stacking: BTM (Self-consumption) + FTM (Market).
- Intelligent EMS control prioritizes applications based on market, tariff, and demand.
What are the prerequisites for an economical PV+BESS solution?
For a combination of a solar system and battery storage to reach its full potential, several prerequisites must be met:
1. Appropriately sizing PV and BESS
- A photovoltaic system should not be planned in isolation.
- Storage capacity must be adapted to the load profile and PV generation.
- Goal: High self-consumption + maximum flexibility
Typical error: memory too small (no effect) or too large (uneconomical)
2. Detailed load profile analysis
- Consumption data updated every 15 minutes is required
- Identification of:
- Load peaks
- Consumption patterns
- Flexibility potentials
Without load-flow analysis, no valid economic feasibility assessment is possible.
3. Smart Energy Management System (EMS)
- Control of PV, BESS, and Consumption
- Prioritization of applications (e.g., self-consumption vs. market)
- Basis for Value Stacking
The EMS decides the economic success of the entire plant
4. Network Integration & Regulatory Assessment
The capacity at the grid connection point and the power output of the BESS are critical. In addition, the following must be checked:
- What are the grid fees?
- What peak and off-peak time windows are contractually agreed upon?
- Does Section 19 of the StromNEV apply to atypical grid usage?
- Is market participation possible?
A battery storage system is particularly worthwhile for a solar system when: * **Your electricity consumption doesn't perfectly align with your solar production:** This is the most common reason. If you use a lot of electricity when the sun isn't shining (e.g., in the morning, evening, or at night), a battery allows you to store the excess solar energy generated during the day and use it later. * **You want to maximize self-consumption:** By storing your own solar power, you reduce your reliance on grid electricity, leading to lower electricity bills. * **Electricity prices have a significant daily fluctuation:** If the price of electricity from the grid is much higher in the evening/night than during the day, storing your own solar power becomes very attractive economically. * **You want to increase your energy independence:** A battery storage system makes you less dependent on the utility company and potential future price increases. * **There are government incentives or subsidies:** In some regions, there are financial incentives that make the purchase and installation of battery storage systems more affordable. * **You have a high electricity demand:** If you have high energy needs, a battery can help manage those peaks and ensure you have power when you need it, especially if you're also considering electric vehicles or heat pumps. * **You want to ensure a stable power supply (especially in areas with unreliable grids):** A battery can act as a backup power source during grid outages. * **You have a large solar installation:** If your solar system generates significantly more electricity than you can consume or feed back into the grid, a battery becomes an efficient way to utilize that surplus.
A BESS is particularly economical when:
- high Load peaks available
- Electricity prices fluctuate strongly
- a high PV surplus arises
- Free capacities are available at the grid connection or an overhead construction is possible
- there are multiple locations or large consumers
- Flexibility in energy use is possible
When is a battery storage system (BESS) not a worthwhile addition?
An additional battery storage system for a solar installation is less sensible when:
- very constant load profile without peaks
- low power consumption
- missing PV system or low surplus
- already exhausted capacities at the grid connection
- lack of market integration possibility
In such cases, the photovoltaic system usually takes center stage.
What common mistakes should companies avoid?
- Planning PV and storage separately leads to inefficient systems
- Focusing on only one or two BTM applications → market potentials remain unused
- Failing to consider future regulatory effects leads to missed opportunities for savings on grid fees.
- No efficient EMS or wrong tax strategy → economic added value is not realized
How is the market for solar power and battery storage evolving?
The combination of PV and BESS will continue to become the standard:
- Rising electricity prices increase economic viability
- Falling battery costs improve ROI
- Increasing volatility in the electricity market is creating new revenue opportunities
- Regulatory adjustments promote flexibility
Companies without storage are increasingly losing their economic advantages.
Conclusion: PV without storage is no longer state-of-the-art
In many cases today, a commercial solar power system alone is no longer sufficient to operate at peak efficiency. Only when combined with a battery storage system does a flexible, economically optimized energy system:
- Higher self-consumption rates
- lower electricity costs
- additional revenue streams
- better grid integration
PV + BESS is therefore not a „nice-to-have,“ but the new standard for companies.
Frequently Asked Questions
Why is BESS essential for PV?
BESS stores excess PV electricity, smooths load peaks, reduces grid fees, and enables market integration. Additionally, it offers regulatory security and flexibility, as well as significant savings potentials and revenue opportunities.
What is FTM vs. BTM?
These are application areas of a BESS. FTM can achieve additional profits and BTM reduces electricity costs.
Which BESS technology is recommended?
Lithium-ion for high power density and cycle life. Flow batteries for long runtimes. An overview of cell technologies is in the report. LFP Cells Compared.
How is BESS financed?
Purchase, Contracting, Leasing. Subsidies are also possible (Innovation tenderswhich reduce CAPEX.