Solar Peak Act: What Investors in PV Systems Need to Know Now

Excerpt

As of February 25, 2025, stricter requirements apply to new photovoltaic systems in Germany: As soon as the price on the electricity exchange turns negative, the feed-in tariff is discontinued—immediately, with no waiting period. With the entry into force of this amendment to the Renewable Energy Sources Act (EEG) and the Energy Industry Act (EnWG), lawmakers are responding to a trend that is clearly evident in the figures: In 2023, there were 301 hours with negative electricity prices; in 2024, this figure rose to 457 hours; and in 2025, it reached a total of 573 hours. For investors in PV systems, this is not just an abstract market statistic—it is a structural factor that directly influences the cost calculations for ongoing and planned projects.

This article explains exactly what the Solar Peak Act entails: which systems it affects, how the new compensation mechanism works, and why existing systems will continue to operate under different conditions. For a broader overview of the electricity market context and the causes of negative prices, see our guide to negative electricity prices and photovoltaics.

• TLDR

  The Solar Peak Act (in effect since February 2025) eliminates the previous 3-hour buffer rule: New PV systems with a capacity of 2 kWp or more will immediately—starting from the first quarter-hour of negative electricity prices—no longer receive EEG feed-in tariffs. At the same time, Section 51a of the EEG introduces a compensation mechanism that makes up for lost payments at the end of the 20-year subsidy period on a monthly basis—with a halving factor of 0.5 for solar systems. Existing systems (commissioned before February 25, 2025) remain protected by grandfathering provisions.

Contents of this article

1. Negative electricity prices on the power exchange: Why this matters to investors

2. Solar Peak Act: Effective February 2025 and Amendments to the EEG

3. Feed-in Tariffs When Electricity Prices Are Negative: Old vs. New Rules for PV Systems

4. Compensation Mechanism under Section 51a of the EEG: Recovering EEG Subsidies

5. Grandfathering provisions for existing photovoltaic systems

6. Energy Storage and Direct Sales: A Strategic Response to Negative Electricity Prices

7. FAQ: Frequently Asked Questions About the Solar Peak Act

8. Sources

Negative electricity prices on the power exchange: Why this matters to investors

Negative electricity prices on the power exchange are no longer a rare exception—they occur systematically when large amounts of solar and wind power flow into the grid and electricity demand is low. In 2025, this will amount to 573 hours, representing approximately 6.5% of all hours in the year. For investors in EEG-subsidized solar power plants, this means: During these periods of negative electricity prices, the feed-in tariff is not paid—and due to the new amendment effective February 25, 2025, this rule applies significantly earlier than before.

The increase in hours with negative prices follows a clear trend that is directly linked to the expansion of renewable energy in Germany. With every gigawatt of additional solar capacity, the supply-demand balance in the power grid shifts further—especially on sunny days around noon, when consumption is low and PV feed-in is high. The Federal Network Agency documents this development annually on its SMARD platform.

The risk for PV system owners lies not in individual instances of negative prices, but in the trend: the number of hours affected has nearly doubled in two years. The Solar Peak Act addresses these challenges—and changes the way new PV systems must be calculated.

Why the expansion of renewable energy is changing the electricity market

The structural context is the expansion of the energy transition in Germany: solar and wind power generate the most electricity when demand is low—on sunny days, especially around noon and on weekends. The power grid cannot always absorb these solar peaks, and the electricity market responds with negative prices. For investors in PV systems, the focus is therefore increasingly on control and flexibility: those who intelligently coordinate feed-in, self-consumption, and storage can operate profitably even during periods of negative electricity rates.

Solar Peak Act: Effective February 2025 and Amendments to the EEG

The Solar Peak Act (Federal Law Gazette 2025 I No. 51) took effect on February 25, 2025, and amends both the Energy Industry Act (EnWG) and the Renewable Energy Sources Act (EEG): New photovoltaic systems with a capacity of 2 kWp or more will immediately cease to receive feed-in tariffs—starting from the first quarter-hour of negative electricity prices. At the same time, the new Section 51a of the EEG establishes a compensation mechanism that retroactively grants extended support for shortfalls occurring at the end of the subsidy period.

The law is an amendment to the Energy Industry Act (EnWG) and the Renewable Energy Sources Act (EEG) with a clear objective: solar peaks—that is, periods when the supply of electricity from photovoltaics exceeds grid demand and drives prices into negative territory—should no longer be subsidized through EEG support. The aim is to make the integration of renewable energy into the power grid more market-oriented.

Objective, Regulations, and Key Figures at a Glance

• Official title: "Act Amending Energy Industry Law to Prevent Temporary Surpluses in Electricity Generation"

• Federal Law Gazette: BGBl. 2025 I No. 51, issued on February 21, 2025, promulgated on February 24, 2025

• Effective Date: February 25, 2025

• Legislative process: Bundestag, January 31, 2025; Bundesrat, February 14, 2025

• Systems affected: New PV systems with a capacity of 2 kWp or more

• New Key Provision: Immediate Zero Remuneration in the Event of a Negative Market Price (Section 51(1) EEG, as amended)

• Compensation: Extension of the subsidy period under Section 51a of the Renewable Energy Sources Act (EEG) — with a factor of 0.5 for photovoltaic systems

• Grandfathering: Existing facilities (built before February 25, 2025) remain subject to the old regulations

Which PV systems are affected — The role of the iMSys smart metering system

The law distinguishes between different system sizes and metering systems. The key factor here is the use of an intelligent metering system (iMSys)—also known as a smart meter—in conjunction with a control box that enables the grid operator to record electricity feed-in at quarter-hourly intervals and to control the system remotely:

• Less than 2 kWp: Permanently exempt — no feed-in limit in the event of negative prices (Section 51(2) of the EEG)

• 2 to 100 kWp: The zero-remuneration rule takes effect only starting the year following the installation of the smart meter and control box. The costs for the smart metering system are generally borne by the metering point operator once the system reaches a certain size.

• 100 kWp and above: Immediate application of the new requirements — Smart meters and control systems are already in place for these systems due to existing telecontrol requirements

The Quarter-Hour Rule: How Negative Prices Are Measured

Since the German day-ahead market switched to 15-minute contracts, the following applies to all new PV systems with a capacity of 2 kWp or more: The feed-in tariff is suspended as soon as the market price turns negative in any 15-minute interval—not only after several consecutive hours, as was the case under the old Section 51 of the EEG. For systems under 100 kWp without a smart meter and control box, a transitional requirement applies in parallel: Until installation is complete, only 60% of the installed system capacity may be fed into the grid (Section 9(2) EEG 2023, as amended).

Smart Meters and Control Boxes: A Mandatory Requirement and an Economic Necessity

Smart meters (iMSys intelligent metering system) and control boxes are required by law for new PV systems—and at the same time provide the technical foundation for several economic benefits, particularly in light of the smart meter mandate taking effect in 2026:

• Quarter-hourly recording of feed-in: A prerequisite for correct billing under Section 51 of the EEG (as amended)

• Participation in the compensation mechanism (Section 51a of the EEG): Only with a smart meter can quarter-hourly outages be recorded without gaps and claimed for the extension of feed-in tariffs

• Direct marketing and dynamic electricity rates: Smart meters and control boxes enable the market-based marketing of PV electricity and participation in flexible rates

• Feed-in control: The control box enables the grid operator to access the system remotely—while simultaneously removing the 60% transitional limit

Without this measurement technology, there is a risk of both reduced revenue due to feed-in limits and the loss of eligibility for an extension of feed-in tariffs under Section 51a of the Renewable Energy Act (EEG).

For typical investor-owned projects involving ground-mounted and commercial rooftop PV systems —which generally have a capacity well in excess of 100 kWp—the new regulations will apply in full for systems commissioned on or after February 25, 2025. The average annual output of photovoltaic systems is only moderately affected by periods of falling prices—and with professional planning, these investments remain economically viable.

60% feed-in limit as a temporary solution (for systems under 100 kWp)

For smaller new installations under 100 kWp without smart meters and control boxes, a feed-in limit of 60% of the rated capacity applies on a transitional basis until installation (Section 9(2) EEG 2023, as amended) — a limit on capacity, not on volume. For the target audience of this article—investor-owned systems over 100 kWp in direct marketing—this transitional provision is not relevant: These systems are immediately subject to the new zero-remuneration rule, and the 60% limit does not apply to direct marketing anyway (Section 21a EEG). For the sake of completeness: Once smart meters and control boxes are installed and tested, the cap is automatically lifted. According to HTW Berlin, revenue losses due to the cap range between 1.1% and 9% depending on orientation—primarily relevant for full-feed-in systems without storage.

Feed-in Tariffs When Electricity Prices Are Negative: Old Rules vs. New Rules for PV Systems

The former Section 51 of the EEG contained a staggered hourly rule: the feed-in tariff was only forfeited after several consecutive negative hours—a buffer that allowed for brief price dips without consequences. The new regulations eliminate this buffer: as of February 25, 2025, every single negative quarter-hour counts for new photovoltaic systems.

Old hourly rate rule for photovoltaic systems with grandfathering provisions (Section 51 of the EEG, previous version)

For plants that began operations before February 25, 2025, a phased-in regulation continues to apply. Depending on the commissioning period, the zero feed-in tariff in the event of negative electricity prices only took effect after a minimum number of consecutive negative hours:

• Commissioning in 2023: Zero remuneration after 4 consecutive hours of negative prices

• Commissioning 2024–Feb. 24, 2025: Zero remuneration after 3 consecutive hours

• Commissioning starting in 2026 (old regulation): Zero remuneration after 2 hours (hypothetically, if grandfathered)

• Starting in 2027 (under the old rules): No payment for the first hour

Important: The previous threshold of 400 kW was considered the minimum size at which Section 51 of the EEG (old version) applied at all. Photovoltaic systems with a capacity of less than 400 kW that were commissioned before February 25, 2025, were therefore eligible for full EEG subsidies in all cases—regardless of electricity prices.

New regulation effective February 2025: Immediate zero feed-in tariff for new solar power systems

• Zero compensation takes effect immediately —starting from the first 15 minutes when the PV electricity exchange price is negative

• No minimum duration, no buffer—feed-in to the grid continues, but payment does not

• Applies to all solar power systems with a capacity of 2 kWp or more (with smart meter differentiation based on capacity; see above)

• No obligation to repay: Any payments already received remain unaffected—the subsidy is reduced to zero but does not become negative

The bottom line is clear: For every 15-minute period during which the market price is negative, all remuneration is forfeited—neither the market premium nor the feed-in tariff. These provisions of the Energy Economy Act (EnWG) and the Renewable Energy Act (EEG) make the handling of negative prices more direct and transparent than before.

If you’d like to delve deeper into the revenue mechanisms and marketing options when prices are negative, you’ll find a comprehensive analysis in the article on current direct-to-consumer prices for PV electricity.

Compensation Mechanism under Section 51a of the EEG: How Investors Under the Solar Peak Act Can Recover Their EEG Subsidies

Section 51a of the EEG is the flip side of the stricter zero-remuneration rule: For every quarter-hour of downtime, the 20-year EEG subsidy period is extended—though with a halving factor of 0.5 for photovoltaic systems. The extension takes effect after the regular subsidy period expires, on a monthly basis, based on the legally defined full-load quarter-hours per month.

This mechanism is the most significant change for investors in new PV systems: it ensures that lost revenue during periods of negative electricity prices is not simply lost, but is recouped at the end of the subsidy period. This makes the impact of the Solar Peak Act on a system’s total yield predictable.

The three steps of the mechanism

Step 1: Track solar power outages during periods of negative electricity prices

• Over the entire 20-year subsidy period, all quarter-hourly intervals with negative electricity prices during which the PV system received no compensation are recorded

• Each affected quarter-hour is recorded as a "downtime quarter-hour"—the data is provided by the smart meter (iMSys intelligent metering system) in conjunction with the system's control unit

• There is no annual settlement—the buffer grows over the entire funding period

Step 2: Halve — Apply a factor of 0.5 for photovoltaic systems

• At the end of the standard 20-year subsidy period, the accumulated quarter-hour outages are multiplied by a factor of 0.5

• Legal basis: Section 51a(2), first sentence, of the EEG 2023 (as amended on February 25, 2025)

• The result is what are known as full-load quarter-hours (VLVS)

• The factor of 0.5 takes into account the fact that solar systems typically do not operate at maximum capacity—the actual amount of electricity fed into the grid during off-peak hours is often significantly below the rated capacity

• For other renewable energy installations (e.g., wind power), Section 51a(1) applies without the 50% cap—solar power thus contributes more significantly to the integration of renewable energy into the grid

Step 3: Extend EEG payments on a monthly basis

• The VLVS credits are "deducted" on a monthly basis after the subsidy period ends—the subsidy continues until the VLVS balance is depleted

• The basis is the monthly full-load quarter-hours specified by law (Section 51a(2), sentence 3 of the EEG), which reflect the seasonal variation in solar power generation in Germany

• Annual total: 3,800 VLVS per year (basis for the renewal calculation)

• The extension runs until the end of the last month that has begun (rounded up to full months)

• The Federal Network Agency may adjust the factor by regulation (Section 85(2)(13) of the Renewable Energy Sources Act)

Monthly full-load quarter-hours: How seasonal PV feed-in determines the extension

Month	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Total
VLVS	87	189	340	442	490	508	498	453	371	231	118	73	3.800

Source: Section 51a(2), sentence 3, of the Renewable Energy Act (EEG) 2023 (as amended on February 25, 2025)

Calculation example: How long will the EEG subsidy for solar power systems be extended?

The following example shows the calculation based on 300 hours of negative prices per year—a realistic estimate for PV power plants based on current market trends in Germany.

• Initial value: 300 hours per year with negative electricity prices (periods of excess electricity demand and generation)

• Conversion to quarter-hours: 300 hours × 4 = 1,200 quarter-hours of downtime per year

• Over 20 years: 1,200 × 20 = 24,000 quarter-hours of downtime over the entire funding period

• Application of the 0.5 factor: 24,000 × 0.5 = 12,000 full-load quarter-hours (FLQH)

• Extension period: 12,000 VLVS ÷ 3 , 800 VLVS/year = approximately 3.2 years of additional EEG support following the regular end of support

⚠️ Model calculation based on current EEG regulations. The exact duration of the extension depends on the actual number of hours with negative prices and the plant’s capacity. As of March 2026.

By way of comparison: If there were 573 hours of negative electricity prices (as in 2025), the VLVS would increase accordingly—and the extension would be extended accordingly. The formula remains the same: Total number of quarter-hours of outage × 0.5 ÷ 3,800 = extension years.

For more information on the EEG feed-in tariff structure and current rates, see the article on EEG feed-in tariffs for 2026.

Economic Context: How severely will the loss of revenue affect PV investors?

Negative electricity prices tend to occur during specific periods—primarily on sunny days between 10 a.m. and 3 p.m., and frequently on weekends and holidays in the spring and summer. In terms of a PV system’s total annual yield, this accounts for less than 7% of all hours in a year, despite the increase to 573 hours in 2025. The average annual yield of photovoltaic systems is thus only moderately affected—provided the project is equipped with smart controls and an energy storage system.

The focus of economic planning is therefore not on avoiding every single hour of negative output, but rather on three key factors:

• Plan for smart meters and control boxes from the start —they provide accurate billing data, help avoid the 60% feed-in limit, and are a prerequisite for the compensation mechanism as well as for dynamic electricity rates

• Maximizing self-consumption — Solar power that is consumed on-site effectively yields 25–35 cents per kWh (in avoided electricity purchases), significantly more than the feed-in tariff. Self-consumption thus remains one of the most cost-effective solutions for PV system operators, regardless of the new regulations

• Integrating energy storage — smart control systems help optimize the feed-in of solar power: charging when prices are negative, and feeding power into the grid or using it when prices are positive. This minimizes financial losses when electricity prices are negative and opens up additional sources of revenue

PV investments remain economically viable despite negative prices—especially when backed by professional planning and technical flexibility provided by storage solutions and smart energy management.

Grandfathering of Existing Photovoltaic Systems: What Rules Still Apply?

Systems commissioned before February 25, 2025, are not subject to the amendments to the Solar Peak Act. For these systems, the versions of Section 51 of the Renewable Energy Act (EEG) in effect at the time of commissioning apply (Section 100(46) of the EEG 2023, as amended)—including the old hourly thresholds and the old capacity limit of 400 kW.

Grandfathering is enshrined in law in Section 100(46) of the EEG 2023 (as amended). It ensures that existing investment calculations are not retroactively undermined by the new amendment—an important aspect of energy transition policy that limits the risk for operators who have already made investments.

Consequences following the commissioning period: What applies to which operators?

The following overview shows the effects by commissioning period:

Commissioning	Performance threshold	Current regulations	Extension of Section 51a
Starting February 25, 2025	2 kWp and above (iMSys classification)	Effective immediately from the first negative quarter-hour (Section 51(1), as amended)	Yes — Section 51a(2) with a factor of 0.5
January 1, 2024–February 24, 2025	400 kW and up	3 consecutive hours	Yes — Section 51a(1) (previous version) (factor 1.0)
January 1, 2023–December 31, 2023	400 kW and up	4 consecutive hours	Yes — Section 51a(1) (previous version) (factor 1.0)
January 1, 2016–December 31, 2022	500 kW and above	6 consecutive hours	No
Before January 1, 2016	No threshold	No reduction in compensation	No

Source: EEG|KWKG Clearing House; Section 100(46) of the EEG 2023, as amended — As of March 2026

Important for investors with rooftop systems: Owners of PV systems with a capacity of less than 400 kW that were commissioned between January 1, 2023, and February 24, 2025, were never subject to the old Section 51—they will receive full EEG remuneration in any case, regardless of how many hours of negative electricity prices occur.

Voluntary switch: Install a smart meter, notify your utility provider, and receive +0.6 ct/kWh

Operators of existing facilities may voluntarily switch to the new system—and in return receive a premium of 0.6 cents per kWh on top of the applicable rate. Requirements:

• Installation of a smart meter (iMSys smart metering system) and a control box by the utility company

• Written statement to the network operator

• The change is voluntary and irrevocable

• Approval under EU state aid law was granted on September 18, 2025 (Section 100(47) of the Renewable Energy Act)

Whether this switch makes financial sense depends on the individual system—specifically on its exposure to negative electricity prices, the costs associated with smart meters and control boxes, and the value of the additional feed-in tariff premium. Those who opt for dynamic electricity rates and direct marketing will benefit from the metering technology in any case. For more information on the impact on feed-in tariffs, see the article on the declining feed-in tariff in 2026. Companies reluctant to invest can also explore solar power models that do not require equity capital.

Energy Storage and Direct Sales: A Strategic Response to Negative Electricity Prices

An energy storage system can temporarily store solar power generated during periods of negative electricity prices and use it for personal consumption at a later time or feed it back into the grid at a positive price—thereby reducing lost revenue. A comprehensive economic analysis of storage solutions and arbitrage revenues can be found in a separate article.

Integrating a battery storage system into a PV project provides flexibility in the face of negative price events: rather than generating no revenue, the PV electricity is time-shifted and takes advantage of the opportunities presented by the growing battery storage market for investors. Especially on sunny days, when solar energy feed-in exceeds grid demand and dynamic electricity rates drop into negative territory, storage solutions with intelligent control offer a direct solution to this structural problem. The energy storage system charges when prices are negative—and feeds into the grid when prices turn positive again. The typical price difference between the midday low and the evening peak is a multiple of the positive average price—which makes the arbitrage opportunity economically attractive for storage operators. A detailed analysis of these revenue sources is provided in the article “When Electricity Is Worth Nothing: Negative Prices as an Investment Signal, ” as well as an overview of PV systems with battery storage on our product page.

For an in-depth look at battery storage, check out our guide.

Self-consumption vs. feeding electricity into the grid: Opportunities for PV system owners

Those who store solar power during periods of negative prices generally have two options: use the electricity for their own consumption to reduce electricity costs, or feed it back into the grid at a later time when the market price is positive and receive compensation through direct marketing. Self-consumption remains one of the most economical solutions for PV system operators—especially under the new requirements of the Solar Peak Act, as demonstrated by our company-specific PV solutions for businesses. Smart control systems that coordinate generation, storage, and consumption help optimize grid feed-in and minimize financial losses during periods of negative electricity prices. Both approaches—self-consumption and direct marketing—reduce the risk of lost revenue and improve the project’s overall return. The comprehensive guide to negative electricity prices as an investment signal explains in detail how storage, arbitrage, and revenue streams work—from balancing energy to instantaneous reserve.

The regulatory landscape surrounding the Solar Peak Act is part of abroader shift—from fixed EEG feed-in tariffs to market-oriented revenue models. Anyone investing in photovoltaics now should understand how these changes fit into a long-term project strategy.

About PV Investments →

The Solar Peak Act has changed the conditions for new PV systems—but it has also established clear structures: The compensation mechanism under Section 51a of the Renewable Energy Sources Act (EEG) makes revenue shortfalls during periods of negative electricity prices predictable, while grandfathering provisions protect ongoing investments. Anyone investing in photovoltaics now does so within a legal framework that does not ignore downtime but systematically compensates for it.

Logic Energy designs and operates PV systems with lifespans ranging from 20 to 40 years—and supports investors from the initial project calculation through to ongoing operations management as a specialized PV project developer for industrial and commercial clients. If you would like to understand how the new regulations are specifically factored into an investment model and what solar energy investment models we offer overall, please feel free to contact us with no obligation. To the investor model → or contact us directly via our contact form.

This article is intended solely for general informational purposes and does not constitute investment, tax, or legal advice. Return figures are based on historical data from the Helm Group and are not a guarantee of future results. For advice tailored to your individual situation, please consult a licensed advisor. All information is provided without warranty. As of March 2026.

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FAQ

• What is the Solar Peak Act, and when does it take effect?

  The Solar Peak Act (officially: “Act Amending Energy Industry Law to Prevent Temporary Generation Surpluses”) entered into force on February 25, 2025 (Federal Law Gazette 2025 I No. 51). It stipulates that EEG-subsidized PV systems of 2 kWp or more will immediately cease to receive feed-in tariffs—starting from the first quarter-hour of negative electricity prices. At the same time, Section 51a of the EEG introduces a compensation mechanism that offsets losses by extending the subsidy period.

• Does the Solar Peak Act also apply to my existing PV system?

  No. Plants commissioned before February 25, 2025, are grandfathered in (Section 100(46) of the EEG). The old provisions of Section 51 of the EEG continue to apply to them—that is, the tiered hourly thresholds, provided the plant had a capacity of at least 400 kW. A voluntary switch to the new system is possible and yields an additional 0.6 cents per kWh.

• What exactly does the compensation mechanism under Section 51a of the EEG entail?

  Section 51a of the EEG provides compensation for periods of negative electricity prices: For every quarter-hour of downtime, the 20-year subsidy period is extended—with a factor of 0.5 for solar installations. For example, 24,000 accumulated quarter-hours of downtime over 20 years result in 12,000 full-load quarter-hours (VLVS), which, at 3,800 VLVS per year, equates to an extension of the EEG subsidy period by approximately 3.2 years.

• Do I have to repay any compensation I’ve already received if the electricity was priced at a negative rate?

  No. The Solar Peak Act does not create an obligation to repay. When electricity prices are negative, the right to compensation drops to zero—but only for the duration of the period of negative prices. Compensation for periods with negative electricity prices is waived prospectively, not retroactively. Compensation for periods with positive prices remains in full.

• For how many hours were electricity prices negative in Germany?

  The trend is clearly on the rise: in 2023, there were 301 hours of negative electricity prices; in 2024, this figure had already risen to 457 hours; and in 2025, it reached a total of 573 hours (Federal Network Agency/SMARD, January 5, 2026). 573 hours correspond to approximately 6.5% of all hours in a year—no longer a statistical anomaly, but a structural challenge for the system integration of solar and other renewable energies.

• What changes will there be for PV systems under 2 kWp?

  Photovoltaic systems with a capacity of less than 2 kWp are permanently exempt (Section 51(2) of the Renewable Energy Sources Act (EEG)). For systems between 2 and 100 kWp, the zero feed-in tariff applies only starting the year following the installation of a smart metering system (iMSys / Smart Meter). Systems of 100 kWp or more are immediately subject to the new regulations upon commissioning after February 25, 2025.

• Can energy storage solutions solve the problem of negative electricity prices?

  Energy storage systems can temporarily store solar power when prices are negative and feed it back into the grid at a later time when market prices are positive, or use it for self-consumption—thereby reducing lost revenue. Opportunities are particularly evident in the direct marketing of temporarily stored PV power and in new business models such as the market for instantaneous reserve capacity using battery storage. The complete economic analysis, including all revenue sources, can be found in the article “When Electricity Is Worth Nothing.”

Sources

• Federal Network Agency/SMARD — “Federal Network Agency Publishes Data on the Electricity Market in 2025” — Number of hours with negative prices in 2025 (573 h). Jan. 5, 2026.

• Federal Network Agency/SMARD — “Federal Network Agency Publishes Data on the Electricity Market in 2024” — Annual figures for hours with negative prices in 2024 (457 h) and 2023 (301 h). January 3, 2025.

• CHP Information Center — “Negative Electricity Prices – Facts and Statistics” — Monthly updated statistics on hours with negative prices, 2015–2025. As of March 2026.

• Federal Law Gazette — Federal Law Gazette 2025 I No. 51 — “Act Amending Energy Industry Law to Prevent Temporary Surpluses in Electricity Generation.” Signed on February 21, 2025; promulgated on February 24, 2025.

• Laws on the Internet (BMJV) — Section 51 EEG 2023 — Reduction of the payment entitlement in the event of negative prices, current version.

• Laws on the Internet (BMJV) — Section 51a EEG 2023 — Extension of the remuneration period in the event of negative prices, current version.

• EEG|KWKG Clearing House — “Solar Peak Act” — Legal Classification and Documentation. Retrieved March 2026.

• EEG|KWKG Clearing House — “Will the remuneration for my plant be reduced due to negative prices?” — Summary table: grandfathering, thresholds, old and new regulations. Retrieved March 2026.

• Grant Thornton Germany — “Economic Impact of the Solar Peak Act on Onshore Photovoltaic and Wind Energy Plants” — Economic Analysis, Effective February 25, 2025. 2025.

• pv magazine Germany — “How the new compensation mechanism for extending EEG subsidies due to hours with negative electricity prices works in detail” — Detailed analysis of Section 51a EEG, including calculation examples. February 7, 2025.

• MASLATON Law Firm — “Peak Solar Law Tightens Rules on Negative Electricity Prices” — Legal Analysis of Sections 51 and 51a of the Renewable Energy Act (EEG), as amended in 2025.

• energiezukunft.eu** / naturstrom** — “Electricity Exchange 2025: Extreme Price Fluctuations in the Electricity Market” — 573 hours of negative electricity prices in 2025. January 6, 2026.

• Next Power Plants — “6- and 4-Hour Rules: Negative Electricity Prices and EEG Subsidies” — Historical Development of Hourly Thresholds. Retrieved March 2026.

• EEG|KWKG Clearing House — “What technical requirements under Section 9 of the EEG must be observed for EEG-eligible systems?” — Explanation of the 60% feed-in limit pursuant to Section 9(2) of the EEG 2023, as amended, effective February 25, 2025. Retrieved March 2026. Yield loss simulation: HTW Berlin, cited from BSW-Solar / co2online (1.1–9% depending on orientation).