Risk of Blackouts Due to Overproduction? The Impact of "Excess Solar Power" in Germany

Risk of Blackouts Due to Overproduction? The Impact of "Excess Solar Power" in Germany

Too Much Solar Power Makes Electricity "Worthless"—The Paradox Facing Renewable Energy Leader Germany

The expansion of renewable energy has long been hailed as a symbol of "success." It increases electricity that does not rely on coal or natural gas, reduces carbon dioxide emissions, and enhances energy security. Germany, in particular, has been in the global spotlight as a representative country of the "Energiewende," simultaneously advancing nuclear phase-out and decarbonization.

However, a paradoxical phenomenon is currently occurring in Germany. As a result of the excessive increase in solar power generation, electricity is in surplus during sunny daytime hours, causing wholesale electricity prices to plummet, sometimes even into negative territory. The German newspaper WELT reported that this "worthless solar power" is flooding the country, resulting in significant costs for handling the surplus electricity. Furthermore, it has pointed out the possibility of regional power cuts, known as brownouts, as a last resort to maintain grid stability.

At first glance, having excess electricity might seem like a good thing. Isn't it more reassuring to have a surplus rather than a shortage? If prices fall, wouldn't that benefit consumers? However, the electricity system is not a simple inventory business. Electricity must essentially be used the moment it is generated. Excess electricity cannot simply be stored in a warehouse, and if the balance between supply and demand is disrupted, it can affect frequency and grid stability.

Solar power in Germany is no longer a peripheral part of the electricity system. As of 2025, there are millions of solar installations nationwide, with an installed capacity exceeding 100 GW. By 2024, solar power alone accounted for a significant portion of Germany's total electricity generation. This is a major achievement from a decarbonization perspective, but it also presents significant challenges to the power grid.

The problem tends to become apparent on sunny days from spring to early summer. While sunlight is strong, cooling demand is not as high as in midsummer. If factory and office operations decrease during holidays or weekends, electricity demand drops even further. At such times, solar panels across the country generate electricity simultaneously. If wind power is also added, supply far exceeds demand.

During such times, strange things happen in the electricity market. The price of electricity falls below zero, and power producers find themselves in a situation where they have to "pay to have electricity taken off their hands." This is known as negative electricity pricing. From a consumer's perspective, it might seem like "electricity is not only free, but you get paid to use it." However, in reality, due to transmission grid fees, taxes, various levies, and the structure of retail contracts, ordinary households may not directly benefit from this.

The real issue lies in how to handle the excess electricity. If it continues to flow into the grid, stability is compromised. On the other hand, stopping solar or wind generation would waste electricity that could have been generated. Even if market prices turn negative, if institutional support or compensation remains, the difference may ultimately burden consumers or taxpayers. WELT highlights this "surplus clean electricity" as a social cost.

It is important to note that solar power itself is not the problem. Solar power incurs no fuel costs and does not emit CO2 during generation. The decline in panel prices has also significantly reduced generation costs. The issue is that the increase in generation facilities has not been matched by developments in batteries, transmission grids, demand control, and market systems.

In other words, Germany has moved from the "stage of increasing renewables" to the "stage of fully utilizing renewables." Until now, the focus of policy was on how much solar and wind could be introduced. But going forward, the questions will be when, where, and how much electricity is generated, and who uses it and how. Simply increasing generation does not create value if it cannot be used.

There is also active debate on social media regarding this issue. On Reddit, in response to news of Germany's electricity prices turning deeply negative, reactions such as "this is a good reason to increase large-scale battery storage" have been observed. Another user pointed out that EVs could also serve as a type of storage resource, charging electric vehicles with excess solar power during the day and supporting the grid at night or during peak demand.

From this perspective, negative electricity pricing is not merely an anomaly but a signal from the market. During times of surplus electricity, batteries should be charged, and during times of shortage, they should be discharged. By utilizing price differences, the profitability of the battery business increases. In fact, with the expansion of renewables in Europe, investment in the battery market is accelerating. As electricity price fluctuations increase, the value of assets that can flexibly charge and discharge rises.

 

On the other hand, there are also skeptical voices on social media. "Ordinary consumers are not benefiting even when wholesale prices turn negative," is a common complaint. Household electricity rates in Germany include grid usage fees and taxes, and even if market prices temporarily fall, it does not necessarily reflect immediately in retail rates. Those with dynamic pricing plans may benefit by charging EVs or running heat pumps during cheaper times. However, for those without such equipment or contracts, negative pricing is just distant news.

One Reddit user posted, "Ordinary consumers are not getting paid to use electricity; rather, they bear the cost of having others take it off their hands." In response, some argue that using dynamic pricing can lower electricity bills. Here, we see the inequality issue of the renewable energy era. Households with solar panels, home batteries, EVs, smart meters, and dynamic pricing contracts can use electricity flexibly. Meanwhile, those in rental housing, low-income households, or those unable to invest in equipment are often left out of the benefits of the system.

Furthermore, there are skeptical voices about the massive introduction of renewables itself. The power grid is an extremely complex infrastructure and cannot be operated based solely on political slogans, critics argue. On social media, there are opinions that the introduction of renewables should be strictly controlled based on technical judgment, not just political goals. While these claims may include backlash or exaggeration against renewables, they contain important points about not overlooking grid stability.

The German government is also beginning to recognize the seriousness of the problem. Going forward, they plan to more closely link the introduction of renewables with the state of grid development and adjust policies to increase facilities in locations where generated electricity can actually be used. Discussions are underway to revise subsidies for rooftop solar and change electricity market rules. For new installations, mechanisms are being introduced to limit subsidies during times when prices are negative.

However, many existing facilities cannot be controlled immediately. This is the difficulty. Some solar installations set up under past systems still have mechanisms in place that guarantee a certain income if they generate electricity. If market prices are negative but there is not enough incentive for generators to stop, surplus electricity will continue to be produced. While the system supported the success of renewable energy proliferation, it is now also hindering flexibility after becoming a main power source.

There is no single solution. First, the expansion of batteries is necessary. Combining home batteries, industrial batteries, and large-scale grid batteries can shift surplus electricity from daytime to evening or night. Next, demand-side flexibility is crucial. EV charging, heat pumps, water heating, some industrial processes, and data centers can adjust power consumption according to prices. Strengthening the transmission grid is also essential. If surplus electricity in the north and east cannot be efficiently sent to high-demand areas in the south or neighboring countries, local congestion will not be resolved.

International interconnection is also important, but it has its limits. When Germany wants to export electricity, neighboring countries may also have surplus solar and wind power. If similar weather conditions occur across Europe, simply exporting surplus electricity abroad will not solve the problem. Europe as a whole needs to advance storage, demand control, hydrogen production, and industrial demand flexibility.

Hydrogen production is also an option. Excess renewable electricity can be used to electrolyze water and store it as green hydrogen. If it can be used in fields where direct electrification is difficult, such as steel, chemicals, aviation, and shipping, surplus electricity can be converted into other value. However, the cost and efficiency of hydrogen production facilities and the challenges of transport infrastructure are significant, making it not a short-term panacea.

For Japan, this is not someone else's problem. In Japan, output control of solar power is frequently conducted in regions like Kyushu. The structure of excess electricity on sunny holidays leading to solar power suppression is similar to Germany. If Japan aims to further increase the renewable energy ratio, it will also need to design batteries, transmission grids, demand control, and market systems as an integrated whole.

The German case highlights the limits of policies that focus solely on the "quantity" of renewables. Increasing solar panels is important, but that alone does not complete a decarbonized society. What is needed is a new electricity system that integrates generation, transmission, storage, and consumption. Using electricity cheaply when there is a surplus and conserving it when there is a shortage. Both households and businesses must act in accordance with fluctuations in the electricity market. The era is coming where the demand side, which has been passive until now, actively moves as part of the electricity system.

Ironically, Germany's concern of "too much solar power" did not arise because the expansion of renewables failed, but because it achieved a certain level of success. If there were less solar power, issues like negative electricity pricing, handling surplus electricity, and brownout concerns would not have become such significant problems. In other words, Germany is not at the entrance to a decarbonized society but has moved into the complex operational stage beyond it.

Therefore, it is premature to simply conclude that "solar power is bad." Instead, the question is how to use solar power wisely. If the cost of generation has decreased, and it can be maximally utilized through storage and demand control, the electricity system could become cheaper, cleaner, and more resilient. Conversely, if the system and infrastructure do not keep up, electricity that should be cheap could become a social burden, increasing backlash against renewables.

The anomaly occurring in Germany's electricity market serves as a warning for the future energy society. Increasing renewables is not the end. How to use, store, and share them after they have increased is crucial. If the design is wrong, even clean electricity can become "worthless." In a country overflowing with solar power, the question is not about generation technology but how society as a whole perceives it.


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