In recent months, the global energy market has witnessed an unusual and increasingly frequent phenomenon: the emergence of negative and/or zero prices in wholesale electricity markets. While this phenomenon is not new, its frequency and intensity have increased considerably, generating uncertainty and debate in society at large about the need to review the design of the market model.
The truth is that, regardless of the wholesale market design adopted (supply-side or cost-side), these prices reflect opportunity cost , which, although it may sound strange, could mean that someone is willing to pay because they cannot store the energy or temporarily lack operational flexibility. In any case, this temporary phenomenon is a call to action for all market agents and institutions where it occurs.
Causes of the Phenomenon
Negative and/or zero prices in wholesale electricity markets occur when inflexible electricity supply exceeds demand requirements , leading producers to be willing to pay consumers to absorb the surplus energy. This situation can be due to various factors, including:
- Increased renewable generation: The growing integration of variable renewable energy sources, such as wind and solar, into the energy mix. These intermittent, marginally zero-cost sources generate electricity variably depending on weather conditions, which can lead to production peaks that sometimes exceed demand and cause temporary price drops. This phenomenon is not limited to wind and solar energy; it also occurs with run-of-river hydroelectric plants, which, due to their constant flow nature, often have to release energy during periods of high generation and low demand. The lack of flexibility in these renewable systems can lead to overproduction and, consequently, to zero prices in the wholesale market.
- Limited transport infrastructure: The electricity transmission and distribution infrastructure is not always prepared for the large-scale integration of variable renewable energies, making it difficult to transport surplus energy to the areas where it is needed, resulting in network congestion.
- Abrupt changes in demand: The rapid growth of self-consumption, energy efficiency and remote work modalities, as well as natural events, pandemics (COVID-19) or economic crises, have caused an unexpected drop in demand, causing a temporary imbalance between supply and demand that takes time to correct.
- Operational and Financial Inflexibilities: Producers who prefer to pay for a few hours to feed their electricity into the grid for various reasons: (1) Renewable projects whose income depends on their generation injected into the grid in order to invoice and collect in their PPAs; (2) Thermal power plants in which it is more efficient and economical to maintain operational continuity than to stop their machines to restart them shortly afterwards or incur “Take or Pay” type costs.
Negative prices occur in wholesale supply market designs, especially during periods of low demand, resulting from price wars due to oversupply.
Implications of the Phenomenon
Negative and/or zero prices have various implications for actors in the electricity market:
- Producers: Electricity producers without power purchase agreements (PPAs) who rely on spot market sales are severely impacted by negative and/or zero prices. This can lead to financial losses, difficulties in financing new investments, and even the risk of bankruptcy. In fact, producers who have sold their output through physical PPAs have an incentive to pay in order to inject electricity into the grid and receive payment.
- Consumers: Consumers may benefit from lower electricity prices, although this impact may be limited depending on current tariff structures and contracts.
- Electrical system: Negative and/or zero prices can test the stability of the electrical system, as they can incentivize excessive consumption or inefficient energy storage.
The European Experience
Over the past year, the European wholesale electricity market has experienced a significant increase in the frequency and duration of negative and zero prices. The most affected markets have been Sweden, the Netherlands, France, and Germany.
- Sweden: Experienced 38 days between September 2022 and September 2023 with negative prices, including a low of -€285/MWh. High hydroelectric generation and low seasonal demand were the main causes.
- The Netherlands: It experienced 48 days with negative prices during the same period, reaching a low of -€400/MWh. The intermittency of wind power and interconnection with neighboring markets with energy surpluses explain this phenomenon.
- France: Recorded 52 days with negative prices during the same period, reaching a low of -€500/MWh. High nuclear production and the export of surplus energy to neighboring countries contributed to this situation.
- Germany: Experienced negative prices during the same period, reaching a low of -€345/MWh. The heavy reliance on wind and solar power, coupled with low industrial demand, were the main contributing factors.
The Future of Negative and/or Zero Prices: Opportunity or Risk?
Negative and/or zero prices are a market signal that incentivizes efficiency and promotes innovation , as they encourage efficient decision-making and accelerate digitalization, electrification, the development of new energy storage technologies, demand management, and system flexibility. However, if these prices become a recurring trend, they could compromise sustainability goals in electricity markets.
Negative and/or zero prices are likely to continue to be a recurring phenomenon in our wholesale electricity markets, making the management of this phenomenon crucial to ensuring the stability, security and sustainability of our electrical systems.
Some Mitigation Recommendations
To mitigate the negative impacts of negative and/or zero prices, various measures can be implemented, such as:
- Development of flexibility mechanisms: Implement mechanisms that allow adjusting the supply and demand of electricity in real time, such as energy storage, demand response and regional interconnections.
- Transmission infrastructure reforms : Modernize and expand transmission infrastructure to better handle the variability of renewable generation and reduce congestion.
- Improving market models : Adjusting market models to better reflect current and future energy market conditions, including the implementation of price signals that incentivize flexibility, energy storage, and system stability.
- Research and innovation : Promote research and development of technologies that enable better integration of renewable energies and more efficient management of the electricity system. Examples include long-duration energy storage, the use of artificial intelligence for grid management and real-time operation, and the integration of electric vehicles into the grid (V2G).
Conclusion
The emergence of negative and/or zero prices in wholesale electricity markets is a clear sign that the global energy system is undergoing a transformation. While this phenomenon presents significant challenges, it also offers a unique opportunity to foster innovation and efficiency in the electricity sector.
The key to effectively managing negative and/or zero prices lies in a combination of infrastructure investments, appropriate regulatory policies, promoting system flexibility, and adopting new technologies. Only through coordinated and proactive action can we ensure that our electricity systems are stable, secure, and sustainable in the future.
By implementing these strategies, not only will the negative impacts of negative and/or zero prices be mitigated, but opportunities will also be seized to transform the electricity system into one that is more resilient and adapted to the needs of the 21st century.
References
Understanding Negative Prices in the Texas Electricity Market
Increases in negative prices: Is it a positive?
https://www.energycouncil.com.au/analysis/increases-in-negative-prices-is-it-a-positive
Negative electricity prices as a signal for lacking flexibility? On the effects of demand flexibility on electricity prices
https://www.emerald.com/insight/content/doi/10.1108/IJESM-12-2021-0005/full/html