The stability of our power grids is often discussed in the context of grid congestion, redispatch measures, or infrastructure expansion. Much less attention is paid to voltage control, although it is a fundamental prerequisite for a secure and reliable energy system. Reactive power management plays a key role in this regard. Without sufficient reactive power availability, voltage levels across the grid cannot be stabilized reliably, which may ultimately jeopardize security of supply.
The Energy Transition Is Changing Voltage Control Requirements
As renewable energy deployment accelerates and electrification continues to expand, the electricity system is undergoing a fundamental transformation. At the same time, conventional power plants, which have traditionally made a significant contribution to the provision and control of reactive power, are increasingly being phased out. Power flows are changing across all voltage levels, creating new challenges for grid operators.
These developments result in different voltage-related situations:
- In lightly loaded distribution grids, particularly cable-dominated networks can lead to voltage increases.
- In heavily loaded transmission and distribution grids, voltage drops occur, especially at locations far from generation sources and along highly utilized overhead lines.
Against this backdrop, the active utilization of reactive power potential from storage systems, generation assets, and electricity consumers is becoming increasingly important.
Market-Based Procurement Unlocks Additional Potential
In addition to the existing requirements set out in Technical Connection Rules (TAR) and Technical Connection Conditions (TAB), market-based procurement of reactive power can help unlock additional potential and improve the efficient use of existing resources.
Many assets already have the technical capability to provide reactive power. Additional potential can often be activated with relatively modest investments and can make a valuable contribution to voltage control. This can help reduce the need for certain grid reinforcement measures while making better use of existing flexibility resources.
Available Potential Is Not Yet Fully Utilized
Reactive power is already available in many locations but is not being fully exploited. Differing technical requirements, a lack of standardization in procurement processes, and limited transparency regarding actual grid needs make it difficult for a functioning market to develop.
In addition, many asset operators lack the planning certainty needed to justify investments in enhanced reactive power capabilities. As a result, available potential remains untapped, and competition develops only to a limited extent.
Three Levers for a Stronger Reactive Power Market
To better unlock the reactive power potential available in storage systems, generation assets, and consumption facilities, three measures are particularly important in the short term:
- Greater transparency regarding grid requirements and actual call-off volumes,
- Standardized and clearly defined market and product structures,
- Reliable regulatory conditions that support investment.
Many of these improvements can already be implemented within the existing legal and regulatory framework. In the medium term, additional measures should be considered to fully unlock available potential and limit overall system costs.
Reactive Power as a Building Block of the Future Energy System
The efficient provision of reactive power is becoming an essential component of a secure and stable future energy system. At the same time, it is emerging as a key success factor for the energy transition. To ensure that existing flexibility resources can be utilized optimally, the right regulatory and market frameworks must be established now.
Our experts Dr. Henrik Schwaeppe, Jennifer Büter, and Gerald Blumberg are pleased to contribute their perspectives and experience to the ongoing discussion.
