• Greenly
  • Posts
  • Harnessing the Sun's Full Potential: Enerthon's Smart Solution to Solar Curtailment

Harnessing the Sun's Full Potential: Enerthon's Smart Solution to Solar Curtailment

As the world accelerates its transition to renewable energy, a significant challenge often lurks behind the scenes: curtailment. This occurs when grid operators are forced to reduce the output of solar or wind farms to prevent grid overload, essentially wasting clean, generated electricity. For homeowners and businesses with rooftop solar, this can mean lost savings and a longer return on investment.

Author

Alan Zhu
October 09, 2025

A Cypriot startup, Enerthon, is tackling this issue head-on with an innovative new device designed to minimize these losses for distributed PV systems.

The Problem: Ripple-Controlled Curtailment

In Cyprus, and increasingly in other European countries, Distribution System Operators (DSOs) use a "ripple signal" to remotely limit the production of residential and commercial inverters during times of low grid demand or high renewable generation. While this protects grid stability, it results in significant financial losses for system owners. Enerthon estimates that an average Cypriot household could lose around €300 (approximately $350) in 2025 due to this curtailment.

The Solution: Introducing 'Elpida'

Enerthon's answer is a smart zero-export control device named Elpida (meaning "hope" in Greek). This device acts as an intelligent intermediary between the grid, the building's electrical load, and the solar inverter. Here’s how it works:

  1. Signal Reception: Elpida is installed on-site and receives the ripple control signal from the DSO.

  2. Load Measurement: It continuously measures the building's real-time electricity consumption.

  3. Dynamic Control: Instead of allowing the inverter to shut down production entirely upon receiving a curtailment signal, Elpida dynamically adjusts the inverter's output to exactly match the on-site consumption. This prevents any solar energy from being exported to the grid while maximizing self-consumption.

By redirecting generation to self-consumption, Elpida ensures that no solar power goes to waste during curtailment events, protecting the owner's investment.

Key Product Parameters of Elpida

  • Function: Smart zero-export control for PV systems

  • Input Supply Voltage: 230 Vac to 270 Vac

  • Voltage Measurement: Capable of reading three phases (L1-N, L2-N, L3-N)

  • Current Measurement: Supports up to three current transformers (CTs)

  • Internal Power Supply: 12 Vdc, 5 Vdc, or 3.3 Vdc

  • Communication Protocol: RS-485 serial standard for inverter control

  • Status: Certification expected in the coming months

The Bigger Picture: A Growing Need Across Europe

The problem is not confined to Cyprus. Enerthon notes that other EU nations, including the United Kingdom, Germany, Spain, and Portugal, are implementing similar zero-injection modes for rooftop PV systems. The need for solutions like Elpida is becoming increasingly urgent.

Recent data from CyprusGrid highlights the severity of the issue:

  • In the first five months of 2025, Cyprus curtailed a staggering 145,000 MWh of renewable energy—a 58% curtailment rate.

  • This is a sharp increase from 2024 (29%), 2023 (13.4%), and 2022 (3.3%), clearly showing a worsening trend driven by grid constraints and a lack of sufficient energy storage.

Comparative Overview: The Solar Curtailment Challenge

The table below summarizes the curtailment situation, illustrating why technologies like Elpida are critical.

Feature / Aspect

Traditional System (Under Curtailment)

System with Enerthon's Elpida Device

Grid Signal

Receives DSO's ripple control signal to curtail.

Receives DSO's ripple control signal to curtail.

System Response

Inverter reduces power output or shuts down completely.

Device dynamically adjusts inverter output to match self-consumption.

Energy Export

Stopped entirely.

Prevented (zero-export).

Self-Consumption

Interrupted; potential generation is lost.

Maximized; energy is used on-site instead of being curtailed.

Financial Impact

Loss of revenue/savings from wasted generation.

Protection of investment; continued savings from solar power.

Grid Impact

Reduces strain on the grid.

Reduces strain on the grid without wasting energy.

Enerthon's Elpida represents a smart, practical step towards a more efficient and resilient energy future. By empowering consumers to maximize their self-consumption, it turns a grid constraint into an opportunity for optimization. As solar penetration continues to rise globally, such innovative technologies will be essential to ensure that every kilowatt-hour of clean energy is put to good use.

Stay tuned for updates on Elpida's certification and market rollout

Reply

or to participate.