Autonomous power supply for remote wind measurements

Background

P99 Energy is a renewable energy consultancy specializing in wind and solar resource assessment across Southeast Europe. Headquartered in Sofia, Bulgaria, the company has successfully completed more than 300 measurement campaigns, contributing to the assessment of over 35 GW of wind, solar PV and hybrid energy projects.

To support these projects, P99 Energy operates LiDAR systems and meteorological masts at remote off-grid locations, including mountain ridges, dense forests and open steppe landscapes. Measurement campaigns typically run between 12-36 months and require a reliable, uninterrupted power supply throughout the entire deployment.

Challenge

Continuous power availability is essential for wind measurement campaigns. Every hour a LiDAR system is offline results in lost measurement data, directly impacting the quality and bankability of a wind energy project.

Many installation sites are located in difficult terrain with no access to the electrical grid and only limited accessibility for maintenance crews. During extended periods of poor weather or low winter solar irradiation, conventional solar-and-battery systems alone cannot reliably maintain operation. Increasing battery capacity and photovoltaic power would significantly increase weight, cost and transportation effort while still leaving the system weather-dependent. Frequent battery replacement trips were both expensive and, during winter months, sometimes impossible.

Solution

P99 Energy integrates the EFOY Pro 2800 fuel cell into its proprietary Containerized Hybrid Power Supply Unit, combining photovoltaic modules, gel batteries and an EFOY Fuel Cell in a compact, transportable system.

The photovoltaic array serves as the primary power source by charging the battery bank. Whenever the battery state of charge drops below a predefined threshold, the EFOY Pro Fuel Cell automatically starts and provides reliable backup power without any manual intervention. This intelligent hybrid architecture ensures uninterrupted operation even during prolonged periods of low solar irradiation or adverse weather conditions.

Depending on project duration and site requirements, the system can be equipped with FM2, FM4 or FM8 methanol cartridge configurations. Remote monitoring via EFOY Cloud and Victron VRM enables operators to continuously monitor battery status, fuel levels and system performance while minimizing maintenance visits.

Result

The hybrid power solution enables P99 Energy to operate LiDAR measurement stations autonomously throughout the year while maintaining exceptionally high system availability.

With the FM4 configuration, the system provides approximately 2,200 hours of backup autonomy, while the integrated battery bank alone delivers around 130 hours of buffer capacity. Under normal operating conditions, the open-frame hybrid system requires only about two methanol cartridges per year, significantly reducing maintenance requirements and field service visits.

The result is reliable, uninterrupted data collection, lower operating costs, fewer maintenance trips to remote locations and measurement data that can be confidently used for financing and project development decisions.