Already in the remote regions of the world today, hybrid plants that include renewable energy sources, such as PV plants, help to cut back on fossil fuel, reduce greenhouse gas emissions and lower the cost of the energy supply. However, the technical features of PV inverters and diesel generators do not currently allow PV power plants to generate a share of more than 30-40% of the total electricity generated. The project “Zukunftskraftwerk PV (Future PV Power Plant)” is aiming to increase this share to more than 90%.

The project partners are therefore developing a power plant concept under the direction of the PV project developer Belectric which, in addition to a PV plant, also includes a diesel generator and a battery bank. The challenge will be not only to integrate these components into the microgrid but also to develop new control concepts for the inverters. Only with the help of new control algorithms will it be possible for the inverters to maintain the voltage and frequency – a task undertaken so far by so-called synchronous generators in isolated diesel-run grids. Inverters that can provide ancillary services such as feeding energy into the grid could be employed in future in the trans-European grid, for instance.

In this project, new concepts will be tested on real inverters in the megawatt range in lab and field tests. A demonstration hybrid power plant in Somaliland, in the Horn of Africa, has been providing the Ministry of Information and its radio and TV station with electricity since 2017. An energy management system there is coordinating a PV plant with 500 kWp set up in an east-westerly direction, a lead-battery storage system with a capacity of 1,000 kWh and a diesel generator with 300 kVA. However, the generator is only switched on at night if the bank of batteries has been depleted.

The project, which comes to an end in December 2018, is already demonstrating that the primary source of power could in future be supplied by renewable energy. A power plant including a PV plant and an energy storage system can stabilise distribution grids with the help of a new planning and control software – and this is easily scalable.