Remote wind power systems often incorporate additional generating systems
such as diesel generators and solar arrays. These "hybrid" systems
provide improved reliability of power supply and operational flexibility.
When When the power from the wind turbine is not sufficient to operate
the load, the alternate power source comes on-line. The alternate source
is used far less frequently in a hybrid system than if the wind system
were not present.
Hybrid photovoltaic systems most commonly take the form of photovoltaic
systems combined with wind turbines or diesel generators. They would most
likely be found on islands, yet they could also be built in other areas.
The largest European PV system used as a part of the hybrid system is
located on Pellworm Island in Germany. A very large hybrid system was
also built on the Canary Islands. The following descriptions depict some
of the world most interesting PV-wind or PV-diesel hybrid systems.
If you wanted a wind system for a remote site a decade ago, the dealer
would happily oblige, sizing the wind turbine and the batteries to carry
your entire load. That's not the case today. Both Bergey Windpower and
Northern Power Systems, two small wind turbine pioneers, have successfully
demonstrated wind and solar hybrids at remote telecommunications stations.
These hybrids capitalize on each technology's assets.
The Kythnos Island hybrid system plant utilizes a 100 kW PV array, a
100 kW wind turbine, and a 600 kWh battery. The entire system is connected
to the existing distribution grid, which is fed by a 200 kVA diesel generator.
Three 50 kVA inverters operate simultaneously delivering power into the
grid. The plant is monitored by control system, which optimises the amount
of renewable energy available to the grid.
The largest European PV wind hybrid system is located on the Pellworm
Island in Germany. The PV array has the capacity of 600 kW, yet it will
be enlarged with an additional 300 kW array. The first 300 kW array was
build in 1983. The total PV power of 900 kW will enable the production
of nearly 800 Mwh/year.