Power Island OFF-GRID POWER SOLUTIONS

Until recent years the only viable way of supplying electricity to remote areas was via a conventional genset, which has led to the installation of more than 50,000 gensets worldwide. With the world market price for diesel fuel the levelized cost of energy has increased significantly. Taking fuel transportation into consideration, the total cost for diesel fuel varies between 1 and 2 €/l. With a typical efficiency of 3 kWh/l the operating cost for conventional gensets results in 33 to 66 ct/kWh. In the same time frame PV prices have dropped by one fifth and will continue to decline in the future, reducing the levelized cost of energy to less than 10 ct/kWh. These numbers illustrate that PV power offers a huge potential for rural electrification. However, due to the volatile nature of solar radiation, the integration of PV is limited to 20–30 % of the rated system power. If a higher share of PV is installed, the system becomes unstable and power outages can occur.

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PV integration beyond 30%

In order to integrate more than 30% of PV renewable energy, and thus fully benefit from the low electricity costs and ecological benefits, a stabilization system is required: THE AEG PS POWER ISLAND. The stability of the system is guaranteed at all times through the usage of battery storage and a converter, which is based on an uninterruptable power supply technology platform. Due to the intelligent interaction of all components, the Power Island allows an increase of PV integration of up to six times when compared to a non-stabilized power system.

Dimensioning of the Power Island

In order to determine the optimal dimensions of the system, it is important to know the main objectives which are to be met with the system. These objectives can be the mitigation of fuel dependency, the maximization of renewable energy penetration, reduction of noise levels during evening and night hours, etc. As the leading company in the installation of utility-scale off-grid power systems, AEG Power Solutions has the extensive knowledge to identify and satisfy our client’s needs, regardless of the pursued goals. A typical system dimensioning that is capable of supplying 400 reference households in remote areas with reliable and clean power is shown in the table below.

Financial performance

The financial performance of the Power Island depends primarily on the local fuel price as well as local solar irradiation. With a fuel price of 1 €/l and a solar yield of 1,500 kWh/kWp, the payback time of the Power Island is already below 6 years.

Payback period in dependency of fuel price and solar yield
 

System layout

The heart of the Power Island is the Central Micro Grid Converter, which governs the power flow within the system. Depending on the availability of the battery and the PV park, the load is either supplied through the DC or the AC circuit. Within the DC system the direct link between the PV park with the batteries enables a reduction of conversion losses. The PV Conditioner allows for the operation of the PV park at MPP as well as for the optimal charging of the batteries. The Static Bypass Switch analogously permits a direct coupling of the genset with the load or optionally with the electric grid. The Power Island stands out through its robustness, which is achieved through the n+1 redundancy of all crucial components.

SBS – Static Bypass Switch; LMU – Local Management Unit ; CMGC – Central Micro Grid Converter

Technical Data*

  • Battery Power: 1 MW
  • Battery Capacity: 2 MWh
  • Genset Power: 3 x 400 kVA
  • PV Power: 1 MWp

* Further information available upon request

 

Benefits:

  • Grid independent
  • Provides high power security
  • CO2 friendly
  • Avoids costly grid expansion
  • Affordable (low overall costs)