POWER ISLAND

Hybrid Battery Energy Storage with PV and gensets

Introduction

The AEG PS’ Power Island is a turnkey solution that integrates all the required components to generate, balance and supply the electrical power for a small village or industrial site. The electrification system is off-grid capable, relies predominantly on renewable energies and is inherently safe through its multiple redundancies. 

The power system is multiple field-proven and recognized as the worldwide leading hybrid power plant system, in terms of installed capacity. The heart of the Power Island, the Central Micro Grid Converter (CMGC) is based on an uninterruptible power supply system and thus capable of supporting, building and stabilizing a three-phase voltage system.

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 hasthe 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.

SUBSTITUTE FOR DIESEL

AEG PS’ Power Island is suited for various applications in the different fields, where hybrid power solutions will be implemented in the future. The most interesting utilization currently is on island grids as a diesel fuel substitution. If the island serves primarily as a tourist attraction, the Power Island offers a cheap and reliable source of electricity which is unique due to its environmentally-friendly operation. In addition, the implementation of the Power Island allows for a significant reduction of the noise level when compared to pure genset power generation. This is a valuable win for small islands and a supplementary advantage. 

A very promising application is the hybridization of power systems for mines. A vast number of mines are located in remote areas without access to the electricity grid. Since their power and energy demand is very high and fuel demand in turn, they are ideally suited for fuel reduction measures. The Power Island offers the additional value adding investment with payback times of less than six years which is a great benefit to the mine. As it is based on the platform of an uninterruptible power supply solution, the hybrid system adds operating safety.

This reduces the overall downtime of the mine and generates economic value. This turnkey solution can also be used in the support of weak electricity grids. In many developing countries the grid is under tremendous stress, which leads to frequent grid outages. For these grids it is very difficult to enable the integration of renewable energies due to their volatile nature, but with the Power Island approach, this situation can be avoided. Through its stabilizing and balancing features, it enables the integration of renewable energies and increases the overall performance of the grid. 

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. 

Rural Electrification

One of the biggest challenges of the 21st century is the rural electrification of the 1.3 billion people currently living without access to the electric grid. 

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 having quadrupled over the past decade, from less than 0.20 €/l to nearly 0.80 €/l, the levelized cost of energy has increased significantly. Taking into consideration that transportation to remote areas adds a significant surplus, 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. 

Furthermore, there is a strong desire for island grid operators to retrofit their existing conventional genset with PV. 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.

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

 

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.