Princess Elisabeth Antarctica: Changing the Way We Think about Using Energy

29 Apr 2010 - Articles, Logistics, Antarctic

Belgium’s new Antarctic research station, the Princess Elisabeth Antarctica (PEA), is unique in that is was designed and built to be the world’s first “zero emission” polar research station, running entirely on renewable wind and solar power. Built in the Dronning Maud Land of East Antarctica as Belgium’s main contribution to the International Polar Year (IPY) 2007-2008, the new Belgian station is a model of sustainable development – not only because it runs on renewable energy, but more importantly because the station uses the energy available in the most efficient manner possible, which forces the inhabitants of the station to re-think their relationship with energy.

Demand meeting energy instead of energy meeting demand

Every aspect of the PEA Station’s creation presented the design and construction teams with technical, logistical and physical challenges. Not least of these was the prospect of energy production and management. Unlike other parts of the world, where energy is readily available, the PEA Station is in Antarctica. Here there is no existing power network or electricity grid to provide a station with a constant and seemingly endless supply of energy, which those living in the more populated and developed parts of the world take for granted.

Being faced with the reality of having to make do with limited energy production, presented not only a task, but an opportunity to completely reverse engineer the way in which energy is produced and used at the PEA Station. Instead of endlessly creating energy to meet an uncontrolled demand, the station’s demand had to meet the energy available, which is distributed as per a hierarchy of pre-determined priorities. Based on energy use studies conducted by energy engineering firm 3E, the engineers at Laborelec (a subsidiary of GDF Suez) were able to develop a detailed schematic for the station’s electrical system.

Powering the Princess Elisabeth Antarctica

The PEA Station runs on energy produced by nine wind turbines and 400 m² of solar photovoltaic panels (402 panels in total, 114 on the main building and 288 on top of the technical area). As the power output from renewable sources is limited (the maximum output for the wind turbines and solar panels is 54kWp and 52.26 kWp, respectively), the station needed to be designed to ensure that energy is used as efficiently as possible. In order to do this, Laborelec created a Demand Power Management System (DPMS) to manage energy use.

The DPMS deals with every piece of data concerning both the input of energy to the station and how energy is used within it. This task alone requires an extremely complex system. It was also vital that such a system be able to react in real time to changing weather conditions, station requirements or emergency situations. The best solution to ensure accuracy and reliability under such strict conditions was to use two redundant  Programmable Logic Controllers (PLCs) provided by Schneider Electric, with one functioning as the primary PLC and the second one as a backup (as is the general practice with PLCs used in industrial applications). The PLC monitors production and consumption of energy and regulates all processes the station’s systems carry out. It can react to any real-time conditions to produce distinct, relevant and desired output.

Powering the Princess Elisabeth Antarctica – a closer look

The Demand Power Management System has 200 circuits, each with various operational modes structured within a priority hierarchy. Each of these circuits is controlled and monitored by the PLC, which uses algorithms to manage some 35,000 variables. Based on its design specifications, the PLC can take in information from all the inputs and decide how the energy in the station should be regulated and prioritized accordingly.

The following levels of priority have been assigned to the system:

1. Human safety, water production and ventilation
2. General station systems such as temperature and humidity control, etc.
3. Storage and maintenance of scientific data
4. Kitchen and bathroom appliances
5. Non-essential devices such as laptops or DVD players

The operational modes are programmed to act in different ways and with different priorities. For example there are “night time” and “emergency” modes. The PLC is also designed to recognize which areas of the station require higher energy supply at certain times (such as the kitchen at meal times) and alter the priority hierarchy accordingly to best fit a specific situation.

So what does this all mean?

For an average visitor to the PEA Station, day-to-day living may take some getting used to. You can’t simply use electricity as you wish. Each power outlet requires that you press a button, sending a request to the PLC for energy at that terminal. Then it’s up to the PLC to determine whether there is sufficient energy at that time to give you electricity; you’ll either be given power or told that other systems in use have higher priority.

Depending on their priority level, users can also have a time constraint on the availability of energy after they ask for it. When a certain pre-set time elapses, users must push a button to ask for more power. Users with low priority can receive very limited time or even have their request for power refused.

Communicating with the station

The PLC handles all of the raw data; however an interface displays measurements, parameters and the status of the system to users via text and graphics. In order to achieve this relationship, a SCADA (Supervisory Control and Data Acquisition) system has been installed, which can be used to monitor and alter processes.

With both a PLC and a SCADA system, the station has been equipped with a processing unit and interface, respectively. The two are connected via a server to ensure efficient communication (just as a modem connects a computer to the internet). By using both systems simultaneously, the station not only provides an operator the means to control a variety of procedures, but also allows raw data to be extracted for both archiving and writing reports on the functioning of the system.

Storing energy and using it efficiently

Another aspect of energy management in the station is to store it and use it, as energy production from wind and solar sources is not always constant. This is why a battery array was integrated into the energy use concept of the station. Four battery packs, each containing 24 battery units with a 2V electric potential and a charge capacity of about 83Ah allow for a total electric potential of 48 V and an electric charge capacity of approximately 2000 Ah.

As energy is produced and used, the batteries are charged and discharged repeatedly Float charging (continual charging using sensors to prevent damage from overcharging) maintains the batteries at full capacity whenever sufficient energy production allows.

However even batteries have their limits in storing and discharging energy.  The batteries and electrical systems of the station could be damaged if they are overcharged, while the batteries’ life could be reduced if they are allowed to be drained below 20% of charge capacity. This is why the station has been designed to deal with extreme situations where way too much or way too little energy is being produced.

Too much energy production

Excess energy must be used or disposed of. The system has different ways of dealing with excess energy depending on the amount being produced and whether the station is occupied or not. Keeping in line with the sustainable design of the station, this energy is put to use in as many ways as possible.

Station occupied (November-February)

• When energy production is balanced with consumption (this is the case during nominal operation in one of the many operational modes of the station,), the batteries remain charged between 60% and 90% of their capacity. In this situation energy use is limited and prioritized.  If energy production is greater than use, then the system charges the batteries.
• If the batteries are almost fully charged, then the station goes into “full power mode”, where no limits are put on energy use. In this situation further excess energy can be used for useful dump loads, such as heating water in the snow melter.

Station unoccupied (March-October)

• Dump loads of excess energy are made to resistors in the station’s technical core, which also serve a double purpose of heating the technical core during the long, cold austral winter.

In the event that energy production is too high for all excess energy to be used or dumped, the system will perform a frequency shift (increase the frequency of the AC current on the grid), which will slow down electricity production.

Too little energy production

If too little energy is being produced, there will be a gradual closedown of systems following a pre-determined hierarchy from least essential to most essential determined by the current mode the station is in. For example, if the station is in “kitchen mode”, not all of the outlets or appliances might be available during a low-energy period.

In the unlikely event that very little energy is being produced and the state of charge of the batteries drops to below 40%, two backup diesel generators providing a total of 44 kW of power will start up to guarantee that the station’s first, second and third tier priority systems continue to function (see diagram above), as loss of energy to these systems would compromise human safety and the data collection objectives of scientific teams at the station.

True Energy Efficiency

In regular power grid systems in homes and office buildings, for example, for the sake of energy efficiency, a user will only be supplied with roughly one-third of the maximum power they would require if all appliances and systems were running at the same time. This is understandable, considering the likelihood of every appliance and system being used simultaneously is very slim. In the PEA Station however, the smart grid has been designed with such efficiency that only one-tenth the maximum power load is provided. This all adds up to an innovative new kind of power grid that's far more efficient than a conventional electrical grid!

By: Joseph Cheek

The International Polar Foundation

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