On the Google map an aerial image of Santander’s harbour is displayed, where a wireless lighting solution from TST to control 25 electric towers will be installed.

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Problem

The Port Authority of Santander was looking for a solution to reduce the energy consumption of the harbour’s electric towers, because each tower has an installed power of 8 kW and consumes 35 MWh annually. The towers are connected in series along a line, thus the Port Authority must turn on all the towers in the line to switch on a single one. By turning on the whole line at once, a power peak is generated in the electric network and the power demanded by the Port Authority surpasses the contracted power with the utility company. Therefore according to the contract between the Port Authority and the utility, the price for the kilowatt-hour jumps to the next level (not just for the extra power demanded during the peak, but for the whole invoice period, typically one month).

Solution

TST has developed for the Port Authority of Santander a wireless control system based on ZigBee technology. On each tower an AleHop node is installed, which basically cosists on a microcontroller with a ZigBee radio and some relais. Depending on the commands received from the control room, the relais controlling the lights are open or closed.

With this system the Port Authority can turn every single tower on and off, illumintaing only those areas where light is necessary on demand and at the appropriate intensity level. Thus, if a ship docks at night on a pier for a couple of hours to load or unload merchandise, instead of turning on all the lights of the pier during the whole night, the Port Authority can program the electric towers to automatically turn themselves on at the time wished and with the appropriate light level. With this tool the Port Authority dramatically reduces the energy consumption and therefore the electric bill. Since not all the towers are turned on at once, the power peaks responsible for a higher kWh price are eliminated.

The network is controlled via a web application that can be accessed from any computer at the Port Authority’s intranet. Through this application, authorized users can control every single light and perform advanced tasks like programming the time for turning the electric towers on and off automatically, adjust the light level from every single tower or program a serialized process to swith the lights on to avoid power peaks.