One of the challenges facing successful manufacturing companies in the Netherlands is that when they wish to expand their factory output, there may not be sufficient grid capacity in their location to support it.

This was the case for the Fiber Line facility based in Drachten. Fiber Line manufacture high-performance, high tech cords and yarns for many demanding applications – including composite building; safety; packaging; transmission; lifting and haulage.

Their electricity grid connection allows for a maximum power draw of 75kW – but their power demand fluctuates between 25kW and 150kW during their manufacturing process.

The workaround which was in place was a 360kW solar panel array. Most days it was capable of producing a lot of energy. Some days it wasn’t. In the summer months, a lot of potential was wasted because there was no facility to store energy – meaning that the solar harvest had to be strangled because they could sell only some of it back to the grid. Limited grid infrastructure in their location means that the maximum allowable grid feed is 150kW.

With continued growth, Fiber Line needed to expand their factory output, so the time had come to re-evaluate their energy provision and to design a solution which can meet their future energy demands …solving the problem once, and for all time. To do this they called Dutch specialists in sustainable energy and climate control, Bekkema Installatietechniek. Bekkema are familiar with the grid energy limitation, of course, and have developed a number of Energy Storage Systems (ESS), to help clients overcome the difficulties associated with expansion where there is a limited grid.

An ESS provides battery storage – sometimes on a huge scale – which can be used night or day either to provide lower cost energy, or to augment a limited grid supply in order to meet peak demands. In the case of Fiber Line, battery stored energy is inverted to AC to meet peak energy demands during their manufacturing process. The backup power is provided both automatically and instantly, whenever required.

How and when do Fiber Line use energy…

Menno Bekkema – grandson of the company’s founder – explains that they began by analysing how power was used everyday at the Fiber Line premises; they also monitored their solar generation, month by month. “From that data we were able to simulate the energy surplus and power shortfalls which were likely to occur throughout the year …and therefore make an accurate prediction of the required energy storage capacity.”

They drew up a list of the devices needed for the new power system. With a list of necessary devices they could create a 3D model to demonstrate how it could be built into a modified shipping container; and they could produce a wiring diagram for the system realisation. The system was built by Hessel Zwaan, who is pictured at the head of this article. Installing the power system into a container brings a number of advantages: The system can be built at Bekkema’s premises – there’s minimum disruption for Fiber Line, and maximum convenience for Bekkema. Also, it is less expensive to meet safety regulations by converting a container than it is to convert an existing bricks-and-mortar building. Bekkema are able to deliver the containerised system – working and tested – with only the infrastructure cable connections left to be made on site.

What’s in the container?

The system has 12 x MultiPlus-II 48/15000/200-100 configured for three-phase.
A Cerbo GX MK2 is the data communication device which provides harmony across the system, and also enables user- and engineering access on site or from anywhere in the world via Victron Remote Management (VRM)
1 CG EM24 Ethernet Energy Meter for the PV-inverters; a EM24 Ethernet Energy Meter for the grid measurements; and a VM-3P75CT Energy Meter for the measurements of the power delivered by the generator.
10 x Lynx Power-In connect the DC cables from the batteries to the MultiPlus’s.
50 US5000 Pylontech batteries (5kW each) and a Pylontech LV-hub for communication with the Cerbo.
There is a 50kW back up generator.

Two air conditioning units have been installed in the container to maintain a temperature of around 20 degrees Celsius. The aircon units can deliver up to 14 kW of cooling capacity.

Smart Office

A unique skill which Bekkema was able to bring to this installation was their experience in climate control.

Victron’s open source software allows them to make a data communication link between the climate control of the premises and the energy system. Bekkema have a long history of building systems to control heating, ventilation and air conditioning (HVAC) for larger villas and offices. Integrating the HVAC with the power system allows ‘smart’ control of both utilities for smooth operation and energy saving.

Fiber Line’s HVAC system has been in place for a few years – now the new ESS is able to communicate seamlessly with it.

An example of this smart control was explained by Auke de Groot who is head of Control technology, home automation, heat pumps at Bekkema Installatietechniek; he says:

“In the summer the PV installation is sufficient to charge the battery. In winter the generator is needed to charge the battery on darker days. The generator runs on natural gas – the heating system for the building also runs on gas and shares the same gas-line. When the generator has to run at full capacity, the heating system can’t do so at the same time because of the limits of the gas supply. So, the generator has to run in the hours when the heating system needs less gas. And the heating system should throttle down when the generator needs gas to charge the battery. Because the Victron ESS and the Building Management System which controls the heating can communicate with each other, both systems know, according to chosen parameters, which of them has priority to use more gas.”

Neat!

The generator will start and stop automatically according to live data – such as battery State of Charge or a power surge – but it will also start automatically ensure there is sufficient battery charge to cover a predicted surge in power-demand. This is also very smart!

Not only does the new power system meet Fibre Line’s power demand, and exceed expectation, but it solves another problem: In the summer when the 360kWp PV array is harvesting a lot of energy, the fluctuating surplus energy can now be used to recharge the batteries as well as sold to the grid – to a maximum of 150kW. So, the EES is not only peak shaving the factory’s power consumption, but also the PV system’s output.

Bekkema chose to install the inverters at an angle to the container wall to create more space around them, allowing better airflow from the air conditioners, ensuring better cooling during operation. The container has its own 14kW airconditioning units which keep the temperature idealised at around 20°C.

The solution is working well for Fiber Line.

Some of Bekkema’s other customers have installed an ESS system so that they can switch to a less expensive gird power connection (saving them several thousand euros per year) and also to benefit from ‘free’ energy when the system has paid for itself …generally at around six years.