E-boiler reduces gas consumption at Vopak Vlaardingen

Electrification is seen as one of the most important routes for industry to become more sustainable. According to the Electrification Roadmap, drawn up by the Dutch government, a minimum of 30 TWh of additional electricity will be needed by 2030 to further electrify industry. The document also calculates that industrial energy demand will rise to between 80 and 130 TWh by 2050, of which 60 per cent will be accounted for by electrification.

However, the Netherlands is grappling with grid congestion: the existing electricity networks are not equipped to handle the growing demand and the characteristically fluctuating supply of electricity from renewable energy sources. Looking at the capacity map of Netbeheer Nederland, two-thirds of the country is marked red, meaning: ‘Insufficient transport capacity with waiting queue’. In some places, the queue for electrification projects has grown to ten to fifteen years.

Heated fats

Nevertheless, new electrification projects from industrial companies regularly make the news. Tank storage company Vopak recently announced that it had installed a new e-boiler at its terminal in Vlaardingen. The reason the tank storage company’s project is not on the waiting list is that the application and installation of a heavier connection was already submitted in 2020, explains site director Geert Dijkshoorn.

At the Vlaardingen terminal, Vopak has 310 tanks with a total capacity of over 600,000m³ for the storage of, amongst other things, edible vegetable oils and animal fats, oleochemicals and biodiesel. For some of these products, heating is necessary to keep them liquid in storage. Dijkshoorn: ‘We heat our tanks with steam at approximately 160 degrees Celsius and 10 bar. That is a temperature achievable with an electric boiler.’

‘When the supply of renewable energy is high, we draw electricity and run our e-boiler. On cold days we need more heat and the gas boiler can step in’

Geert Dijkshoorn

According to Dijkshoorn, the use of geothermal energy or residual heat from a heat network is not worthwhile. ‘Geothermal energy typically has a temperature of only 40 to 50 degrees Celsius. And heat from heat networks comes in at around 75 degrees Celsius. That means we would need to upgrade it. It is more efficient to do so using the steam we have generated after it has given off its heat and routing it back to the boilerhouse. By that point it has cooled to around 80 to 90 degrees, and we can then feed it back into the e-boiler.’

The gas boilers will, incidentally, remain in service at Vopak. Dijkshoorn: ‘When the supply of renewable energy is high, we draw electricity and run our e-boiler. When the availability of green power is lower, we automatically switch over to the existing gas boilers. On cold days we need more heat and the gas boiler can step in. In this way, Vopak makes use of green electricity whilst reducing the strain on the grid during periods of high wind and/or strong sunshine.’

Cost-neutral

The e-boiler has a capacity of 10MW and requires a considerable investment of over €5 million. Dijkshoorn: ‘The e-boiler operates at a voltage of 10 kV. The cables, connections and installations are expensive. But the cost of electricity is also high. In relative terms, we pay well over twice as much for electricity as for the equivalent amount of gas, averaged over the year in the Netherlands. The benefit lies in sustainability and CO₂ reduction. By using green electricity at the right moments, we can run the e-boiler on a cost-neutral basis.’

The new e-boiler can reduce the site’s total natural gas consumption by a third. ‘The footprint of the new installation is also smaller because the e-boiler has a higher efficiency. The gas boiler has an energy efficiency of 92 per cent, while the electric boiler achieves 98 per cent.’

Osmosis

Using an e-boiler does, however, require a different approach compared to a gas boiler, explains project engineer Frank Groen. ‘An important difference is the higher water quality required for the e-boiler. The output and service life of the boiler are influenced by water quality, and the water must be pre-treated in several stages. Using reverse osmosis, we remove the excess salts from the water to bring the conductivity to a level suitable for the e-boiler. The water must also be degassed to remove oxygen and CO₂, and softened to prevent limescale build-up.’

According to Dijkshoorn and Groen, e-boilers could be deployed at several other Vopak Netherlands storage terminals. The fact that this has not yet happened is, as one might expect, down to the queue for electrification projects and the price differential between gas and electricity averaged over the year. The technical challenge is therefore a relatively minor concern. ‘Obtaining a heavier connection is almost nowhere near straightforward any more.’