Generating your own green biogas in hotel? It is possible...

Residual flows become energy

Turning waste streams into renewable energy that can be used immediately in a hotel. It seems utopian, but this is exactly what Circ Energy's BioTransformers do. Enzymes convert food waste into usable BioGas and valuable BioWater. 

A cow's digestive ring is similar to how the BioTransformer works.

René Schers is one of the founders of the company, which started three years ago. "The principle of biofermentation was already known in itself. Now it is also possible to use it locally and efficiently. We have developed a unique machine that can be used wherever there is food waste and energy demand. For this reason, our BioTransformers are ideally suited for use in hotels." Circ Energy started as a start-up and has grown into a professional company, with BioTransformers in dozens of locations.

From food scraps to energy

The principle of the BioTransformer is simple. Food scraps are converted into BioGas and BioWater in the machine. "Anything a person can eat can go in it. Our principle uses enzymes to ferment food waste, creating BioWater (plant food) and BioGas. This green alternative to natural gas can be used directly for central heating, hot tap water, cooking systems or, for example, heating a swimming pool." The principle of fermentation is not new, but a digester that can be used locally and on a small scale was not yet available for hotels. This has changed with the development of the Circ Biotransformer. 

Schers: "We also optimise the process by using smart software systems. Our advanced app makes it possible to see how much BioGas and BioWater the BioTransformer generates and how much CO2 this saves." Circ Energy's BioTransformers are modularly built and can therefore be adapted to the user. "We make machines with processing capacities ranging from 30 to 600 kilos of GFE. We always analyse for a potential customer which model is most suitable."

Sustainability and savings

According to Schers, the BioTransformer is of interest to entrepreneurs for several reasons. "Many hotels have an intrinsic motivation to become more sustainable. Using a BioTransformer contributes to this. Both to guests and to the government, the company can clearly show what is being done to combat food waste. It is also a good choice financially. After all, the payback time of a BioTransformer is always under five years (for large machines, around two years). There are various subsidies that make the purchase less expensive. Leasing arrangements are also possible." The BioTransformer helps to generate even more renewable energy, for example in combination with solar panels and a water pump. "From one kilo of GFE you get about 0.4 m3 of biogas. And that's a lot! So you are less dependent on natural gas and if you convert the BioGas to electricity less dependent on the capacity of the grid operator, for example at peak times." 

Hotel guests themselves also demand sustainable operations, René observes. "Certain guests choose to visit only hotels that hold certain certificates, such as Green Key. In addition, waste collection and processing is becoming increasingly expensive. How do you tackle waste. Do you throw something away or can you still do something with it?" So a good story, while the hotel directly reduces its energy costs and CO2 emissions. A hotel, by the way, is a broad term for Circ Energy, because a lot of food is also consumed in saunas and this is where guests increasingly stay overnight. "For example, there is a BioTransformer at Thermen Bussloo. Here they dry bathrobes on biogas and they still smell like lavender."

Heating water 

One of the hotels using a BioTransformer is Hotel de Walvisvaarder on Terschelling. Schers explains that the owner had a clear goal in mind. "He thinks sustainability is very important. By combining all kinds of measures, the hotel has had the Green Key Gold label since 2014." The hotel's gas consumption is 100 per cent offset by the combination of a heat pump, solar water heaters, solar panels and thus a BioTransformer. "This he uses to heat thousands of litres of water. It saves on natural gas costs and waste costs and what it does with the residual streams it makes transparent on the menu." 

According to Schers, sustainable business practices have become an indispensable part of the hospitality industry. "We like to propagate this, also through collaborations with education. There is a BioTransformer at Hotelschool Leeuwarden, and a minor in Circular Hospitality is already being taught here. Other courses are now also looking at this."