Frequently asked questions

The general terms and conditions can be accessed via this link, and they are also registered with the Chamber of Commerce; Watermeln B.V.

It depends on the project, the duration, the energy demand, and the market price for hydrogen. Generally, the more energy is consumed, the smaller the price difference. This is because our system is more efficient, resulting in lower costs per kWh. Due to the novelty of fuel cell technology, the rental price is currently higher. When you combine both costs into a total cost of operations (TCOP), in most cases, we can compete with hybrid diesel generators.

Energy itself is already complex enough, we therefore simplified our pricing model

It’s based on two components

1. A service tariff 
2. Usage tariff 

The service tariff includes: rent, installation, transport, and online monitoring (incl. user access) 

The usage tariff includes: hydrogen gas, and transport  

What is not included?

• Cabling 
• Transport to remote locations (islands, mountains, unpaved roads) 
• Deliveries and pick-ups outside normal business hours

The Watermeln unit is CE approved by an independent party and thereby meets the corresponding standards (ISO and NEN). It also complies with European ATEX directives and has an explosive safety survey and documentation.

Other than a Diesel genset, the Watermeln 200 unit is working according to a chemical reaction, instead of a combustion oxidation reaction. Therefore, current Dutch regulatory aspects for “Stookinstallaties'' do not apply for the Watermeln installation. 

The activities are of a temporary nature and are therefore not considered as “inrichting”. This means that it does not fall under the Besluit Activiteiten Leefomgeving (BAL) en Besluit Omgevingsrecht (BOR).

The supply and installation of the H2 gas cylinders must comply with the PGS 15 guidelines. As long as the total hydrogen gas bottle system contains <1 ton H2 and remains directly connected to the system, these activities are not subject to a permit requirement. However, an official notification (notification requirement) > 4 weeks prior to the hydrogen activities to the competent authority is required. Certain local regulations may possibly apply. We therefore recommend notification and discussion with local environmental and safety authorities.

The overall system follows the guidelines of PGS 15 and ATEX, which include:

• ATEX zoning; zone 2 applicable. This zone is not accessible to unauthorized persons, is free of ignition sources and PPE's are applicable.
• The system is surrounded by fencing (min. 1 meter high), with closed perimeter and is accessible to authorized personnel from outside and inside.
• Placement on a straight and reinforced surface capable of supporting at least the following weights

  • Watermeln: 470 kg per m2

  • Hydrogen: 650 kg per m2
• Direct access to the installation at all times on foot and by vehicle for security services.
• Recommended safety footprint is 12×8 meters, free of sources that ignite. Minimal distance between Watermeln and hydrogen tank is 5 meters. Smaller footprint is possible with use of fire proof separation between hydrogen and sources that can ignite.
• Electrically grounded system, for the hydrogen tank a ground stake should be struck for this purpose. The Watermeln unit itself is a floating system and grounded with an ISO watcher.

Specific safety requirements are tied to location, accessibility and project description. Watermeln can guide you through this process.

The carbon footprint of hydrogen depends on its source. While hydrogen is free of harmful emissions at the point of use, carbon can be released to the atmosphere during its production. There are numerous ways to produce hydrogen, but let’s focus for the purpose of the question on the three main types of hydrogen production techniques:

Green hydrogen is produced by electrolysis of water (dividing H2O, into H2; hydrogen, and 02; oxygen) using only electricity from renewable sources, it can therefore be considered “zero-carbon hydrogen”

Blue hydrogen is produced from natural gas via a process called steam reforming, and the residual CO2 is captured via some form of carbon capture and storage (CCS), and can be considered “low-carbon”

Gray hydrogen produced from natural gas without carbon capture and storage (CSS), and can be considered “with-carbon”

Most of the existing users of hydrogen (mainly industrial companies) are using gray hydrogen, as this is the most common form of hydrogen. Due to decreasing costs of renewable energy and equipment, and tighter regulations, the amount of produced green hydrogen is increasing fast. 

Watermeln is only using high quality (5.0) green certified hydrogen made from electrolysis that’s directly connected to a renewable energy source, or PPA wind and solar contract.

No, this is not necessary. Watermeln has long-term agreements with producers, and will supply and install the required hydrogen.

Fuel cells work like batteries, both work with a chemical reaction, but fuel cells do not run down or need recharging. They produce electricity and heat as long as fuel is supplied. A fuel cell consists of two electrodes—a negative electrode (or anode) and a positive electrode (or cathode)—sandwiched around an electrolyte. A fuel, such as hydrogen, is fed to the anode, and air is fed to the cathode. In a hydrogen fuel cell, a catalyst at the anode separates hydrogen molecules into protons and electrons, which take different paths to the cathode. The electrons go through an external circuit, creating a flow of electricity. The protons migrate through the electrolyte to the cathode, where they unite with oxygen and the electrons to produce water and heat ^[1]. 

There are different types of fuel cells, each with its own characteristics. Watermeln is using a PEM fuel cell. 

Source:

1. Energy gov. https://www.energy.gov/eere/fuelcells/fuel-cells#:~:text=A%20fuel%2C%20such%20as%20hydrogen,creating%20a%20flow%20of%20electricity.

The graph below shows the average efficiency of a Stage 5 diesel generator and a hybrid system (stage 5 diesel generator and li-ion battery). By applying a battery to a diesel generator, large fuel savings can be realized, and therefore lower the CO2 impact. However, combustion as a electricity production method, will never meet the same high efficiency standards with a chemical reaction like a fuel cell, therefore Watermeln’s system typically delivers up to 4 times higher efficiency than conventional combustion engines. 

Sources: 

1. Average diesel generator efficiency; “Article Use of a Hybrid Wind–Solar–Diesel–Battery Energy System to Power Buildings in Remote Areas: A Case Study” by Amir Ebrahimi-Moghadam and Mohammad Hossein Ahmadi
2. Average improvement of efficiencies with hybrid generators; https://www.greener.nl/blog/energy-storage/differences-diesel-generators-mobile-batteries/ 

Graph: electrical efficiency comparison between Diesel ^[1] / hybrid generators ^[2] and Watermeln system

We have set-out a comparison from “Well to Power”(WtP) for 4 variants in the table below (Diesel, Hybrid, Gray Hydrogen and Green Hydrogen). Well to Power (WtP) means that we have considered the CO2 emissions emitted throughout the complete value chain (resources, production, transport, and consumption). 

Watermeln uses only green hydrogen, therefore we realize a 96% CO2 reduction on average compared to a diesel generator (WtP). 

Table 1: Well to power CO2 emission comparison between 4 solutions

Sources: 

1 https://www.co2emissiefactoren.nl/lijst-emissiefactoren/ 

2. https://www.engineeringtoolbox.com/fuels-higher-calorific-values-d_169.html

Hydrotreated Vegetable Oil (HVO) can function as a diesel replacement. There are various mixtures HVO 20 (meaning 20% HVO mixed with fossil diesel) and HVO 100 (being 100% HVO diesel). Due to the carbon absorption nature of plants, HVO can technically realize up to 85% CO2 reduction ^[1] from Well to Power (from production to usage).

There is currently much debate around reduction claims as, depending on the feedstock and the supply chain, the production of HVO can lead directly or indirectly to deforestation (e.g. palm oil is often used as a resource ^[2]), which has significant environmental, ecological and CO2 implications. Also, unlike hydrogen used in fuel cells, HVO still is used in combustion applications that are 4 times less efficient, and are emitting large amounts of CO2, NOx and other pollutants at the point of use (tail-pipe emissions). Causing a significant amount of local pollution - contributing to global warming, and major health issues for humans^[3]. 

Therefore, we can conclude that HVO is a short term solution on minimizing conventional diesel, however it is not a sustainable replacement, or equal solution to renewable energy. 

Sources: 

1 https://www.co2emissiefactoren.nl/lijst-emissiefactoren/ 

2 https://biofuels-news.com/news/palm-oil-dominated-biofuel-feedstock-in-2021-quota-year/ 

3 https://www.eea.europa.eu/publications/air-quality-in-europe-2022 

Batteries (most commonly Li-ion batteries) and fuel cell hydrogen generators are not the same thing. Both use a chemical reaction to release energy in the form of electricity, however batteries are meant to store and quickly charge or discharge electricity - and fuel cell hydrogen generators are designed to produce electricity from hydrogen gas. 

For a fuel cell system, storage and power are separated, by use of a hydrogen gas tank (often compressed to up to 500 bar) and the fuel cell to release electrical energy from the hydrogen gas.

Battery technology is a great way to provide electricity for short term use cases that require high power, and limited energy capacity. But for a battery to be usable, it must be recharged. Therefore, it is often combined with a (small) grid connection. 

For off-grid applications where high energy output and capacity is required, a battery solution with enough capacity will prove too bulky and expensive, and would also need to be transported off site to be recharged (even several times a day). The long charging time between uses also means batteries are not practical for assets that are highly utilized. So while batteries can be useful for providing additional peak power for grid connected use cases, or short term projects with low energy capacity needs, hydrogen is much better suited for use cases where diesel has traditionally been employed – off grid, high-power & energy consumption, long to medium term applications.

To simplify we have made a pro and con comparison between both technologies

Table 2: comparison between battery and hydrogen fuel cell generator technologies

As you can see, both technologies are complementary to each other, and both play an important role in the transition to renewable energy usage and storage. Therefore, Watermeln combines the best of both technologies into its system. By adding a battery we can deliver instant power, higher efficiencies and seamless refueling when the hydrogen is decoupled.