Pressure of hydrogen inside a vehicle reaches 70 MPa during fuelling. Moreover, in order to achieve a quick charging cycle of around 3 minutes, the hydrogen needs to be compressed to maximum 100 MPa to ensure sufficient flow. This is a pressure level that is beyond most available standard compressor types.

Fuel cells are very sensitive to contamination of the hydrogen supplied to them. Impurities may result in irreversible damage to the membrane and the fuel cell as a whole. The compression system plays a large role in this, as it can be the primary source of contamination if the wrong solution is chosen. Therefore a diaphragm compressor is the most ideal compressor type because of the lack of lubrication and wearing parts in the compression chamber.

Reliability is a key factor. Since hydrogen fuelling stations are not around in abundance, down time of the components of the fuelling stations will without doubt lead to vehicles standing still for lack of fuel. End-users are depending on an interrupted fuel supply, and since this is a critical issue all suppliers have a responsibility to do the utmost to prevent this.

Since the technology is still developing, there is no standardised solution. For example, hydrogen can be supplied by tube trailer, made on site from natural gas in a SMR or made from wind or solar energy with an electrolyser.

All these different options put different demands on the compressor at the suction side. So customisation is a key feature.

Lead time is essential when a new fuelling station is planned. Once a concession is given, every day counts, with delay resulting in unexpected costs.

The compressor is, as the most specialized piece of equipment on-site, a major factor in the cost of a fuelling station. In order to minimise investment and financial risk, the cost must be reduced as much as possible.

A good example of this is the use of diaphragm compressors in the nuclear industry. The hydrogen in the machine is only exposed to the metal diaphragm that acts as a piston and is 100% leak free. There are no rider rings or piston rings that can cause contamination.

The special design of the 'head' of the compressor makes very high pressure ratios possible in a single stage machine. This allows us to reach 100 MPa at discharge from 5 MPa at suction with only two stages.

Howden diaphragm compressors are designed for pressures up to 300 MPa. A long lifetime is ensured by the fact that we use the demanding API618 standards as a guideline for design and manufacture.

We have created a modular range, which allows us to use standard components while at the same time maintaining the possibility to customise the package for each application.

Modularisation also allows us to reduce the lead time and cost of the compressor package, as it consists of parts that are ordered on a regular basis.

A cloud based monitoring system can be added to the compressor to make sure any malfunction is swiftly detected, or even prevented by early warning.