Hydrogen is a ideal way to store energy. It shares the advantages of all technical gases what are used in the energy sector. You can carry it, liquify it, burn it or use it in a fuel cell to create electricity and heat. It can be generated if there is excess energy from renewables and it can be converted in electricity if there is a demand of energy.

If you look to the well known ESS based on renewables and batteries you can observe that the renewables face a limitation of power during noon time or early afternoon. The power is mostly limited to current demand of the load. This is not a satisfying way of operation. In systems like that battery and hydrogen can create a perfect team. The renewables can work at a higher output power and the hydrogen once used again create minimize the cycles to the battrey significantly. This again extends the lifecycle of the batteries and reduces the operational costs of the system.

Is Hydrogen a solution for private use?

Due to the new systems what are actually entering the market hydrogen reaches also the end costumers.The investment will be higher than for similar systems based on other technologies but the advantages of long time storing and the possibility to use the electricity and the heat brings this kind of systems back in the game.

An example is the PICEA system of the Berlin based company  Home Power Solutions. The price of about 70.000,- € and the additional installation costs for the system a still expensive.

• Hydrogen storages are a big investment also the regular maintenance will create costs. The needed safety equipment has to be checked by professionals only.
• The capacity of stored energy is not as much compared to the required space.
• Still hydrogen is in combination with oxygen highly explosive like Propane or LPG. This needs to be clarified with your insurance in advance to avoid further costs.

How to generate hydrogen?

The common way to produce hydrogen are elctrolysers. This devices use water and  a crack the element into the oxygen and  a the hydrogen. Usually the oxygen is  a released to the environment. The needed fuel is purified water. From the financial view an eelectrolyzerwhat is capable to drive a fuel cell direct creates about ten times more investment than the fuel cell what converts the hydrogen back into electricity and heat. Therefore it makes sense to keep the electrolyzer smaller than the fuel cell and crate hydrogen if excess energy is given.

How can I store the hydrogen? 

1. under pressure in bottles,
2. Metal hydrid storages

What are the differences between these two storages?

1. First difference is the pressure level the storages operate.     
2. The way the hydrogen is stored is completely different.
3. The flow rates of the storages differ because of the used storing technologies. The rate is defined by the technology of the storage.

In compressed gas bottles the pressure level can have levels of 200, 300, 500 or 700 bar.In Metal-Büros canisters the pressure level is usually mutch lower. The maximum level is up to 50 bar. This difference is caused by the storing technology. The impressed gas bottles use only pressure the metal,,-hydrid canister use a chemical storing of the hydrogen.

It is comparable to the way a sponge sucks water inside. Because of this the flow rate for storing and releasing the hydrogen is much slower. Additionally during the filling the metal-hydrid canister generates heat. Vice versa during the release it takes heat from the environment. To keep the canisters at nearly constant flow rates a thermal management is needed.

Fuel cells usually need a minimum purity like cars for gasoline, metal-hydrid canisters release always hydrogen with a purity of 5.0. on the other hand this means that all additional elemts will stay in the canister and guide to a decreasing capacity over the live time.

How to generate electricity from hydrogen?

There are several ways to generate electricity from given hydrogen. The most popular principles are:

1. Burn the hydrogen in a motor what is linked to a generatorz
2. Burn the hydrogen in a turbine what is linked to a generator,
3. Using a fuel cell.
   • Water-cooled fuel cells allow to use the generated heat in an easy way.
   • Air-cooled fuel cells usually are only used to generate electricity.

Popular fuel cells:

1. Jupiter (a 2500 kW system with an air-cooled stack)
2. FC 42 (a water-cooled system from the company named Fa. Schunk. The stack consists of modules with 360W eachmit einzelnen Brennstoffzellen die je 360W besitzen). The system of the former cand Berlin based company Heliocentris  consists of a process  module to supply the fuel cell with hydrogen, air and  water and a control module for controlling and as interface to a computer. It's an On-Desk System for demonstration and research . It allows to install further sensors into the connections and is perfectly design for the research in universities and for  show cases.welchesAnschauung und Demonstration geeignet ist.
3. PICEA - a fuel cell heating system of the Berlin based company HomePowerSolutions. The system is designed to increase the autonomously of private homes. Please feel free to contakt us.