InfoRmation about Hydrogen
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The federal government’s energy concept incorporates a clear plan for increasing the share of renewable energy – from currently 20 percent up to 80 percent in 2050*. A prerequisite for the use of renewable energy is an electricity grid capable of handling the fluctuating amounts of energy from renewable sources. Wind farms, for example, can produce more energy at particular points in time than is needed at that particular period (e.g. during times of strong wind). To ensure that this energy is not lost, it must be temporarily stored. Storage capacities in Germany are, however, currently insufficient to enable this.
According to the Bundesnetzagentur (federal electricity grid agency of Germany), the amount of lost energy caused by throttling the uptake of power from wind energy plants amounted to 127 GWh in 2010. Hydrogen can assume a key role as as storage medium as it can be applied for large amounts of energy and enables a demand-oriented feed of renewable energy into the electricity grid as required. Surplus renewable energy can therefore be stored and thereby avoids a loss of energy resulting from throttling the uptake of power. Hydrogen as a storage medium would therefore be incorporated in the entire energy cycle – from the production of energy, over the storage of energy, and right through to the consumption of energy. One application is using H2 as a fuel.
*(As at: first half 2011, source: BMU)
Produced renewably, hydrogen can become a key element for promoting the energy turnaround in Germany and enabling CO2-free mobility.
Further information can be found here:
Hydrogen as a storage medium combined with its production from renewable energy represents a textbook-perfect example of an environmentally friendly circular system: electricity is produced in a hydroelectric, wind or solar manner, and water is then separated into its basic components of hydrogen and oxygen. The hydrogen is stored and later used to produce heat by burning it, in fuel cells to produce electricity or filled in tanks of vehicles and used as fuel. The by-product of its use is pure water.
Electrolysis describes the electrochemical breakdown of liquid compounds via electrical energy. An example is the separation of water into hydrogen and oxygen. In this case the hydrogen gas gathers around the negative electrode and the oxygen gas around the positive electrode. The electrical energy used for this process is thereby stored as chemical energy in the hydrogen. The reverse process takes place in fuel cells: here, by adding oxygen from the surrounding air, the energy stored in the hydrogen is reconverted to electrical energy and water – emission free.
The Clean Energy Partnership (CEP) is Europe’s largest demonstration project for hydrogen mobility and a lighthouse project of the National Hydrogen and Fuel Cell Technology Innovation Programme (NIP). The CEP is a public-private partnership. Involved in this project are technology, oil and energy companies, along with most of the major car manufacturers and two leading public transport providers.
As associate partners, the German states of Baden-Württemberg, Hesse and North Rhine-Westphalia are also supporting the CEP to pave the way to becoming a hydrogen-based society by the time the project concludes in 2016.
To ensure the continued development of hydrogen and fuel cell technologies, government, industry and science together initiated the National Innovation Programme Hydrogen and Fuel Cell Technology (NIP) with a strategic alliance in 2006. Through the support of large-scale demonstration projects and research and development, market preparation of products implementing this future-oriented technology is to be significantly accelerated.
The NIP divided into three programme areas: »Transport and Hydrogen Infrastructure«, »Stationary Supply of Energy« and »Special Markets«. The focus in all areas is on the development of components for mass production as well as an explicit strengthening of the supplier industry.
Clean Energy Partnership:
German Hydrogen and Fuel Cell Association:
Currently, two pressure levels are used at H2 fuelling stations – each of which has their own coupling (nozzle). Most fuel cell vehicles are refuelled with gaseous hydrogen at a pressure of 700 bar. Some vehicles, however, are refuelled at 350 bar. Depending on the location, it should be assessed whether a 350 bar vehicle and/or bus refuelling possibility should be installed besides the more usual 700 bar type for passenger vehicles.
Refuelling passenger vehicles using cryogenic liquid hydrogen was also tested in the past. However, due to the lower level of energy loss, refuelling using gaseous hydrogen has now established itself as the global standard.
Hydrogen infrastructure for sustainable mobility(Wasserstoff-Infrastruktur für eine nachhaltige Mobilität - PDF in German only, 3.89 MB)
H2-refuelling stations have been tested for over 10 years. There are currently around 200 such stations across the globe. No serious incidents have been recorded to date. The safety requirements are very high. Before a station goes into service, an inspection of the installed H2 facility is necessary, according to §14 of the Ordinance on Industrial Safety and Health (BetrSichV). The inspection is carried out by an expert of an approved inspection agency. Following successful acceptance and thus confirmation of the secure operation of the facility, the hydrogen fuelling station can go into public operation.
The worldwide accepted SAE J2601 refuelling standard sets out important parameters to enable the safe and reliable refuelling of fuel cell vehicles at 700 bar as well as avoiding, for example, the overheating or overfilling of the vehicles.
The standard can be procured here:
Further information (in German language) on the subject of H2 and safety can be found in the Hydrogen Safety Compendium of the German Hydrogen and Fuel Cell Association (Wasserstoff-Sicherheits-Kompendium des Deutschen Wasserstoff- und Brennstfzellenverbandes) or in the Safe Hydrogen Infrastructure (Sichere Wasserstoffinfrastruktur) publications:
www.dwv-info.de (PDF in German only, 2 MB)
Sichere Wasserstoffinfrastruktur (PDF in German only, 2.7 MB)
Gaseous hydrogen is generally delivered to the refuelling stations from centralised production sites using pressurised tanks on trucks. At other stations, the delivery of cryogenic liquid hydrogen is possible.
At some locations, the hydrogen is produced directly on site via electrolysis using renewable sources of energy. This can even be generated on location using photovoltaic or wind energy. In this way, the station is largely autonomous and does not incur costs for the delivery of hydrogen. However, the production of larger quantities of H2 is currently still more economical using centralised production facilities.
There are currently 15 hydrogen refuelling stations for public use in Germany. The Federal Ministry for Transport together with partners from industry including Air Liquide, Air Products, Daimler, Linde and Total Deutschland have signed a joint Memorandum of Understanding to expand the network of stations to number 50 by the end of 2015. In this way, Germany wishes to become the first country in the world to possess a basic supply network covering the most important urban regions and connecting these with one another.
Further information can be found on the Clean Energy Partnership (CEP) website.
Besides publically accessible stations, some refuelling plants are located on depot sites or at research institutes.
An overview of H2 refuelling stations around the world can be found on the h2stations.org website.
Hydrogen is sold at the public refuelling stations within the Clean Energy Partnership at a price of 0.95 euros per 100g. This represents a special “political” price set by the project partners. Only when the number of vehicles and refuelling stations rise significantly and thereby also the volume sold, is a real price to be reckoned with – one that covers the real costs of production. The development of the hydrogen price will also depend on the political support it receives and the level of taxation this environmentally friendly fuel is subjected to.
Overview of H2 refuelling stations:
International refuelling standard:
In vehicles with a fuel cell electric drive, the chemical energy stored in the compressed gas hydrogen tank is converted to electrical energy via an electrochemical process and continually fed through to the downstream electric motor. As the central energy converter, the fuel cell also assumes the role of the vehicle’s alternator – providing power for the car electronics and other consumers of power.
A fuel cell is an electrochemical energy converter in which hydrogen and oxygen react, in a controlled manner and without combustion, to water, thereby generating power and heat. The same process operates in reverse during electrolysis. A fuel cell is divided into two via a thin membrane – a Polymer Electrolyte Membrane (PEM). The membrane is coated on both sides with a catalyser and a gas-permeable electrode. Hydrogen and oxygen can migrate from one side to the other through the fine gas channels. The catalyser separates the hydrogen into an electron and a proton. The positively charged protons can pass through the PEM, the negative electrons, however, cannot. Current is thereby generated. If the electrodes are connected, direct current will flow. Pure water (H2O) is the by-product of this electrochemical reaction.
Several fuel cells are lined up to form stacks when deployed in vehicles, in order to boost the electric current.
Fuel cell vehicles have also been tested for more than 10 years. No serious incidents have been recorded to date. The safety requirements are very high. Before going into service, the German inspection and approval authority TÜV as well as other responsible local authorities inspect the vehicles.
The vehicle tanks are made of a plastic core around which carbon fibres are wound. The individual components are tested by TÜV. Furthermore, a range of national and international standards is in existence (EN, ISO, IEC, etc.).
Vehicle manufacturer safety concepts fundamentally ensure that tanks, pipelines and valves must be completely tight and free of leaks. In this way, the vehicles may drive into tunnels, garages and other types of parking facilities. In no German state are there restrictions placed on hydrogen vehicles from entering parking areas. Only for gasses that are heavier than air (such as LPG) do some localised restrictions apply. Hydrogen is often associated with explosiveness. However, a detonation of hydrogen would require it mixing with oxygen (min. 4% vol. H2 in the air) as well as there being a source of ignition (e.g. a spark). In contrast to a petrol or kerosene tank, a high-pressure hydrogen tank will never contain any oxygen. A detonation is therefore impossible. Pressure tanks are typically constructed with a safety factor of 2 in terms of operating pressure. This means that a 700 bar tank must be capable of withstanding a pressure level of at least 1400 bar – which means there is a high safety margin in the case of a traffic accident.
Should the vehicle sensors detect the escape of hydrogen, all valves are immediately closed to ensure no further hydrogen can escape. The risk of harm in the vehicle due to damaged valves is further reduced as the pressure existing in the tank (700 or 350 bar) is reduced by pressure reduction valves to a low pressure level of 20-30 bar as soon as the hydrogen leaves the tank. The pressure of gas in the lines and in the fuel cell is therefore significantly lower.
A film (in German) on the subject of “Are hydrogen cars more dangerous than conventional petrol models” can be seen here.
Further information (in German only) on the topic of safety and H2 can be found here:
Fuel cell vehicles that power an electric motor with hydrogen are currently not in series production and therefore still more expensive than conventional vehicles. Nearly all carmakers are, however, working intensively on developing these for series maturity. But until then, much research must still be undertaken. Besides the actual vehicle technology, it is also necessary to establish a refuelling infrastructure. The vehicles are currently still being tested for their suitability for day-to-day deployment in various demonstration projects around the world – with great success. Fleet trials and individual demonstrations show that hydrogen vehicles are every bit as good as their conventional counterparts in terms of safety and driving comfort. To accelerate the market introduction of fuel cell vehicles, a strategic cooperation between large car manufacturers was agreed on. Some manufacturers are forecasting the appearance of the first series production vehicles for 2015.
Clean Energy Partnership:
Film „Are hydrogen vehicles more dangerous than conventional petrol-based vehicles?“ (in German only)
General information on TÜV:
www.tuev-hessen.de (PDF in German only, 0,3 MB)