Next months, these posts deal with the challenges of Earthlings of bringing humane cities closer. These posts represent the most important findings of my e-book Humane cities. Always humane. Smart if helpful, updates and supplements included. The English version of this book can be downloaded for free here and the Dutch version here.
Hydrogen can play an important role in the storage of cheap and surplus green electricity, as an alternative to natural gas and as a fuel for buses, trains, planes, and ships.
The production of hydrogen
The process of electrolysis brings water into contact with electricity, resulting in oxygen and hydrogen. A 100% clean process, provided the use of energy from carbon-free sources. ‘Blue’ hydrogen occurs when the CO2 released during the production of electricity is collected and stored.
Advantages and disadvantages of hydrogen.
The storage of hydrogen is easy, particularly if conversed into ammonia. A kilo of hydrogen is producing the same amount of energy as a fully-fledged Tesla Power Wall. A tank with 60,000 m3 of ammonia can deliver more than 200 million kilowatt hours. That is the annual production of 30 wind turbines on land. The problem with hydrogen is that 60% of energetic value is lost when electricity is used to make hydrogen and hydrogen is converted it into electricity again. Storing electricity in a battery yields only 5% loss of value.
Heating
A possible application of hydrogen is as a substitute for natural gas, which limits energy loss to 30%. For an apartment complex in Rotterdam, hydrogen will be produced locally and transported via dedicated gas pipelines (photo). An electric heat pump would have reduced energy use with 75%, given perfect isolation. Exactly to avoid cost of isolation, housing corporations are considering hydrogen in older houses. Eventually, heating on hydrogen will be reserved for historic city centers, where few alternatives are available.
Transport
An also frequently mentioned application of hydrogen is transport. In the meantime, for all forms of transport – even bicycling – hydrogen models are available.
With the foregoing in mind, hydrogen as fuel for passenger cars – not to speak of e-bicycles – is quite odd. Although the range is about 600 km and refueling is fast, the difference with electric cars is reducing fast. For other means of transport, the verdict may be more positive. The rule is, the larger the desired range and the heavier the load, the more the benefits of hydrogen equal or outweigh the advantages of batteries. Examples are buses, lorries, but also planes and ships.
Energy storage
The production costs of solar energy in desert areas are considerably lower than those in Europe. This is mainly due to the considerably greater light intensity, which means that the yield of solar panels and collectors is twice as high. The Gulf States see themselves as future export countries of hydrogen, in the form of ammonia.
The gas group Air Products & Chemicals has announced that it will build a hydrogen factory in NEOM, a mega city in Saudi Arabia, which is under development. This factory will produce annually 2.3 million tons of hydrogen (1.2 million tons of ammonia). This factory, due to be completed in 2025, will be the largest in the world.
The European Union also has biggest plans. In 2024, 1 million to hydrogen must already be produced, which should have increased tenfold by 2013.
The Netherlands is investigating the possibility of converting wind energy generated in the North Sea to hydrogen on site, if there is an overcapacity on the network. This can save billions in grid reinforcement. The powerful sea breeze may ensure that production is competitive with to imported hydrogen.
Whether the substantial potential of hydrogen is realized depends in the first place from the availability of cheap sources of wind or solar energy and the willingness of the western world to engage in new dependency from the ‘former’ oil producing countries who can deliver cheap hydrogen.
Science for Society 