The future of renewable energy does not necessarily rely on “traditional” renewable technologies. New ways of creating our power are being investigated, and they promise great things for the future. Could our renewable energy problems be solved by technological advances?
The Hydrogen Economy was coined in the 70’s by John Bockris at a General Motor conference. It represents a new energy system where power is delivered using hydrogen. The current economy is named hydrocarbon because most of our energy is delivered by burning hydrocarbons that are found in fossil fuels. Any hydrocarbon combustion necessarily creates Carbon Dioxide (CO2) and therefore pollutes the atmosphere. This is where the benefits of a hydrogen economy come in to play; molecular hydrogen can be used as a fuel that does not release any pollutants.
Why are new fuel sources such as hydrogen not used on a global scale?
- Production
Hydrogen can be generated in different ways. The method most used today is steam reforming from hydrocarbons. This procedure makes steam react at very high temperature with a hydrocarbon such as natural gas. This method is very wasteful and still contributes to our dependance on fossil fuels. Other ways are known (electrolysis and thermolysis) but are not used as much.
The production of hydrogen can also be done by splitting the molecules of hydrogen (H) out of water (H2O). This method has however not yet yielded any industrially applicable results but as the science advances so do the hopes of using water as the source of our hydrogen.
- Storage
Hydrogen can be stored in two ways. Liquid hydrogen has less energy intensity by volume than hydrocarbon fuels which means that less energy can be created out of a litre of pure hydrogen compared to a litre of gasoline. Furthermore, the storage of liquid hydrogen requires cryogenic storage because of the very low boiling temperature of the liquid (-253 °C). This storage method requires even more energy to keep the hydrogen cold and requires a specific costly technology wherever the molecule is to be stored.
Compressed hydrogen is stored quite differently under the form of a gas. Hydrogen gas has a good energy intensity by weight but very poor energy intensity by volume. This entails the creation of larger tanks in cars for example to store it.
Three other storage methods are also candidates but they all have their own barriers interfering with industrial application of the technology as described by Li Zhou in this article.
- Costs
The production of a unit of hydrogen fuel by steam electrolysis (water splitting) is today six times more expensive than the production of an equivalent unit of fuel from hydrocarbon sources (source). The main problem with the cost of hydrogen fuel is that it is compared through the market to fossil fuels. For the case of hydrogen however, the cost of creating the molecule of hydrogen from water splitting or steam reforming contributes to the final price. For fossil fuels, only the extraction, refining, transportation and distribution contribute to the market price. Therefore, until the depletion of fossil fuels or government incentives push the price of hydrocarbons higher than hydrogen, it will always be more economically viable to use fossil fuels.
- Infrastructure
A hydrogen infrastructure would require industrial hydrogen pipelines and hydrogen filling stations. This entails the transformation of our whole energy system to accommodate the new gas. Furthermore, the vulnerabilities of steel to hydrogen means that the steel natural gas pipelines would need to be changed if hydrogen were to be transported through them.
What can be done is a swap from centralized to distributed production sites. This means that hydrogen generating facilities can be created locally in order to bypass the distribution line (hydrogen creation necessitates less infrastructure than fossil fuel extraction and refining).
A final point must be made about the required personal infrastructures. All fossil fuel using machines would need to be transformed in order to use hydrogen. The hydrogen fuel cell would replace the combustion engine and therefore represents a huge investment in anything ranging from cars and buses to gas heating and cooking.
- Safety
Hydrogen has one of the most potent explosive and ignition mix with air. This entails that whenever there is a hydrogen leak into air there will most likely be an explosion (see hydrogen bomb). To increase the danger further, hydrogen leaks are odorless and very difficult to recognize. This leads to worries about the safety of using hydrogen as a fuel where any accidents can lead to large explosions.
Each of these points indicate that hydrogen fuel is not yet an energy source that we are ready for. The production of pure hydrogen still uses fossil fuels at the moment and the technology is not yet present to significantly create it otherwise. Hydrogen storage is also lacking as we are not yet ready to store in at any industrial scale. The costs of both the fuel itself and the costs of adapting our infrastructures to be able to accommodate it are too high in particular when compared to fossil fuels. Finally, the dangers that hydrogen represent are hindering not only the large scaled adaptation of the energy but also the smaller scale tests and trials of the fuel. Until the science and technology solve these problems and governments and corporations enable the adaptation of the fuel through incentives, the hydrogen economy will remain out of reach.
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