In this article we will look at the hydrogen economy and the role of photovoltaic in it and how it will enable the development of the African continent.
The hydrogen basics
Hydrogen is the first element in the periodic table and its symbol is H. Hydrogen gas consists of hydrogen molecules and a hydrogen molecule is made up of two hydrogen atoms and both hydrogen gas and hydrogen molecule have the symbol H2. The energy stored in the molecule is known as chemical energy. To break up the bond external energy is to be applied. When molecules undergo chemical reactions, energy is released.
Hydrogen in the sun
The sun is the center of our solar systems. 73% of the sun consists of hydrogen. This hydrogen is the fuel for the fusion reactions happening in the sun which produce the heat and light as well as helium.
The process of fusion in the sun is the reason why life exists on planet earth. It is solar energy, among a number of other reasons, which has made the planet inhabitable.
Hydrogen on earth
Hydrogen is in abundance on earth in the form of the water molecule. A water molecule H2O consists of 2 hydrogen atoms and 1 oxygen atom. Water is also a source of life on this planet.
When the rays of the sun reach the surface of the planet, then plants use the energy of the sun in a process called photosynthesis to facilitate the reaction of CO2 captured from the atmosphere and H2O captured from the ground to create carbon based products and the release of oxygen gas O2 into the atmosphere.
The modern economy is founded on the use of these plant based carbon products as an energy source. By burning carbon based products, this thermal energy is harnessed for producing electricity, cooking, industry and mobility. This causes a large amount of CO2 and other harmful chemicals being produced which pollute the environment and are leading to the problem of climate change. These carbon based products are used to produce harmful materials which also pollute the environment such as plastics.
How is hydrogen a source of energy
Science has found out that by using hydrogen as a source of energy, one can move away from fossil fuels. The idea is to use hydrogen to react with oxygen producing energy and the by-product water. Then using water as a source of hydrogen through utilising photovoltaics. In this closed loop process there are no harmful by-products being created as the case is in fossil fuels.
The forms of energy created by the reaction of hydrogen and oxygen are thermal energy as well as electrical energy depending on the reaction type. The technologies of reaction commonly used are either combustion or fuel cells. The reaction based on fusion has not been mastered yet and is therefore not implemented but could be an important source of energy in the future.
Storage and distribution of hydrogen
Hydrogen gas H2 is easily combustable when coming in contact with oxygen at normal pressure and temperature. Therefore, the problem of storage and distribution is very important to master.
How to store hydrogen in a safe way, is important as it will allow it to be used in the propulsion of vehicles, boats and planes. It will also be important to be stored in industrial sites for industrial processing.
A distribution method based on tankers to move hydrogen safely around the economy might also be necessary and must be mastered. Progress is being done but more is needed to make hydrogen a viable energy option.
Photovoltaics and the production of green hydrogen
There are a number of technologies which can be used to produce hydrogen. The prominent methods are photovoltaic, wind energy and wave energy. The source of hydrogen is water.
With photovoltaics, solar energy from the sun is converted into electricity. This electricity could then be used to split water (H2O) into hydrogen gas (H2) and oxygen (O2). This process is called hydrolysis of water. The two hydrogen atoms are held together in the hydrogen gas molecule by what is known as a covalent bond (symbol: H-H). The DC current from the photovoltaics is connected to two plates anode and cathode immersed in water. At the cathode hydrogen will appear and at the anode oxygen will appear. Hydrogen gas provides the ultimate fuel for energy production in situ or as a source of stored energy. This integrated process (energy from the sun and hydrogen from water) forms the basis for a sustainable energy source: inexhaustible radiation from the sun and abundant water supply. The process is also:
- environmentally friendly (green) as it is nonpolluting
- potentially available for African countries where energy is in short supply and expensive
Industrial use of hydrogen
Hydrogen can be used in numerous industries both as a fuel and a component for the production process. Some of the industries where hydrogen can be used are:
- fertiliser production
- steel production
- paper production
- glass production
- production facilities using high pressure steam.
Hydrogen use in mobility
One of the main uses of hydrogen is in the area of mobility.
The number of vehicles populating the planet are 1.371 billion vehicles in 2017. It is projected that the number will increase to around 2.0 billion vehicles by 2030. They all rely on oil derived fuels to power the combustion engine. The same applies to ships and aeroplanes. Electricity is being produced by burning coal, natural gas, and oil. Theses sources of energy are finite and will one day become depleted. They are a major contributor to global warming and pollution. This is definitely not good for the planet and its inhabitants.
Hydrogen is used in fuel cells in hydrogen powered vehicles. The idea of a fuel cell is to convert hydrogen and oxygen into electrical energy and the by-product water. This is a clean form of energy.
The main obstacle is the safe storage of hydrogen. This is a technological problem to be solved by technological means. Once this is done then the adoption of hydrogen in mobility will increase.
The environmentally friendly, closed loop, hydrogen cycle
Water is the source of hydrogen. The by-product of this extraction is Oxygen which is beneficial to the environment. Through combustion of hydrogen in an industrial process the by-product is water, which is also the by-product of fuel cells. All of these are processes which are friendly to the environment we live in.
The move from fossil fuel to hydrogen fuel
It is inevitable that once the main technological obstacles are overcome, that the move from fossil fuel economy to hydrogen fuel will progress. Both of these will coexist for a considerable amount of time as there are advantages to fossil fuels.
The result will be the reduction of harm towards the environment especially global warming, and pollution through the oil spills, plastics and fracking.
How will Africa profit from the hydrogen economy
It is important when designing a modern industrial complex in emerging markets, such as Africa, is to colocate the production of hydrogen and the use of it in industry. This will reduce the costs associated with the transport of hydrogen.
The production of hydrogen will require a reservoir of water, an abundance of solar energy and the raw materials used in these industries. The first 2 should be colocated. The distance to the raw materials should be short. The distance to the markets should be also be short.
A possible location for these industry complexes is near the sea. One would use the sea water as a hydrogen source by converting it through osmosis and solar energy into sweet water and then using solar energy in the electrolysis process. It is still not possible to convert sea water into hydrogen and oxygen directly. This is a field to be studied, there are some ideas to use membranes similar to mangroves to stop the salts from entry and mimic nature. Another research avenue is to find materials that would catalyse the process of generating hydrogen from salt water.
The combination of sea water and sun power in many costal regions of the continent means that a large number of areas can benefit in producing hydrogen and drinking water in large quantities. These industrial areas can be distributed along the costal regions in Africa thereby improving the economies of these regions.
The numbers
A 100 MW solar plant today can produce up to 15,000 tones of hydrogen per year and costs 150 million Euros to build. 100 MW solar plant will needs around 340,000 solar panels each solar panel of around 300Wp.
A car would have a capacity of 5 kg and a range of 500 km. So 1 kg of hydrogen will provide 100 km of range. Therefore, 1,500 tones will be used for 1,500 million kms or travelling 37,500 times around the earth in a year
Result
The chemistry and physics is relatively simple and fairly well known. The engineering and technology is a challenge with regards to optimisation, handling, scaling up, efficiency, storage and transport. The use of photovoltaics to generate hydrogen gas colocated with the its usage infrastructure is the way to go as it eliminates the requirement for transport.
Apart from the current uses of photovoltaics in Africa to produce electricity directly, new uses of photovoltaics in the hydrogen economy will emerge. This will transform the economies of the continent from relying on fossil fuels to hydrogen for industry and mobility. New use cases will emerge once the technology of transportation of hydrogen will be perfected and high level of safety is achieved. The abundance of solar energy all over the continent will help improve the livelihood of Africans.
This means it is safe to assume that a workforce versed in the technology of photovoltaic and its applications will be needed. The economical future for the photovoltaic industry is assured and it will never cease. The same applies to the hydrogen economy.