Researchers and engineers around the globe are developing and refining ways to generate, store, transport and distribute clean, fossil-free energy. One of the most promising approaches, dubbed the Hydrogen Economy, relies on hydrogen to handle these tasks. Hydrogen is not only a clean substitute for oil, gas and coal, but is also a great storage medium. As the international community seeks to respond to the world’s energy and climate challenges, particularly in the light of the targets set by the 2015 Paris Climate Agreement and recent climate activism around the world, hydrogen can prove to be the most reliable engine to fuel their economies and mitigating the impacts of climate change. Unlike fossil fuels, when hydrogen is used as a fuel instead of hazardous greenhouse gases, the only by-product is water vapour. Hydrogen, for this reason, is considered a great alternative source of energy in an economy that uses low to no carbon.
What is hydrogen economy?
The term “hydrogen economy” refers to the vision of using hydrogen as a clean, low-carbon energy resource to meet the world’s energy needs, replacing traditional fossil fuels, e.g. gasoline as a transport fuel or natural gas as a heating fuel, and forming a substantial part of a clean energy portfolio. In simple words, it refers to using hydrogen, as both a fuel and in fuel cells, to decarbonise economic sectors which are hard to electrify or switch to other alternative sources of power. Vehicular emission, aviation, shipping, utility and heating are some of the sectors where hydrogen can have the best benefits.
According to the Hydrogen Council, the international hydrogen market could be worth up to US$2.5 trillion by 2050, meeting 18 percent of global energy demand, providing 30 million jobs around the world and reducing carbon dioxide emissions by 6 gigatonnes per year.
A rising star of the renewable energy sector, hydrogen is a versatile and environment-friendly resource that produces only pure water and heat when combusted. Although hydrogen has been traditionally used as a feedstock in several industrial processes (such as ammonia synthesis and the refining of crude oil), recent developments have shown that it can also be used for a number of applications, including electricity generation, transportation and storing energy from intermittent renewable sources.
How is hydrogen produced?
Hydrogen is not found in pure form on Earth, so it must be produced from other compounds such as natural gas, biomass, alcohol or water. In all cases, it takes energy to convert these into pure hydrogen. For that reason, hydrogen is really an energy carrier or storage medium rather than an energy source in itself – and the climate change impact of using it depends on the carbon footprint of the energy used to produce it.
At present, the current global demand for hydrogen is 70 million metric tonnes, most of which is being produced from fossil fuels– 76% from natural gas and 23% from coal and the remaining from the electrolysis of water— consumes 6% of the global natural gas and 2% of the global coal. This results in CO2 emissions of around 830Mt/year out of which only 130Mt/year is being captured and used in the fertilizer industry.
Much of the hydrogen produced is used for oil refining (33%), ammonia (27%), methanol production (11%), steel production via DRI (3%) and others.
Hydrogen production from natural gas without CCUS is the most economic method at a cost of USD1/kgH2 in the Middle East, while the electrolysis of water is the most expensive one. However, if the renewables meet the heat/electricity requirements, hydrogen is produced using electrolysis or thermochemical method.
Benefits of hydrogen
Hydrogen has three basic benefits that address these concerns.
1. The use of hydrogen greatly reduces pollution. When hydrogen is combined with oxygen in a fuel cell, energy in the form of electricity is produced. This electricity can be used to power vehicles as a heat source and for many other uses. The advantage of using hydrogen as an energy carrier is that when it combines with oxygen the only byproducts are water and heat. No greenhouse gasses or other particulates are produced by the use of hydrogen fuel cells.
2. Hydrogen can be produced locally from numerous sources. Hydrogen can be produced either centrally, and then distributed, or onsite where it will be used. Hydrogen gas can be produced from methane, gasoline, biomass, coal or water. Each of these sources brings with it different amounts of pollution, technical challenges and energy requirements.
3. If hydrogen is produced from water, we have a sustainable production system . Electrolysis is the method of separating water into hydrogen and oxygen. Renewable energy can be used to power electrolyzers to produce hydrogen from water. Using renewable energy provides a sustainable system that is independent of petroleum products and is non-polluting. Some of the renewable sources used to power electrolyzers are wind, hydro, solar and tidal energy. After hydrogen is produced in an electrolyzer, it can be used in a fuel cell to produce electricity. The by-products of the fuel cell process are water and heat. If fuel cells operate at high temperatures, the system can be set up as a co-generator, with the waste energy used for heating.
The major move to hydrogen
Around the world companies and governments are recognizing that hydrogen is an abundant source of low-cost, clean energy. Not wanting to be left behind in the race to incorporate hydrogen into their energy strategies, over 30 countries having released plans for hydrogen and more than 200 projects backed by more than $70 billion in public funding have been announced by industry.
The US announced “Energy Earthshot” a program that intends to lower the cost of green hydrogen to $1 per kilogram within a decade. European governments and energy companies are working with Morocco and Algeria to build solar and wind farms to produce green hydrogen. Their next step is to transport the hydrogen to Europe with tankers and pipelines.
Saudi Arabia and the United Arab Emirates know the future of oil is limited, so they want to get on the hydrogen bandwagon as well and are investing billions in giant solar plants that will make hydrogen and ship to other countries via tankers. Saudi Arabia, for example, is investing $5 billion in a green hydrogen plant at Neom, a planned city. Australia, Korea, UAE, Chile, Morocco and Brazil, as well as multinational corporations such as Shell, BP and Toyota, are also investing in green hydrogen production.
Hydrogen cars vs battery EVs
Elon Musk, CEO of Tesla Motors, calls hydrogen vehicle to be a dumb thing, but General Electric and GM have great plans in this respect. Hydrogen cars have started to compete in the transport sector. Both electric and hydrogen cars are electric vehicles (EVs) – one has electric batteries which have to be charged through a power grid whereas the other produces electricity on board from hydrogen.
Hydrogen cylinders have to be charged from hydrogen pumps as petrol and diesel are filled. EVs are far ahead in the market and charging stations are being installed on fast track in many counties. EVs can be charged at home as well.
However, the race between EVs and hydrogen cars has yet to be called off. Major automotive companies like Toyota are planning to adopt the hydrogen route. It appears that EVs would have a larger market share in the case of cars, but for large vehicles, EVs may not be able to compete with hydrogen vehicles.
Although, at present, battery electric vehicles (BEVs) seem to be ahead, in Europe, the US and even India, there are programmes to introduce fuel cell-based hydrogen trains.
In Europe, on smaller scales, hydrogen trains have already been introduced. By 2025, there may be substantial inroads of hydrogen trains into these countries.
Problems with hydrogen
Apart from infrastructure issues that prevent the large-scale adoption of hydrogen, the most debilitating setback to hydrogen is the energy required to process it. Hydrogen is notoriously difficult to extract. The lightest element in the universe usually is found in water and hydrocarbons, the elements that make up fossil fuel, among many other substances.
Extracting hydrogen from water, H2O, is notoriously difficult since the water molecule is so stable and subsequently requires quite a lot of effort and energy, which usually comes from renewable sources. This hydrogen extracted by using this process is known as green hydrogen.
Other methods of hydrogen extraction include the burning of coal oil to produce brown hydrogen, using bituminous tar to produce black hydrogen, using methane or natural gas (CH4) to produce grey hydrogen. Blue hydrogen is extracted using the same method as grey hydrogen, with the added step of capturing and storing the carbon dioxide released into the ground. It was held as being a cheap yet clean alternative to green hydrogen, which is still extremely expensive to extract.
Recent studies have shown that the hidden emissions behind the energy required to extract hydrogen using other methods, often result in greater emissions than using fossil fuels in the first place.
Where does Pakistan stand?
According to informed statistics, Pakistan’s energy mix is formed of 64% fossil fuels, 27% hydropower, 5% nuclear power and 4% renewables. While Pakistan has strong potential for producing renewable energy, it is still far behind much of the world in developing these resources.
Realising this pending need, the Government of Pakistan formally approved the Alternative and Renewable Energy Policy 2019 which aims to boost the share of electricity generated from renewable sources from around 5 percent at present to 20 percent by 2025 and 30 percent by 2030. It lists, among other things, alternative renewable energy technologies, such as geothermal energy, hydrogen, synthetic gas (produced from sources other than fossil fuels), solar power and on-shore and off-shore wind energy. As a developing country, Pakistan has also to make a strategic choice. We do not have to mimic the industrial countries, and go through a phase that is dirty and wasteful and creates an enormous legacy of pollution. We should leapfrog over some of the steps followed by industrial countries and incorporate modern, efficient technologies.
The way forward
Using carbon capture and storage (CCS) methods, along with improved methods of hydrogen production, can allow it to be more emission-efficient as a fuel so that it can serve as a bridge to carbon-free fuel sources. As the share of renewable energy increases in the global power grid, the availability of green hydrogen will increase as well, thus making it more easily accessible and affordable.
The true goal of the hydrogen economy is to reach a stage where green hydrogen is affordable and accessible to the point where it starts to penetrate into economic sectors to replace carbon-based fuel sources.
The writer is a member of staff.