Green Hydrogen - Would it be green' enough for a sustainable future?
According to reports by the Intergovernmental Panel on Climate Change, if the global warming potential is to be kept below 1.5 degrees C, then it is paramount that the CO2 emissions must be net zero by the year 2050?[2]. It is paramount that we limit our Greenhouse Gas (GHG) emissions rapidly to prevent extreme climate changes. Data suggest that more than 70% of the GHG emissions arise from the energy sector (which comprises electricity, heating and transportation). Hence it is vital to source power and energy from clean and non-conventional sources of energy?[8]. Hydrogen as fuel provides one way forward for the decarbonization of a range of industrial sectors?[7].
There are around 70 million tonnes of hydrogen produced every year. The main uses of hydrogen are to refine petroleum, production of ammonia and methanol?[11]. Other uses include fuel for launching space shuttles, processing food and also can be used as combustion fuels for transportation[4]. There are many more uses of hydrogen and it is likely that the demand for it would increase going at the current rate. It is important though to produce the hydrogen in the most sustainable way. Let's take a look at the main types of hydrogen and how they are produced.
The different colours of hydrogen
95% of hydrogen is made from fossil fuels using a process called steam reformation. The hydrogen made using this process is known as?‘grey hydrogen’?[11]. This is a high-temperature process in which steam reacts with hydrocarbon fuels (like gasoline, propane, methane etc) to produce hydrogen?[5]. Grey hydrogen uses natural gas or methane as fuel?[3]?to produce steam for the production of hydrogen.
The other form of hydrogen is?‘blue hydrogen’, which is also made using fossil fuels. Unlike grey hydrogen, here the CO2 produced during the production of hydrogen is captured and stored using a Carbon Capture and Storage (CCS) technique, reducing the environmental impact. This process is able to capture 85 to 90% of the CO2 emitted, the rest 10-15% lost may not seem as much, but when produced on large scale has the possibility to cause significant climate change issues?[11].
Then there is?‘green hydrogen, which is produced without the emissions of harmful gases. This hydrogen is made using the process of electrolysis, where when an electric current passed through water, gives us oxygen and hydrogen?[4]. The hydrogen produced using this process produces the lowest carbon impact and is hence quoted ‘green’?[11], but the devil lies in the details. The main problem here is that the electricity produced for the electrolysis is usually sourced from fossil fuels?[4], making the process not so green. So it is of vital importance to make sure to source the electricity from renewable sources, which will aid in reducing the environmental impact.
Another way around is using the energy from the sun to do the electrolysis, this is known as photoelectrolysis. Here, solar panels produce the required energy for electrolysis of water to produce the required hydrogen. This kind of hydrogen is termed ‘yellow hydrogen’?[4].
Okay so now we know what hydrogen is used for, the different types of hydrogen, and how to get hydrogen. Now would be good to know why and how hydrogen is a viable option to curb climate change.
Hydrogen is one clean alternative to natural gas/methane which acts as a chemical energy carrier. When it burns to produce energy, it combines with oxygen to give water as the only by-product?[11]; hence one of the cleanest alternative forms of combustible fuel out there. Moreover, hydrogen fuel is three times more efficient when used as a combustible fuel, than gasoline?[5]. Unlike gasoline, hydrogen is fuel-lean, meaning it can burn well where there is a lot of oxygen. This makes hydrogen fuel greatly efficient along with reducing nitrogen oxide emissions during combustion. The most promising and potential use of hydrogen is in hydrogen fuel cells, These fuel cells can be a great source of clean energy?[4].
Fuel Cell - Packing the Power of Hydrogen
Hydrogen fuel cell is nothing but a power generator that converts chemical reactions to electrical energy. Imagine a fuel cell to be the same as that of a battery, the batteries/fuel cells can be of varying sizes?[10]. The only fuel required to run the fuel cell is hydrogen, the hydrogen combines with oxygen within the fuel cells to produce electrical energy, heat and water as the output?[6]. A single fuel cell does not provide enough energy so they are usually stacked together to provide power for the intended purpose, be it to power a drone or a football stadium. Even though hydrogen fuel cells are compared to batteries, fuel cells won't run out of charge, or need replacing or recharging as long as the fuel (in this case hydrogen) is supplied?[10]. Since there are no moving parts the operation of the fuel cells are silent and extremely reliable.
The main drive to use hydrogen fuel cells is that they do not produce harmful emissions while in operation. The only by-products are water and heat. The waste heat produced has the potential to be used in a combined heat and power generated, further increasing their efficiency?[10]. Hydrogen fuel cells can provide an efficiency of 40-60%, unlike that of internal combustion engines which give 25%?[6]?or for solar cells which give 15-30 % efficiency respectively?[12]. With many benefits, hydrogen fuel cells seem to be a good bet for the future of clean power generation sources.
The potential future for Hydrogen
Green hydrogen has been identified as one of the promising fuels to aid in reducing climate change. The US department of energy has agreed to put 100$ million towards the research of hydrogen and fuel cells. The EU will also invest a whopping 430$ billion towards green hydrogen by 2030. Countries like Japan, Australia, Germany, Saudi Arabia etc, are all making investments and policies to transit to this clean source of energy?[1]. The market for hydrogen looks promising and provides a good time for investment in this field.
As mentioned above that around 70% of emissions is due to the energy, transport and heat sector. Let's take a look at how hydrogen would be able to help reduce a large chunk of those emissions for these sectors.
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Energy
Hydrogen fuel is a potential alternative for the generation of electricity, paving the way toward a low carbon economy. Power generation from hydrogen does not suffer from the instantaneous supply demand balancing. Fuel cells, if used for electricity generation can benefit the grid system in many ways, the energy production is more controllable, flexible and collected with demand (reducing transmission and distribution losses). Another key advantage of fuel cells is that they are able to retain the performance efficiency at smaller scales , allowing small modular units to be used on demand for houses, industries and vehicles. Households and industries are retrofitted with rapid , powerful and compact response heating systems, these can be modified to use hydrogen. These properties enable hydrogen to provide multiple avenues for decarbonisation of the electricity and heat sector?[9].
Heat
For the manufacturing industry sector, hydrogen could replace natural gas, for providing heat and power in a number of industry sectors. Minor updates to the existing burners and furnaces would allow industries to transition to the use of hydrogen as a combustion fuel for heat and power generation (Staffell et al., 2019).
Transportation
Out of the three main low carbon transport alternatives hydrogen is a potential one, besides biomass and electric vehicles. Hydrogen fuel cells can be used to run passenger cars, buses and trains. Since hydrogen fuel provides high energy density, low manufacturing volumes are required to run these vehicles, so it is a viable option for long distances. Fuel cell vehicles have relatively high costs compared with battery run electric vehicles, but with mass production of hydrogen, the economy would be able to attain parity by year 2025-2030. The range and refuelling time required for hydrogen-powered fuel-cell transportation are significantly better than premium electric vehicles. Plus hydrogen vehicles can tackle the problem of air quality by producing zero exhaust emissions. Hydrogen has the potential to drive clean transport development for the modern economy?[9].
Well, why isn't hydrogen being used on the full scale??
Hydrogen is highly flammable and light, thus it needs to be handled with care. Since hydrogen is less dense, it is a trouble to transport it and needs to be cooled to -253 degrees Celsius or needs to be compressed to 700 times that of atmospheric pressure. Currently, hydrogen is being transported using dedicated pipelines, low temperature liquid tankers or by rail or barge. The existing natural gas pipelines are rarely used, as hydrogen can make the pipes and welds brittle, causing cracks. To distribute pure hydrogen these pipelines have to be altered and upgraded to avoid embrittlement?[1].
Way ahead for green hydrogen
Successful implementation of hydrogen powered systems requires focused, predictable and consistent policies and strategies to aid economies in transit to this clean fuel. Countries must be able to develop a support system of policies for hydrogen and fuel cell technologies. With the aid of sustained support and technological advances in hydrogen and fuel cells, there are strong possibilities for hydrogen to experience a cost and performance trajectory similar to those of solar PV and batteries?[9].
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Associate Vice President at Jindal Saw Limited
2 年Thanks for sharing, insightful