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Solar Energy and Electrolyzers Working Together: Could Hydrogen Solve The Climate Change Challenge?
- As with all forms of power generation, not every type of hydrogen production is environmentally friendly. There are currently three main categories of hydrogen: grey, blue, and green. Among these options, green hydrogen stands out as the ultimate environmentally friendly type.
- One of the most encouraging forms of green hydrogen production is made using a device known as an electrolyzer. Electrolyzers use electricity to split water into hydrogen and oxygen. The hydrogen produced in this way is emission-free, provided that the electricity used comes from a renewable energy source such as solar.
- Unfortunately, less than 5% of the hydrogen currently produced is emission-free. Green hydrogen is much more expensive to make than the grey version. In addition, hydrogen is more expensive than conventional fuels such as diesel.
- Hydrogen opportunities in Canada are substantial, especially following the approved Bill C-12, which has made national greenhouse gas emissions targets a matter of law. Furthermore, the 2021 budget proposed a tax credit for carbon capture, use and storage technology investments.
- An ideal energy storage system consists of an electrolyzer powered by excess solar electricity coupled with a hydrogen storage system. This is something that Canada has the perfect geology and policies to implement.
Hydrogen has the potential to be a green energy carrier that could perform a vital role in the global energy transition. As with all energy forms, its sourcing is critical as not all types of hydrogen production are environmentally friendly. Green hydrogen produced using renewable sources has a near-zero carbon production route. Some significant synergies are occurring between the accelerated deployment of renewable energy and hydrogen production.
Climate experts now consider green or renewable hydrogen made from the electrolysis of water powered by renewable energy sources (such as solar power) indispensable to climate neutrality. It is held in such high regard that green hydrogen is referenced in all eight of the European Commission’s net-zero emissions scenarios for 2050.
Hydrogen has the potential to power trucks, planes and ships. It could also heat our homes, balance electricity grids, and help the heavy industry make everything from steel to cement. But doing all these things with hydrogen requires a staggering amount of fuel. Thus, hydrogen is only as clean as the processes used to produce it. This article explores the basics of hydrogen production and how solar energy and electrolyzers are working together to create a green fuel source that could help tackle the climate crisis.
The Basics of Hydrogen
The push for green hydrogen production is very much in the works. Experts are working on encouraging sources for hydrogen made without producing emissions and in an economical way.
Hydrogen is one of the most abundant elements in the world, but it needs to be separated from other substances, such as water (H2O) or fossil fuels (hydrocarbons). In addition, the method in which hydrogen is produced has a considerable effect on its environmental impact.
Three main categories of hydrogen are discussed in today’s market:
- Grey Hydrogen – Unfortunately, grey hydrogen makes up the vast majority of hydrogen in use, and there is plenty of it. It is made from natural gas and emits CO2. This type of hydrogen is predominately used in industry.
- Blue Hydrogen – Also known in the gas industry as ‘decarbonised’, blue hydrogen is produced from natural gas with carbon capture and storage (CCS). CO2 emissions are captured and stored during the production process.
- Green Hydrogen – The ultimate goal for every hydrogen advocate, green hydrogen or ‘renewable’ hydrogen, is made from the electrolysis of water powered by renewable sources such as solar power. This process produces nearly zero CO2.
There are other hydrogen colours, although they are not spoken about as much. The additional primary colour on the horizon is turquoise hydrogen. It is made using molten metal pyrolysis, which involves the thermal cracking of natural gas into hydrogen and solid carbon. The appeal of turquoise hydrogen is twofold. Firstly, the method does not require CCS, and secondly, instead of CO2, it produces a material called natural graphite, which has been on the EU critical raw materials list for years. Some corporations, such as Russia’s Gazprom and Germany’s BASF, are looking into it, but the technology is still in very early stages.
Sadly, less than 5% of the hydrogen produced today is emission-free, and the environmentally friendly kind is much more expensive to produce than the grey version. What’s more, it is currently more expensive than conventional fuels such as diesel. As a result, industries like oil refining use vast quantities of grey hydrogen, which is mainly made by separating hydrogen from natural gas. This process generates more greenhouse-gas emissions than burning diesel.
The push for green hydrogen production is very much in the works. Experts are working on encouraging sources for hydrogen made without producing emissions and in an economical way. One of the most promising green hydrogen production methods is made using a device known as an electrolyzer. The method uses electricity to split water into hydrogen and oxygen. The hydrogen produced is emission-free, provided that the electricity comes from renewable energy sources like solar and wind.
In theory, green hydrogen can do three very useful things:
- Store surplus renewable energy when main grids cannot absorb it.
- Help decarbonise hard-to-electrify sectors such as long-distance transport and the heavy industry.
- Replace fossil fuels as a zero-carbon feedstock in fuel and chemical production.
For the reasons listed above, the research into electrolyzers is crucial for tackling climate change. So let’s now look into the different types of electrolyzers and how they work.
How Does Hydrogen Electrolysis Work?
The hydrogen production process takes place in a unit called an electrolyzer that uses electricity to split water into hydrogen and oxygen.
Electrolysis is an effective method for carbon-free hydrogen production using renewable resources. The hydrogen production process occurs in an electrolyzer that uses electricity to split water into hydrogen and oxygen. Electrolyzers come in a range of sizes, from small appliance-sized features for small-scale distributed hydrogen production to massive units suitable for large-scale central production facilities. The more substantial electrolyzers could be attached directly to renewable energy production sites such as a solar array when it comes to utility projects.
Electrolyzers are composed of an anode and a cathode separated by an electrolyte, similar to fuel cells. Due to the different types of electrolyte material and the ionic species it conducts, different electrolyzers function in different ways. Here are examples of the three main electrolyzers:
- Polymer Electrolyte Membrane (PEM) electrolyzers – In a PEM electrolyzer, the electrolyte is made of a solid speciality plastic material. The water reacts at the anode to create oxygen and positively charged hydrogen ions (protons). The electrons then flow through an external circuit, and the hydrogen ions selectively move over the PEM to the cathode. Once at the cathode, hydrogen ions combine with electrons from the external circuit to form hydrogen gas.
- Alkaline electrolyzers – Alkaline electrolyzers function via the transport of hydroxide ions (OH-) through the electrolyte from the cathode to the anode. Hydrogen is generated on the cathode side. The electrolyzers use a liquid alkaline solution made of sodium or potassium hydroxide. This type of electrolyte has been commercially available for many years, but newer approaches are being tested. For example, solid alkaline exchange membranes (AEM) are being considered in terms of their electrolyte potential.
- Solid Oxide electrolyzer – Solid oxide electrolysis uses a solid ceramic material as the electrolyte, which selectively conducts negatively charged oxygen ions (O2-) at an elevated temperature. This method generates hydrogen in a slightly different way from the two electrolyzers listed above. First, steam at the cathode merges with electrons sourced from the external circuit to produce hydrogen gas and negatively charged oxygen ions. The oxygen ions then go through the solid ceramic membrane and react at the anode to form oxygen gas and generate electrons for the external circuit.
Hydrogen Opportunities in Canada
Canada is set to become one of the leading green and blue hydrogen exporters in the world.
At the end of June 2021, Canada’s Senate approved Bill C-12, which resulted in writing national greenhouse gas emissions targets into law. Canada also proposed a tax credit for carbon capture, use, and storage technology investments in the 2021 budget. The clean fuels initiative and carbon tax represent the additional steps needed to create incentives and the regulatory certainty required to encourage private investment.
Drawing from the similar measure implemented in the United States, the Canadian tax credit will directly support hydrogen production. In addition, there is a public consultation open until 7th September 2021, providing an opportunity to refine and harmonise the role of hydrogen in Canada’s energy transition.
Canada is set to become one of the leading green and blue hydrogen exporters in the world. The country has been considered a global leader in hydrogen technologies over the last 100 years. To maintain Canada’s leadership and allow the country to continue to respond to global market signals, there is a need to scale up investment and increase domestic hydrogen demand.
Canada is currently the world’s fourth-largest hydropower producer, which offers zero-carbon electricity and facilitates green hydrogen production. Canada also has the perfect geology for large-scale carbon sequestration to convert grey hydrogen into blue hydrogen.
British Columbia, Manitoba, Québec and Ontario all have the potential to export green hydrogen made using hydroelectricity and solar energy. Alberta could also repurpose its oil and gas infrastructure and labour force to generate blue hydrogen at globally competitive prices.
Commercial products based on Canadian technologies are now running cars, buses and trains all around the world. But beyond powering clean cars, the links between hydrogen and renewable electricity can help decarbonise steel manufacturing, seasonal energy storage, urban and industrial heating, and aviation. By leading the way in hydrogen and renewable energy sources, Canada has a unique opportunity to move away from a resource-based economy to a low-carbon economy in a single generation.
The main challenge associated with implementing green hydrogen is linked to its production and storage. There have been many hydrogen storage options proposed with the feasibility of different strategies which are dependent on the demands of the target sector.
An ideal energy storage system consists of an electrolyzer that is powered by excess solar electricity coupled with a hydrogen storage system. A fuel cell power generation system would utilise hydrogen to yield and supply power when required. Research teams are working hard to make this technology a viable option, and it may not be long until hydrogen is making an impact on tackling the climate change challenge.
Frequently Asked Questions (FAQs)
Is hydrogen good for climate change?
When hydrogen is produced using renewable energy such as solar power, it could help reduce global emissions and improve energy-intensive sectors like steel-making and transport by replacing fossil fuels.
Can green hydrogen explode?
Hydrogen is a highly flammable fuel, and under certain conditions, could detonate. However, green hydrogen has been proven to be safer than conventional fuels as hydrogen is not toxic. Many conventional fuels are toxic or contain hazardous substances, in addition to being potent carcinogens.
Is hydrogen expensive to produce?
The cost of hydrogen production is a big issue and one that scientists are trying to tackle. Hydrogen produced through the steam reformation method costs around three times the cost of natural gas per unit of energy produced. This means that if natural gas costs $6/million British thermal unit (BTU), then hydrogen will be $18/million BTU.
What is the value of green hydrogen?
Why is hydrogen not already a key part of the energy mix?
Compared to conventional fuels, hydrogen is traditionally more expensive to produce, store and transport. There is also efficiency loss when converting electricity and natural gas to hydrogen, making a case for hydrogen even more tricky. Hydrogen is still energy-intensive to store and deliver.