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  • Hydrogen Cars – something doesn’t smell right
  • lesshaste
    Full Member

    Ammonia energy storage? Does anyone know if this is going anywhere? Seems like it may be a way round storing H2.

    I read a while ago that Australia were pushing for an ammonia economy to be set up around the pacific rim, the ammonia to be supplied by them from all the renewables they were going to build.

    Full Member

    Yes, Ammonia is a thing and has some advantages – easier storage being one.

    Some info below on a few different options. One thing to note – no individual solution is “best”. Some simple facts on Ammonia and some other options for fuels / storage in this blog from my work here. The key word here is “journey” – as a planet we can’t switch immediately even if everyone wanted to, so it’s a pragmatic set of changes.

    You may have been reading about alternative fuels on this blog—or elsewhere. We know it can be confusing. So here is a handy glossary to help you remember the difference between diesel, renewable diesel, biodiesel, and other fuels.

    Ammonia is a chemical used industrially on a large scale as a precursor to a variety of nitrogen-containing substances, such as fertilizers and explosives. It also has many other applications, ranging from being used as a glass cleaner, to a reagent used in flue gas scrubbing systems, to being used as a rocket fuel (the X-15, an experimental rocket-power aircraft, which still holds the speed record for a manned aircraft, ran on ammonia).

    Ammonia has also seen some historical use as a motor fuel. During World War II, for example, the Belgian regional bus company converted some of its buses to run on ammonia due to the shortage of diesel fuel.

    Almost all ammonia being manufactured today is obtained via a chemical reaction between hydrogen and nitrogen. Since most hydrogen used for this purpose is made from natural gas using a process that releases significant amounts of CO2, manufacturing of ammonia is CO2-intensive. If green hydrogen is used, however, ammonia can be made with no or minimal CO2 emissions. In other words, green ammonia can be made.

    This is of interest for industries that are heavy users of ammonia. Fertilizer companies such as Spain’s Fertiberia, for example, are actively pursuing this strategy.

    In the transportation sector, green ammonia is seen as an energy carrier that is easier to handle and store than green hydrogen. The shipping industry, in particular, has shown substantial interest in powering large ship engines with ammonia. A recent survey by Lloyd’s register indicates industry participants expect ammonia use in the shipping industry will significantly increase in the next 10 years.

    In Japan, where utilities are looking for ways to keep their coal-power plants open, green ammonia is used as a partial substitute for coal in pilot projects. In the long term, supporters see green ammonia as a way to turn existing power plants into zero-emissions facilities by 2050.

    Biodiesel is a renewable low-carbon intensity or carbon-neutral fuel made from fats such as vegetable oil, animal fats or used cooking oil through a chemical process known as transesterification. The oils can also be blended with diesel to reduce well-to-wheels CO2 and other polluting emissions. Blends with varying proportions of biodiesel are available. B20, containing 20% biodiesel, is a common blend which advantageously balances cost and emissions. It can be used in most engines with no modifications. Many Cummins Inc. diesel engines can run on B20, and the company plans to make its new engines compatible with an increasing range of biodiesel blends. Besides motor vehicles, biodiesels are used across a range of industries, from data centers to ships.

    Diesel is a fossil fuel obtained from oil. It is relatively cheap, widely available and performs well. Diesel engines are durable, reliable, and can provide all the torque needed for heavy-duty applications. The infrastructure needed to produce, transport and distribute diesel is universally available. Diesel, however, is not without drawbacks. Besides causing greenhouse gas emissions, diesel vehicles release nitrogen oxides, carbon monoxide, soot, and other pollutants. All of these cause air pollution and can be harmful to human health. Regulations on the use of diesel are therefore tightening in countries around the world. Diesel may lose some ground to alternative fuels, but it is not about to go away. Diesel engines have come a long way towards cleaning up their emissions. And while no aftertreatment system can truly scrub CO2 emissions from diesel engines, there are applications where it will make more sense to offset CO2 emissions somewhere else than to seek to directly decarbonize the application. The emission reductions capability of alternative fuels should be evaluated when making a selection.

    Hydrotreated vegetable oil (HVO) or renewable diesel is made from vegetable fats and oils. It can be used in most diesel engines without modification, across all Cummins standby generator sets and many Cummins engines used for on-highway applications. Used as a drop-in replacement for diesel, it performs equally well. After factoring in the emissions associated with the processing, transportation and distribution, HVO well-to-wheels emissions are about 70% lower than those of diesel.

    The use of HVO is limited by the amount that can be made using existing production plants—about 550 million gallons per year in the United States. Multiple new plants are under construction, which should significantly expand the amount of HVO available and may lead to an increase in adoption.
    There are a range of examples of companies that are successfully using alternative fuels. Companies such as Microsoft, for example, have switched to HVO fuel for their Cummins-supplied generators that provide backup power to its data centers in Des Moines, Iowa (U.S.) and Phoenix, Arizona (U.S.).

    Green hydrogen, or hydrogen made using renewable energy, may very well be the green energy carrier of the future. Green hydrogen can fuel both fuel cell electric vehicles and vehicles equipped with an internal combustion engine specially modified for hydrogen. Hydrogen will make a lot of sense for heavy-duty commercial applications, which is why Cummins is currently developing a 15-liter and a 6.7-liter hydrogen engine. Cummins’ hydrogen fuel cells are already powering vehicles around the world—from buses and trucks to trains. Besides being manufactured using renewable energy, part of hydrogen’s appeal is that the main waste product of hydrogen combustion or fuel-cells is water, and although hydrogen fueled internal combustion engines will have NOx emissions, they can be reduced to very low levels.

    Natural gas has been used as a fuel in vehicles for decades and is the most widely used alternative fuel. It performs as well as diesel in vehicles, and in some cases lowers emissions of greenhouse gases and other pollutants such as NOx and particulate matter. Natural gas is therefore a popular choice for heavy vehicles that operate in urban environments, such as garbage trucks, buses and delivery trucks.

    Natural gas is also widely used in stationary applications. Natural gas, for example, can be used in highly efficient cogeneration systems providing electricity, heat, and, in some cases, cooling. Cummins has supplied equipment for numerous cogeneration systems, such as the system at Clark University, in Massachusetts (U.S.), where Cummins supplied a 2 MW QSV91G gas generator.

    Renewable natural gas is obtained from biogas, a methane-rich gas resulting from the fermentation of organic waste such as cow manure, sewage sludge or landfill organics. Adequately processed, renewable natural gas is nearly indistinguishable from natural gas. It can be used in any natural gas engine and in many industrial applications, such as power generation, giving up to a 97% reduction in CO₂, compared with diesel. Renewable natural gas is already emerging as a fuel for prime power generation in niche applications near to sources of renewable natural gas. Cummins carried out one such project in Delaware (U.S.) where landfill gas is used to power a combined heat and power (CHP) system to provide industrial customers with clean energy.

    Green hydrogen can be blended with natural gas and injected into existing natural gas distribution systems. This automatically reduces the carbon intensity of all natural gas uses served by the pipeline. Using pipeline systems to distribute fuel blends that include hydrogen is not new and, for example, has been practiced for years on the island of Oahu in Hawaii (U.S.). Various pilot schemes plan to replace up to 20% of natural gas by volume content in distribution systems and blending will be widespread in Europe over the next 10 years, with the U.S. not far behind.

    Methanol, also known as wood alcohol, is a promising energy carrier derived from hydrogen or from biomass. Unlike hydrogen, methanol is a liquid at ambient temperature, making it easier to store and handle. It can be readily synthetized from hydrogen using well-known industrial processes. Methanol is a versatile fuel that is being used in a variety of applications today including Indy cars and monster trucks.

    Several pilot projects designed to produce methanol from captured CO₂ and green hydrogen are up and running with more to come on-line in the next five years. The development of the process will be linked to the expansion of green hydrogen and CO₂ capture technologies.

    When choosing an alternative fuel, it is important to consider the advantages and disadvantages of the alternative fuel and its state of adoption.

    Full Member

    Thanks WGU very interesting.

    Full Member

    Some good insights into Hydrogen here, from the company I used to work for, Ricardo.
    They talk a bit about the various applications and uses for it.

    If you click through on some of the links there is some more info, including a free technical update PDF download on this page

    Free Member

    I think ammonia got covered a few pages back.

    It’s not “a way round storing hydrogen” as such, it’s a fuel you can sort-of use instead of other fuels but the byproduct is NOx rather than CO2.

    Ammonia NH3
    Methane CH4

    NOx is not good for environment.

    It’s produced from oil and gas (or coal). The upside is you can then capture and store the carbon part of it at the refinery rather than trying to do it on the ship or wherever. It’s already widely produced as an industrial product as it’s the main component in fertilizer, the “new” bit is trying to create a market for it as a fuel.

    On a small-ish scale you can also thermally/catalytically crack the NH3 back to N2 and H2 and put the H2 through a fuel cell, but you’re trading easier storage for another expensive step in the system that adds inefficiency.

    Full Member

    Ammonia is produced from hydrogen so every problem with potentially manufacturing green hydrogen in the future is also a problem with manufacturing green ammonia. In addition ammonia must be produce by reacting it with nitrogen from the atmosphere at high temperatures and pressures, so it is even more expensive than hydrogen.  And if you burn it as a fuel in an ICE vehicle it is way less efficient than H2 in a fuel cell so you need to produce even more which makes it more expensive again – and of course by burning it as an ICE fuel you make NOx which is a major pollutant that an H2 fuel cell avoids.

    As a liquid it is generally much easier to store and handle than hydrogen, which is helpful.  But it is toxic so any leaks from the storage, especially such as if a tank was broken in a road accident, would mean a large cloud of toxic gas wafting around potentially killing more people than the original impact.  So it is not all roses.

    Overall compared to hydrogen, ammonia trades higher cost and a toxic risk for easier handling.  But like “green hydrogen” it is a long way away from being produced at the industrial quantities we would need for our transport system because you need so much green electricity that is not available today – but for ammonia even more again than for hydrogen.  So for the foreseeable future it is at best a possible alternative to H2 for large HGVs, ships, etc, not a credible  alternative to EVs for cars.

    In the long term, supporters see green ammonia as a way to turn existing power plants into zero-emissions facilities by 2050.

    So you get green electricity to inefficiently make green hydrogen to inefficiently make green ammonia to burn and inefficiently make . . . . . green electricity?  What is that all about, other than keeping Japanese coal fired power stations open?

    Full Member

    In the long term, supporters see green ammonia as a way to turn existing power plants into zero-emissions facilities by 2050.

    Burning ammonia also creates a massive amount of NOx (lots more than burning gas), so there’s no way at all that you can call it zero emissions.  Ammonia as an LH2 carrier is another tough sell, but a direct ammonia fuel cell is a subject of interest, especially for heavier industries.

    Free Member

    So you get green electricity to inefficiently make green hydrogen to inefficiently make green ammonia to burn and inefficiently make . . . . . green electricity?  What is that all about, other than keeping Japanese coal fired power stations open?

    I presume the plan was more like

    Australian coal -> Ammonia + CCS -> no carbon emission power stations -> ecological devastation of Korea due to acid rain.

    Full Member

    I presume the plan was more like Australian coal -> Ammonia + CCS -> no carbon emission power stations

    Maybe, but still makes no sense compared to: Australian coal -> electricity & CCS in a power station. No need to make ammonia to then burn it in a Japanese power station?

    Full Member

    As per the info I posted above – as well as the other (non green) approaches ammonia can be produced from H2 which can be produced from electricity (from solar / wind etc as well as from non-green sources) but it’s use is an an additional step from using H2 then it’s another step less efficient than H2. So it’s use would realistically be for applications where the storage benefits of ammonia outweigh the loss of efficiency compared to H2.

    It’s all a series of compromises which mean that different solutions best fit different applications – but that’s engineering for you.

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