Biofuels, Alternative/Renewable Fuels
The marine shipping industry, which accounts for 80% of global trade and 3% of annual global carbon emissions,1 must adhere to stringent International Maritime Organization (IMO) goals of reducing total annual greenhouse gas (GHG) emissions by at least 50% below 2008 levels by 2050.2
Bushiri, D., Refinery Automation Institute
The marine shipping industry, which accounts for 80% of global trade and 3% of annual global carbon emissions,1 must adhere to stringent International Maritime Organization (IMO) goals of reducing total annual greenhouse gas (GHG) emissions by at least 50% below 2008 levels by 2050.2 Essentially, GHGs—in the form of carbon dioxide (CO2) emissions—must be reduced by 40% by 2030 and by 70% by 2050 to achieve this goal. Similarly, the European Union (EU) plans to reduce its annual CO2 emissions to 40% below 2005 levels by 2050.3 To achieve these reductions, marine fuels must produce near-zero emissions at every step of their lifecycles.
Large oil companies have been pressured to undertake the GHG emissions footprint reduction. Part of this push is to make green fuels with inherently lower GHG emissions than conventional fossil fuels. The U.S. Environmental Protection Agency (EPA) defines alternative fuels to include gaseous fuels (such as hydrogen, natural gas and propane), alcohols (such as ethanol, methanol and butanol), vegetable and waste-derived oils, and electricity.4 Of these alternative fuels, LNG, hydrogen, ammonia, methanol and biofuels are considered potential green fuels for the marine industry. These alternative fuels must not only reduce emissions, but must also be transportable, storable, producible and inexpensive, and able to generate enough energy to propel large ships across the world.
However, the shipping industry primarily uses hydrocarbons—in the form of heavy fuel oil (HFO) and marine gasoil (MGO)—in its engines because they are cost effective and widely available. To adhere to emissions reductions by 2050, the Institute of Electrical and Electronics Engineers (IEEE) forecasts that at least 50% of all marine engines will run on green fuels by the mid-2040s (FIG. 1).
FIG. 1. Forecast of fuel usage in the marine industry. Source: IEEE.
Significant efforts are required to innovate pathways to use green fuels in existing or new engines and in bunkering/port infrastructures. As an initial step, an assessment of the technical performance and environmental impacts of each future green fuel is required. Multiple factors such as cost, availability, production and infrastructure vary for these fuels and may influence the feasibility of their use. A thorough investigation of these potential fuels is needed to evaluate the practicality and feasibility of each option. Do these green fuels actually reduce GHG emissions? Will they operate with the same throughput as fossil fuels? How much will they cost to implement? For green fuels to be attractive to both shipowners and fuel producers, they must correlate to the functionality of fossil fuels and not just meet the emissions requirements.
Finally, standardized engineering definitions and calculations are needed to be able to make comparisons on an equal basis, such as the use of standardized emissions lifecycle models to calculate carbon footprints.
Green fuels for marine engines
This article examines five potential green fuels for marine engines: LNG, hydrogen, ammonia, methanol and biofuels.
LNG. LNG is leading the race as a substitute green fuel. It has a relatively high energy density of 22.2 MJ/L, a rapidly developing infrastructure and is widely available. However, it is viewed as a non-sustainable transition fuel since it emits 2% more carbon during its lifecycle. LNG has the potential to be a bridge fuel to hydrogen due to similar cryogenic storage requirements.
Hydrogen. Hydrogen is an energy-dense fuel (FIG. 2) and can be produced with no GHG emissions. With an energy density of 8.5 MJ/L, liquid hydrogen can be used in both internal combustion engines (ICEs) and fuel cells. However, the journey using hydrogen sustainably is long winded. At present, gray hydrogen is produced via methane reforming, which emits GHGs comparable to HFOs. Zero-carbon-emissions hydrogen is produced from renewable-electricity-driven water electrolysis, which is more expensive than gray hydrogen production. Although hydrogen-energy dense, it has a much lower energy density vs. fossil fuels, which will result in cargo capacity limitations.
FIG. 2. Energy density of fuels per liter equivalent of fuel. Source: The Royal Society.
Ammonia. With an energy density of 11.5 MJ/L, liquid ammonia is another viable option that can be used in existing engines and bunkering facilities. Used either as a hydrogen carrier or as a fuel, green ammonia can have zero emissions within its lifecycle when produced with green hydrogen or directly via electrochemical cells. However, just like hydrogen, ammonia is less energy dense than conventional fossil fuels. It is also highly toxic and requires strict guidelines.
Methanol. Methanol has a high energy density of 16 MJ/L. It gained popularity due its availability and easy storability. Renewable methanol (i.e., bio-methanol or e-methanol) has the potential of reducing GHG emissions by 65%–95%. However, it is less dense than traditional fuels, and renewable methods are significantly more expensive than conventional fossil-fuel-derived methanol.
Biofuels. Biofuels are the most researched alternative fuel. Several marine engines and fueling infrastructures are compatible with biofuels, with minimum modifications. Bio-derived fuels (e.g., biodiesel) show potential. The major challenge with the use of biofuels in the marine industry is the significant increase in production required to satisfy demand, which will necessitate more land reuse and the elimination of vegetation. The sustainability of biofuels is put into question when the lifecycle analysis and carbon offset are considered. GHG emissions reductions are hindered by land-use changes and other upstream emissions.
These green fuels have the potential to reduce carbon emissions. However, when the exact quantities are presented alongside the lifecycle analysis, their viability is questioned. The primary challenges are that green fuels have lower energy densities vs. conventional fossil fuels. There are also diverse issues regarding availability, port and bunker infrastructure, engine development challenges, cost, supply and safety. The lifecycle emissions further highlight the misconception that people have about green fuels and their emissions reductions.
As a possible solution, a multistage strategy must be developed. Since infrastructure exists for LNG, biofuels and conventional methanol, these fuels can be viable as short-term solutions (5 yr–10 yr). Corporations should start moving away from LNG, gray methanol and biofuels in the medium term (10 yr–15 yr) and begin focusing on converting LNG engines/facilities to use green hydrogen fuel and converting biofuels/methanol to e-methanol. As a long-term solution (15 yr–20 yr), corporations should invest in advancing green ammonia technology. Since ammonia infrastructure already exists and can be used in existing engines/bunking facilities, green ammonia has the capability to be used as a sustainable fuel for the marine industry, while also ensuring zero GHG emissions. It would also be beneficial for diverse fuel alternatives to continue being used to provide flexibility to the industry. Therefore, in the long term, most ships should be fueled by ammonia, while smaller ships can be fueled by hydrogen and existing methanol ships should continue operations using e-methanol.
Statement of the problem
The questions that the marine industry are battling with is which green fuel is the most feasible alternative for short-term and long-term sustainability, and is it realistic? This article provides a review analyzing the feasibility and practicality of several green fuels. First, it is important to consider the source/feedstock and production mechanism used to produce the fuel—the amount of energy required to produce the fuel and the relative cost of production. Then, the practicality of each fuel is investigated based on the port and bunker infrastructure required, fuel engine development, projection of the correlation between fossil fuels, the fuel’s suitability among long-range vessels, supply issues and the associated risks involved. The short-term and long-term initiatives associated with each green fuel are analyzed through an assessment of current and projected technological projects, research and development initiatives and projects, and competing industries. Finally, the overall feasibility outlining the benefits of each fuel and the lifecycle analysis of GHG reduction of each fuel are provided as recommendations.
Part 1 of this article will examine LNG, hydrogen and ammonia. Part 2, to be published in the February issue, will examine methanol and biofuels.
The following are the results and findings for LNG, hydrogen and ammonia.
As a preliminary requirement, an alternative marine fuel should contain less carbon than the existing hydrocarbons used in the industry. LNG is considered an interim potential solution, since it contains less carbon per unit of energy.5 When burned during combustion, LNG will release less CO2 vs. conventional fuels. For years, LNG has been used as a secondary fuel through combusting boil-off gas from LNG cargoes.6 Due to the IMO’s sulfur standard regulations, LNG could act as a fuel replacement. Many companies in the marine industry considered switching to LNG-fueled engines, since they emit less than 0.1% of the fuel-equivalent threshold.7
LNG is produced via the hydraulic fracturing extraction of natural gas, which is then liquefied and stored under cryogenic conditions (–160°C). The main source of natural gas is primarily underground reserves, but some companies utilize biogas. Natural gas in its liquid state is about 600 times smaller in volume than in its gaseous state.8 Therefore, natural gas is liquefied to enable easy global transportation.
In terms of energy requirement, the production process extraction and liquification is energy intensive. It requires a relatively high initial capital investment, which involves exploration, drilling, piping to a coastal liquification plant and the liquification process. In addition, shipowners can expect to pay approximately $5 MM more for an LNG-fueled vessel than one that is run off conventional marine fuels.9 LNG engines require a larger investment than installing scrubbers on ship, which is another alternative solution to adhere to the IMO requirement. However, an offset of the capital investment is expected, due to fuel cost advantages—LNG is the most cost-efficient fossil fuel, once its production infrastructure is secure.10
However, LNG has a lower energy density than diesel. The Alternative Fuels Data Center reports that LNG has a specific energy density of 21,240 Btu/lb and a mass density of 3.49 lb/gal, while low-sulfur diesel has a specific energy density of 18,122 Btu/lb and a mass density of 7.09 lb/gal.11 While the specific energy density is slightly comparable, the large difference in mass densities means that diesel has nearly twice the amount of energy/gal when compared to LNG. Ships fueled by LNG also require more space for fuel tanks, which may limit cargo capacity.
All major shipping companies are either developing, or have already launched, a variety of engines that run on LNG. These technologies include a two-stroke engine and a dual-fuel, slow-speed engine that operates on LNG as the primary fuel and on diesel as a secondary fuel.12 A variety of engines can use LNG or natural gas. These include steam engines, lean-burn spark-ignition engines, low-pressure injection dual-fuel (LPDF) engines, high-pressure injection dual-fuel (HPDF) engines and gas turbines.
Although LNG emits 20%–30% less carbon during combustion, LNG has a large carbon footprint. Pavlenko et al. analyzed LNG’s lifecycle when used in different engines.13 Since LNG is mostly methane, each engine releases unburned methane due to incomplete combustion. Fugitive methane is a more potent GHG than CO2, and its emissions are more detrimental to the environment. To perform a complete lifecycle analysis, the upstream and downstream emissions had to be evaluated. Pavlenko et al. evaluated the upstream emissions of LNG using GHS, regulated emissions and energy use in transportation (GREET) modeled by the Argonne National Laboratory. Downstream emissions were sourced from available company data sets. As shown in FIG. 3, LNG has higher upstream emissions than conventional fuels such as MGO, very-low-sulfur fuel oil (VLSFO) and HFO. These high emissions are a result of high methane emissions due to leakage that occurs during extraction, processing and transport. In addition, the liquification process contributes to upstream emissions. Although LNG has lower downstream emissions than conventional fuels, LNG has a higher total GHG emissions rate when the upstream emissions and methane slips are accounted for, irrespective of engine types.
FIG. 3. Lifecycle GHG emissions by engine and fuel type.5
According to the International Energy Agency (IEA), hydrogen is a potential carbon-zero fuel alternative. With byproducts like water and steam, hydrogen can eliminate pollutants from the transportation industry. Hydrogen is also abundant in the environment and can be produced from diverse sources. Its use in the transportation sector is still in the primary phase. Hydrogen became popular with the use of fuel-cell-powered vehicles. Using hydrogen fuel cells integrated with an electric motor is about three times more efficient than gasoline-powered ICEs.14 Hydrogen is used in light-duty, fuel-cell vehicles; however, can it be used to propel ships across the ocean?
One challenge with using hydrogen as a fuel is its production process. Readily available substances, such as organic matter, water and hydrocarbons, can be used as a source of hydrogen.14 FIG. 4 depicts the relevant sources of hydrogen and their associated names. The most common source of hydrogen is methane/natural gas, which is called gray hydrogen. Steam methane reforming is used to convert methane to hydrogen through the process of synthesis gas generation, hydrogen generation and gas purification. CO2 is the primary dilutant removed during the purification process. Similarly, brown hydrogen is hydrogen that is produced from coal, using the same steam methane reforming (SMR) process.
FIG. 4. The different types of hydrogen production.15
Although SMR is the cheapest way to produce hydrogen, this process emits a significant amount of carbon, resulting in emitting CO2 as a byproduct.15 SMR emits about 10 t of CO2/t of natural gas, while coal produces 19 t of CO2/t of coal.16 To minimize the emissions associated with brown hydrogen, carbon capture technologies are added to the SMR purification step to create blue hydrogen. However, this process relies on fossil fuel sources, which still have a carbon footprint. Hydrogen produced via water electrolysis has the potential to eliminate emissions from this production step. Water electrolysis uses electricity to separate hydrogen and oxygen from water. Electrolysis powered by fossil-fuel-sourced grid electricity is called blue hydrogen, while electrolysis powered by renewable energy is referred to as green hydrogen. While green hydrogen is the most environmentally friendly way of producing hydrogen, it is the most expensive option. Another production option—turquoise hydrogen—is still in the research phase. Turquoise hydrogen is produced through the process of pyrolysis, which converts methane to pure solid carbon and hydrogen.
For hydrogen to be a reasonable fuel alterative, green hydrogen should be the primary type used in engines or fuel cells. Significant investments are required in renewable energy technology. At present, only 3.9% of the hydrogen produced comes from water electrolysis.15 Intervention is needed to reduce the cost of green hydrogen, so that it may be used as a fuel. Fortunately, the cost of green hydrogen has reduced by approximately 50% since 2015 and is forecast to continue to decrease as more projects focus on renewable energy.16 Hydrogen production will also need to increase significantly to meet the demands of the marine industry. Most produced hydrogen is used as a component in the chemical industry and in oil refineries.
Like LNG, hydrogen has a lower energy density than conventional marine fuels. Hydrogen has an energy density of 8.5 MJ/L, which is about 15% less than the energy density of diesel.16,17 Therefore, ship capacity becomes a significant disadvantage for hydrogen’s use in the marine industry. To store the same amount of cargo on board will require fuel tanks to be seven times larger than diesel tanks.16 Hydrogen could be ideal for smaller ships or for shorter trips that have frequent access to bunkering stations. Larger ships would need hydrogen storage that takes up less space on the ship (e.g., ammonia or liquid hydrogen).
Hydrogen must also be stored at high cryogenic conditions (–253°C), requiring expensive bunkering facility requirements and stringent safety procedures. According to the IEA, the cost infrastructure is offset by the cost of fuel when calculated at a 15 yr–20 yr lifespan.17 Once the fuel cost becomes competitive, hydrogen may be a viable fuel alternative in the future.
Hydrogen can be used directly as a fuel in an ICE and in fuel cells to generate electricity. Dual-fuel ICEs are a possible route for hydrogen; whereby, MGO can be used when the hydrogen inventory on ships runs out.15 However, there is presently no hydrogen fuel engine commercially available. There are also no federal regulations for design considerations for the use of hydrogen as a marine fuel, and, therefore, there is no formal approval for its commercial use. The U.S. Coast Guard may approve alternative design proposals for companies on a case-by-case basis.18 The knowledge gained from the use of LNG may bridge to developing design solutions for hydrogen-fueled vessels. Overall, there are many projects geared toward developing hydrogen technologies. For example, the U.S. Department of Energy (DOE) has funded many projects that focus on overcoming hydrogen’s shortfalls.
Hydrogen’s lifecycle analysis as a fuel is dependent on the source of production. Hydrogen production emits 60 MMtpy of CO2, primarily from brown/gray hydrogen production, according to the U.S. EPA. Brown/gray hydrogen and HFO emit roughly the same amount of carbon.16 Like LNG, gray hydrogen has high upstream emissions that results from the extraction of natural gas. This includes methane leakage during the extraction process, along with methane slips during transportation and SMR processes. Blue hydrogen captures approximately 90% of the CO2 emitted during the SMR process.19 However, this option still involves major upstream emissions. Howarth et al. conducted a study on blue hydrogen and found that it emits 9%–25% less CO2 than gray hydrogen. However, since methane is used to power carbon capture technology, fugitive methane emissions are much greater than gray hydrogen. Howarth et al. concluded that the lifecycle GHG emissions of blue hydrogen are 20% times greater than with burning natural gas or coal. Turquoise hydrogen is still being researched, but it has the potential of minimizing carbon emissions from the hydrogen fuel lifecycle. The process produces solid carbon instead of CO2, which eliminates the need for carbon capture. The solid carbon can be used for other applications. However, methane is used as the feedstock and produces significant upstream emissions. These emissions can be reduced by using renewable energy to drive pyrolysis.20 Green hydrogen is the optimal solution, since it does not produce emissions during production or combustion. However, emissions associated with renewable electricity production are not considered.
While some may think of ammonia as a hydrogen storage medium, ammonia can be used as a fuel in marine engines. In recent years, ammonia received a lot of attention as a potential future carbon-zero alternative fuel for the transportation industry. For example, Kang and Holbrook evaluated the feasibility of using ammonia as a fuel in light-duty cars.21 Marine shipping companies are also investing in ammonia-fueled vessels and engines.
Ammonia is a beneficial fuel alternative, since combustion produces only nitrogen and water. It is already shipped globally in huge quantities for the fertilizer industry. Ammonia is a liquid at room temperature and at moderate pressures, meaning it is relatively easy to store, and, despite common misconceptions, ammonia can be relatively safe to use.
Anhydrous ammonia is primarily produced from nitrogen and hydrogen via the Haber-Bosch process. There are different types of ammonia: gray/brown, blue, turquoise and green. The lifecycle emissions and prices are also dependent on the hydrogen production. Nitrogen is separated from air, using a low-energy technology. Additional research is being conducted on novel ways to produce ammonia. Biological nitrogen fixation is a potential source for green ammonia. It uses the nitrogenase enzyme to catalytically convert atmospheric nitrogen to anhydrous ammonia.22 Electrochemical cells can also be used to convert water and nitrogen to green ammonia, which can eliminate the need for a separate hydrogen production step. Renewable energy may be used in this process to ensure zero carbon emissions.
With a density of 11.5 MJ/L, ammonia is twice as dense as hydrogen and more dense than liquid hydrogen.21 However, ammonia is less dense than diesel and requires less fuel tank capacity than hydrogen. Since ammonia is a liquid fuel at room temperature and has similar properties to propane, it can be used in existing bunkering facilities. Minor changes to materials on vessels would be needed to ensure safety on board. Material compatibility requirements for shipping ammonia are well known and can be easily implemented at bunkering facilities and on marine vessels.
Regarding ammonia supplies, global ammonia production would have to significantly increase to meet global fuel demand. All the raw materials are readily available in the environment to meet the demand; however, large amounts of electricity will be required.23 More bunkering facilities must be built to accommodate the increased production.
The associated risk with using ammonia is its toxic and corrosive nature. While ammonia is a toxic chemical requiring strict safety precautions, it is less flammable than hydrogen and LNG. It has the potential to emit nitrous oxide, which can be eliminated with the use of a catalyst to favor the reaction that produces atmospheric nitrogen and water as combustion products.
Corporations are in a race to develop different engines to facilitate the use of ammonia as a fuel. These technologies include two-stroke and four-stroke ammonia engines, as well as ammonia fuel cells that will convert ammonia to hydrogen to produce electricity. One major shortfall of ammonia is its inability to ignite quickly. Secondary fuels, such as hydrogen or conventional fuels, could solve this issue in a dual-fuel ICE. Another solution is to develop a spark-ignited gas engine to facilitate the combustion of ammonia.
Part 2 will be published in the February issue. HP
- Sirimanne, S., et al., “Review of maritime transport 2019,” United Nations Conference on Trade and Development, 2019, online: https://unctad.org/system/files/official-document/rmt2019_en.pdf
- IMO, “Initial IMO GHG Strategy,” IMO, London, UK, 2018, online: https://www.imo.org/en/MediaCentre/HotTopics/Pages/Reducing-greenhouse-gas-emissions-from-ships.aspx
- Kallas, S., “Roadmap to a Single European Transport Area—Towards a Competitive and Resource-Efficient Transport System,” European Commission, 2011.
- U.S. EPA, “Renewable Fuel Standard Program: Alternative Fuels,” https://www.epa.gov/renewable-fuel-standard-program/alternative-fuels
- Pavlenko, N., B. Comer, Y. Zhou, N. Clark and D. Rutherford, “The Climate Implications of Using LNG as a Marine Fuel,” International Council on Clean Transportation, January 2020, online: https://theicct.org/publications/climate-impacts-LNG-marine-fuel-2020
- DNV GL, Highlight Projects in the LNG as Fuel History, fact sheet, 2016, https://www.dnvgl.com/Images/LNG%20as%20fuel%20highlight%20projects_new_tcm8-6116.pdf
- Thomson, H., J. Corbett and J. Winebrake, “Natural Gas as a Marine Fuel,” Energy Policy, December 2015.
- U.S. EIA, “Natural Gas Explained: LNG,” online: https://www.eia.gov/energyexplained/natural-gas/liquefied-natural-gas.php
- Saul, J. and N. Chestney, “New Fuel Rules Push Shipowners to Go Green with LNG,” Reuters, August 15, 2018, online: https://www.reuters.com/article/us-shipping-fuel-lng-analysis/new-fuel-rules-push-shipowners-to-go-green-with-lng-idUSKBN1L01I8
- Parfomak, P., J. Frittelli, R. Lattanzio and M. Ratner, LNG as a Maritime Fuel: Prospects and Policy, Congressional Research Service, February 2019, online: https://sgp.fas.org/crs/misc/R45488.pdf
- Alternative Fuels Data Center, “Fuel Properties Comparison,” U.S. DOE, May 21, 2017, online: https://www.afdc.energy.gov/fuels/fuel_properties.php
- MI News Network, “10 Noteworthy LNG-Powered Vessels, Marine Insight, November 5, 2020, online: https://www.marineinsight.com/tech/10-noteworthy-lng-fueled-vessels
- Pavlenko, N., B. Comer, Y. Zhou, N. Clark and D. Rutherford, “The Climate Implications of Using LNG as a Marine Fuel,” International Council on Clean Transportation, January 2020, online: https://theicct.org/publications/climate-impacts-LNG-marine-fuel-2020
- Alternative Fuels Data Center, “Hydrogen Basics,” U.S. DOE, online: https://afdc.energy.gov/fuels/hydrogen_basics.html
- Maritime Industry Decarbonization Council, “Alternative Marine Fuels,” online: https://midc.be/alternative-marine-fuels
- Mamlis, S., “Understanding the Potential of Hydrogen as a Marine Fuel,” Safety4Sea, February 4, 2021, online: https://safety4sea.com/understanding-the-potential-of-hydrogen-as-a-marine-fuel/?__cf_chl_jschl_tk__=pmd_IlJlUi.ixeTztLykhkLsTLjQ43Isvn8m5pkdftDVpco-1630288035-0-gqNtZGzNAqWjcnBszQjR
- Lan, R. and S. Tao, “Ammonia as a Suitable Fuel for Fuel Cells,” Frontiers in Energy Research, August 2014.
- Pribyl, S. and J. Haines, “Future Fuels in the Maritime Sector—Building the Bridge to Hydrogen,” Holland & Knight, April 16, 2021, online: https://www.hklaw.com/en/insights/publications/2021/04/future-fuels-in-the-maritime-sector-building-the-bridge-to-hydrogen
- Howarth, R. and M. Jacobson, “How Green is Blue Hydrogen?” Energy Science & Engineering, August 2021.
- Florence School of Regulation, “Between Green and Blue: A Debate on Turquoise Hydrogen,” March 18, 2021, online: https://fsr.eui.eu/between-green-and-blue-a-debate-on-turquoise-hydrogen
- Kang, D. W. and J. H. Holbrook, “Use of NH3 Fuel to Achieve Deep Greenhouse Gas Reductions from U.S. Transportation,” Energy Reports, November 2015.
- Cherkasov, N., A. O. Ibhadon and P. Fitzpatrick, “A Review of the Existing and Alternative Methods for Greener Nitrogen Fixation,” Chemical Engineering and Processing: Process Intensification, April 2015.
- Cord, D., “Successful Tests Pave the Way for Ammonia as a Future Marine Fuel,” Wartsila, July 1, 2020, online: https://www.wartsila.com/insights/article/successful-tests-pave-the-way-for-ammonia-as-a-future-marine-fuel
Bushiri, D. - Refinery Automation Institute, Morristown, New Jersey
Daniela Bushiri is a Chemical Engineer at the Refinery Automation Institute, where she leads research and development in marine green fuel evaluations. Previously, she was involved in a U.S. Gulf Coast refinery blending modernization project. She is pursuing a doctorate in chemical engineering at Columbia University in New York.
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Ethanol. Ethanol is a widely used renewable fuel made from corn and other plant materials. It is blended with gasoline for use in vehicles.What are the alternative fuels for marine engines? ›
The introduction of several alternative marine fuels is considered an important strategy for maritime decarbonization. These alternative marine fuels include liquefied natural gas (LNG), liquefied biogas (LBG), hydrogen, ammonia, methanol, ethanol, hydrotreated vegetable oil (HVO), etc.Is methanol better than LNG for marine fuel? ›
Compared with LNG, methanol fuel systems are less costly and easier both for the yard to fit – in particular on smaller vessels – and for the owners to operate. 2022 was the year in which methanol established itself as an alternative to LNG with engine makers reporting record high interest for methanol capable engines.What is the difference between MGO and HFO? ›
Marine gasoil usually consists of a blend of various distillates. Marine gasoil is similar to diesel fuel, but has a higher density. Unlike heavy fuel oil (HFO), marine gasoil does not have to be heated during storage. Marine gasoil and standard heating oil largely share the same properties.What is the cleanest burning biofuel? ›
Biodiesel is a domestically produced, clean-burning, renewable substitute for petroleum diesel. Using biodiesel as a vehicle fuel increases energy security, improves air quality and the environment, and provides safety benefits.What is the best survival fuel? ›
Propane, alcohol, wood, and charcoal are examples of good emergency storage fuels that can be stored indefinitely and still remain viable. The more appropriate question is which fuel has the longest shelf life and will meet my needs.What is the best alternative fuel for ships? ›
Liquefied natural gas (LNG)
Also, its carbon dioxide emissions are approximately 20 per cent lower than that of distillate fuels and very low sulphur fuel oil (VLSFO) products.
Marine fuels are very similar to the types of fuel you would use in your car, but they're created specifically for use in boats and other water craft.What is the most used marine fuel? ›
HFO or heavy fuel oil is the most widely used type of fuels for commercial vessels. The fuel oil releases energy to rotate the ship propeller or the alternator by burning fuel inside the combustion chamber of the engine or to generate steam inside the boiler.What is the disadvantage of methanol fuel? ›
A main drawback of direct methanol fuel cells (DMFCs) is the very sluggish anode reaction, which coupled with the inefficient cathode reaction, gives rise to low overall performance, particularly at low temperatures.
Some of the disadvantages of Methanol are that although its emissions are safer than that of gasoline, it has a high amount of formaldehyde emissions. As with Ethanol, it gets less gas mileage, so it would require more frequent fueling.What is the difference between blue methanol and green methanol? ›
Blue methanol is produced using blue hydrogen in combination with carbon capture technology, vastly reducing well-to-tank carbon dioxide emissions. Green methanol may be bio-methanol produced from biomass or e-methanol produced from green hydrogen, captured CO2 and renewable electricity.Is MDO the same as MGO? ›
While MGO is made only from distillates, MDO is a distillate blended with HFO that may contain very small amounts of black refinery feed stock. When residual fuel oil is blended with distillates, the blend is called Intermediate Fuel Oil (IFO).Which MGO is best? ›
MGO Manuka Honey – What The Labels Mean
The higher the number, the higher the level of plant phenols inside the jar. We recommend the lower levels of MGO Manuka Honey for daily use, while the higher strength Manuka is used when you need more support in your daily diet - such as during cold and flu season.
Also from the given option, CaO is the only s-block metals oxide. So it most closely resembles properties of MgO. Hence most suitable replacement of MgO would be Calcium Oxide CaO (option B)What is the most promising biofuel? ›
DEA assigns an efficiency score to each biofuel, ranking them from best to worst. Renewable diesel was found the best fuel type, followed by biodiesel and ethanol. Waste biomass is preferred over lignocellulosic and 1st generation carbon sources.What is the most environmentally-friendly biofuel? ›
Biodiesel is a greenhouse gas reducing, advanced biofuel that is a great alternative for diesel users. Biodiesel is not only sustainable, it's a more environmentally-friendly, cleaner-burning option that can be used in diesel engines without modification.What is the cheapest and cleanest fuel? ›
Natural Gas is Clean and Economical
In fact, natural gas is the most economical source for home energy needs, costing one-third as much as electricity.
Carbohydrates, such as sugar and starch, for example, are readily broken down into glucose, the body's principal energy source. Glucose can be used immediately as fuel, or can be sent to the liver and muscles and stored as glycogen.Which fuel will last the longest on earth? ›
Conclusion: how long will fossil fuels last? It is predicted that we will run out of fossil fuels in this century. Oil can last up to 50 years, natural gas up to 53 years, and coal up to 114 years.
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The primary petroleum-based fuels aboard Navy vessels are aviation gasoline, jet propulsion fuel (JP-51, Navy distillate, Navy special fuel oil, and diesel fuel marine. These fuels are transported to Navy vessels by Navy oilers.What fuel do most cruise ships use? ›
Most cruise ships burn heavy fuel oil (HFO), which is the dirtiest fossil fuel available. Most of these ships also do not have any diesel particulate filters or selective catalytic converters to clean the exhaust – technologies that are standard for road vehicles like trucks.What is the best gas for a boat motor? ›
Choosing Boat Fuel. All of the current boat models that have outboard, sterndrive, and inboard gasoline engines use fuel with no more than 10% ethanol. Accordingly, this fuel is known as E10. You should never use E15, E85, or another type of fuel with a higher concentration of ethanol.What is the best fuel for outboard motors? ›
Current recommendations are to use a minimum of 87 octane, 89 octane is preferred. There is no additional benefit from using higher-octane fuels, in fact they may cause hard starting conditions in hot weather.What is the best motor oil for inboard marine engines? ›
AMSOIL SAE 10W-40 Synthetic Marine Motor Oil
AMSOIL Synthetic Marine Engine Oil is recommended for gasoline-fueled four-stroke outboard, inboard, inboard/outboard (I/O) and personal watercraft motors.
Although REC-90 is marketed to the marine industry and is commonly found at marinas, there are other octane levels of ethanol-free gasoline on the market such as ethanol-free 87 or 92 octane. While always refer to your owner's manual, these other common octane levels are typically suitable for marine engines.Can I run 87 octane in my boat? ›
All of the later model boats have high compression engines that were designed to run on 93 octane (US Octane) fuel. They all have the ability to run on 87 but that does NOT mean you are getting the best out of your boat.What uses 63000 gallons of marine fuel per day? ›
A Panamax container ship can consume 63,000 gallons of marine fuel per day at that speed. Fuel use drops sharply as speeds decrease. A container ship can decrease fuel use close to one-third if it drops its speed 10%.What is the most environmentally-friendly fuel? ›
CNG or compressed natural gas is a smoke-free gas and does not spread pollution, and thus used in our vehicles. Therefore, CNG is considered as an eco-friendly fuel.
Out of all energy resources, we consider green power (solar, wind, biomass and geothermal) as the cleanest form of energy. So, if we were looking at clean energy on a spectrum, these would be farthest from “dirty” or emissions-heavy energy.What is the best home fuel for the environment? ›
- Solar Heating. Solar power is one of the best ways to power homes as solar energy is the most energy-efficient. ...
- Pellet Heating. ...
- Wood Burners. ...
- Wind Power. ...
- Geothermal Heating. ...
- Masonry Heater. ...
- Hydronic Heat Systems.
Alternative fuels include gaseous fuels such as hydrogen, natural gas, and propane; alcohols such as ethanol, methanol, and butanol; vegetable and waste-derived oils; and electricity.What fuel has lowest emissions? ›
Hydrogen Fuel Has the Lowest Carbon Footprint at 0 Pounds of CO2 Emitted Per Gallon. Hydrogen (H2) is a colorless, odorless, tasteless, flammable gas and is the most abundant element in the universe.Which is the least polluting fuel for a? ›
Least polluting fuel for vehicles is compressed natural gas (CNG).Which is the most less polluting fuel? ›
Natural Gas : The Least Polluting of the Fossil Fuels | Energy and Climate: Vision for the Future | Oxford Academic.What are the 3 most cleanest renewable energy? ›
The three main sources of clean energy are wind energy, solar energy, and hydroelectric energy.What is the cheapest green energy? ›
What is the cheapest renewable energy source? Hydroelectric power is currently the cheapest renewable energy source, costing $0.05 per kilowatt-hour on average. Hydroelectric power is the cheapest because the infrastructure has been in place for a long time, and it produces electricity consistently.What is the least efficient green energy? ›
The least efficient renewable energy source is solar thermal energy. This is different from the solar power we normally think of that converts the sun's rays into energy. Solar thermal energy uses the sun's heat to create steam, which then turns a turbine to generate electricity.What is the cleanest fuel source? ›
Nuclear is a zero-emission clean energy source. It generates power through fission, which is the process of splitting uranium atoms to produce energy. The heat released by fission is used to create steam that spins a turbine to generate electricity without the harmful byproducts emitted by fossil fuels.
Hydrogen gas is a clean-burning fuel, because when it is combined with oxygen in a fuel cell, hydrogen produces heat and electricity with water vapor. So, hydrogen fuel does not produce any harmful gases, so it is considered as the cleanest fuel.What is the safest and cleanest fuel? ›
Natural gas one of the safest and cleanest fuels available. It emits less pollution than other fossil fuel sources. When natural gas is burned, it produces mostly carbon dioxide and water vapor -- the same substances emitted when humans exhale.