Biofuels are fuels, which are chemically similar to gasoline and diesel, but are produced by processing crops, algae or microbial culture. The carbon in biofuels comes from carbon dioxide that plants convert to their biomass through photosynthesis.
Biofuels are regarded as promising alternative to satisfy growing energy demands. Biomass derived biodiesel and bioethanol can be successfully utilized in modem vehicle engines with little or no modifications and thus contribute to lower combustion emissions in comparison to the former. Automobile engines can burn gasoline blended with 5%–10% bioethanol with little or no modifications. Biodiesel with lower blends of 2% and 5% in diesel fuel has been found to run successfully in both existing and newer diesel engines without modification and even blends with up to 20% biodiesel can be used.
Generally, biofuels are classified into three or four generations, based on the source of raw materials. First-generation (1G) biofuels are extracted from edible feedstocks. Second-generation (2G) biofuels are produced from non-edible feedstocks, and agricultural residue, the latter being obtained from edible feedstocks. Agricultural residues can be rice straw, rice husk, sugarcane bagasse, etc. Third-generation (3G) ones involve sources that do not compete for land, such as microalgae, waste animal fat, and waste cooking oil. Fourth-generation (4G) biofuels consist of solar fuels and electro-fuels.
Primary sources of biofuels include soybean, corn, forestry, agricultural crops, also the waste from food services as well as ago industries. These fuels are available in solid, liquid, or gaseous forms and are chiefly used in various end use applications counting generation of energy, transportation fuels, lubrication & greasing, cooking purposes, charging of electronics and others.
Bioethanol can be produced from sugar-based materials such as sugarcane, beet, molasses, starch-based feedstock like corn, wheat, potato, and cellulosic-based feedstock such as rice straw, bagasse. The steps for producing bioethanol typically involve extracting the sugar from the raw materials, fermenting the sugar into bioethanol, and then running a distillation process to purify the bioethanol
Bioethanol and biodiesel are the two most popular biofuels that are being used as substitutes for regular gasoline and diesel. Some of the commercially used biofuels are biomethane, bioethanol, and biodiesel where in biomethane is manufactured by using domestic and agricultural wastes, bioethanol is produced from sugar beet, wheat, and algae. Further, biodiesels are manufactured using animal fats, algae lipids and vegetable oils.
Biodiesel can generally be obtained from both edible and non-edible oils such as corn, palm, soybean, sunflower, castor and also animal fats and chicken skin, and waste cooking oil. Microemulsion, thermal cracking, and transesterification are the commonly used processes for producing biodiesel
For example, Brazil, being one of the leaders in biofuels, provides a unique setting to increase the knowledge about biofuel policy and the interactions within and between the gasoline and ethanol markets. Policy in Brazil includes a mixture of 27% ethanol and 10% biodiesel by volume, and 100% hydrous ethanol is marketed in all gas stations in the country. In China, four biofuel standards have been set up since 2001: the Denatured Fuel Ethanol (GB, 18350) and Ethanol Gasoline for Motor Vehicles (GB, 18351) both initiated in 2001, Biodiesel Blend Stock (GBT,20828) initiated in 2007, and Biodiesel Fuel Blend (GBT 25199) initiated in 2010.
Production of biofuel is drawing sound attention all over the world and its global production is over 35 billion litres . In 2009 Europe decided in its Renewable Energy Directive (RED) that every member state should have at least 10% renewable energy in transport fuel by 2020. Subsequent ‘national renewable energy action plans’ (NREAPS) suggested that almost all (9.4%) of this renewable energy in 2020 would consist of biofuels.
As of 2019, USA and Brazil produce close to 62% of global biofuel with 697,000 barrels of oil equivalent and 444,000 barrels of oil equivalent, respectively (BP, 2020). The USA primarily produces bioethanol from corn (starch-based) while Brazil mainly relies on sugarcane (sugar-based). Global biodiesel production stood at 699,000 barrels of oil equivalent in 2019 and is predicted to reach 41.4 billion litres by 2025. Among Asian countries, Indonesia, Malaysia, and Thailand produced the highest amounts of biodiesel with palm oil being the leading feedstock. Besides being a renewable resource with lower greenhouse gas emissions, biofuels are also cleaner in the sense that they produce less particulate matter after burning.
Adequate production not only serves as long term replacement of fossil fuels, but it also offers novel opportunities to diversify income and fuel supply sources, promotes rural employment and notably helps in reducing greenhouse gas (GHG) emissions.
Biofuel Challenges economic viability
A critical barrier to widespread commercialization and market competitiveness of advanced alternative fuels is the issue of scaling, supply of raw materials, additional costs related with need of biomass pretreatment processes. US efforts to use food crops as green fuel sources have been criticised for raising global food prices, eroding soil quality and increasing instead of reducing greenhouse gas emissions.
Unfortunately, our energy needs far out-pace our ability to grown biomass to make biofuels for one simple reason, land area. There is only so much land fit for farming in the world and growing biofuels necessarily detracts from the process of growing food. As the population grows, our demands for both energy and food grow. At this point, we do not have enough land to grow both enough biofuel and enough food to meet both needs. The result of this limit has an impact on both the cost of biofuel and the cost of food. For wealthier countries, the cost of food is less of an issue. However, for poorer nations, the use of land for biofuels, which drives up the cost of food, can have a tremendous impact.
The energy balance for ethanol production refers to the energy used to grow and process the raw material into ethanol versus the energy contained in the ethanol itself. When cellulosic residues are used as raw mate¬rials, there is no doubt that ethanol production will have a strongly positive energy output. However, when cornstarch is used as a raw material, the energy bal¬ance is not conclusive. A 2005 study from Cornell University found that producing ethanol from corn used almost 30% more energy than it produced. In other words, you can’t produce a perpetual motion machine using biofuels because you lose the energy you invest in creating them in the first place. In fact, you can’t even break even.
“The Department of Energy is investing a lot of money into algae-based fuels, which are promising, but often the greenest fuels are also the most expensive ones,” says Emily Cassidy, a research analyst at the Washington, DC-based Environmental Working Group. Since it costs more to turn seeds, weeds, or beef trimmings into usable fuel than it does to extract fossil fuels from the ground and refine them, it’s all but impossible for the fleet to use substantial amounts of biofuels with crude oil prices are as low as they currently are.
That said, it’s not necessarily economics that have been holding back the wider use of biofuels, says Professor Chris Somerville, who holds the Philomathia Chair in Alternative Energy at the University of California, Berkeley. The greater problem, he says, has been producing enough of it. Despite the supply chain problems, biofuel is less competitive than fossil fuel ono price as the immature technique or high biomass costs. So government’s policy support is key to the survival of biofuel companies.
The cost of alternative fuels is heavily dependent on biomass availability, origin, and feedstock treatments. Finding more efficient energy crops and cost-effective materials for alternative fuel production, as well as, development of more efficient conversion technologies will lead to a significant cost reduction in the production of alternative fuels and increasing their competitiveness compared to fossil fuels.
Advanced fuels production promotes technology concepts, such as power-to-X, X-to-liquid and waste-to-energy, which facilitate the low-carbon economy development.Alternative fuel production will contribute to the realization of ’zero emission’ and ’zero waste’ concepts.
China plans nationwide use of biofuel petrol
By 2020, all petrol for vehicles will need to contain at least 10 per cent ethanol – a renewable fuel made from corn and other plant materials, according to a statement released by the National Development and Reform Commission, the National Energy Administration and other departments. The Chinese government is pledging to reduce greenhouse gas emissions and investing heavily in electric cars. It has already introduced ethanol in petrol across 11 provinces, including Jilin, Liaoning and Guangxi. Other countries including the United States and Brazil require petrol to contain a certain amount of ethanol. The US and Brazil pioneered the use of ethanol as fuel but mainly produce it from corn and sugar cane. As well as using up stockpiles of corn, China wants to produce ethanol from cellulose – a plant’s stringy fibre rather than its seeds or fruit – in a “structural way” by 2025.
Some 5 per cent of the 170 million tonnes of corn and cassava China trades on the international market each year could generate 3 million tonnes of biofuel, according to the statement. But 30 per cent of its straw stalks and other agricultural waste could produce 20 million tonnes of ethanol.
“It will be killing two birds with one stone if China can turn one of the sources of pollution – straw stalks and farm waste – into biofuel,” said Han Xiaoping, chief executive of energy news portal China5e.com. “China could also reduce its dependence on oil imports with this plan in the long run.” Emissions from farmers burning waste after harvesting have been identified as a serious contributor to air pollution in the country, and the China Meteorological Administration now uses satellites to monitor these fires.
But Luo Yong, an environmental scientist with the Chinese Academy of Social Sciences, said the plan for wider use of ethanol petrol could actually make pollution worse. “The process of producing ethanol petrol could also produce harmful emissions,” he said. “The result of this plan might not be as good as we think.”
Xiamen University energy policy specialist Lin Boqiang also doubted whether agricultural waste would be a practical source to make ethanol in the long run. “There is no incentive for farmers to cooperate with this policy because transporting a full truck of straw stalks could cost more than the price of the straw itself,” he said. “Oil companies also don’t want to use straw to generate ethanol because it takes much more straw than it does corn to generate the same amount of usable petrol,” Lin said. “Food products will remain the major source of generating ethanol in the foreseeable future.”
But Lauri Myllyvirta, an energy analyst at Greenpeace in Beijing, said the policy was the right direction for China. “The key challenge is making sure that any targets or mandates for using ethanol in transport do not lead to using edible raw materials,” he said. “This has been a problem in many other places that have set targets for biofuel use.”
Biofuels for maritime vessel propulsion
Biofuels for maritime vessel propulsion have potential to revolutionise marine sector as they are renewable, environment-friendly and have relatively less impact on marine ecosystems worldwide. However, this transition can only be driven by considerable improvement in technologies for producing biofuels suitable for maritime use. Biofuels for maritime vessels are used in the form of biodiesel, biomethane, and algal biofuels.
Hyundai Heavy Industries is one of the leading patent filers in the maritime vessel propulsion using biofuels. The company’s HiMSEN Engine uses biofuels and an onshore demonstrated was held in 2021 with an aim of reducing carbon emissions.
Wärtsilä is conducting research into a wide range of fuels, including biofuels with an ultimate aim of reducing GHG emissions. The company formed a partnership with Boskalis and GoodFuels Marine for rapid development of marine biofuels. The purpose of the two-year programme is to test biofuels produced from industrial sector.
To reduce the environmental impact, Mitsubishi is planning to use renewable hydrotreated vegetable oil (HVO) for their marine engines. The HVO is produced from biomass and vegetable oils.
Biofuels for Military
Biofuels can also contribute to military renewable drive. Department of Defense (DoD) had embarked upon an ambitious program of expanded renewable energy generation on bases and in the field, with a goal of producing 25% of its energy from renewable sources by 2025. The three military-spec biofuel refineries in the US, which were financed by the US government under the Defense Production Act, are aiming to produce roughly 100 million gallons this year. For 2016, the Navy has purchased just under 80 million gallons of the 10/90 biofuel blend, about 6 percent of the 1.3 billion gallons of fuel the Navy uses annually. The Navy paid $2.05 per gallon, which is roughly in line with the cost of regular marine diesel thanks to robust biofuel subsidies.
Several successful test flights have been conducted with the Swedish air force’s JAS 39 Gripen using a mixture of fossil-free fuel.
Ongoing tests have shown good aircraft performance with the biofuel when compared to traditional jet fuel. Engine tests have been performed in order to study possible differences in performance and engine function when using a 50/50 mix of biofuel compared to performance in engines using only jet fuel. The tests showed that the engine using biofuel had unchanged performance both regarding thrust power and fuel consumption.
In the UK, algae, alcohol and household waste will power RAF fighter jets under bold Ministry of Defense plans to slash carbon emissions.
Aircraft including F-35s, Typhoons and Wildcat helicopters currently use conventional fuel, but could use up to 50 per cent sustainable sources in the future, after MOD’s changed aviation fuel standards came into effect in November 2020. The MOD’s move to allow up to 50 per cent sustainable fuel marks a huge shift in global fuel consumption and opens the door for thousands of civilian and military aircraft to be fueled with Sustainable Aviation Fuels (SAFs).
Experimental rocket powers into sub-orbit on biofuels
Space startup company bluShift successfully launched its first rocket powered by biofuels in Feb 2021. The fuel, which are intended to be used to propel small satellites into space, was employed in a single-stage prototype that can only carry up to 18 lbs of payload and is designed to achieve suborbital space.
Stardust’s first launch carried three small payloads to an altitude of 4,000 feet (1,220 metres) and then parachuted back to Earth. The entire flight lasted about a minute-and-a-half. Stardust 1.0 was designed by the Brunswick, Maine-based startup to be reusable, although it was still a prototype. However, its successor, known as Stardust 2.0, is expected to have an increased payload capacity. The fuels differ from traditional propellants in that they offer safety advantages during handling and ecological advantages during production and use.
The startup, which is backed by the Maine Technology Institute and NASA’s Small Business Innovation Research, has been working on its solid rocket biofuel since its formation seven years ago.
Global Bioenergies delivers SAF for tests by French armed forces
IN Dec 2022, Global Bioenergies delivered a 200-liter batch of sustainable aviation fuel for tests commissioned as part of the GENOPTAIRE project funded by the French government defence procurement and technology agency (DGA). The project, which forms part of the ministry’s defence energy strategy, seeks to promote technological advances in the design and use of military platforms making use of electric-powered transport and alternative fuels. At the moment, in order to streamline logistics in the armed forces, aviation fuel is used in both aircraft and land vehicles.
One of the aims of the GENOPTAIRE project is to identify and assess the impact of biosourced components mixed with conventional aviation fuels on engine performance in land vehicles used by the French Army. Representatives of the DGA and military staff involved in the project issued the following statement: “The batch delivered by Global Bioenergies will be tested first by the project participants (IFPEN, ONERA and SEO) in combination with fossil kerosene for physico-chemical analysis. Subsequently, the Military Staff’s operational energy department (EMA/SEO) plans to conduct engine trials.”
Marc Delcourt, CEO of Global Bioenergies, said: “Having our products assessed by the French Army is a major step forward in our trajectory. We imagine that converting local feedstocks into both civil and military transportation fuels could be of strategic interest for the country.”
Indian Bio-Jet Fuel Technology Receives Formal Military Certification
CSIR-IIP Dehradun’s home-grown technology to produce bio-jet fuel was formally approved for use on military aircraft of the Indian Air Force (IAF) in Nov 2021.
The technology, developed by the Indian Institute of Petroleum (CSIR-IIP), a constituent laboratory of the Council of Scientific and Industrial Research, has undergone evaluation tests and trials over the last three years. The testing of airborne items is a complex and meticulous process involving intricate checks while ensuring the highest levels of flight safety. International aviation standards define the scope of these rigorous assessments. Fuel being the lifeline of aircraft requires thorough analysis before being filled into manned flying machines. The certification received by the lab today is an acknowledgment of the satisfactory results obtained from various ground and inflight tests performed on the indigenous bio-jet fuel by various test agencies supported by the IAF.
This clearance will enable Indian armed forces to use bio-jet fuel produced using indigenous technology across all its operational aircraft. This will also enable early commercialization of the technology and its mass production. Indian bio-jet fuel can be produced from used cooking oil, tree-borne oils, short gestation oilseed crops grown off-season by farmers, and waste extracts from edible oil processing units. It will reduce air pollution by virtue of its ultralow sulphur content compared with conventional jet fuel and contribute to India’s Net-Zero greenhouse gas emissions targets. It will also enhance the livelihoods of farmers and tribals engaged in producing, collecting, and extracting non-edible oils.
As part of efforts to reduce its carbon footprint, the Indian Air Force (IAF) is looking to fly an AN-32 transport aircraft modified to operate on 10% blended biodiesel for 200 flight hours in the next six months, said Air Vice Marshal S. K. Jain, Assistant Chief of Air Force (maintenance plans) in Sep 2022.
The IAF AN-32 took flight on biodiesel blended with aviation turbine uel (ATF) for the first time in December 2018. “So far an AN-32 has flown 65 hours with a 10% blend of biofuel and the performance has been very satisfactory,” AVM Jain said, speaking a seminar on sustainable aviation biofuels organised by The Aeronautical Society of India on Friday. The target is to fly 200 flight hours, which should happen within the next six months
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