In the United States, ethanol produced from corn reached 6.5 billion gallons (24.6 billion L) in 2007 and in 2012 this total doubled to approximately 13.2 billion gallons (50.0 billion L). In 2018 the United States exported a total of 6.5 billion L of ethanol, expanding the share of world exports of ethanol to 61%. Most ethanol produced in the United States is from starch-based crops by dry or wet-mill processing technologies. In 2020, there were 208 ethanol production plants in the United States with a total installed capacity of 17.44 billion gallons per year (66.0 billion L per year). The total production in 2020 was 13.8 billion gallons (52.2 billion L), which represented a 12.7% decrease from the production total of 15.8 billion gallons (59.8 billion L) in the previous year [11,59]. The decrease in ethanol production was mainly caused by the reduction in transportation fuel demand, which was the direct consequence of the COVID-19 pandemic. Whereas a number of plants were shut down, some plants modified the production process to produce an ethanol product which is suitable for use in hand sanitizers to cope with the economic downturn. It is expected that production of ethanol will go back up in 2021. The ethanol co-products generated in 2020 included 29.4 million metric tons (MT) distillers grains, 3.1 million MT corn gluten feed, 0.6 million MT corn gluten meal, 1.5 million MT corn oil and 2.1 million MT captured CO₂. Corn was the major feedstock, which accounted for 93.2% of the total ethanol production in 2020. Other feedstocks included sorghum, corn fiber, waste sugars, waste starch and lignocellulosic biomass. The interest in biomass as a potential feedstock for ethanol production continued to be strong. Despite previous failures by large corporations such as Poet and DuPont, New Energy Blue announced in July 2021 the plan to construct a full-scale ethanol biorefinery, which would consume 250,000 MT per year agricultural residues generated locally for ethanol production. The proposed plant would use the Inbicon process, which would also produce a lignin co-product for use as a solid biofuel and a natural binder and possibly xylitol as a specialty chemical with potential food applications [60,61].

Canada is a net importer of ethanol since the volume consumed in Canada generally exceeded the ethanol this country produced. In 1980, Canadian produced merely 8000 L but in 2010 the annual ethanol production of Canada reached 1.9 billion L. In 2019, ethanol consumption in Canada reached 3.33 billion L compared to 2 billion L in production. However, ethanol production in Canada has grown in recent years largely due to changes in feedstocks and increased capacity at existing ethanol facilities in Canada.

In 2020, Canada was ranked as the sixth largest ethanol producer in the world. The ethanol production in Canada represented 1.6% of the total global production. The two major feedstocks used for ethanol production were corn and wheat, which contributed 1534.3 million L and 360.7 million L, respectively [59]. Winter barley has been considered as a potential feedstock for ethanol production. However, this grain has not been used in any commercial ethanol production plant.

Brazil continued to be the second largest ethanol producer in the world. In 2019, Brazil ethanol production including anhydrous and hydrous ethanol amounted to more than 35.3 million M³, an increase of nearly seven percent in comparison to a year of 2018. This is the highest volume of fuel ethanol that Brazil has produced in the decade. In Brazil, sugarcane bagasse is commonly used as boiler fuel to produce energy to supply sugar mills. This is practiced to minimize the energy costs and also as an alternative to the utilization of the biomass left over.

In 2020, the ethanol production in Brazil represented 26.7% of the total global ethanol production [53]. There were 360 first-generation (sugar cane, corn) ethanol plants in Brazil in 2020 with a total nameplate capacity of 42,800 million L. However, only 67% of the capacity was used. There were three plants that used lignocellulosic feedstock with a total nameplate capacity of 127 million L. In 2020, these second-generation ethanol plants only operated at 25% capacity. The feedstocks included sugar cane (326.6 million MT), corn (6.0 million MT) and bagasse (178,000 MT). The total ethanol production in 2020 was 31.35 billion L, which included 32 million L produced from lignocellulosic feedstock (bagasse). The 2020 ethanol production was about 16% lower compared to the previous year (37.38 billion L). The decrease in ethanol production in 2020 was mainly caused by the diversion of sugar cane juice toward more sugar production in sugar-ethanol plants. The co-products included 120.1 million MT bagasse, 1.88 million MT DDGS and 108,000 MT corn oil. The traditional feedstock for first-generation ethanol production in Brazil is sugar cane. However, corn has become an important feedstock and its use for ethanol production has steadily gained ground. In 2020, 2.5 billion L ethanol was produced from corn, which was 1.17 million L higher than the previous year. The Corn Ethanol National Union (UNEM) predicted that corn ethanol production would reach 8 billion L by 2028. There currently are 11 corn ethanol plants, which include nine full-plant types (corn only) and 2 flex-plant types (corn and sugarcane). Two full-plants and one flex-plant are currently under construction [55].

In 2020, Argentina was ranked 8th in the world with a contribution of 1.0% toward the total global ethanol production [53]. There were 22 ethanol plants with a total nameplate capacity of 1580 million L per year. The ethanol plants, however, were operated only at 55.1% capacity. Corn and molasses were used as feedstocks at 1.09 million MT and 1.70 million MT, respectively. The total ethanol production was 870 million liters, which was significantly lower than the total production in the previous year (1073 million L). The DDGS co-product was also produced at 345,000 MT [62].

Colombia was ranked 13th in the world in 2020 with a contribution of 0.44% toward the total global ethanol production [60]. The country had six ethanol plants, which used sugar cane as the only feedstock. The total nameplate capacity of the plants was 540 million liters. These plants were run at only 73.1% capacity in 2020. The total ethanol production in 2020 was 395 million liters with 1.34 million MT bagasse co-product. Five of the six ethanol plants were directly linked to the sugar production plants. The bagasse obtained after juice extraction was used to generate energy for internal use in these plants. Most ethanol plants in Colombia were energy self-sufficient and even generated surplus energy to sell to the national grid [63].

The total ethanol production in the EU in 2020 was 4.8% of the total global production [53]. The major feedstocks used for ethanol production were sugar beets (7.45 million MT), corn (6.35 million MT), and wheat (2.64 million MT). Other first-generation feedstocks were triticale (1.04 million MT), rye (520,000 MT) and barley (450,000 million MT). Wheat was predominantly used in Belgium, Germany, France and the UK. Corn was the preferred feedstock in Hungary, where corn was abundantly available, and in the Netherlands, Spain, and the UK, where the majority of corn came from the Ukraine to provide the feedstock for ethanol plants, which are located near seaports. The inland ethanol plants in Spain used a combination of corn and barley as the feedstock. Sugar beets and their derivatives were used for ethanol production in France, Germany, the UK, the Czech Republic, Belgium and Austria. The usage of lignocellulosic feedstocks in 2020 was doubled to 200,000 MT compared to the previous year. There were 57 first-generation ethanol plants with a total nameplate capacity of 8.15 billion L, which were operated at 58% capacity. There were also 3 lignocellulosic ethanol plants with a total nameplate capacity of 90 million L. However, these second-generation ethanol plants were operated at only 28% capacity. Five other lignocellulosic ethanol plants were under construction in Finland (sawdust, 10 million L per year), Italy (biomass, 28 million L per year), Austria (wood sugars, 30 million L per year), Romania (wheat straw, 65 million L per year) and Bulgaria (corn stover, 50 million L per year). All of these plants are expected to be in operation soon. The ethanol production in the EU in 2020 was 5.47 billion L. Due to the COVID-19 pandemic, ethanol consumption in the EU has decreased by 10.1%. However, this number was still slightly lower than the 13.0% decrease in gasoline consumption. According to the 2021 European Union Biofuels Annual Report, the co-products included 3.33 million MT DDGS and 188,000 MT corn oil [56].

2.4. Asia and Rest of the World

2.4.1. Vietnam

Vietnam is an agriculture-based country and has abundant natural resources for renewable power development. However, the pace of renewable energy development including ethanol production is not yet rapid due to barriers such as the small size of the country’s economy, the lack of financial capacity, advanced technologies and human resources. Institutional barriers such as market-controlled mechanisms and unstable supporting policies also limit the development of renewable power sectors [64].

In terms of ethanol development, due to the economic development, Vietnam has consumed lots of gasoline in recent years. The United States Department of Agriculture (USDA) estimated gasoline consumption of Vietnam in recent years has grown approximately 4–5 percent per year. In the first quarter of 2020, Vietnam spent about $2.5 billion on importing crude oil and petroleum products, including ethanol, in addition to its production [65]. Since 2007 ethanol supporting regulations have gradually increased, however, the commercialization and sales of five percent ethanol blended gasoline (E5) was pushed back to 2018 due to a lack of understanding of the environmental benefits of ethanol blended gasoline by consumers, together with some persistent rumors and myths that usage of ethanol might harm vehicle engines.

2.4.2. Korea

Korea is the 7th ranked CO₂ emitter in the world and similar to other countries is concerned about its high CO₂ emissions and its dependence on imported crude oil. All of the oil Korea consumes is imported from foreign countries. South Korea is a main importer of United States ethanol, with a total volume of 263.84 million L (24.7 million bushels in corn equivalent) in 2017–2018. In the mid-1990s, production of ethanol for fuel use in Korea using imported cassava as a feedstock was initiated. The Korea Ministry of Knowledge Economy (KMKE) announced an action plan to increase the use of biofuels in the transport sector from 0.2 billion L in 2008 to 5 billion L by 2030 [66].

2.4.3. China

From 2004 to 2016, China produced ethanol with an average annual increase in production rate of 16.8 percent. In 2017, China had an ethanol production of 2.8 million MT. In 2018, China produced 6.6 million MT, making it the fourth-largest ethanol producing country/region in the world, after the United States, Brazil, and the EU. China set a policy that gasoline supplies across the country were required to be blended with ethanol by 2020. According to a news source, China aimed to have 15 million MT by 2020, which is almost triple its current ethanol production capacity, in order to keep up with growing demands for cleaner fuels [57]. The target would exceed the estimated domestic production capacity of China and the country would need to import ethanol from foreign countries such as the United States and Brazil. Corn is China’s main feedstock, which is currently accounting for 64 percent of total output for China’s ethanol production [67].

2.4.4. India

India ranked 6th among the leading ethanol producers in the world. In 2020, India still remained one of the biggest importers of the United States ethanol, with a market share of 99 percent. With Modi’s “self-resilient” strategies, India sets its ambitious goal of E-20 by 2025 while retaining its immediate goal of E-10 by 2022. India has a total installed ethanol capacity of 5 billion L, of which molasses-based distilleries constitute 4.2 billion L, or 85 percent of the overall production capacity, while grain-based distilleries constitute 750 million L (equivalent to 15 percent).

Formerly, ethanol in India could only be produced from molasses or sugar juice. However, India’s existing ethanol is produced from a variety of feedstocks such as cereals (rice, wheat, barley, maize, and sorghum). In 2020, an estimated 2.98 billion L of ethanol was produced from molasses. In 2021, India’s ethanol production was forecast at 3.17 billion L, 7% above 2020 due to surplus sugarcane production, and 2021 average ethanol blending rate in gasoline of India was estimated at 7.5 percent, due to accelerated government efforts to divert more feedstock toward ethanol [68].

2.4.5. Thailand

Thailand is the 7th largest ethanol producer in the world. Thailand consumed 1500 million L of ethanol in 2020. Thailand’s 20-year Alternative Energy Development Plan (AEDP) for 2018–2037 targeted 2.0 billion L for ethanol in 2021 and 2.7 billion L for ethanol consumption in 2037. Molasses is the primary feedstock for ethanol production in Thailand. Molasses supplies in Thailand have been tight due to reduced sugarcane production for two consecutive years. Ethanol demand is primarily expected to be fulfilled by cassava-based ethanol in Thailand [69].

2.4.6. Australia

Australia’s ethanol consumption is forecast to remain stable in 2020 at only 1.4% of gasoline consumption. Ethanol in Australia is primarily produced as a biofuel for passenger and commercial vehicles and also for alcoholic beverage, industrial chemicals, and solvents used in pharmaceutical and cosmetic applications. In spite of large feedstock availability, Australia’s ethanol production volumes remain small because there is no nationwide fuel ethanol program. In Australia only two states, which are New South Wales and Queensland, have mandates with a fuel ethanol program, and have the highest consumption of ethanol blended fuel.

In New South Wales, Manildra is the largest ethanol producer with a capacity of over 300 million L. In this plant wheat starch is processed through an integrated process which separates the gluten and processes the remaining starch into a range of food and industrial-grade starches, glucose syrups, and ethanol products. In Queensland, a plant at Dalby producing ethanol from starch-based feedstock is operated by United Petroleum. This biorefinery with a capacity of 80 million L fuel-grade ethanol is located in a sorghum growing region in the Darling Downs and processes up to 0.2 million MT of sorghum grain a year from local growers. At full capacity, the biorefinery can also produce 830,000 MT of wet distillers grain, which is used for animal feed supplements [70].

2.4.7. Zimbabwe and Other African countries

Zimbabwe has adopted ethanol petrol blending regulations. Two ethanol plants in Zimbabwe, namely Triangle Sugar and Hippo Valley, were installed. In 2010, the Triangle plant resumed ethanol production after refurbishing its ethanol plant with a capacity of 27 million L per year. The government of Zimbabwe also initiated the Chisumbanje sugar/bioethanol project with an aim of using 10,000 hectares of sugarcane for this project. In March 2012, owners of this project halted production because the plant was running out of storage space. In Zimbabwe, some oil companies were only selling E10 at a few of their filling stations [71].

In other African countries, lead additives are still heavily used in gasoline and where sugarcane production cost is high, ethanol can be a cheap source of octane in gasoline. It is estimated that in Africa, to replace all the lead used in African gasoline, this would require Africa to produce about 20% of the amount of ethanol currently produced in Brazil, and would require the shift of some sugar production to ethanol production. African countries that could replace lead with ethanol using primarily their by-product molasses production include Zimbabwe, Kenya, Egypt, Zaire, Zambia, Sudan, Swaziland, and Mauritius at a more modest scale [72].