Assessment of Green Methanol Production Potential and Related Economic and Environmental Beneﬁts: the Case of China

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Article Assessment of Green Methanol Production Potential and Related Economic and Environmental Beneﬁts: The Case of China

Oleg Bazaluk 1 , Valerii Havrysh 2 , Vitalii Nitsenko 3,* , Tomas Baležentis 4 , Dalia Streimikiene 4,* and Elena A. Tarkhanova 5

1 Belt and Road Initiative Centre for Chinese-European studies, Guangdong University of Petrochemical Technology, Maoming 525000, China; [email protected] 2 Department of Tractors and Agricultural Machinery, Operating and Maintenance, Mykolayiv National Agrarian University, 54020 Mykolaiv, Ukraine; [email protected] 3 SCIRE Foundation, 00867 Warsaw, Poland 4 Division of Farms and Enterprises Economics, Lithuanian Institute of Agrarian Economics, 03220 Vilnius, Lithuania; [email protected] 5 Department of Economics and Finance, University of Tyumen, 625003 Tyumen, Russian; [email protected] * Correspondence: [email protected] (V.N.); [email protected] (D.S.)

Received: 19 May 2020; Accepted: 11 June 2020; Published: 16 June 2020

Abstract: Adopting a new paradigm for social development implies a transition to a circular economy. The above requires the reduction of greenhouse gas emissions, the utilization of wastes, and the use of renewable energy sources. The most promising way is the use of methanol for industrial and transport applications. China is experiencing a boom in methanol production and its use in almost every sector of the economy. The purpose of this study was to reveal economic beneﬁts, carbon dioxide emissions and the potential production of green methanol. Fuel price history, energy costs and fuel economy were used for economic assessment. Life cycle analysis to evaluate carbon dioxide emissions was applied. It was revealed that only the use of green methanol as a fuel results in decreases in well-to-wheel CO2 emissions compared to fossil fuels. The potential methanol production by using recycled waste and wind power was determined. Its annual production can range from 6.83 to 32.43 million tones. On this basis, a gradual transition to a circular and methanol economy is possible. Policymakers are recommended to support green methanol production in China. It can result in boosting the application of vehicles fueled by methanol and can control CO2 emissions.

Keywords: methanol; biomethanol; vehicle; carbon dioxide; eﬃciency

1. Introduction Road transport consumes around 33% of total energy consumption by transport [1]. Petroleum fuels are the primary fuels of road transportation. Their burning results in harmful emissions including carbon dioxide emissions. According to the International Energy Agency (IEA) carbon dioxide emissions are increasing. In 2018, their value exceeded 33 Gt [2]. To mitigate climate change, the United Nations Intergovernmental Panel on Climate Change recommended reduction of greenhouse gas emissions by 50–85% by 2050 [3]. The decrease of harmful emissions can be reached by using alternative vehicle fuels, including methanol [4,5]. Methanol could bring economic and ecological beneﬁts to China. This fuel is environmentally friendly [6]. Moreover, its application results in reduced fuel costs [7]. China imports around 65% oil and 31% natural gas. The use of methanol-based fuel can decrease the import of the above energy

Energies 2020, 13, 3113; doi:10.3390/en13123113 www.mdpi.com/journal/energies Energies 2020, 13, 3113 2 of 23 and 31% natural gas. The use of methanol-based fuel can decrease the import of the above energy resources [8]. Since 2000, the Chinese government has improved national energy independence and resourcescut harmful [8]. Since emissions. 2000, theTherefore, Chinese the government increase of the has methanol improved vehicle national fleet energyensures independencethe sustainable and cut harmfuleconomic emissions. growth of the Therefore, country. the increase of the methanol vehicle fleet ensures the sustainable economicMethanol growth ofis themainly country. converted into the following fuels: neat methanol—M100; methanol and petrolMethanol blend is (M5, mainly M10, convertedM15, M30, M50 into and the M85); following methanol fuels: based neat petrol; methanol—M100; methyl tertiary b methanolutyl ether and petrol(MTBE); blend (M5, dimethy M10,l M15,ether M30, (DME); M50 and and M85);biodiese methanoll. Methanol based can petrol; be methylconverted tertiary to different butyl ether (MTBE);hydrocarbons, dimethyl ether including (DME); olefins. and Olefins biodiesel. are Methanol valuable raw can materials be converted for the to production different hydrocarbons, of liquid includingvehicle olefins. fuels such Olefins as gasoline, are valuable distillate raw and materials dimethyl for ether the [ production9,10]. of liquid vehicle fuels such as gasoline,In distillate 2018, road and transport dimethyl in ether China [9 consumed,10]. 126 million tons of petrol and 156 million tons of diesel fuel [11]. Meanwhile, methanol consumption was around 17.4 million tons [12]. The In 2018, road transport in China consumed 126 million tons of petrol and 156 million tons of diesel production and use of methanol is growing mainly due to the use of methanol by transport in China fuel [11]. Meanwhile, methanol consumption was around 17.4 million tons [12]. The production and use (Figures 1 and 2) [12,13]. of methanol is growing mainly due to the use of methanol by transport in China (Figures1 and2)[ 12,13].

120 20 18 100 16 80 14 12 60 10

Production, mln t mln Production, 8 Growth, % Growth, 40 6 20 4 2 0 0 2014 2015 2016 2017 2018 2019

Period, year

global production China production growth, global

growth, China trend, World trend, China

Figure 1. Global and China methanol production. Figure 1. Global and China methanol production. 31 8 The largest methanol producer in the world is China (around 70 million tons) [127,13]. Other 30 countries produced much less methanol. For example, in 2018 the USA produced 5.7 million6 tons and Russia29 produced 4.46 million tons [14,15]. Methanol is an important chemical. It is used5 mainly in Asia, and China is the largest methanol consumer. Methanol usage by region of the 4world is as 28 follows, in percent: China—58%; the rest of Asia-Pacific—16%; Europe—13%; Latin America3 —2%; Consumption, t mln 27 2

North America—10% [16]. Growth, % 1 The growth26 of methanol production in China has had a positive trend despite global0 methanol production growth having slowed. There has been an increase in methanol-based fuel consumption-1 25 (Figure 2). -2 24 -3 2014 2015 2016 2017 2018 2019

Period, year

global consumption growth, global trend, World

Figure 2. Global methanol consumption as fuel. Figure 2. Global methanol consumption as fuel. The largest methanol producer in the world is China (around 70 million tons) [12,13]. Other Green methanol is very attractive for the energy sector. It makes possible the development of countriesthe methanol produced economy. much less This methanol. idea has been For example,proposed by in 2018 Nobel the laureate USA producedG.A. Olah 5.7[17, million18]. The tons and Russiatransition produced to the methanol 4.46 million economy tons may [14 allow,15]. MethanolChina to reach is an the important following chemical.results: strengthening It is used mainly of in Asia,energy and security; China isreduction the largest of air methanol pollution and consumer. carbon dioxide Methanol emissions; usage and by regionincreases of in the the world added is as follows,value in of percent: the domestic China—58%; economy [1 the9]. restTherefore of Asia-Paciﬁc—16%;, the methanol economy Europe—13%; gives tangible Latin benefits. America—2%; North America—10% [16]. 2. Literature Review

2.1. Benefits of Methanol Based Fuels The use of methanol as fuel (neat or blends) has considerable advantages over traditional uses. Tian et al. [20] provided a comparative description of the use of methanol in fuel mixtures. The use of M20 caused an increase in the thermal efficiency of engines and reduction of emissions of CO, CO2 and NOx. Wang et al. [21] reported that M15 and M25 are more acceptable compared to petrol. They have better environmental and economic indicators. Sun et al. [22] found that methanol based fuels are an excellent and inexpensive alternative to petrol and diesel fuel. This alcohol can meet new emissions standards. Huang et al. [23] analyzed methanol as a feedstock for manufacturing DME, biodiesel, MTBE and gasoline (MTG). Duraisamy et al. [24], Jia and Denbratt [25] and Prasad et al. [26] studied the use of methanol in diesel engines. They found that methanol does not impact diesel efficiency; however, it reduces HC and CO emissions by 30–40%. However, well-to-wake carbon dioxide emissions factored in fuel economy and engine efficiency were not studied enough. Methanol is biodegradable. This fuel degrades faster than petroleum fuels. At high concentrations, methanol is a poison. However, there was not a single case of accidental methanol poisoning [27].

2.2. Methanol Market Forecasts The methanol market can be divided into two distinct groups, namely non-renewable and green methanol. Thus, the forecasting of experts is carried out by the specified groups. However, large consulting companies take into account the overall methanol market in the long-term forecasting process without the renewable component selection. According to various forecasts, methanol production is predicted to be increased [28–35]. Total methanol production may grow from 110 million metric tons in 2018 to 220 in 2030 [36]. Projections of Council on Energy, Environment and Water (CEEW) and International Energy Agency (IEA) suggest that the cost of

Energies 2020, 13, 3113 3 of 23

The growth of methanol production in China has had a positive trend despite global methanol production growth having slowed. There has been an increase in methanol-based fuel consumption (Figure2). Green methanol is very attractive for the energy sector. It makes possible the development of the methanol economy. This idea has been proposed by Nobel laureate G.A. Olah [17,18]. The transition to the methanol economy may allow China to reach the following results: strengthening of energy security; reduction of air pollution and carbon dioxide emissions; and increases in the added value of the domestic economy [19]. Therefore, the methanol economy gives tangible beneﬁts.

2. Literature Review

2.1. Benefits of Methanol Based Fuels The use of methanol as fuel (neat or blends) has considerable advantages over traditional uses. Tian et al. [20] provided a comparative description of the use of methanol in fuel mixtures. The use of M20 caused an increase in the thermal efficiency of engines and reduction of emissions of CO, CO2 and NOx. Wang et al. [21] reported that M15 and M25 are more acceptable compared to petrol. They have better environmental and economic indicators. Sun et al. [22] found that methanol based fuels are an excellent and inexpensive alternative to petrol and diesel fuel. This alcohol can meet new emissions standards. Huang et al. [23] analyzed methanol as a feedstock for manufacturing DME, biodiesel, MTBE and gasoline (MTG). Duraisamy et al. [24], Jia and Denbratt [25] and Prasad et al. [26] studied the use of methanol in diesel engines. They found that methanol does not impact diesel efficiency; however, it reduces HC and CO emissions by 30–40%. However, well-to-wake carbon dioxide emissions factored in fuel economy and engine efficiency were not studied enough. Methanol is biodegradable. This fuel degrades faster than petroleum fuels. At high concentrations, methanol is a poison. However, there was not a single case of accidental methanol poisoning [27].

2.2. Methanol Market Forecasts The methanol market can be divided into two distinct groups, namely non-renewable and green methanol. Thus, the forecasting of experts is carried out by the speciﬁed groups. However, large consulting companies take into account the overall methanol market in the long-term forecasting process without the renewable component selection. According to various forecasts, methanol production is predicted to be increased [28–35]. Total methanol production may grow from 110 million metric tons in 2018 to 220 in 2030 [36]. Projections of Council on Energy, Environment and Water (CEEW) and International Energy Agency (IEA) suggest that the cost of production of renewable methanol will be gradually reduced by 2030, making it cheaper than coal and natural gas [37].

2.3. Feedstock and Methanol Production In China the most common types of feedstock for methanol production are currently coal, natural gas and coke gases. Meanwhile, globally, municipal and industrial waste, biomass and carbon dioxide are promising feedstock for green methanol. The technology for methanol production strongly depends on the feedstock type. Thus, synthesis gas can be produced by the reforming of gaseous hydrocarbons and the gasiﬁcation of solid and liquid hydrocarbons. In addition, hydrogen and carbon dioxide can be used. A number of scientists and experts have focused on the use of coal [38–40] and natural gas [41,42] as feedstocks for methanol production. Another group of scientists emphasized the feasibility of biomass based methanol [43–46]. Cellulosic biomass [47], sawdust [48], glycerol [49], carbon dioxide [50–52] and wind [42,53] have also been studied as feedstock for methanol production. Liu [40] proposed use of combined feedstock such as coal (50%) and biomass (50%). Scientists have paid much attention to the use of industrial and municipal waste as a feedstock for methanol production. Yang et al. emphasized the importance of a gradual transition Energies 2020, 13, 3113 4 of 23

from coal-to-methanol technology to biomass-to-methanol. This can reduce CO2 emissions [43]. Roode-Gutzmer et al. considered the combined use of fossil fuels (coal and natural gas) and biomass for methanol production [45]. Municipal solid wastes are recommended for use for the realization of the circular economy model [46]. Borgwardt drew the conclusion that cellulosic biomass may be promising substitution of crude oil [47]. Wood biomass is potentially effective for the use in methanol production for woodland [48]. The most cost-effective and promising way to produce methanol is the use of renewable hydrogen and recycled carbon dioxide [49]. Ishaq and Dincer demonstrated the efficiency of the use of wind energy and hydrogen for the production of methanol [53]. To realize a sustainable and low-carbon economy, renewable energy should be introduced in the fuel production chain. A key strategic factor of this scenario is the conversion of carbon dioxide into feedstock for methanol and DME production [54]. Special attention has been paid to the methanol-to-DME and the one-pot carbon dioxide-to-DME process [55,56]. Thus, the use of certain resources for the production of methanol depends on natural resources and waste in various sectors of the economy. The above studies are the driving force behind innovative positive changes in the automotive industry. The use of methanol as a mixture or clean fuel results in improving engine efficiency, reducing harmful emissions and increasing economic efficiency. China has experience in the use of neat methanol or M100 as a vehicle fuel. For example, Geely Auto has produced a methanol version of cars. They are used in Jinzhong in Shanxi Province [57]. However, there is a lack of studies concerning sustainable methanol production potential from available feedstocks and related economic and environmental benefits (carbon dioxide emissions). The purpose of this study is to reveal the advantages of methanol as a sustainable fuel for land transport and a component of derived fuels, namely (i) fuel cost saving; (ii) well-to-wake carbon dioxide emissions; (iii) promising green electricity source and volume of renewable methanol production; and (iv) promising resources and volume of biomethanol production. The third section introduces methods and data, the fourth section deals with results, and the fifth section concludes the paper.

3. Materials and Methods

3.1. Fuels Methanol and petroleum fuels were analyzed in this study. Methanol has a low cetane number and, therefore, it cannot be used for diesel engines. This kind of fuel is suitable for spark ignition engines, gas turbines and fuel cells. Its lower heating values are less than those of petroleum fuel and it has a high heat of vaporization. Molecular compositions are the main diﬀerences between conventional fuels and methanol. Diesel fuel or gasoline do not contain oxygen, whereas methanol has 50% oxygen by mass (Table1)[58–62].

Table 1. Physical and chemical properties of selected fuels.

Properties Unit Diesel Gasoline Methanol Density kg/m3 840 740 796 Cetane number - >40 <5 Octane number - - 95 - Boiling point K 453–643 298–488 338 Lower heating value MJ/kg 42.5 44 19.67 Stoichiometric air–fuel ratio - 14.6 14.7 6.45 Heat of vaporization kJ/kg 243 180–350 1100 Viscosity cSt 4.59 0.57 0.65 Auto-ignition temperature K 503 465–743 736 Carbon content by mass % 85 86 37.5 Hydrogen content by mass % 15 14 12.5 Oxygen content by mass % 0 0 50 Speciﬁc carbon dioxide emission g/MJ 73.33 73.95 68.44 Energies 2020, 13, 3113 5 of 23

3.2. Carbon Dioxide Emissions Indicator Carbon dioxide emissions of any fuel depend on the engine eﬃciency and fuel properties, such as lower heating value and carbon content. Speciﬁc fuel consumption of any engine is

1 SFC = 3600 η LHV − , kg/kWh, (1) · · f where η is the engine eﬃciency; LHVf is the lower heating value of the fuel, kJ/kg. Carbon dioxide emission depends on the carbon content in fuel

11 CDE = FCC, kg/kg, (2) 3 · where FCC is the carbon content in the fuel in kg/kg. Then the speciﬁc carbon dioxide emission can be calculated by the following formula:

1 11 1 SCDE = SFC CDE = 3600 η LHV − FCC = 13200 FCC η LHV − , kg/kWh, (3) · · · f · 3 · · · · f In our study, we took into account the total fuel life cycle and calculated well-to-wake (WTW) emissions. The well-to-wake carbon dioxide emissions of any engine and any fuel can be calculated by the following formula [63]:

3600 11 WTW = FCC + WTT , kg/kWh, (4) η LHV · · 3 f · where WTTf is the well-to-tank carbon dioxide emissions for a certain fuel in kg CO2-eq/kg. Therefore, to decrease carbon dioxide emissions in the atmosphere, the engine eﬃciency must be augmented, and the carbon content of fuel must be reduced. The WTW emissions for vehicles can be calculated by using the following expression:

n X 11 WTW = FE ρ FCC + WTT , kg/100 km, (5) i · i · 3 · i i i=1 where WTTi is the well-to-tank carbon dioxide emissions for ith fuel component in kg CO2-eq/kg; FEi is the fuel economy of ith fuel component in L/100 km.

3.3. Eﬃciency Indicators and Economic Assessment In this study we used the following indicators:

Engine efficiency; • Specific fuel consumption; • Fuel economy. • The above indicators were used for different fuels and engines. To estimate economic efficiency of different fuels, the fuel energy cost was computed as follows [62]:

1 ECF = Fpr LHV − , USD/GJ, (6) · f where Fpr is the price of fuel in USD/t; LHVf is the lower heat value of the fuel in GJ/t. The energy cost for useful work factors in the engine eﬃciency and is calculated as [51]

1 ECUW = Fpr η LHV − , USD/GJ. (7) · · f Energies 2020, 13, 3113 6 of 23

The same value per MWh is calculated by the following formula [51]:

1 ECUW = Fpr 3.6 η LHV − , USD/MWh. (8) · · · f An acceptable methanol to conventional fuel price ratio, which take into account lower heating values and densities, is the thermal ratio [62]:

LHVM ρM FprM RMCP = · < , (9) th LHV ρ Fpr C · C C where ρM is the density of methanol-based fuel in kg/L; ρC is the density of conventional fuel in kg/L. If the actual methanol to conventional fuel price ratio is less than RMCPth, then the methanol-based fuel is competitive.

3.4. Information Base The economic analysis was fulfilled for diesel fuel, petrol and methanol based fuels. The average fuel prices were taken from official information sources. Official prices of Methanex (the world’s largest producer of methanol) were applied for this study.

4. Results This section is divided by the following subsections: pathway for methanol utilization, carbon dioxide emissions, economic assessment and potential green methanol production.

4.1. Pathway for Methanol Utilization A fuel application of methanol is a key component of its consumption. In 2018, pure methanol (M100), and the methanol-petrol blends MTBE and DME totaled around 17.4 million tons or approximately 25–27% of national application [11]. Methanol may be used in several pathways, including direct burning (pure methanol or methanol blends), derived fuels (biodiesel or dimethyl ether (DME) and fuel cells (Figure3). Low level methanol blends such as M15–M25 can be used in spark ignition engines. These engines need no change. High level methanol blends (M85–M100) can be used only in dedicated engines [64].

Methanol

Burning Conversion

Pure and blends Derived fuels

Single fuel Dual-fuel systems systems

–

Pure

ether

ethanol

Fuel cell

Biodiesel

Methanol

Dimethyl

diesel fuel

Methanol

petrol blend

Methanol and

Figure 3. Methanol utilization as vehicle fuel. Figure 3. Methanol utilization as vehicle fuel.

Methanol-based fuels are not yet implemented in transport in the European Union. However, new alcohol-based fuels have been developed. A new A7 fuel contains 3% methanol and 4% ethanol. It can substitute E5 [66]. A new A20 fuel contains 20% alcohol (15% methanol, 5% ethanol, 80% petrol) [67].

4.2. Carbon Dioxide Emissions Specific carbon dioxide emissions of fuels depend on primary factors such as carbon content, lower heating value and engine efficiency. Carbon dioxide emissions were computed using Equation (1). Diesel fuel (for diesel engines), petrol and methanol (for spark ignition engines and fuel cells) were analyzed. The obtained results are shown in Figure 4. However, they do not take into account well-to-tank (WTT) emissions for different vehicle fuels. The figures show that the type of fuel has no significant influence on carbon dioxide emissions. Emissions primarily depend on engine efficiency. This may be explained by the following fact, that the specific carbon content (by mass) per unit of energy is slightly dependent on the fuel type. The above value for methanol is equal to 19.065 g/MJ. Conventional fuels have similar values: petrol—19.55 g/MJ and diesel fuel—20 g/MJ. Therefore, improving efficiency is the main way to reduce greenhouse gas emissions. In 2019, the Gumpert Aiways Automobile Company presented a methanol fuel cell. This company developed an electric car in a methanol fuel cell version. This system has an electric efficiency of 45% and converts 1 liter on methanol into 2 kWh of electricity. The fuel economy is 21 kWh per 100 km or 9.65 L of methanol per 100 km [68].

Energies 2020, 13, 3113 7 of 23

Diesel engines can be retroﬁtted for methanol application. As a rule, these are dual-fuel engines. This solution results in reduction of harmful emissions [65]. Methanol-based fuels are not yet implemented in transport in the European Union. However, new alcohol-based fuels have been developed. A new A7 fuel contains 3% methanol and 4% ethanol. It can substitute E5 [66]. A new A20 fuel contains 20% alcohol (15% methanol, 5% ethanol, 80% petrol) [67].

4.2. Carbon Dioxide Emissions Specific carbon dioxide emissions of fuels depend on primary factors such as carbon content, lower heating value and engine efficiency. Carbon dioxide emissions were computed using Equation (1). Diesel fuel (for diesel engines), petrol and methanol (for spark ignition engines and fuel cells) were analyzed. The obtained results are shown in Figure4. However, they do not take into account well-to-tank (WTT) emissions for different vehicle fuels.

1.8

1.6

1.4

1.2

1.0

0.8

0.6

0.4

Specific carbon dioxide emission, kg/kWh emission, dioxide carbon Specific 15 20 25 30 35 40 45 50 55 60 Engine efficiency, %

diesel fuel petrol methanol methanol fuel cell

Figure 4. Speciﬁc tank-to-wheel carbon dioxide emissions. Figure 4. Specific tank-to-wheel carbon dioxide emissions.

TheWTT figures carbon show dioxide that theemissions type of from fuel different has no significant fuels vary in influence a wide range. on carbon Regarding dioxide methanol emissions. Emissionsfuel, WTT primarily depends depend on the on production engine effi technologyciency. This and may thebe type explained of feedstock. by the This following indicator fact, has that a the specificminimum carbon value content for (by renewable mass) per feedstock unit of (biomass) energy is slightlyand green dependent electricity. on However, the fuel type. it is worse The above valuecompared for methanol to bioethanol is equal (Table to 19.065 2). g/MJ. Conventional fuels have similar values: petrol—19.55 g/MJ and diesel fuel—20 g/MJ. Therefore, improving efficiency is the main way to reduce greenhouse gas emissions. Table 2. Well-to-tank (WTT) carbon dioxide emissions for selected fuels.

In 2019, the Gumpert Aiways AutomobileWTT Company Carbon D presentedioxide Emission a methanols (g CO2-eq/kg fuel) cell. This company Fuel References developed an electric car in a methanol fuel cell version.minimum This systemmaximum has an electric eﬃciency of 45% Diesel fuel 284 1020 [57] and converts 1 L on methanolGasoline into 2 kWh of electricity.294.8 The fuel economy1188 is 21 kWh[57] per 100 km or 9.65 L of methanol perNatural 100 km gas [68]. 909.5 1290.9 [57–60] WTTBiomethanol carbon dioxide(biomass and emissions renewable fromelectricity) diﬀ erent fuels vary in– a898 wide range. Regarding[61] methanol fuel, Methanol (coal) 2965 [61] WTT depends on the productionBioethanol technology and the– type1493 of feedstock. This–352 indicator has[62] a minimum value for renewable feedstock (biomass) and green electricity. However, it is worse compared to bioethanolCarbon (Table dioxide2). emissions per 100 km for a Geely methanol car were determined. TankCarbon-to-w dioxideheel, well emissions-to-wake permaximum 100 km and for w aell Geely-to-wake methanol minimum car values were determined. were calculated. Tank-to-wheel, Actual well-to-wakedata about maximumfuel economy and was well-to-wake used [67]. According minimum to our values calculations, were calculated. M100 (neat Actual methanol data) ha aboutd the fuel best values of carbon dioxide emissions compared to petrol (Figure 5). Biomethanol had four times economy was used [67]. According to our calculations, M100 (neat methanol) had the best values of less emissions than petrol. However, methanol produced from coal had higher WTW emissions. carbon dioxide emissions compared to petrol (Figure5). Biomethanol had four times less emissions Methanol fuel cell is a perspective technology. All kinds of methanol (biomethanol and coal-based thanmethanol) petrol. However, provide the methanol best environmental produced from performance coal had compared higher WTW to petrol emissions.. Methanol fuel cell is a perspective technology. All kinds of methanol (biomethanol and coal-based methanol) provide the best environmental performance compared to petrol.

Energies 2020, 13, 3113 8 of 23

Table 2. Well-to-tank (WTT) carbon dioxide emissions for selected fuels.

WTT Carbon Dioxide Emissions (g CO -eq/kg) Fuel 2 References Minimum Maximum Diesel fuel 284 1020 [57] Gasoline 294.8 1188 [57] Natural gas 909.5 1290.9 [57–60] Biomethanol (biomass and renewable electricity) 898 [61] − Methanol (coal) 2965 [61] Bioethanol 1493 352 [62] − −

50 46.64 5045 46.64 4540 4035 3530 25.70 23.32 3025 20.41 25.70 18.67 23.32 2520 20.41 18.67 14.78 2015 14.78 7.39 1510 5.13

Carbon dioxide kg/kWh dioxide Carbon emissions, 7.39 2.56 105 5.13 Carbon dioxide kg/kWh dioxide Carbon emissions, 50 2.56 0 petrol M100 methanol fuel cell petrol M100 methanol fuel cell Tank to Wheel emissions Well-to-Wake minimum Well-to-Wake maximum

Tank to Wheel emissions Well-to-Wake minimum Well-to-Wake maximum FigureFigure 5. Carbon 5. Carbon dioxide dioxide emissions emissions per per 100 100km. km. Figure 5. Carbon dioxide emissions per 100 km. The cetaneThe number cetane number of methanol of methanol is less is lessthan than 5. Nevertheless, 5. Nevertheless, neatneat methanol may may be be used used in in diesel engines. Todiesel useThe engines. it cetane in compressed To number use it in of compressed methanol ignition is engines, ignition less than engines, a 5. diesel Nevertheless, a diesel methanol methanol neat compound methanol compound may combustion combustion be used in (DMCC) system hasdiesel(DMCC) been engines. developed. system To has use beenit The in compressed develope DMCCd. system Theignition DMCC consistsengines, system a of diesel consists two methanol injection of two compound injection subsystems: subsystems:combustion methanol and methanol and diesel fuel. Methanol is injected into the intake port of each cylinder to form an diesel fuel.(DMCC) Methanol system is hasinjected been intodevelope thed. intake The DMCC port of system each consistscylinder of to two form injection an air subsystems:/methanol mixture. methanolair/methanol and mixture. diesel fuel. The Methanol mixture is is ignited injected by into diesel the intakefuel. The port diesel of each fuel cylinder injection to system form an is The mixture is ignited by diesel fuel. The diesel fuel injection system is modiﬁed to limit the volume air/methanolmodified to limit mixture. the volume The mixture of injected is ignited diesel fuel. by diesel At engine fuel. start The and diesel low fuel load, injection the diesel system engine is of injectedmodifioperates dieseled on to fuel. diesellimit Atthe fuel enginevolume only. At of start medium injected and anddiesel low high fuel. load, loads, At theengine the dieselengine start operates engineand low on operatesload, methanol the diesel on and dieselengine diesel fuel only. At mediumoperatesfuels. and Pilot highon diesel diesel loads, fuel fuel istheonly. used engine At to medium ignite operates the and air/methanol high on loads, methanol mtheixture. engine and DMCC operates diesel engine fuels.on methanols have Pilot lower and diesel smoke diesel fuel is used to ignite thefuels.opacity air Pilot / andmethanol diesel nitrogen fuel mixture. is oxides used toemissions ignite DMCC the as enginesair/methanol compared have to m conventionalixture. lower DMCC smoke diesel engine opacity enginess have andlower[69]. nitrogenCarbon smoke oxides dioxide emissions of the above trucks were analyzed. The use of methanol resulted in slight emissionsopacity as compared and nitrogen to conventional oxides emissions diesel as compared engines to[ 69conventional]. Carbon diesel dioxide engines emissions [69]. Carbon of the above dioxidereduction emissions of TTW emissions of the above. The trucksWTW wereemissions analyzed. for biomethanol The use of depend methanoled on result methanoled in origin slight trucks werereduction(Figure analyzed. 6). of TTW The emissions use of. methanolThe WTW emissions resulted for in slightbiomethanol reduction depend ofed TTW on methanol emissions. origin The WTW emissions(Figure for biomethanol 6). depended on methanol origin (Figure6). 173.18 180 173.18 180160 125.69 160140 125.69 140120 103.53 93.87 92.55 103.53 120100 81.59 93.87 92.55 10080 81.59 8060 6040

Carbon dioxide kg/kWh dioxide Carbon emissions, 4020

Carbon dioxide kg/kWh dioxide Carbon emissions, 200 0 diesel DMCC diesel DMCC Tank to Wheel emissions WTW minimum WTW maximum

Tank to Wheel emissions WTW minimum WTW maximum Figure 6. Carbon dioxide emissions per 100 km for diesel methanol compound combustion (DMCC) Figure 6.FiguresystemCarbon .6. Carbon dioxide dioxideemissions emissions per per 100 km 100 for km diesel for methanol diesel compound methanol combustion compound (DMCC combustion) (DMCC) system.system.

The use of methanol gives the best results for spark ignition engines (SIE). There is a 21% decreaseEnergies 2020 in, 13tank, 3113-to-wheel emissions for SIE and a 1.5% decrease for diesel engines. WTW emissions9 of 23 The use of methanol gives the best results for spark ignition engines (SIE). There is a 21% are cut by 75% for SIE and 21.2% for DMCC (if biomethanol is used). decrease in tank-to-wheel emissions for SIE and a 1.5% decrease for diesel engines. WTW emissions 4.3.are cutEconomicThe by use 75% ofA ssessmentfor methanol SIE and gives 21.2% the for best DMCC results (if for biomethanol spark ignition is used) engines. (SIE). There is a 21% decrease in tank-to-wheel emissions for SIE and a 1.5% decrease for diesel engines. WTW emissions are cut by A number of researchers have stated that the target markets for methanol as a fuel are land 4.3.75% Economic for SIE and Assessment 21.2% for DMCC (if biomethanol is used). vehicles; methanol vessels (to improve environmental indicators); the energy supply of recreation A number of researchers have stated that the target markets for methanol as a fuel are land areas;4.3. Economic and the Assessment energy supply if there is lack of inexpensive fossil fuels such as natural gas, propane, vehicles; methanol vessels (to improve environmental indicators); the energy supply of recreation fuel oil, etc.) [70]. In this study, the economic assessment of methanol as a vehicle fuel was areas;A and number the energy of researchers supply if havethere statedis lack thatof in theexpensive target marketsfossil fuels for such methanol as natural as a gas, fuel propane, are land considered. fuelvehicles; oil, etc.)methanol [70]. vesselsIn this (to study, improve the economicenvironmental assessment indicators); of methanol the energy as supply a vehicle of recreationfuel was To compare petrol and diesel fuel with methanol, an economic analysis was carried out. The consideredareas; and the. energy supply if there is lack of inexpensive fossil fuels such as natural gas, propane, China petrol prices [71] and Mathenex methanol prices for Asia markets [72,73] were used (Figure 7). fuel oil,To etc.)compare [70]. petrol In this and study, diesel the economic fuel with assessment methanol, ofan methanol economic as analysis a vehicle was fuel ca wasrried considered. out. The These fuels have different physical properties such as lower heating value and density; therefore, ChinaTo petrol compare prices petrol [71] and and diesel Mathenex fuel with methanol methanol, prices an for economic Asia market analysiss [72 was,73] carried were used out. ( TheFigure China 7). their energy costs were calculated (Figure 8). Since October 2018, petrol energy costs have been Tpetrolhese fuels prices hav [71e] different and Mathenex physical methanol properties prices such foras lower Asia markets heating [value72,73 ]and were density used; (Figuretherefore,7). higher compared to those of methanol. theirThese energy fuels have costs di ﬀwereerent calculated physical properties (Figure 8 such). Since as lower October heating 2018 value, petrol and energy density; cost therefore,s have been their higherenergy compared costs were to calculated those of methanol (Figure8.). Since October 2018, petrol energy costs have been higher compared to those of methanol. 1200

12001000

1000800

800600

Price, USD/t Price, 600400

Price, USD/t Price, 400200

2000

18/08/2016 06/03/2017 22/09/2017 10/04/2018 27/10/2018 15/05/2019 01/12/2019 18/06/2020

Period

18/08/2016 06/03/2017 22/09/2017 10/04/2018 27/10/2018 15/05/2019 01/12/2019 18/06/2020 Period methanol petrol

methanol petrol Figure 7. Selected fuel prices. Figure 7. Selected fuel prices. Figure 7. Selected fuel prices. 30

25 30 20 25 15 20 10 15 Energy Energy USD/MJ cost, 5 10

Energy Energy USD/MJ cost, 0 5

18/08/2016 06/03/2017 22/09/2017 10/04/2018 27/10/2018 15/05/2019 01/12/2019 18/06/2020

Period

18/08/2016 06/03/2017 22/09/2017 10/04/2018 27/10/2018 15/05/2019 01/12/2019 18/06/2020 Period methanol petrol

Figure 8.methanolEnergy cost. petrol Figure 8. Energy cost.

Figure 8. Energy cost.

Energies 2020, 13, 3113 10 of 23 For consumers, a methanol to petroleum fuel price ratio indicator has been recommended for making decision [62,74]. This ratio should be less than an equilibrium point. The equilibrium point For consumers, a methanol to petroleum fuel price ratio indicator has been recommended for takes into account principle indicators of fuels and engine efficiency. It can be computed by the making decision [62,74]. This ratio should be less than an equilibrium point. The equilibrium point following expression: takes into account principle indicators of fuels and engine efficiency. It can be computed by the Fpr LHV  following expression: m m m PFR0   , (10) Fprp FprLHVm p LHVp m ηm PFR0 = = · (10) Fprp LHVp ηp · where LHVm is the lower heating value of methanol in MJ/kg;· LHVp is the lower heating value of petrolwhere inLHV MJ/kg;m is the m loweris the heatingengine valueefficiency of methanol when methanol in MJ/kg; isLHV used;p is  thep is lowerthe engine heating efficiency value of when petrol petrolin MJ/ iskg; used.ηm is the engine efficiency when methanol is used; ηp is the engine efficiency when petrol is used.If the actual methanol to petrol price ratio is less than calculated PFR0, then the application of methanolIf the is actual acceptable. methanol If there to petrol is information price ratio about is less actual than calculatedfuel economy,PFR 0the, then equilibrium the application point is of determinedmethanol is by acceptable. the formula If there is information about actual fuel economy, the equilibrium point is determined by the formula Fpr FE p PFR  m   , 0 Fprm FEp (11) Fprp FEm PFR0 = = (11) Fprp FEm · where FEm is the fuel economy of a methanol-fueled vehicle in L/100 km; FEp is the fuel economy of a petrolwhere-fueledFEm is vehicle the fuel in economy L/100 km. of a methanol-fueled vehicle in L/100 km; FEp is the fuel economy of a petrol-fueledOur calculations vehicle inwere L/100 done km. for a Geely car. Its fuel economy for petrol is 8 L/100 km, and for neat methanolOur calculations fuel M100 were its done fuel foreconomy a Geely is car.13.5 ItsL/100 fuel km economy [67]. Methanol for petrol and is 8 petrol L/100 km,prices and have for beenneat methanol investigated fuel since M100 2017. its fuel For economy that period, is 13.5 methanol L/100 km demonstrated[67]. Methanol economic and petrol superiority prices have over been petrolinvestigated (Figure since 9). T 2017.he actual For that methanol/ period,petrol methanol price demonstrated ratios were less economic than the superiority equilibrium over point. petrol Th(Figureerefore,9). methanol The actual was methanol a competitive/petrol pricealternative ratios wereto petrol. less thanThe thermal the equilibrium methanol point. to petrol Therefore, price ratiomethanol was lower was athan competitive the actual alternative one. This means to petrol. that Thethe methanol thermal methanol engine efficiency to petrol wa prices higher ratio than was thelower petrol than engine the actual efficiency. one. This means that the methanol engine efficiency was higher than the petrol engine efficiency.

0.65 0.60 0.55 0.50 0.45 0.40 0.35

0.30 Methanol/petrol price price ratio Methanol/petrol

0.25

18/08/2016 06/03/2017 22/09/2017 10/04/2018 27/10/2018 15/05/2019 01/12/2019 18/06/2020 Period

Methanol/petrol price ratio (equilibrium point) Actual methanol/petrol price ratio Thermal methanol/petrol price ratio FigureFigure 9. 9. Methanol/Methanol/petrolpetrol prices prices ratio ratio..

MM1515 fuel fuel is is widespread widespread in in China. China. An An engine engine fueled fueled by by M15 M15 has has higher higher thermal thermal brake brake efficiency efficiency comparedcompared to to petrol. petrol. The The increase increase of of methanol methanol concentration concentration results results in in increases increases of of the the thermal thermal brake brake efficiency.efficiency. China China ha hass been been success successfulful in in commercializing commercializing M15 fuel. The The e existingxisting vehicle vehicle fleet fleet does does not not needneed modification modification,, and and the the price price of M15 is also competitive ( (FigureFigure 10). Some Chinese companies such as Sinotruk Jinan Truck Co., Ltd and Shaanxi Automobile group Co., Ltd. produce methanol diesel dual fuel dump trucks. For example, Shacman SX3317DR456HM and ZZ3317N4667D1M are powered by a 245 kW dual fuel engine [75,76]. Chinese companies (Yulin City of Shannxi Province) have experience in the use of M100 by trucks equipped by DMCC engines. The energy share of diesel fuel ranges from 0.64 to 0.697 [11].

Energies 2020, 13, 3113 11 of 23

1.00 0.95 0.90 0.85 0.80 FPR 1.00 0.75 0.95 0.70 0.90 0.65 0.85 0.60

0.80 FPR 0.75

0.70

24/02/2019 16/03/2019 05/04/2019 25/04/2019 15/05/2019 04/06/2019 24/06/2019 0.65 Period 0.60 M15/No. 89 M15/No. 92 FPRth

Figure 10. M15/petrol prices ratio.

24/02/2019 16/03/2019 05/04/2019 25/04/2019 15/05/2019 04/06/2019 24/06/2019 Some Chinese companies such as Sinotruk JinanPeriod Truck Co., Ltd and Shaanxi Automobile group Co., Ltd.An acceptable produce methanol methanol diesel to diesel dual fuel fuel price dump ratio trucks. may be For found example, by the Shacman following SX3317DR456HM formula: M15/No. 89 M15/No. 92 FPRth and ZZ3317N4667D1M are poweredFEd  Fpr byd a 245FE kWm  Fpr dualm fuel engine [75,76]. Chinese companies (Yulin 1 , (12) City of Shannxi Province) have experienceFEd0  inFpr thed use of M100 by trucks equipped by DMCC engines. The energy share of diesel fuel rangesFigure from 10. 0.64M15/petrol to 0.697 prices [11]. ratio. where FEd is the diesel fuel economy of a vehicle equipped by DMCC engine in L/100 km; FEm is the An acceptable methanol to diesel fuel price ratio may be found by the following formula: methanolAn acceptable fuel economy methanol of ato vehicle diesel fuel equipped price ratio by DMCCmay be found engine by in the L/100 following km; FE formulad0 is the: fuel economy of a diesel-fueled vehicle equipped by conventional diesel engine in L/100 km. FEd  FprFEdd FprFEdm+ FprFEmm Fprm · · 1 , < 1,( (12)12) Hence, the equilibrium point of theFE acceptableFEFpr Fpr methanol to diesel fuel price ratio is equal to d0 d0d · d Fpr m FEd0  FEd d FPR   . m where FEd isis the the diesel diesel fuel fuel economy economyd0 of of a a vehicle vehicle equipped equipped by by DMCC DMCC engine in L/100 L/100 km; FEm isis( the13 the) Fprd FEm methanol fuel economy of a vehicle equipped by DMCC engine in L/100 km; FEd0 is the fuel methanol fuel economy of a vehicle equipped by DMCC engine in L/100 km; FEd0 is the fuel economy economyof a diesel-fueledThe equilibriumof a diesel vehicle-fueled point equipped vehicleis higher equipped by than conventional the by actual conventional diesel methanol engine diesel to indiesel engine L/100 fuel km. in priceL/100 ratiokm. (Figure 11) [77]. Hence,Hence,The price the ratioequilibrium makes point the use of the of M100acceptable profitable. methanol According to diesel to fuel our price calculations, ratio is equal the useto of Fpr FE  FE methanol fuel results in fuel costFPR saving of m6–7%. d0 d . d0 Fprrm FEd0 FEd (13) FPRFprd0 =d FE

0.2 0.5 Price Price ratiofuels of 0.1 0.438 0.438 0.352 0.40 0.3 Actual Equilibrium, DMCC Equilibrium, fuel properties 0.2

Price Price ratiofuels of 0.1 Figure 11. Methanol to diesel fuel price ratio: actual, maximum acceptable. 0 4.4. Methanol Production Actual Equilibrium, DMCC Equilibrium, fuel properties

A conventionalFigure methanol 11. Methanol plant to comprises diesel fuel pricethe following ratio: actual, processes: maximum production acceptable. of syngas and its cleaning, reforming of higher hydrocarbons, water–gas shift, methanol synthesis and its Figure 11. Methanol to diesel fuel price ratio: actual, maximum acceptable. purification 4.4. MethanolMethanol P roductionproduction processes depend on the feedstock. Solid feedstock (such as coal, biomass and waste) is gasified into syngas (a mixture of carbon monoxide and hydrogen, as well as water A conventional methanol plant comprises the following processes: production of syngas and its cleaning, reforming of higher hydrocarbons, water–gas shift, methanol synthesis and its purification Methanol production processes depend on the feedstock. Solid feedstock (such as coal, biomass and waste) is gasified into syngas (a mixture of carbon monoxide and hydrogen, as well as water

Energies 2020, 13, 3113 12 of 23

4.4. Methanol Production A conventional methanol plant comprises the following processes: production of syngas and its cleaning, reforming of higher hydrocarbons, water–gas shift, methanol synthesis and its purification. Methanol production processes depend on the feedstock. Solid feedstock (such as coal, biomass and waste) is gasified into syngas (a mixture of carbon monoxide and hydrogen, as well as water and hydrocarbons). However, if air is used as the oxidant, syngas contains nitrogen. It increases the gas flow through the gasifier. This results in higher investment costs. The use of pure oxygen decreases equipment costs. However, this oxidant is rather expensive. If biomass is used as the feedstock, a pre-treatment is required. It may be chipping, drying, etc. The pre-treatment increases investment and operational costs. If gaseous feedstock (such as natural gas or biomethane) is used for methanol production, it should be reformed to produce syngas. Biomethane is a result of biogas upgrading. Its production requires anaerobic digestion, biogas cleaning and biogas upgrading. Therefore, biomethane production needs more investment costs. Moreover, this renewable combustible gas has higher production costs compared to natural gas. Renewable methanol is produced from carbon dioxide and renewable hydrogen. Hydrogen can be obtained from water by electrolysis. This process needs electricity produced by solar photovoltaic, hydro and wind power plants. As a rule, it is the most expensive methanol, although this process shows the highest carbon dioxide saving [78–80].

4.4.1. Green Methanol In this study, we distinguish low-carbon methanol (LCM), biomethanol and renewable methanol [81]. Biomethanol is produced from organic feedstock. Renewable methanol is produced from carbon dioxide and renewable electricity. LCM is produced from natural gas or other fossil fuel by adding carbon dioxide from industrial facilities. According to the Methanol Institute, renewable methanol is produced from the following feedstocks: biomass, industrial waste, municipal waste and carbon dioxide plus green electricity [82]. Methanol production and utilization pathways are presented in Figure 12. Renewable feedstock and electricity meet the circular economy.

feedstock Direct fuels Fuel cells

Pure methanol Renewable

Methanol-petrol Thermal engines Non-Renewable blends

Spark ignition engine

Derived fuels Energy Gas turbine engine

Production Production

Biodiesel Dual-fuel engine Renewable Diesel engine

Non-Renewable Dimethyl ether

Figure 12. Methanol-based fuel production and utilization. Figure 12. Methanol-based fuel production and utilization.

Some kinds of renewable resources may be used to produce biomethanol, such as biomass (forest residues, agricultural residues and energy crops), municipal waste water and municipal solid waste. China has a relatively small forested area at less than 23% [86]. Wood and wood residues were not considered in this study. The use of wood and agricultural residues requires specific approaches and will be explored in subsequent studies [87,88]. To produce renewable methanol, carbon dioxide and renewable electricity are needed. Based on economic feasibility and the availability of resources, we further considered the following feedstocks: municipal waste water, municipal solid waste, carbon dioxide and renewable electricity.

4.4.2. Renewable Methanol (Carbon Dioxide and Renewable Electricity)

Zhang et al. reported that CO2-to-methanol technology is economically feasible if the electricity price is less than USD 0.047/kWh [89]. There are different sources of carbon dioxide such as flue gases, exhaust gases, atmosphere, biogas, pre-combustion, etc. (Figure 13). The largest sources of carbon dioxide are cement and steel industries [90]. Costs for carbon dioxide capture vary from EUR26/t to EUR59/t [91–93]. The average global renewable electricity production costs are falling. Among them, onshore wind and biomass power plants generate electricity with the lowest costs. Some of these projects can reach competitive costs of electricity [94]. Therefore, the production of renewable methanol may be competitive.

Energies 2020, 13, 3113 13 of 23

Methanol is currently produced from fossil fuels, mainly natural gas. China is the biggest methanol producer. This country uses primarily coal (around 64%) [45,83]. Methanol production costs mainly depend on feedstock and an electricity price. Natural gas-based methanol production costs range from EUR50/t to EUR400/t. The share of feedstock in production costs varies from 39.6 to 85.7% [84]. Coal-based methanol, as a rule, is more expensive. For example, in 2017 in China, its cost was EUR235/t [38]. China can produce biomethanol and renewable methanol from the following resources: biomass, municipal solid and water waste, carbon dioxide and renewable electricity. Biomass-based methanol cannot compete with fossil fuel based methanol. Its production cost ranges from EUR500/t to EUR600/t. The production costs of renewable methanol based on wind power and carbon dioxide depend on electricity cost and vary from EUR610/t to EUR1520/t, but are falling [45,85]. Some kinds of renewable resources may be used to produce biomethanol, such as biomass (forest residues, agricultural residues and energy crops), municipal waste water and municipal solid waste. China has a relatively small forested area at less than 23% [86]. Wood and wood residues were not considered in this study. The use of wood and agricultural residues requires speciﬁc approaches and will be explored in subsequent studies [87,88]. To produce renewable methanol, carbon dioxide and renewable electricity are needed. Based on economic feasibility and the availability of resources, we further considered the following feedstocks: municipal waste water, municipal solid waste, carbon dioxide and renewable electricity.

4.4.2. Renewable Methanol (Carbon Dioxide and Renewable Electricity)

Zhang et al. reported that CO2-to-methanol technology is economically feasible if the electricity price is less than USD 0.047/kWh [89]. There are diﬀerent sources of carbon dioxide such as ﬂue gases, exhaust gases, atmosphere, biogas, pre-combustion, etc. (Figure 13). The largest sources of carbon dioxide are cement and steel industries [90]. Costs for carbon dioxide capture vary from EUR26/t to EUR59/t [91–93]. The average global renewable electricity production costs are falling. Among them, onshore wind and biomass power plants generate electricity with the lowest costs. Some of these projects can reach competitive costs of electricity [94]. Therefore, the production of renewable methanol may be competitive. Wind power plants have high potential to produce sustainable hydrogen and, therefore, methanol. Due to technological innovations, the generation costs are decreasing. According to the IRENA reports, in 2018 the global average cost of electricity generated by onshore wind power plants was USD 0.056/kWh. In general, it ranged from USD 0.04/kWh to USD 0.10/kWh. Around 5% of electricity was cheaper than USD 0.05/kWh. The average levelized cost of electricity of onshore wind power plants commissioned in 2018 was under USD 0.048/kWh [94]. That fact allows us to look with optimism at the power-to-methanol technology. China is a leader of the wind power market. In 2019, its total onshore installations had a rated power of 229,954 MW [95] and generated 405,700 GWh [96]. This sector of the economy has positive dynamics (Figure 14). The potential renewable methanol production using power-to-liquid technology is

3 1 TPMPWW = 10− W SW η LHVmw− million t (14) · · · pl · · where W is the total national electricity production by wind power plants in GWh; SW is the share of competitive wind power plants, and SW = 5%; ηpl is the conversion efficiency, in percent; LHVm0 is the lower heating value of methanol, and LHVm0 = 5.464 kWh/kg. The power-to-methanol conversion efficiency is 48.2% [66]. Therefore, the theoretical feasible methanol production is 1.789 million tons. These wind power plants may integrate with sources of carbon dioxide such as alcohol refineries, steel plants, biogas plants, etc. Energies 2020, 13, 3113 14 of 23

Renewable Electricity

Biomass

Photovoltaic

Solar

Solar concentrated Electrolysis

Onshore

Wind H2 Offshore Renewable

methanol Geothermal

Carbon dioxide Conversion

Atmosphere

Burning of fuel CO2

Product

Burning of biomass

Capture CO2 Flue gases

By-product

Fermentation

Anaerobic digestion

Figure 13. Renewable methanol production. Figure 13. Renewable methanol production.

Wind250 power plants have high potential to produce sustainable hydrogen and,450 therefore, methanol. Due to technological innovations, the generation costs are decreasing. According400 to the IRENA reports,200 in 2018 the global average cost of electricity generated by onshore 350 wind power plants was USD 0.056/kWh. In general, it ranged from USD 0.04/kWh to USD 0.10/kWh.300 Around 5% of electricity150 was cheaper than USD 0.05/kWh. The average levelized cost of electricity of onshore 250 wind power plants commissioned in 2018 was under USD 0.048/kWh [94]. That fact allows us to look 200 with optimism100 at the power-to-methanol technology. 150 China is a leader of the wind power market. In 2019, its total onshore installations had a rated power of 22950 ,954 MW [95] and generated 405,700 GWh [96]. This sector of the economy100 has positive

dynamics (Figure 14). 50 Generation, thousand GWh

Installed power, Installedpower, thousand MW 0 0 2013 2014 2015 2016 2017 2018 2019

Period, year

Rated power Generation

Figure 14. Onshore wind farm installations and electricity generation history. Figure 14. Onshore wind farm installations and electricity generation history.

The potential renewable methanol production using power-to-liquid technology is

3 1 TPMPWW  10 W  SW  pl  LHVmw  , million t, (14) where W is the total national electricity production by wind power plants in GWh; SW is the share of competitive wind power plants, and SW = 5%; pl is the conversion efficiency, in percent; LHVm0 is the lower heating value of methanol, and LHVm0 = 5.464 kWh/kg. The power-to-methanol conversion efficiency is 48.2% [66]. Therefore, the theoretical feasible methanol production is 1.789 million tons. These wind power plants may integrate with sources of carbon dioxide such as alcohol refineries, steel plants, biogas plants, etc.

4.4.3. Biomethanol There are several sources of biomass for the production of biomethanol (Figure 15). Waste water can be used to produce biogas. Upgraded biogas (biomethane) can be converted to methanol. This process is like the natural gas to methanol conversion [65]. Nowadays there are commercial projects producing renewable methanol (biomethanol) from biogas. For example, BioMethanol Chemie Nederland B.V., doing business as BioMCN (the Netherlands), has replaced natural gas with biogas in its methanol production process. This company uses upgraded biogas (biomethane) from different sources. In 2017, BioMCN produced around 60 thousand tons of biomethanol. This form of renewable methanol production can contribute to the circular green economy [81]. Lu et al. explored possible solutions for optimizing the operation of wastewater treatment plants in China [97]. They found that sludge anaerobic digestion is a most sustainable pathway to sort out the sludge disposal problem. This idea was supported by Li and Feng [98]. Biogas production strategies to reduce the operating costs were supported by Cano et al. [99] and Holaby et al. [100]. In China, annual sewage sludge generation is around 6.25 million tons of dry matter [101]. Its specific value (per inhabitant) is less than in European Union countries, Japan, the USA, etc. Therefore, its volume is expected to grow. Waste water treatment plants (WWTP) may be integrated into biogas and biomethane systems [102].

Energies 2020, 13, 3113 15 of 23

4.4.3. Biomethanol There are several sources of biomass for the production of biomethanol (Figure 15).

Wood

Energy crop

Crop residues

Crop growing

Agriculture

Product Anaerobic digestion

CO2

Livestock Residue Biogas upgrading

Biomethanol

Conversion Waste water

Municipal waste Municipal solid waste Gasifier

FigureFigure 15. 15. Biomethanol production production.. There is a number of large-scale WWTPs, for example, treatment capacity in thousands of cubic Waste water can be used to produce biogas. Upgraded biogas (biomethane) can be converted meters per day, as follows: Dalian Malan River—120; Wuxi Lucun Village—200; Tianjin to methanol.Jizhuangzi This—260; process Shanghai is like Shidongkou the natural—400; gas Beijing to methanol Water Reclamation conversion Plant [65—1000]. Nowadays; Qinghe there are commercialWastewater projects Treatment producing Plant—240 renewable [96,103]. They methanol are more (biomethanol) suitable for biogas from production biogas. For. The example, BioMethanolupgraded Chemie biogas Nederland can be used B.V.,doingas a feedstock business for methanol as BioMCN production. (the Large Netherlands),-scale WWTPs has (capacity replaced natural gas withmore biogas than in 500 its thousand methanol cubic production meters per process. day) treat This around company 5.2% usesof the upgraded total waste biogas water. (biomethane) The potential biomethanol production was computed by the following formula: from diﬀerent sources. In 2017, BioMCN produced around 60 thousand tons of biomethanol. This form of renewable methanol production6 can contribute to the circular1 green economy [81]. TPMPWW 10 MWWDM SLS VS BCE YB LHVB  LHVm  , thousand t, (15) Lu et al. explored possible solutions for optimizing the operation of wastewater treatment plants in Chinawhere [97]. M TheyWWDM foundis the annual that sludge sewage anaerobic sludge generation digestion in million is a mosts of sustainabletons; SLS is the pathway share of to large sort out the sludgescale disposal WWTPs, problem. in percent This; ideaVS is was the supported volatile solid by fraction, Li and Fengin percent [98].; BiogasBCE is the production conversion strategies 3 to reduceefficiency, the operating in percent costs; YB wereis the biogas supported yield byin m Cano/t; LHV etB al. is [the99] lower and Holabyheating value et al. of [100 biogas]. in MJ/m3; LHVm is the lower heating value of methanol in MJ/kg. In China, annual sewage sludge generation is around 6.25 million tons of dry matter [101]. The energy efficiency of biomethane-to-methanol technology is equal to 69% [66]. We assumed Its speciﬁcthe following value (perinitial inhabitant) data: volatile issolids less fraction than in—87 European% [104]; biogas Union yield countries,—700 m3/t Japan,[104]; share the of USA, etc. Therefore,large its scale volume WWTPs is expected(more than to 200 grow.,000 m Waste3/day)— water24.57% treatment [105]; lower plants heating (WWTP) value of maybiogas be— integrated21 into biogasMJ/m and3. Our biomethane calculations show systemsed that [102 the]. theoretical potential of biogas-based methanol production Thereis 688.9 is athousand number tons of. large-scale WWTPs, for example, treatment capacity in thousands of cubic meters per day,This as idea follows: is feasible. Dalian For Malan example, River—120; in Sweden Wuxi, WWTPs Lucun annually Village—200; produce Tianjin 700 GWh Jizhuangzi—260; or 120 million cubic meters of biogas. Himmerfjärdsverket WWTP (the capacity is 130,000 m3/day) has Shanghaiannual Shidongkou—400; biogas production Beijingof 7.68 million Water m Reclamation3. It produces Plant—1000;around 2.7 million Qinghe m3 of Wastewater biomethane. Its Treatment Plant—240production [96,103 cost]. Theywas EUR are 509/m more3 [ suitable106]. for biogas production. The upgraded biogas can be used as a feedstockMunicipal for methanol Solid Waste: production. Large-scale WWTPs (capacity more than 500 thousand cubic meters per day) treat around 5.2% of the total waste water. The potential biomethanol production was computed by the following formula: Energies 2020, 13, 3113 16 of 23

6 1 TPMPWW = 10− MWWDM SLS VS η YB LHVB LHVm− thousand t (15) · · · · BCE · · · · where MWWDM is the annual sewage sludge generation in millions of tons; SLS is the share of large scale WWTPs, in percent; VS is the volatile solid fraction, in percent; ηBCE is the conversion efficiency, 3 3 in percent; YB is the biogas yield in m /t; LHVB is the lower heating value of biogas in MJ/m ; LHVm is the lower heating value of methanol in MJ/kg. The energy efficiency of biomethane-to-methanol technology is equal to 69% [66]. We assumed the following initial data: volatile solids fraction—87% [104]; biogas yield—700 m3/t [104]; share of large scale WWTPs (more than 200,000 m3/day)—24.57% [105]; lower heating value of biogas—21 MJ/m3. Our calculations showed that the theoretical potential of biogas-based methanol production is 688.9 thousand tons. This idea is feasible. For example, in Sweden, WWTPs annually produce 700 GWh or 120 million 3 cubic metersA ofprospect biogas.ive Himmerfjärdsverketbiomass source is municipal WWTP solid (the waste capacity (MSW). is This 130,000 kind of m feedstock/day) has is used annual by biogas productionthe Canadian of 7.68 million company m Enerken.3. It produces Its methanol around production 2.7 million cost m was3 of estimated biomethane. at EUR Its 110/t production [107]. cost was EURThere 509 is/ man3 agreement[106]. between Enerken Inc. and Sinobioway Group to implement this technology in MunicipalChina [108 Solid]. Waste: Therefore, MSW for methanol production is a promising technology. In China, the volume of A prospective biomass source is municipal solid waste (MSW). This kind of feedstock is used MSW is rising [109]. In 2018, the above value exceeded 228 million tons (Figure 16). According to by theforecasting, Canadian companythis value may Enerken. reach 480 Its million methanol tons by production 2030. The combustible cost was estimatedfraction of MSW at EUR (such 110 as /t [107]. There ispaper, an agreement plastics, textile, between wood, Enerken etc.) ranges Inc. from and 19.07 Sinobioway to 56.35%. Group Its lower to heating implement valuethis varies technology from in China [3.572108]. MJ/kg to 8.322 MJ/kg [110]. This feedstock may be used to produce methanol. The theoretical Therefore,potential ofMSW MSW-forbased methanol methanol production can be calculated is a by promising the following technology. formula: In China, the volume of MSW is rising [109]. In 2018, the above value exceeded 228 million tons (Figure 16). According to TPMP  104  MmswCS   LHV  LHV 1  (16) forecasting, this value may reach 480 millionCE tons byMSW 2030. Them combustible, mln t, fraction of MSW (such as paper, plastics,where Mmsw textile, is collected wood, etc.) MSW ranges in million froms of 19.07 tons; to CS 56.35%. is the combustible Its lower heating fraction value of MSW varies in from 3.572 MJpercent/kg to;  8.322CE is the MJ conversion/kg [110]. efficiency This feedstock in percent may; LHV beMSW used is the to producelower heating methanol. value of TheMSW theoretical in potentialMJ/kg; of MSW LHVm-based is the lower methanol heating can value be of calculated methanol in by MJ/kg. the following formula: The energy efficiency of waste-to-methanol technology is around 55% [111]. We computed the 4 1 theoretical potentialTPMP for 2018= 10 and− 2023Mmsw (we usedCS theηCE massLHV of MSWMSW predictedLHVm− bymln the approximation t of (16) a function). Our calculations show· ed that· in 2018· the· theoretical· potential· was between 4.35 and where Mmsw29.95 millionis collected tons. By MSW2023 the in above millions potential of tons; may CS increase is the to combustible values between fraction 5.14 and of 35.4 MSW million in percent; tons (Figure 17). Therefore, the potential MSW-based methanol production can be between 6.69% ηCE is the conversion efficiency in percent; LHVMSW is the lower heating value of MSW in MJ/kg; LHVm and 54.46% of its current production [12]. is the lower heating value of methanol in MJ/kg.

280 260 240 220 200 180 160 140 120

100 Municipal wastes, mln t mln wastes, Municipal 80 60 40 20 0 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023

Period, year

Figure 16. Municipal solid waste collected. Actual value increment approximation approximation, increment

The energy eﬃciency of waste-to-methanolFigure 16. Municipal technology solid waste collected is around. 55% [111]. We computed the theoretical potential for 2018 and 2023 (we used the mass of MSW predicted by the approximation

Energies 2020, 13, 3113 17 of 23 of a function). Our calculations showed that in 2018 the theoretical potential was between 4.35 and 29.95 million tons. By 2023 the above potential may increase to values between 5.14 and 35.4 million tons (Figure 17). Therefore, the potential MSW-based methanol production can be between 6.69% and 54.46% of its current production [12].

70 65.00

40 35.40 29.95 30

Methanol production, mln t mln production, Methanol 20

10 4.35 5.14

0 2018 2023 Actual

minimum maximum Actual, 2018

Figure 17. Potential production of MSW-based methanol. Figure 17. Potential production of MSW-based methanol. 5. Conclusions 5. Conclusions Since 2000 there has been an increase in methanol production and application as a vehicle fuel. China,Since as a2000 leader there in has methanol been an production, increase in hasmethanol demonstrated production the and gradual application transition as a to vehicle a methanol fuel. Chinaeconomy., as a The leader analysis in methanol showed thatproduction the global, has methanol demonstrate economyd the has gradual an average transition annual to a growth methanol rate economy.of 5.9%. Meanwhile, The analysis China showed showed that an the increase global ofmethanol about 10%. economy In 2019, has global an average methanol annual consumption growth rateas fuel of exceeded 5.9%. Meanwhile, 30 million tonsChina and showed is growing. an increase of about 10%. In 2019, global methanol consumptionThe thermal as fuel effi ciencyexceeded of methanol 30 million fueled tons enginesand is growing. is not less than the efficiency of engines powered by conventionalThe thermal fuels. efficiency Methanol of methanol fuel increases fueled the engines efficiency is notof spark less ignitionthan the engines. efficiency Methanol of engines fuel poweredcells have by the conventional best results. Since fuels. October Methanol 2018, fuel methanol increases has the been efficiency competitive of spark compared ignition to petroleum engines. Methanolfuels. The fuel cost cells saving have ranged the best from results. 6–7% S (forince diesel October engines) 2018 to, methanol 30% (for SIE). has been competitive comparedSpecific to petroleum carbon dioxide fuels. emissions The fuel cost do notsaving depend ranged on from the type 6–7% of (for fuel. diesel They engines) mainly dependsto 30% (for on SIE).engine efficiency. Only green methanol can reduce WTW carbon dioxide emissions. Spark ignition enginesSpecific and fuelcarbon cells dioxide are expected emissions to have do not the depend best results. on the type of fuel. They mainly depends on engineTo ef ensureficiency. the Only sustainable green developmentmethanol can of reduce the automotive WTW carbon industry, dioxide it is necessaryemissions. to Spark use renewable ignition enginesfuels, including and fuel biomethanol. cells are expected The use to ofhave MSW, the windbest results. power and WWTP biogas are promising pathways for greenTo ensure methanol the production. sustainable MSW development as a feedstock of the is automotive ranked first. industry, it is necessary to use renewableImproved fuels living, including standards biomethanol. have resulted The inuse increased of MSW, volumes wind power of MSW. and Its WWTP volume biogas exceeded are promising238 million pathways tons in 2018. for MSWgreen is methanol a promising production feedstock. MSW to produce as a feedstock green methanol. is ranked Existing first. technologies allowImprov chemicaled living companies standards to convert have MSWresulted into in methanol increased. Involume 2018,s the of theoreticalMSW. Its volume annual exceeded potential 238ranged million from tons 4.35 toin 29.95 2018. million MSW tons.is a promising Wind power feedstock plants (power-to-liquid) to produce green and methanol. biogas of Existing WWTPs technologiescan currently allow produce chemical 1.79 and companies 0.69 million to tons, convert respectively. MSW into methanol. In 2018, the theoretical annualBased potential on the range above,d from policymakers 4.35 to 29.95 should million support tons. the Wind development power plants of green (power methanol-to-liquid) projects and biogasin China. of WWTPs can currently produce 1.79 and 0.69 million tons, respectively. BasedAgricultural on the residuesabove, policymakers and wood as should feedstock support for methanol the development production of havegreen significant methanol potential.projects inThey China. are subjects for further study. In order to assess the potential of agricultural residues for biomethanolAgricultural production, residue furthers and research wood as will feedstock be focused for on methanolthe quantity production of agricultural have crop significant residues, potential.the quantity They of manure,are subjects their for geographical further study. locations In order and to cluster assess analysis.the potential Special of agricultural attention will residues be paid forto determinebiomethanol the production, synergetic e fffurtherects of biomethanolresearch willproduction. be focused on the quantity of agricultural crop residues, the quantity of manure, their geographical locations and cluster analysis. Special attention will be paid to determine the synergetic effects of biomethanol production.

Author Contributions: Conceptualization, E.T.; Formal analysis, V.H. and V.N.; Investigation, O.B.; Writing—original draft, V.H. and V.N.; Writing—review and editing, T.B. and D.S. All authors have read and agreed to the published version of the manuscript.

Energies 2020, 13, 3113 18 of 23

Author Contributions: Conceptualization, E.A.T.; Formal analysis, V.H. and V.N.; Investigation, O.B.; Writing—original draft, V.H. and V.N.; Writing—review and editing, T.B. and D.S. All authors have read and agreed to the published version of the manuscript. Funding: This study was carried out as part of the project “Belt and Road Initiative Centre for Chinese–European studies” and was funded by the Guangdong University of Petrochemical Technology. Conﬂicts of Interest: The authors declare no conﬂict of interest.

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