**2. Energy consumption trends and future of diesel engines and DME**

**Figure 1** presents the global energy consumption from 1971 to 2019 in Exajoules (10<sup>18</sup> J). World energy consumption has been increasing steadily from 1971 (176.8 EJ) to 2019 (418 EJ), an increase of 136% [2]. Largest increase has been in oil and electricity consumption. It is expected that the increase in these two sources will continue in the future. With the development of new battery technologies and solar PVs, increase in rate of electricity consumption including that generated from renewables will increase further.

**Figure 2** gives the world energy consumption history and projections. **Figure 2(a)** shows that increase in industrial energy consumption is expected to be the largest followed by the transportation sector although growth in residential and commercial sectors is also expected at a relatively moderate rate. **Figure 2(b)** gives the world energy consumption on the basis of fuel. Use of petroleum and other liquids are anticipated to increase till 2050 and will be about 250 quadrillion Btu. Renewables, during the same period, are expected to rise to 40 quadrillion Btu. Therefore, the share of petroleum and other liquids will be around six times that of renewables. In the heavy-duty sector diesel-based compression ignition engines are the preferred power source. Therefore, there is a sound future for the CI engines in all sectors, i.e., power generation, transportation, industry etc. Conversion of CI engines to use DME will lead to reduction in fossil fuel consumption and prevent degradation of environment.

**Figure 1.** *World total energy consumption by source (1971–2019) [2].*

*Replacement of Diesel Fuel by DME in Compression Ignition Engines: Case for India DOI: http://dx.doi.org/10.5772/intechopen.104969*

#### **Figure 2.**

*World energy consumption, history and projections [3]. a) World end-use consumption by sector. b) World enduse energy consumption by fuel.*

#### **2.1 Consumption of diesel by end use**

Among the petroleum fuels, diesel is a critical fuel for transportation especially heavy-duty vehicles, agricultural vehicles, construction and earth moving equipment. Power generation is another important area where diesel is used. **Figure 3** shows the end-use of diesel fuel in the USA, Japan and India, countries which are the one of the largest consumers of diesel fuel. In all three countries transport sector is the major consumer of mineral diesel. Conversion of trucks and busses to DME will lead to major reduction of fossil fuel and associated emissions.

#### **2.2 Categorization of diesel engine market**

IMARC group has categorized the global diesel engine market as shown in **Figure 4**.

Power rating of the diesel engines varies from 0.5 MW to more than 5 MW used in automotive and non-automotive applications all over the world. **Figure 4** illustrates that development of engine technology to utilize DME in diesel engines will have a positive effect in all sectors and across continents. Thus, a concentrated effort by different OEMs to come out with DME conversion kits or even new DME engine

#### **Figure 3.**

*End-use of diesel fuel in USA, Japan and India [4–6]. (a) USA – 241 billion liters per year. (b) Japan – 60 billion liters per year. (c) India – 100 billion liters per year.*

#### **Figure 4.**

*Categorization of the diesel engine market based on power rating and end-user [7].*

designs will not only reduce fossil fuel consumption and environmental deterioration but also has a firm economic viability. All sectors are expected to exhibit increase in use of diesel engines, however highest growth is expected from the power generation sector, trucks and busses and industrial sector. The global diesel engine market reached a value of US\$ 212.4 billion in 2021 [7]. It has been predicted that the demand for diesel engines including all sectors and sizes should increase to US\$ 240 billion in the year 2025 registering a compound annual growth rate of over 3% from 2020 to 2025 [8].
