Greenhouse gas emissions causing global warming come mostly from the energy sector, which accounts for about 61 per cent of total carbon dioxide equivalent emissions mostly due to the burning of fossil fuels.
Out of these, about 50 per cent are from electric supply, 20 per cent from industrial fuel combustion and around 11 per cent from transport. Road transport accounts for nearly 90 per cent of transport emissions and the rest 10 per cent comes from the rail, aviation and shipping. Global warming, which causes a lot of harm to human beings and other living beings on this earth, has to be reduced drastically by using renewal energy in place of fossil fuels. In this regard, an account of some steps taken by different countries in using some important renewable energies in the transport sector can be of help.
Biofuels
Bio-fuels which are being produced using advanced technology have got a promising future as fuel in place of coal, oil etc., in the transport sector. The following benefits can be derived by using biofuels.
- While the oil price is rising and is increasingly volatile, bio-fuels (produced from biomass including agricultural wastes) can have relatively steady pricing.
- Global transport fuel demand is growing rapidly and biofuels can replace fossil fuels to any extent.
- Bio-fuels can create additional opportunities for income in rural areas.
- Bio-fuels can reduce carbon dioxide and other greenhouse gas emissions compared to gasoline or diesel.
- Bio-fuels are only low-carbon fuels suitable for heavy transport models like planes, trucks, marine vehicles, etc.
The production of biofuels in the world with 22 per cent annual growth between 2000 – 2010, has reached 110 billion litres in 2012. Biofuels provide around 3 per cent of the total road transport till today. Most of the countries in the world support policies for the development and use of biofuels, which is the main drive behind bio-fuel development.
It is encouraging to note that biofuels, mainly ethanol, biodiesel, other liquid biofuels and biogas are being produced and used increasingly in road transport. Within a period of a decade between 2000 and 2010, the use of biofuels has increased from 417 PJ to 2410 PJ (one PJ = 1015 Joules). During this period, ethanol consumption grew from 272 PJ in 2000 to 1 426 PJ in 2010, whereas biodiesel grew in a more impressive manner from 18 PJ to 616 PJ.
However, the production of ethanol and bio-diesel is much less compared to their demand in the transport sector. While the United States produced 69 per cent of ethanol of the total global in 2010, Brazil produced about 25 per cent and the rest was produced in mostly Europe, China and Canada.
The production of ethanol in the United States is mostly from corn, while in Brazil it is mostly from sugar cane. Global biodiesel production grew to nearly 29 times more from 2000 to 2012. In 2012, 83 billion litres of ethanol and 26 billion litres of biodiesel were produced in the world. By the beginning of 2013, global advanced biofuel production capacity reached 230 million litres per year. It was estimated that by 2015, global advanced cellulosic bio-fuels capacity could reach 1.5 billion litres per year out of which nearly 75 per cent could be in the United States.
Solar energy
In recent years, through intense R&D studies, it has been possible to make solar energy a viable alternative for power generation and has the highest global warming mitigation potential amongst the available clean energy sources. The recent technological developments have been able to materialise the application of solar energy on a small scale in form of concentrated solar power and on large scale as a photovoltaic (PV) system, which is able to feed electricity into grids.
It has been estimated that solar PV would contribute about 20% of the world’s energy by 2050 and over 60 per cent in 2100. The world PV market grew more than 60 per cent by 2007. The cumulative global capacity of the PV system is expected to reach 1600 to 2000 GW (1GW = 109 watts) by 2030. It is suggested that to make solar energy more attractive, the development of high performer flat plate PV and concentrator PV models with an efficiency of 25 per cent and 40 per cent respectively, is necessary.
In view of recent technological developments, it is possible to harness solar energy economically in large quantity and use it in place of fossil fuels in the electric transport system.
In this regard, all countries in the world, particularly those in tropic regions like India with a large number of sunny days in a year, should give due importance to harnessing solar energy and utilise it in the transport and other sectors. Further development in technology and its application for harnessing solar energy with necessary incentives from respective governments should be given high priority.
Wind energy
Energy from wind is the fastest-growing sector in the world with an average annual growth of 25 per cent. The installed capacity increased from 60 GW to 160 GW during 2002-2010. It was estimated to go up to 460 GW by the end of 2015. Both from the technical and economic points of view, harnessing large amounts of wind energy to produce electricity is very promising. The total global capacity of wind energy in 2013, was 296065 MW.
There is a great scope of using wind energy for producing electricity and using it in the transport sector. In recent years, battery electric vehicles powered by regenerating energy, are considered to be the best option, in view of the increasing price of fossil fuels and their polluting effect on the environment. The small windmill system can be utilised to charge batteries. Generally, for two-wheelers, the battery requirement is 12V, 2amp (24 watts). By using a 304mm rotor diameter windmill, one can generate the required wattage i.e. 24 watts power at 30 km/ph speed of the vehicle.
Electric vehicles
In recent years, electric vehicles have gone through various technical developments. The new electric vehicles are environmentally attractive and can contribute immensely in minimising global warming.
At present, mostly in the USA, Europe and Japan, the use of electric vehicles is becoming more promising due to many technical developments, favourable legislations etc. Leading car manufacturers are also concentrating on making efficient electric vehicles. National time targeted development programmes for electric vehicles using battery technology, have been taken up in advanced countries like the USA, Japan and Europe. However, it has got certain limitations and problems too.
For example, in electric vehicles recharging, the batteries during the peak load periods can cause complications in power supply. The problem can be solved if recharging is done during the low pick period or at night. Electric vehicles hybrid with wind or solar power can solve the problem of energy in the transport system considerably.
Efforts are being made to use battery electric vehicles (BEV) and fuel cell vehicles based on hydrogen (HFCV) to gradually replace the conventional internal combustion engine vehicle (ICEV). BEV technology is considered to be more energy-efficient among the technologies considered in the transport system. Efforts are being made to have one million BEVs by 2030. In place of ICEV, direct HFCV is expected to offer better energy efficiency and carbon dioxide emission gains. Similarly, by 2030, HFCV is expected to be on the road. To decrease greenhouse gas emissions by 50 per cent by 2030, it is highly beneficial to use combined BEV and HFCV. This is the programme for the Danish Road Directorate, Ministry of Road, Denmark.
The transport system is essential for our socio-economic development and in general for a better living. At present, the benefits we derive from the transport system using mostly fossil fuels, are being annulled to a great extent due to the liberation of greenhouse gases, which is highly detrimental for us and other living beings on this planet. Therefore, all over the world, efforts are being made to utilise clean renewable energy, particularly from sun, wind, small hydropower and biomass in the transport sector. International Energy Agency (IEA) has suggested substituting significantly fossil fuels with renewable energy by 2030.
In view of this, the transport system should run as much as possible by electric energy produced from renewable sources or can be in hybrid with fossil fuels. It is also suggested that all transport systems should be equipped with facilities like PV cells and wind turbines to harness solar and wind energy respectively and using these for charging batteries. The energy thus stored, can be utilised for providing the necessary fuel for transport systems as such or in a hybrid form with fossil fuel.
India, like China and other developed countries, should undertake electric vehicle programmes on high priority. Having large resources of solar and wind energy, India should harness these and produce electricity for providing energy for the transport sector, particularly for road and rail transport. In addition, the government should give various incentives to use increasing amounts of renewable energy in the transport sector.
