Alternatives to fossil fuels

Alternatives to fossil fuels, such as hydrogen, are explored in Box 6.2 and Section 14.3. Coal, which is mostly carbon, can be converted into fuels with a lower proportion of carbon. Its conversion into methane, CH4, for instance, would reduce C02 emissions per unit of energy. We can also work with nature by accelerating the uptake of carbon by the natural processes of the carbon cycle. For example, one proposed solution is to pump C02 exhaust deep into the ocean, where it would dissolve to form carbonic acid and bicarbonate ions. Carbon dioxide can also be removed from power plant exhaust gases by passing the exhaust through an aqueous slurry of calcium silicate to produce harmless solid products ... 

C02 sequestration technology is a viable contender among a set of options to stabilize the atmospheric C02 level over the next few decades (Lackner, 2002). The technical ability to start such a process exists today, but the institutional structures required to reduce C02 emissions are still missing. For hydrogen production, carbon sequestration at the very least will buy time for alternatives to fossil fuels to become competitive. It is, however, equally possible that carbon sequestration removes the major environmental obstacles to the use of fossil fuels in which case it may prove competitive with alternatives for a long time to come. 

We present a short discussion of the economic and societal backgrounds for the search of alternatives to fossil fuels or technologies that make their use environmentally sustainable. 

The need for an alternative to fossil fuels has been well established. Also, the needs for the development of transition technologies that allow for a gradual transition to the hydrogen economy have been proposed. And finally, the tools that will contribute to the achievement of this goal have been developed. 

Biofuels such as biodiesel and bioethanol are, for now, the main alternatives to fossil fuels for the most polluting activities related to transportation. Presently, feedstocks for biofuels production are all of natural origin and as such are subject to uncontrolled seasonal variations. For economic reasons the purchase of these feedstocks from different parts of the world follows the dynamics of commodities markets. ... 

The figures in Table 10.5 indicate that the biomass fuel ethanol, proposed as an alternative to fossil fuels, yields significantly less energy per gram than octane. This means that driving a vehicle with ethanol will decrease the fuel efficiency of... 

It is widely believed that hydrogen will play an important part as a fuel in the future. It is already being trialled by major motor manufacturers as an alternative to fossil fuels such as petrol (Figure 6.17). 

However, despite all the stress around the development of new alternatives to fossil fuels, the world is not at all running out of oil. In fact, and in parallel to the sustainability dilemma, we are confronted with the challenge of economic definitions and harmonization of concepts given the uncertainty that surrounds the definition of remaining reserves , reinforced by the lack of data to support better estimations. Consequently, as observed by Mitchell et al. (2001) there is a definitional problem since remaining reserves means the quantity of in-place resources that can be recovered economically, and this is far from a consensus around the world. 

The diversification of energy sources tailored to the requirements and resources of each country using nature s renewable resources such as the sun (photovoltaics), wind power, geothermal energy and biomass is a definite requirement. If solar cells are chosen to provide an alternative to fossil fuels, significant research work is needed (i) to develop new routes for the production of crystalline silicon, (ii) in the development of amorphous silicon hybrid materials that could result in enhanced efficiencies, (iii) for further development of thin-layer technology, (iv) in concerted efforts for cheaper and more stable dyes, (v) in improving the efficiency of the dye-sensitized cells and (vi) in process development to deliver enhanced device performances, ensure sustainability and reduce production costs on an industrial scale. 

Transportation infrastructures require, or at least privilege, the availability of liquid fuels. In the field of transportation fuel, biofuels are the most feasible alternative to fossil fuels. 

Nuclear power is the only alternative to fossil fuels that is currently competitive on a cost per kilowatt-hour basis. In addition, nuclear power has the potential to minimize many of the problems associated with the use of fossil fuels, including greenhouse gas emissions, emissions of other pollutants, and potential supply problems. 

As part of the search for alternatives to fossil fuel, recent studies have focused on the production of hydrogen, a clean and renewable energy carrier, by direct water splitting... 

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