Aviation propulsion development continues to rely upon fossil fuels for the vast majority of commercial and military applications. Until these fuels are depleted or abandoned, burning them will continue to jeopardize air quality and provoke increased regulation. With those challenges in mind, research and development of more efficient and electric propulsion systems will expand. Fuel-cell technology is but one example that addresses such emission and resource challenges, and others, including negligible acoustic emissions and the potential to leverage current infrastructure models. For now, these technologies are consigned to smaller aircraft applications, but are expected to mature toward use in larger aircraft. Additionally, measures such as electric/conventional hybrid configurations will ultimately increase efficiencies and knowledge of electric systems while minimizing industrial costs.
Development of higher-voltage electrical systems in vehicles has been slowly progressing over the past few decades. However, tightening vehicle efficiency and emissions regulations and increasing demand for onboard electrical power means that higher voltages, in the form of supplemental 48 V subsystems, may soon be nearing production as the most cost-effective way to meet regulations. The displacement of high-wattage loads to more efficient 48 V networks is expected to be the next step in the development of a new generation of mild hybrid vehicles. In addition to improved fuel economy and reduced emissions, 48 V systems could potentially save costs on new electrical features and help better address the emerging needs of future drivers. Challenges to 48 V system implementation remain, leading to discussions by experts from leading car makers and suppliers on the need for an international 48 V standard. Initial steps toward a proposed standard have already been taken.
Half the electric vehicle market value lies in larger road vehicles, notably cars, and here the legal restrictions are weaker or non-existent, and range anxiety compels most people to buy hybrids if they go electric at all. Over eight million hybrid cars will be made in 2025, each with a range extender, the additional power source that distinguishes them from pure electric cars. Add to that significant money spent on the same devices in buses, military vehicles, boats and so on and a major new market emerges. Whereas today's range extenders usually consist of little more than off- the- shelf internal combustion engines, these are rapidly being replaced by second- generation range extenders consisting of piston engines designed from scratch for fairly constant load. However, a more radical departure is the third- generation micro turbines and fuel cells that work at constant load.
Energy storage, and in particular electrical storage of energy, has become a very talked about topic in circles ranging from lay persons, in regard to hybrid and battery electric vehicles, to professionals, and certainly by legislators and energy policy makers. This book takes a critical look at the physical storage of electricity in the devices known collectively as electrochemical capacitors and particularly as ultracapacitors. Its 12 chapters cover ultracapacitor and advanced battery topics with an emphasis on a clear understanding of fundamental principles, models and applications. But even to professionals, the distinctions between physical and chemical forms of electric energy storage are unclear and, at times, poorly understood, if at all. The reader will appreciate the case studies from commercial to industrial to automotive applications of not only ultracapacitors, but of these power dense components in combination with energy dense battery technologies.