Environmental Engineering Reference
In-Depth Information
Kawada reviews the potential for the 'Hydrogen Economy' and the demands that
would make for fuel cells. Hydrogen's strengths and weaknesses as an energy car-
rier are examined, and the current development and commercialization of PEFC
and SOFC fuel cells in transport and domestic combined heat and power systems
reviewed.
In Chap. 5, Professor Smith focuses on the role of supercritical fluids in energy
and green chemical processes. Energy remains the single most critical foundation
for a healthy and buoyant society, yet its generation increases threats to global sus-
tainability. Supercritical fluids can offer low-energy systems; for instance by pro-
ducing 4 kW of heat from 1 kW of electricity. They can also contribute to lower
energy of mixing and new materials, leading to a range of green chemical processes.
This chapter introduces the reader to a range of potential environmentally friendly
futures involving these processes.
Chap. 6 focuses on a source of renewable energy which could be very significant
in Japan and similar geologically active zones, with a review by Professor Hashida
on geothermal energy and its potential. Geothermal energy has the advantage of
heat and electricity with minimal environmental impact. The various types of geo-
thermal energy extraction (both passive and active) are reviewed and the relevant
factors for the design of geothermal energy extraction systems detailed. Mathemati-
cal models to simulate engineered geothermal systems are introduced and the role of
injection to achieve a sustainable level of geothermal power generation described.
In Chap. 7, Professors Tanaka and Tohji introduce a 'small' energy and solar
energy storage DC-based system developed at Tohoku University. This is based
on technological development of systems which will allow current centralized en-
ergy systems to be replaced by more dispersed and multiple low-energy renewable
sources. Such a system poses challenges both in maximizing possible sources of
small energy and also in developing the batteries necessary to deal with their in-
termittent supply. This chapter describes the systems which run on limited sources
of DC energy, and the interaction between the supply sources and the batteries to
provide systems which are resilient to blackouts from natural disasters.
In Chap. 8, Professor Li and colleagues review the potential of waste biomass
available from wastewater treatment and other sources to provide alternative fuels
such as bio-hydrogen and bio-methane. In this chapter, various fermentation ap-
proaches are introduced and how these can be adjusted to produce biomass energy
through single and two-phase fermentation technologies. Such technologies can
also be used to apply biogas technology to wastes such as cattle manure, chicken
manure and sewage sludge.
The next section of the topic moves to themes of resources and their efficient
use or re-use. The first contribution (Chap. 9) is from Associate Professor Matsubae
who reviews the importance of phosphorus and the phosphorus cycle in agriculture.
Supplies of phosphorus are limited and this poses a potential limit on future agri-
cultural development. To make the maximum use of available supplies, it is impor-
tant to develop a sustainable phosphorus resource management approach across the
whole international phosphorus demand and supply network. This chapter describes
a model of the international flow of phosphorus from sources to applications, and
