Archive for July 2008
Integrated Food–Energy Systems (IFES)
Submitted by: Karl Ramjohn
Our life on Earth depends on a dynamic complex of linkages, synergies and interactions among the processes, components and sub-systems of the atmosphere, hydrosphere, lithosphere and biosphere. The ecological view of sustainability focuses on the stability of biological and physical systems. Of particular importance is the viability of sub-systems that are crucial to the global stability of the overall ecosystem. Protection of biodiversity is a key aspect. Furthermore “natural” ecosystems may be interpreted to include all aspects of the biosphere, including man-made environments like intensive agriculture, cities and industrial estates. The emphasis is on preserving the resilience and dynamic ability of the totality of systems to adapt to change, rather than conservation of some “ideal” static state of the environment. Therefore, expansion of renewable bio-energy will require not only advances in technology, but also tangible economic accounting of their environmental and social benefits, compared to fossil fuels.
The development of sustainable, multi-purpose, integrated biomass conversion systems, is based on highly efficient photosynthesis and microbial processes, generating a number of products including energy resources (biofuels). Such systems have the potential for reducing the adverse impacts of agriculture and forestry, while providing food, fibre, pharmaceuticals and supplementary biofuels, to enhance the requirements for an acceptable standard of living. Energy production via biomass conversion of agricultural wastes reduces the environmental costs of food production systems, and provides economic benefit for the farmer, as well as reducing social impacts. As such, it provides a platform for integrating food and energy production in a sustainable manner.
The major social aims of Integrated Food – Energy Systems (IFES) is to maximize synergies between food crops, livestock, fish production and sources of renewable energy (e.g. biodigestion of wastes). This is achieved by adoption of agro-industrial technology that allows maximum utilization of by-products, diversification of raw materials, waste production on a smaller scale, and encouraging recycling and economic utilization of residues, for harmonization of energy and food production.
The essential features of IFES include:
• Using technology mix to provide a minimum cost alternative;
• Meeting energy needs not only for agriculture, but also other social needs (e.g. domestic, commercial, industrial);
• Maximizing utilization of available bio-resources with minimum environmental impact;
• Benefiting all classes of the community;
• Increasing food productivity;
• Generating additional income and employment opportunities; and
• Requirement of minimum maintenance to integrate community participation in management.
The design of IFES requires a simultaneous consideration of:
• The bio-physical components of resource management;
• The social and ecological impacts of technologies used; and
• The institutional settings involved
For each site-specific configuration of climatic and environmental conditions, several socially desirable, ecologically sustainable and economically efficient production systems are conceivable, differing in output mix, forms of social organization and community participation, size of operation, complexity of design and technical sophistication. Ideally, they should have a modular structure, allowing progressive implementation by adding new modules to the initial structure. While, in practice, these systems are often implemented as private enterprises, they can provide a template for the design and adoption of IFES technology at the community level in other circumstances, with appropriate modification, to mitigate environmental impacts and supply other benefits, towards improving the sustainability of food and energy production systems.
Related Posts:
http://tropicalenv.conforums.com/index.cgi?board=energy03&action=display&num=1217141112
http://213.238.59.20/app/forum?op=showarticles;id=8635448;articleid=8635448
http://www.theenvironmentsite.org/forum/biofuel-forum/11964-integrated-food-energy-systems-ifes.html
http://discuss.greenoptions.com/viewtopic.php?f=40&t=500
http://www.unu.edu/unupress/unupbooks/80757e/80757E03.htm
“Spatial Footprint” Challenges of Solar Energy Use
Submitted by: Karl Ramjohn
Solar energy can be utilized in either passive or active systems. Passive systems do not contain any internal energy sources, and can be used for direct heating (e.g. solar dryers, water heaters, etc.) or day-time lighting (e.g. “green” office buildings). Photovoltaic devices are an example of active systems based on semiconductor technology, often using silicon (an indirect semiconductor).
The advantages of using solar radiation are well established and often cited – such as their ability (with proper design) to lower energy costs, reduce emissions and other environmental pollution, thereby initiating the process of competitively replacing hydrocarbon use, and thus contributing to sustainable development.
Solar energy approaches are also frequently suggested as a sustainable solution in less-developed countries in the tropical environment, on the assumption of having less seasonal variation in day-length and more hours of direct sunlight each day (i.e., usually a higher intensity and longer duration of incident solar radiation each day). The fuel medium (solar radiation) is also an “open-access” resource (no direct user cost). The overall decline in the operational costs seen over the past 35+ years is also typically acknowledged.
However, one major challenge remains with regard to conversion to solar energy use – their spatial footprint (land use requirement) in the event that larger scale utilization is proven feasible. In particular, for the use of flat-plate collectors or PV systems in tropical environments, this becomes an issue.
The primary reason is that to optimize the use of solar radiation, the panels (or plates) need to be sloped so as to correspond to the latitude of the specific area of the Earth, hence taking up more horizontal space in the tropics. If we take the example of an island in the middle-tropics such Trinidad & Tobago, implementation will require the slope of the panels to be 10 degrees (corresponding to latitude) for the same technology that may be placed at an angle of 40 degrees in countries within temperate regions. The implication is that the area set aside for power generation (or other solar energy use) will no longer be available for other land uses (such as agriculture) and this may be a significant limiting factor, especially in the case of small-island developing states. After all, any large-scale conversion will require much more than a rooftop, and island geography often restricts the feasibility of wind energy.
Some recent discussions aimed at solving or mitigating these potential challenges to sustainable energy:
http://cr4.globalspec.com/thread/20329
Non-Turbine Wind Generator
From: Green Tech Gazette – June 23, 2008
An interesting article (with video) on a non-traditional form of Wind Energy: Non-Turbine Wind Generator | Green Tech Gazette
According to that article, instead of generating electricity using a turbine based on the traditional two- or three-blade design, the non-turbine wind generator is based upon the flutter of long strands of kite material spanning a gap and connected to button magnets on the ends that produce electrical current. The design was conceived to provide an inexpensive solution to micro-wind energy, but has the option to be scaled up to meet larger power generation needs.
Some perspectives on the science of climate change
“Climate” is distinguished from “weather”, in that weather is the day-to-day state of the atmosphere and environment, whereas climate is the statistical average of weather patterns over a limited region and a long period (usually, minimum 30 years). A number factors have some influence on variations in the climate in the various regions or zones of the Earth – but it must be noted that none of these changes work (or actually initiate themselves) in isolation.
The natural climatic systems of the Earth are primarily determined by a dynamic complex of linkages, synergies and interactions among the processes, components and sub-systems of the atmosphere, hydrosphere, lithosphere and biosphere. The hydrosphere in this context includes all of the Earth’s water – oceans, rivers, lakes and the cryosphere (ice caps and snow). The main variables which characterize climate are temperature and precipitation (rainfall), humidity and cloudiness (special disturbances such as droughts and hurricances are sometimes included). These elements are in turn dependent on the meteorological variables (of weather) – such as insolation (solar radiation), wind speed and direction, ocean surface temperature, etc. To this must be added the variability of the Sun’s radiation and the Earth’s orbit, which result in an extremely complex and dynamic system.
Thus the climate system is a global complex of linkages and interactions. Inhomogeneities of all scales exist from the very large scale (e.g., 10,000 km) to the very small scale (e.g., 1 mm). This complex system is acted upon by a range of stimuli associated with the Sun, the Moon, and the Earth’s orbit around the sun. The main factors affecting climate change (natural variability) include: (1) Diurnal oscillations, due to the Earth’s rotation; (2) Tidal oscillations, due to gravitational effects of the Sun and Moon, with main periods of 12.4 hr and 24.8 hr; (3) Seasonal oscillations, due to the inclination of the equator to the ecliptic, and to changes in Sun-Earth distance; (4) Synoptic oscillations, caused by Rossby waves, with scales of 1000 km and periods of days; (5) Global oscillations with periods from weeks to months; (6) Inter-annual oscillations with periods ranging from 2 to 5 years, including El Niño/La Niña phenomena in the Pacific; and (7) Secular or long period oscillations with periods ranging from years to tens of thousands of years (the ice ages), likely due to orbital variations.
Having established the above – one of the main issues in the current debate is the possible effects of human industrial and other activities on the global climate. Despite the assertions in some quarters, anthropogenic effects are for the moment much less significant than these natural effects, the main concern being time-scales – their effects are felt within lifetimes rather than thousands of years. The critical point, is that many of the factors (“forcers” and “reactors”) in our current environment never existed in the past – many of the culprits (such as CFC) do not occur freely in nature, further to which, the rate of change of the release of naturally occurring greenhouse gases (such as carbon dioxide) over the past 200 yr or so (since the “industrial revolution”) is unprecedented and likely a result of human activities (such as deforestation). While, it is very true that global warming and climate change are a natural process on the Earth; the main issue is that the new or additional parameters added by human activities make it very difficult to use past cycles of “Ice Ages” and “Tropical Ages” to predict what is to be expected. Even if our activities are less significant than natural variations (in the global context), they definitely are not helping the situation. Environmental changes by human activities also affect the micro-climate in which we live, on an obviously much shorter time-scale.
http://www.geo-earth.com/forums/index.php?showtopic=7453
http://discuss.greenoptions.com/viewtopic.php?f=31&t=531
http://www.its2hot.in/viewtopic.php?f=27&t=96
http://www.physicsforums.com/showthread.php?t=236709
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