Towards a Cleaner Planet

For many years coal and oil have been used as energy sources. Currently oil is the dominant source of energy, but experts predict that in a few decades it will no longer be profitable. Burning fossil fuels generates atmospheric contaminants that give rise to the greenhouse effect that artificially warms the earth, damages the earth ozone layer, and produces acid rain, all of which are very dangerous for living beings. As a consequence, abnormal phenomena such as the melting of glaciers, changes in the Gulf Stream, unprecedented heat waves, floods, hurricanes, and damage to marine organisms are now occurring. Although there are many skeptics, there is a general consensus that the earth is warming up. In order to reduce CO₂ and other greenhouse gas emissions, the extensive use of alternative and cleaner sources of energy have been proposed, including CO₂ emission-free nuclear energy and other alternative sources, among which are hydraulic, hydrogen, solar, eolic, biomass and geothermal. Another future alternative is to use methane hydrates, which have clean combustion and are believed to have considerable, still-unexplored reserves. It is also important to implement measures to improve energy efficiency for reducing greenhouse gas emissions. In this paper we review present and future energy sources, including both primary non-renewable and alternative sources of energy. There is still time to take corrective measures by replacing some polluting fuels with clean sources of energy that can contribute to inherit a clean and sustainable world for future generations.

It is useful to look back into the past when trying to understand the present, and when attempting to analyze the future, particularly in the case of energy, whose role in development has been and will continue to be fundamental.

One of the major challenges for research in the future is to provide energy on a world wide scale against the background of vanishing resources, climatic changes and economic impact based on novel fuels and new technologies.

The above sentence can be read immediately below the heading “Energy Efficiency Is Top Priority” in the International Energy Agency report “Energy Technology Perspectives — Scenarios and Strategies to 2050”, published in 2006. The report was elaborated at the request of the G8 to provide advice on alternative scenarios and strategies for a clean and secure energy future.

Based on documental references, this paper enumerates and briefly describes Mexico’s main energy conservation programs and institutions, highlighting the main elements and factors for their success. These programs and institutions have been in place since the end of the 1980’s, have been generally successful and are certainly the main drivers for a significant reduction of the country’s energy intensity in the last twenty five years. The document also describes some of the barriers and challenges for future energy conservation policies.

Mexico has a major challenge to go from being an emergent economy to an industrialized country. Its electrical installed capacity has been growing during the last 10 years with a 4.5 % annual pace and it is planned to grow for the next 10 years with a 5.2 % annual pace. In 2005 the annual electrical consumption per inhabitant was of 2237 kWh, which is around the world’s average. This represents almost one quarter of the average of the industrial countries consumption. The current document shows the prospective for the Mexican electricity sector for the 2005–2014 time frame. It also shows the technologies that will be used to cover the requirements of electricity by region.

This work presents a thermo-economic study of combined-cycle gas turbine (CCGT) facilities based on a flexible genetic algorithm search technique. The results here presented will maximize the cash flow by pointing out the correct parameter values for plant design when the turbines have already been chosen among the existing commercial options.

Carbon dioxide is considered to be the major source of greenhouse gases responsible for global warming; man-made CO₂ contributes approximately 63.5 % to all greenhouse gases. Efforts towards reducing greenhouse gas emissions have increased in the past few years, offering promising alternatives in power generation and better fuel efficiency. However, the incorporation of these new technologies to our daily lives represents a big challenge to be solved in the mid- to long-term, leaving separation and CO₂ sequestration to be an immediate priority for researchers. CO₂ capture and storage can support the transition of our fossil fuel based energy supply towards a sustainable energy system, based upon nuclear and renewable sources. Our present energy infrastructure will largely remain the same during this transition period. For example, electric power plants will be equipped with CO₂ capture units, but will produce the same electricity, transported and distributed over the same grid. The first step in the CO₂ capture and storage chain is to capture carbon in a high concentration. This can be done before or after combustion of the fuel. Capture is best carried out at large sources of emissions, such as power stations, refineries and other industrial complexes. There are several ways to capture CO₂, some of the main methods are absorbents using solvents or solid sorbents, which have been used in industry for several years and seems to be the most feasible solution at this time; membranes have also become an interesting alternative and although extensive research is in progress, new materials for membranes have yet to be discovered. Other methods like pressure- and temperature-swing adsorption using various solid sorbents, cryogenic distillation and new emerging technologies show promising results in the bench testing scale. This report presents a comparison between these different methods.

World energy demand has been increasing continuously with human development and the increase of world population. An increase of energy consumption is forecasted to rise by 50 % in the next three decades. Fossil resources — natural gas, coal and oil — are more widely used to supply consumers with this energy. At present time, fossil fuels continue to be the dominant energy source. Fossil resources supply almost 88 % of the total energy consumed in the world, followed by hydrodynamic (6.3 %) and nuclear (6 %). In spite of the development and use of other sources of energy such as nuclear, hydrodynamic and renewable sources, future energy supply will continue to rely on fossil resources, although with a lower relative utilization.

Nuclear power is a viable, economically competitive and safe option to contribute to the high electricity demand expected for the next decades. Nuclear energy is currently the largest source of electricity without emission of greenhouse gases. In several countries, for baseload electricity generation, the capacity factors of NPPs are the highest for any type of fuel and, at same time, except for hydroelectric power, production costs from nuclear power are the lowest. These two factors, among others, have led the nuclear power industry to become competitive today in the electricity generation market. However, public acceptance is still a major issue to overcome before nuclear power can be exploited to its fullest. Issues as nuclear plant security, waste management and reactor safety are constantly being debated by society, even when such issues have been shown to have technically sound solutions. In particular, NPP safety will be discussed in this work.

Although safe operation of current nuclear plants is at its highest level, misinformation and lack of understanding of the physical fundamentals on nuclear reactor design and operation have led general public opinion to still show concerns regarding nuclear reactor safety. In this work, it is presented a short description of the fundamental physical principles behind the safety core and plant design and operation of BWRs, with the intention of helping to better understand and clarify concepts of frequent use in the nuclear engineering and safety areas.

Nuclear energy has a half of a century contributing to the generation of electricity in the world. The way has not been easy, since risk perception on part of the public opinion has not remained totally favorable to this technology, as some issues like accidents and waste management have been misused by detractors. However, as security of energy supply, climate change, and profitability have raised as concerning issues in energy planning, the generation of electricity by nuclear means has started to be on the table again, and a renaissance seems to be close. This article intends to provide with a brief description on the current situation of Nuclear Energy, and their perspectives, pointing out its main characteristics that can be advantageous in order to be included in the fuel mixings of the future.

Despite energy saving efforts and improved efficiency of energy production, projections of the World Energy Council indicate a significant increase in global energy consumption in the medium and long term due to a further growing world population and rising prosperity. On the other hand, the energy supply is connected with a threatening of the earth’s environmental and climate system. The present share of fossil fuels of 80 % in the world’s energy consumption is hardly expected to change in the short and medium term. Continuation of the extended use of natural resources of coal, oil, and natural gas, however, carries the danger of over-stressing the environment. In addition, strongly fluctuating energy prices, the dependence of many countries on energy imports from politically unstable regions, and the uncertainty about how long oil and gas reserves will last, are raising fears of supply security. This all urgently calls for political and technological counteractions.

The economic viability of the energy sector is fundamental for the development of Mexico. The main objective of the economic sectors is to reduce the cost of energy production. The application of the nuclear and renewable energy sources can be developed in Mexico with a limitless potential for the electricity production, heat, hydrogen and seawater desalination, without Greenhouse Gases (GHG’s) emissions and under acceptable economic conditions. For the future development of this potential, it is required to make deep institutional changes by state promotion and with the public acceptance. However, it is at present when we most settle down the bases for a new energy politics by means of appropriate clear objectives. In order to attain such goals, the participation of the universities, institutions, public administration and companies is required. The proposed energy program until the year 2030 includes expansion mainly for the period 2007–2015 of the electrical sector using the renewable energy resources, hydro, geothermal, biomass and wind, for being more competitive for the country instead of a gas-based combined cycle plant. This paper analyses the benefits to develop the power sector mainly using High Temperature Gas-cooled Reactors (HTGR’s), in 2015-2030, adding to renewable power technologies.

Recent construction technique developments and technology evolution have made the nuclear option a cost competitive option with other load base technologies such as coal and combined cycle facilities based on natural gas. Construction period, from first concrete to commercial operation, is around five years, as it has been confirmed by the most recent reactors built in Asia (e.g. Japan and China). At present, the cost for a new nuclear power plant has dropped overnight and is lower than in the past. The different reactors suppliers are offering new plants between 1200 and 1600 USD/kW with an output power between 1100 and 1600 MWe. In this work different scenarios of electricity generation using combined cycles by using natural gas and nuclear power stations are assessed from an economical point of view. The scenarios considered comprise three different discount rates, 5 %, 8 % and 10 %.

The public acceptance of an increase program of nuclear energy requires an openly and straight forward discussion, in an understandable way of the main issues against nuclear energy as: nuclear accidents, proliferation of nuclear weapons and safety storage of nuclear waste. Regarding this last issue, there are doubts concerning stability of geological sites to storage nuclear waste as well as possible leakage and migration of radioactive waste from containers, which potentially could contaminate underground aquifers. Technical explanations about safety designs of those nuclear waste storages do not convince general public because of the thousand of year half-life of the radioactive generating material from uranium fuel.

Nature has contributed to present us a wonderful example concerning immobility of nuclear waste, not in a period of thousand of years, but thousands of million of years. This paper describes the discovery of several Nuclear Reactors (NRs) that operated two thousand of million years ago, in the Republic of Gabon, Africa.

The discovery of at least 17 NRs in Oklo uranium mine in Gabon was possible from the analysis of the nuclear waste that remaining undisturbed in that mine for nearly two thousand of million years. The reactors were very small of about ten centimeters in diameter and had a power of around 100 kilowatts and were intermittently operating during 150,000 years.

Xenon gases generated from the reactors were kept in the crystalline matrix of aluminium phosphate glasses. Recent analysis of the whole production and trapping process of xenon gasses permitted to know that reactors were intermittently operating in cycles of about 30 minutes and additionally aluminium phosphate glasses showed the capability of trapping xenon gasses in its crystalline matrix for nearly two thousand of millions years.

This paper presents the “design”, functioning and safety storage of nucl waste of NRs that were performed by interdisciplinary work by nature in Oklo, long before man appeared on earth.

Nuclear power set off commercially in the 50’s, with very high hopes in Russia, the United Kingdom and the United States among others. Under the oil crisis, France started a very aggressive program to generate about 70 % of its electrical production from nuclear power. However, in the eighties, as a result of the Three Mile Island accident, several safety concerns were raised, resulting in considerable construction and operation delays. Many planned reactors were left behind and after the Chernobyl accident, reactor construction was stopped in the western world. However in the meantime, the Industry made improvements in safety measurements and performance of its nuclear power facilities. The capacity factor of nuclear plants grew to be around 90 %. The operation licensees of many units were renewed for another 20 years after their first 40 years of operation. Today there are new expectations for nuclear power not only because its economical competitiveness but its potential to produce electricity without greenhouse gas emissions consequently making feasible to achieve Kyoto protocol goals to alleviate global warming. This paper shows the potential of nuclear power as a clean, safe and innovative energy.

This paper reviews the current situation and the future prospects for the application of renewable energy in Mexico. It shows that, in spite of the abundance of renewable energy resources, generation of electricity and other non-electric applications are minimal. Opportunities to use renew-ables as part of the Mexican energy mix are many, and could bring a number of benefits, social, economic, political and environmental, among others. Barriers to do so are also many and are outlined here. It is concluded that Mexico is lagging behind other countries of similar economic capacity with respect to the development of its renewable energy resources, and that a concerted action among different sectors of the economy is necessary to alter the present situation. Otherwise, the opportunity ahead will be lost and Mexico will remain a net importer of new energy technologies.

The sustainability of the energy sector in México, as in many countries of Latin America will depend on decisions that have to be taken now in order to expand the use of clean and renewable energy sources. The use of solar, wind, biomass, as well as other renewable energy sources, will provide México with the diversification of energy resources that will help to reduce the dependence on fossil fuels and decrease CO₂ and other emissions. The increased role of renewable energy sources in Europe and specifically in Germany will have an impact on México, where the development of clean energies needs collaboration between the two countries to accelerate its use.

The generation of electric power for supplying the populations of large cities is effected at an elevated cost, given that this cost does not include solely the price of generating the electric power itself, i.e., production, storage, labor, maintenance of installations, distribution, etc., but, in addition, bears the associated costs of damage to the environment due to the production of residual pollutants, and the consequent damage to the health of humans, and to the flora and fauna.

Mexico is located in the Earth’s sunbelt, where solar energy is plentiful for potential applications of solar energy conversion systems. According to several estimations (Renné et al. 2000), the average insolation over the country’s surface amounts to 5 kWh/day, which puts Mexico in a privileged situation for the deployment of solar energy technologies. Other renewable energy sources such as: wind, biomass, geothermal, large and small hydrological, the ocean, play a role in the national energy supply system or have the potential for being an important factor, but none of them has the potential of solar energy, which could easily satisfy all of the country’s energy requirements. In spite of this, the development of solar energy in México is still marginal. There are several small industries that have been producing and installing flat plate solar collectors for household hot water production and swimming pools for several decades, and the installed capacity has been growing steadily for some years now (68,725 m² of collectors were installed during 2004). Also, PV panels are imported and installed in a regular basis but not in very large quantities (9,923 kW were installed during 2004) (SENER 2005).

At present, wind energy is one of the most promising alternatives for diversifying electricity generation towards the sustainable development worldwide. Wind power technology is one of the most mature renewable energy technologies. In fact, over the last 20 years, almost all of the industrialised countries progressed towards the implementation of wind energy, looking to attain significant levels of contribution for satisfying the electrical demand at the national level. An increasing number of developing countries are already following the example.

The current contribution of 3.1 % of geothermal energy to México’s electricity supply is relatively elevated in comparison to a global offer of primary geothermal energy of 0.442 % (ISES 2002), or 0.8 % by renewable technologies, including geothermal, solar, wind and tide/wave/ocean technology (IEA 2006), but potential favorable national resources are still underexploited. Feasibility studies proved a potential for national reserves of 3,650 MW, whose generation (20,460 GWh) could provide more than 12 % (20,460 GWh) of the total electricity generation. The exploitation of middle- and high-enthalpy geothermal reservoirs could represent a major contribution towards a more environmental friendly electricity production in México, as the combustion of more than 40 million barrels of fossil fuels per year and the emission of approximately 16.5 million tons of CO₂ into the atmosphere could be avoided by geothermal expansion strategies. On an economic point of view, the average generation costs of 3.98 USD cents per kWh for geothermal electricity are currently lower than for any other renewable energy type, and competitive with most conventional energy types. Low- to middle temperature sites (< 170°C) are still undeveloped in México, although an estimated heat potential of several thousands of megawatt could be used for private and industrial consumption, such as district and greenhouse heating, spas, and aquaculture. The implantation of decentralized small-scale plants (< 5 MW) with binary-cycle or heat pump technology could be fundamental for the energetic development of remote rural areas. As a basic condition to expand the national geothermal energy market, the legal and regulatory frame has to appropriate in order to fortify the renewable energy sector, as well as market incentives and innovative financing schemes have to be established to promote private inversions.

The proposed research is designed to upgrade sugarcane biomass byproducts (bagasse) to high-grade fuel (hydrogen), activated carbon, and chemical feedstocks (synthesized gas). It is shown how gasification can significantly enhance the value of sugarcane through the production of energy, synthesis gas, and carbon, which is required in the sugar purification and decoloring process. Furthermore, it can act as a valuable associate to sugar fermentation processes used to produce ethanol employed as a substitute for hydrocarbon fuels and raw materials. Through this project one can make the large sugarcane-growing regions of Mexico and other Latin American, African, and Asian countries more economically diverse and self-sufficient, increasing local employment and enabling support of larger rural populations. A key part of the proposed research is the training of highly skilled professionals to guide the Mexican sugarcane agro-industry toward production of high added value products in addition to sugar.

Mexico, as many other countries, needs the substitution of fossil fuels to avoid the environmental and health problems produced by their burning. Hydrogen is an important alternative energy source for the growing energy demand and the answer to the present need of a clean, efficient, and environmentally-friendly fuel. While the proved hydrocarbon reserves in Mexico will last for just some more decades, hydrogen, in counterpart, is the most abundant element in the universe and the third one in the earth’s surface. Burning hydrogen in a combustion engine produces water and a small amount of nitrogen oxides, which can be eliminated in proton exchange membrane fuel cells or in alkaline fuel cells. Fuel cells working with hydrogen are electrochemical devices where the recombination of hydrogen with oxygen produces electricity, heat and water in a silent manner. In the seventies, most countries started in hydrogen research and development due to the petroleum crisis; being Germany, Canada and Japan the most advanced countries in the area. USA announced in 2003 a $1.2 billion Hydrogen Fuel Initiative to develop technology for commercially viable hydrogen-powered fuel cells. Iceland, one of the countries with large contaminant emissions, is working to become the first hydrogen based economy. In the other hand, two hydrogen isotopes, deuterium and tritium, could produce energy for the future through thermonuclear reactions. Mexico needs to include in its energetic program research and development in hydrogen for its use as an energy carrier of the renewable and still non renewable energy sources. Mexico should also explore the possibility of becoming a member of the International Thermonuclear Experimental Reactor ITER project, like other countries (e.g. India), to develop a clean energy future.

For more than 50 years, controlled nuclear fusion has been promised as a safe, clean and environmentally acceptable energy alternative for the future. Fusion was actually known from particle accelerator experiments well before nuclear fission, and by the time the latter was being discovered, there were already well developed theories of how fusion is the source of energy in the stars, including our Sun, and how stars work as the element factories in the Universe (Bethe 1939). Yet, after several decades of work by researchers in several countries, producing more energy than is invested in fusion devices has been elusive. This has led to the common joke that the date in which fusion reactors will become available is a new constant in physics; always 30 years away. Actually, the international controlled fusion research programme is sound and healthy, and has achieved significant progress (International Fusion Research Council 2005), but the road to the reactor is more difficult than originally envisioned. In the process, it has influenced the development of plasma science as an interdisciplinary endeavour which requires the collaboration of physicists and engineers, and has led to important spin-offs in other applications. The limitations of fusion reactors will depend as much on physics issues as on engineering and materials design, and its competitiveness will depend on the results of further research and development in these areas.