Nanotechnology as a Tool for Enhanced Renewable Energy Application in Developing Countries

Abstract

Editorial Energy plays a key role in the socioeconomic , technological and political development of any nation. Inadequate supply of energy restricts socioeconomic activity, limits technological and hence economic growth and adversely affects the quality of life. In fact, it is widely accepted that there is a strong correlation between socioeconomic development and energy availability of a given nation. Most developing countries are faced with acute energy problems; yet many have vast renewable and non-renewable energy potentials. In particular, energy supply in form of electricity is so poor in many of these countries that industrial and economic activities are seriously retarded. For example, Nigeria, which is a typical example of a developing country, has a total of 14 power plants, consisting of hydro and thermal power stations with an installed capacity of 7,876 MW. The country generates less than 4,000 MW to feed a population of nearly 180 million. This is grossly inadequate and results in massive load shedding which cannot be relied upon for meaningful industrial development expected of a country with such human and materials resources. To ameliorate this problem, industries and household tremendously engage in using generating set to offset this short fall in power supply. Among other problems, this form of energy supply is not reliable for robust industrial and economic activities. It also results in the emission of GHG which helps to worsen the global warming problem. In addition to the inadequate and epileptic power generation, there is also the problem of antiquated transmission lines and poor transmission coverage in the country. This scenario is typical of many developing countries. As pointed out in an earlier editorial, renewable energy, defined as energy that comes from resources which is naturally replenished on a human timescale, is vital to the much needed socioeconomic development of the developing countries. Nanotechnology has the potential to provide cleaner, more affordable, more efficient and more reliable ways to harness renewable energy resources. This can help developing countries to overcome their energy supply challenges and move towards energy self-sufficiency while simultaneously reducing dependence on non-renewable, contaminating energy sources. Nanotechnology is the study, design, creation, synthesis, manipulation, and application of functional materials, devices, and systems through control of matter at the scale of 1-100 nm as well as the exploitation of novel phenomena and properties of matter which are known to arise at that scale including physical, chemical, electrical, mechanical, optical and magnetic properties. It is employed to improve the efficiency of energy generation, particularly in form of photovoltaic (PV) cells or to develop new methods to generate energy. It is also utilized for improved wind and geothermal power generation, energy storage, lighting and hydrogen fuel cells among others renewable energy applications. In the area of energy generation, the greatest application of nanotechnology seems to be in the area of efficiently harnessing solar energy using PV cells. Efficient PV system has a lot of potentials for overcoming the energy supply challenges in developing countries. It is very convenient for powering street lights and for charging inverters which are becoming a very good alternative to the usual fossil fuel-powered electric generators predominantly used presently to augment the epileptic power supply in developing countries. PV cells are made out of semi-conducting materials such as crystalline silicon which is presently considered the most efficient material. When light of the right band gap energy hits the cells, they absorb solar radiation in form of photon which knocks out electrons in the silicon. Addition of different impurities in the silicon such as phosphorus or boron, results in the creation of electric fields which acts as diodes by allowing electrons to flow in one direction resulting in electrical energy generation. The current drawback in the use of solar cells are the high cost of manufacturing which reflects in the present high cost of conventional PV cells. The efficiency of solar energy absorption is also currently very poor (less than 40%) with only a fraction of the absorbed energy converted into electrical energy. Alternative material such as TiO2 which results in cheaper PV cells has even lower conversion efficiency. Nanotechnology can be used to introduce alternative materials and fabrication methods to produce cost effective PV cells with acceptable if not higher energy conversion efficiency. Classic nanostructures such as carbon nanotubes (CNT), fullerenes and quantum dots are being used to make solar cells lighter, cheaper and more efficient. The increased surface area to volume ratio of nanoparticles enhances solar radiation collection by exposing more conducting surfaces to solar radiation. Also the use of nanomaterials such as lead selenide results in more electrons (and therefore more electricity) to be released when hit by a photon of light. Structural properties of PV cells are additionally being modified using nanotechnology. Nanotechnology is also used in improving the efficiency of windmills. An epoxy-containing carbon nanotubes is now used to make stronger and lighter windmill blades resulting longer blades which increase the amount of electricity generated by such windmills. The wind turbine life span can also be increased by using nano paints. Geothermal energy generation is also enhanced by nanotechnology. In conventional geothermal energy production, cold fluids are injected into naturally heated hot rocks usually found over 1500m below the earth surface. The heated fluid is then extracted and used to generate