Renewable Energy: Brief General Introduction (Part One)
Renewable energy comes under different headings and can cover a wide area of various types of natural energy sources, examples: biomass, geothermal, hydropower (waves, underwater current, and flowing water from higher ground), solar (sunlight & sun clean energy sources heat) and wind.
By utilising a range of technologies, renewable energy is produced from renewable sources mainly for the purpose of replacing the present limited resources associated with fossil fuels, as well as in finding economical, sustainable sources of energy. However, there is an urgent reason to search for an alternative source of energy, besides this. This urgency is connected to the issue of ‘global warming’, and the protection of the environment. By using certain types of renewable sources of energy, it is possible to balance the emission of known gaseous associated with fossil fuels, such as CO2, which, among other gases, reportedly is one of the main causes of global warming.
Some of the costs associated with renewable energy are in decline and may continue to decline in the foreseeable future (NREL, 2002).
In regard to the current prospect of ‘renewable energy’, presently there is fast growth and development taking place in this field. This is mainly due to the recently increased level of investments in a number of countries across the world, i.e. around $71 billion has been invested worldwide during the year 2007, in comparison to $55 billion in 2006 and $40 billion in 2005 (REN21, 2009).
Various types of biomass materials such as agricultural crops, wood, animal waste, different species of grasses and fast growing bushes, can be used in one way or another, to produce heat and electricity, as well as fuel for transportation. In comparison with fossil fuel usage, the biomass industry is still small. Recently, however, the development in this field has been reported to be growing fast (REN21, 2009).
One of the reasons attributed to this kind of growth is related to the price increase of limited energy sources, such as crude oil.
The forest products industry is one of the biggest users of biomass, using it to generate heat and electricity. Cost for biomass is steadily decreasing in the shape of a downward straight line.
Biomass materials are part of the bio-cycle of the environment, i.e. natural raw materials, and therefore not as toxic as, for example, crude oil. This means it can break down relatively quickly into its natural elements.
Some of the biomass materials are widely available, and, on occasions, can be free or at a very low cost to purchase. In comparison to the other sources of renewable energy, biomass can decrease the CO2 in the atmosphere, if energy crops are used in rotational cycle, i.e. the amount (number) of crops burnt equal the same number of individual crops being planted, at the same time.
However, biomass fuels are still relatively expensive to produce on a large commercial scale (U.S. Department of Energy, 2009).
One aspect of using biomass as a source of energy is that to produce biomass materials (e.g. energy crops) there is a need for land and regular supply of water.
In the process of obtaining energy from biomass, various by-pr