Solar energy- radiant light and heat from the Sun, has been harnessed by humans since ancient times using a range of ever-evolving technologies. Solar radiation, along with secondary solar-powered resources such as wind and wave power, hydroelectricity and biomass, account for most of the available renewable energy on Earth. Only a minuscule fraction of the available solar energy is used.
Solar powered electrical generation relies on heat engines and photovoltaics. Solar energy's uses are limited only by human ingenuity. A partial list of solar applications includes space heating and cooling through solar architecture, potable water via distillation and disinfection, daylighting, solar hot water, solar cooking, and high temperature process heat for industrial purposes.
Solar technologies are broadly characterized as either passive solar or active solar depending on the way they capture, convert and distribute solar energy. Active solar techniques include the use of photovoltaic panels and solar thermal collectors to harness the energy. Passive solar techniques include orienting a building to the Sun, selecting materials with favorable thermal mass or light dispersing properties, and designing spaces that naturally circulate air.
Wind power is the conversion of wind energy into a useful form of energy, such as electricity, using wind turbines. At the end of 2008, worldwide nameplate capacity of wind-powered generators was 121.2 gigawatts (GW).[1] In 2008, wind power produced about 1.5% of worldwide electricity usage;[1][2] and is growing rapidly, having doubled in the three years between 2005 and 2008. Several countries have achieved relatively high levels of wind power penetration, such as 19% of stationary electricity production in Denmark, 11% in Spain and Portugal, and 7% in Germany and the Republic of Ireland in 2008. As of May 2009, eighty countries around the world are using wind power on a commercial basis.[2]
Large-scale wind farms are connected to the electric power transmission network; smaller facilities are used to provide electricity to isolated locations. Utility companies increasingly buy back surplus electricity produced by small domestic turbines. Wind energy as a power source is attractive as an alternative to fossil fuels, because it is plentiful, renewable, widely distributed, clean, and produces no greenhouse gas emissions. However, the construction of wind farms is not universally welcomed because of their visual impact and other effects on the environment.
Wind power-is non-dispatchable, meaning that for economic operation, all of the available output must be taken when it is available. Other resources, such as hydropower, and standard load management techniques must be used to match supply with demand. The intermittency of wind seldom creates problems when using wind power to supply a low proportion of total demand. Where wind is to be used for a moderate fraction of demand such as 40%, additional costs for compensation of intermittency are considered to be modest.[3][4]
Water Energy-Major investment is flocking to the world’s water resources, with tycoons referring to water as the new oil. Originally a clean water discussion, water for energy production is beginning to receive main-stream attention.While the energy side often receives much of the publicity, individuals and business are becoming aware of the link to water. Most people understand that it takes energy to produce water and that water can produce energy (hydroelectric power); however, the complexity of the relationship can be seen in just about every aspect of our society.
•Water and energy are essential to every aspect of life: social equity, ecosystem integrity, economic and business sustainability.
•Water is used to generate energy; energy is used to provide water.
•Water and energy are used to produce crops; crops can in turn be used to generate energy through biofuels.
Recent growth in eco awareness has accelerated research to expand within technical circles towards framing the water and energy related issues and searching for solutions. A report by the World Business Council for Sustainable Development discusses the complexities and interrelationships between water, energy and climate change.The report comments: “If we truly want to find sustainable solutions, we must ensure that we address all three in a holistic way. They are pieces of the same puzzle and therefore it is not practical to look at them in isolation.”Leading businesses are beginning to understand the implications of the water/energy link and are improving business sustainability through the implementation of best practices.
•Reduce water and energy consumption through improved operations
•Treat and recycle own water and waste water (with associated energy costs)
•Recover and reuse water and energy (e.g., using steam or heat, recycle other industrial and municipal waste water.
•Develop new markets for water and energy-saving technologies and services
•Engage with local communities to reduce water and energy consumption
As a sustainability consultant, I encourage clients to examine their energy and water consumption. Through greater eco awareness of the links between water and energy, businesses and individuals can make internal improvements and be advocates for change within their communities and industries.
Biofuels – liquid fuels derived from plant materials – are entering the market, driven by factors such as oil price spikes and the need for increased energy security.
Bioethanol is an alcohol made by fermenting the sugar components of plant materials and it is made mostly from sugar and starch crops. With advanced technology being developed, cellulosic biomass, such as trees and grasses, are also used as feedstocks for ethanol production. Ethanol can be used as a fuel for vehicles in its pure form, but it is usually used as a gasoline additive to increase octane and improve vehicle emissions. Bioethanol is widely used in the USA and Brazil.
Biodiesel is made from vegetable oils, animal fats or recycled greases. Biodiesel can be used as a fuel for vehicles in its pure form, but it is usually used as a diesel additive to reduce levels of particulates, carbon monoxide, and hydrocarbons from diesel-powered vehicles. Biodiesel is produced from oils or fats using transesterification and is the most common biofuel in Europe.
Biofuels provided 1.8% of the world’s transport fuel in 2008. Investment into biofuels production capacity exceeded $4 billion worldwide in 2007 and is growing.[1]
geothermal-is the rate at which the Earth's temperature increases with depth, indicating outward heat flows from a hot interior. Away from tectonic plate boundaries, it is 25-30°C per km of depth in most of the world.[1] Strictly speaking, geo-thermal necessarily refers to the Earth but the concept may be applied to other planets. The Earth's internal heat comes from a combination of residual heat from planetary accretion (about 20%) and heat produced through radioactive decay (80%).[2] The major heat-producing isotopes in the Earth are potassium-40, uranium-238, uranium-235, and thorium-232.[3] At the center of the planet, the temperature may be up to 7,000 K and the pressure could reach 360 GPa.[4] Because much of the heat is provided by radioactive decay, scientists believe that early in Earth history, before isotopes with short half-lives had been depleted, Earth's heat production would have been much higher. This extra heat production, twice present-day at approximately 3 billion years ago,[2] would have increased temperature gradients within the Earth, increasing the rates of mantle convection and plate tectonics, and allowing the production of igneous rocks such as komatiites that are not formed today.[5]
