renewable energy

Examples of renewable energy in the following topics:

• New Energy Sources

  • Alternative and renewable energy sources can reduce the environmental impact of energy production and consumption.
  • Renewable energy is energy that comes from natural resources, such as sunlight, wind, rain, tides, waves, and geothermal heat, which are all naturally replenished.
  • Brazil has one of the largest renewable energy programs in the world, involving production of ethanol fuel from sugarcane.
  • While many renewable energy projects are large-scale, renewable technologies can also be suited to rural and remote areas, where energy is often crucial in human development.
  • Ethanol is a quasi-renewable energy source.

• Present Sources of Energy

  • Present sources of energy include fossil fuels, various types of renewable energy, and nuclear power.
  • The estimates for remaining non-renewable worldwide energy resources vary; the remaining fossil fuels total an estimated 0.4 YJ (1 YJ = yottajoule, or 1024 J) and the the energy available from nuclear fuels such as uranium exceeds 2.5 YJ.
  • The total energy flux from the sun is 3.8 YJ/yr, which dwarfs all non-renewable resources.
  • As of 2010, use of fossil fuels as an energy source comprised over 80% of total energy consumed.
  • Renewable energy sources only comprised 16.7% of our energy in 2010.

• Fuel Cells

  • The energy efficiency of a fuel cell is generally between 40-60 percent; it can reach 85 percent if waste heat is captured for use.
  • First of all, since the energy used to produce the hydrogen is comparable to the energy in the hydrogen, it is inefficient, and therefore expensive.
  • If the electricity produced by clean, renewable energy sources, such as solar and wind power, is used to produce hydrogen, the energy can be stored more easily than in large battery complexes.
  • Fuel cells are a potential energy source for cars that do not run on gasoline.
  • However, although fuel cells offer clean, renewable energy, there are several barriers to its widespread adoption.

• Energy Consumption

  • The environmental impact of the energy industry is diverse.
  • Energy has been harnessed by humans for millennia.
  • In recent years, however, there has been a trend towards the increased commercialization of various renewable energy sources.
  • However, if we explore viable alternative energy resources, we could reduce our impact on the environment.
  • The study also found that the environmental and health costs of nuclear power, per unit of energy delivered, was €0.0019/kWh, which was found to be lower than that of many renewable sources including biomass and photovoltaic solar panels.

• The Hydrogen Economy

  • As such, hydrogen is not a primary energy source, but an energy carrier.
  • The feasibility of a hydrogen economy depends on issues including the use of fossil fuel, the generation of sustainable energy, and energy sourcing.
  • Fuel cells are electrochemical devices capable of transforming chemical energy into electrical energy.
  • Although H2 has high energy density based on mass, it has very low energy density based on volume.
  • Other issues include the fact that hydrogen generation via electrolysis requires a greater energy input than directly using renewable energy, and the possibility of other side products.

• Nuclear Reactors

  • The energy released from nuclear fission can be harnessed to make electricity with a nuclear reactor.
  • The amount of free energy in nuclear fuels is far greater than the energy in a similar amount of other fuels such as gasoline.
  • In many countries, nuclear power is seen as an environmentally friendly alternative to fossil fuels, which are non-renewable and release large amounts of greenhouse gases.
  • A neutron moderator works to reduce a newly produced neutron's kinetic energy from several MeV to thermal energies of less than one eV, making them more likely to induce further fission.
  • Just as many conventional thermal power stations generate electricity by harnessing the thermal energy released from burning fossil fuels, nuclear power plants convert the energy released from nuclear fission.

• Pressure and Free Energy

  • Gibbs free energy measures the useful work obtainable from a thermodynamic system at a constant temperature and pressure.
  • Just as in mechanics, where potential energy is defined as capacity to do work, similarly different potentials have different meanings.
  • The Gibbs free energy is the maximum amount of non-expansion work that can be extracted from a closed system.
  • Gibbs energy (also referred to as ∆G) is also the chemical potential that is minimized when a system reaches equilibrium at constant pressure and temperature.
  • Therefore, Gibbs free energy is most useful for thermochemical processes at constant temperature and pressure.

• Energy Changes in Chemical Reactions

  • Due to the absorption of energy when chemical bonds are broken, and the release of energy when chemical bonds are formed, chemical reactions almost always involve a change in energy between products and reactants.
  • By the Law of Conservation of Energy, however, we know that the total energy of a system must remain unchanged, and that oftentimes a chemical reaction will absorb or release energy in the form of heat, light, or both.
  • The energy change in a chemical reaction is due to the difference in the amounts of stored chemical energy between the products and the reactants.
  • This means that the energy required to break the bonds in the reactants is less than the energy released when new bonds form in the products.
  • This means that the energy required to break the bonds in the reactants is more than the energy released when new bonds form in the products; in other words, the reaction requires energy to proceed.

• Free Energy and Work

  • The Gibbs free energy is the maximum amount of non-expansion work that can be extracted from a closed system.
  • The Gibbs free energy is the maximum amount of non-expansion work that can be extracted from a closed system.
  • The work is done at the expense of the system's internal energy.
  • Energy that is not extracted as work is exchanged with the surroundings as heat.
  • ΔG is the maximum amount of energy which can be "freed" from the system to perform useful work.

• Ionization Energy

  • The ionization energy of a chemical species (i.e., an atom or molecule) is the energy required to remove electrons from gaseous atoms or ions.
  • Large atoms or molecules have low ionization energy, while small molecules tend to have higher ionization energies.
  • More generally, the nth ionization energy is the energy required to strip off the nth electron after the first n-1 electrons have been removed.
  • The ionization energy may be an indicator of the reactivity of an element.
  • This video explains the periodic trends in ionization energy....periodicity.