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The importance of affordability and accessibility for making clean energy more usable to the public

A team at MIT believes that this lead can be cut out of the waste stream entirely -- and put to good use creating emissions-free energy. Cheap, Flexible Solar Fri, March 20, 2015 An engineering student is tuning energy levels through surface chemistry, showing promise for higher efficiency quantum dot solar cells. Solar Impulse completes epic flight to Hawaii Mon, August 24, 2015 Solar Impulse, the aeroplane that is powered only by the sun, has landed in Hawaii after making a historic 7,200km flight across the Pacific from Japan.

Mon, November 23, 2015 A pair of researchers suggest an underground solution to store energy to keep the grid stable for total transition to renewable sources.

  • Nano Letters 7 8;
  • Why is solar energy important?
  • But thin layers would not absorb as much sunlight to begin with;
  • It is environmentally clean, and its energy is transmitted from the sun to the Earth free of charge;
  • Many of the technologies to address these issues are already in hand;
  • Solar Impulse completes epic flight to Hawaii Mon, August 24, 2015 Solar Impulse, the aeroplane that is powered only by the sun, has landed in Hawaii after making a historic 7,200km flight across the Pacific from Japan.

As a source of energy, nothing matches the sun. It out-powers anything that human technology could ever produce. Why is solar energy important? Those fossil fuels cannot remain the dominant sources of energy forever.

Whatever the precise timetable for their depletion, oil and gas supplies will not keep up with growing energy demands. Coal is available in abundance, but its use exacerbates air and water pollution problems, and coal contributes even more substantially than the other fossil fuels to the buildup of carbon dioxide in the atmosphere.

For a long-term, sustainable energy source, solar power offers an attractive alternative. Its availability far exceeds any conceivable future energy demands. It is environmentally clean, and its energy is transmitted from the sun to the Earth free of charge. Many of the technologies to address these issues are already in hand. Another popular avenue is direct production of electric current from captured sunlight, which has long been possible with solar photovoltaic cells.

How efficient is solar energy technology?

Make Solar Energy Economical

To make solar economically competitive, engineers must find ways to improve the efficiency of the cells and to lower their manufacturing costs. Prospects for improving solar efficiency are promising. Current standard cells have a theoretical maximum efficiency of 31 percent because of the electronic properties of the silicon material. But new materials, arranged in novel ways, can evade that limit, with some multilayer cells reaching 34 percent efficiency.

Experimental cells have exceeded 40 percent efficiency. Another idea for enhancing efficiency involves developments in nanotechnology, the engineering of structures on sizes comparable to those of atoms and molecules, measured in nanometers one nanometer is a billionth of a meter. Recent experiments have reported intriguing advances in the use of nanocrystals made from the elements lead and selenium. Lead-selenium nanocrystals enhance the chance of releasing a second electron rather than the heat, boosting the electric current output.

Other experiments suggest this phenomenon can occur in silicon as well. Engineering advances will be required to find ways of integrating such nanocrystal cells into a system that can transmit the energy into a circuit. How do you make solar energy more economical? Other new materials for solar cells may help reduce fabrication costs.

Goal 7: Affordable and clean energy

Current solar cell designs require high-purity, and therefore expensive, materials, because impurities block the flow of electric charge. That problem would be diminished if charges had to travel only a short distance, through a thin layer of material. But thin layers would not absorb as much sunlight to begin with. One way around that dilemma would be to use materials thick in one dimension, for absorbing sunlight, and thin in another direction, through which charges could travel.

One such strategy envisions cells made with tiny cylinders, or nanorods. Another approach involves a combination of dye molecules to absorb sunlight with titanium dioxide molecules to collect electric charges. But large improvements in efficiency will be needed to make such systems competitive. How do you store solar energy? At times and locations where sunlight is plentiful, its energy must be captured and stored for use at other times and places.

Many technologies offer mass-storage opportunities. Pumping water for recovery as hydroelectric power or large banks of batteries are proven methods of energy storage, but they face serious problems when scaled up to power-grid proportions. New materials could greatly enhance the effectiveness of capacitors, superconducting magnets, or flyweels, all of which could provide convenient power storage in many applications. For example, sunlight could power the electrolysis of water, generating hydrogen as a fuel.

Hydrogen could then power fuel cells, electricity-generating devices that produce virtually no polluting byproducts, as the hydrogen combines with oxygen to produce water again. But splitting water efficiently will require advances in chemical reaction efficiencies, perhaps through engineering new catalysts.

Developing catalysts that can match those found in living cells would dramatically enhance the attractiveness of a solar production-fuel cell storage system for a solar energy economy.

  • A global economy reliant on fossil fuels, and the increase of greenhouse gas emissions is creating drastic changes to our climate system;
  • How do you store solar energy?
  • Mon, November 23, 2015 A pair of researchers suggest an underground solution to store energy to keep the grid stable for total transition to renewable sources;
  • Knowledge Hub Power for All has a knowledge platform , generating and disseminating infographics, factsheets, research summaries and reports on decentralized energy, with the aim of building support and awareness in this area.

Fuel cells have other advantages. They could be distributed widely, avoiding the vulnerabilities of centralized power generation. Nano Letters 7 8: Office of Energy Efficiency and Renewable Energy. Physical Review Letters 99: Implications for Solar Energy Conversion. Physical Review Letters 92 18: