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According to a 2011 projection by the International Energy Agency, solar power generators may produce most of the world’s electricity within 50 years, dramatically reducing the emissions of greenhouse gases that harm the environment.[14]

Predications from the 2006 time-frame expected retail grid parity for solar in the 2016 to 2020 era,[4][5] but due to rapid downward pricing changes, more recent calculations have forced dramatic reductions in time scale, and the suggestion that solar has already reached grid parity in a wide variety of locations.[2] The European Photovoltaic Industry Association (EPIA) defines the moment at which the value of PV electricity equals the cost of traditional grid power as dynamic grid parity. EPIA expects that PV power achieves this target in many of the European countries by 2020, with costs declining to about half of those of 2010.[1] However, this report was based on the prediction that prices would fall 36 to 51% over 10 years, a decrease that actually took place during the year the report was authored. The line was claimed to have been crossed in Australia in September 2011,[6] and module prices have continued to fall since then. By late 2011, the fully loaded cost of solar PV was projected to likely fall below $0.15/kWh for most of the OECD and reach $0.10/kWh in sunnier regions like the southern United States or Spain.[7] This is below the retail rate for power in much of the OECD already.

Concentrated Solar Thermoelectric Power

The Rohsenow-Kendall Heat Transfer Lab at Massachusetts Institute of Technology(MIT), under the 2012 SunShot Concentrating Solar Power (CSP) R&D FOA, is developing concentrated solar thermoelectric generators (CSTEGs) for CSP systems. This innovative distributed solution contains no moving parts and converts heat directly into electricity. Thermal storage can be integrated into the system, creating a reliable and flexible source of electricity.

The goals of MIT's CSTEGs project are to:
• Achieve a >10% solar-to-electricity energy conversion efficiency
• Limit optical concentration to less than ten and potentially less than four
• Demonstrate the potential for 24-hour operation by using phase-change materials.
Innovation

MIT's innovative approach is a significant departure from current CSP systems. The solar thermoelectric generators are based on solid-state thermoelectric devices, and yet, they can store solar energy in the form of heat. When combined with thermal storage, such CSTEGs can provide electricity day and night while eliminating the mechanical power generation blocks. Furthermore, CSTEGs can also be used at small scale, such as commercial rooftops, to provide 24-hour distributed solar power. If successful, CSTEGs introduce a new and viable CSP technology capable of achieving the SunShot Initiative's goal of $0.06 per kilowatt-hour.

Jag tror helt klart mer på Moores lag när det gäller solceller än när det gäller batterier...

Det stora problemet är att vi bara får in ca 1000w/m² energi i form av strålning från solen. Vi behöver PV-celler som kan omvandla större bandbredder.

Gallium arsenide multijunction
Main article: Multijunction photovoltaic cell
High-efficiency multijunction cells were originally developed for special applications such as satellites and space exploration, but at present, their use in terrestrial concentrators might be the lowest cost alternative in terms of $/kWh and $/W.[32] These multijunction cells consist of multiple thin films produced using metalorganic vapour phase epitaxy. A triple-junction cell, for example, may consist of the semiconductors: GaAs, Ge, and GaInP2.[33] Each type of semiconductor will have a characteristic band gap energy which, loosely speaking, causes it to absorb light most efficiently at a certain color, or more precisely, to absorb electromagnetic radiation over a portion of the spectrum. The semiconductors are carefully chosen to absorb nearly all of the solar spectrum, thus generating electricity from as much of the solar energy as possible.
GaAs based multijunction devices are the most efficient solar cells to date. In April 2011, triple junction metamorphic cell reached a record high of 43.5%.[34] This technology is currently being utilized in the Mars Exploration Rover missions, which have run far past their 90 day design life.

Tandem solar cells based on monolithic, series connected, gallium indium phosphide (GaInP), gallium arsenide GaAs, and germanium Ge p-n junctions, are seeing demand rapidly rise. Between December 2006 and December 2007, the cost of 4N gallium metal rose from about $350 per kg to $680 per kg. Additionally, germanium metal prices have risen substantially to $1000–1200 per kg this year. Those materials include gallium (4N, 6N and 7N Ga), arsenic (4N, 6N and 7N) and germanium, pyrolitic boron nitride (pBN) crucibles for growing crystals, and boron oxide, these products are critical to the entire substrate manufacturing industry.

The Dutch Radboud University Nijmegen set the record for thin film solar cell efficiency using a single junction GaAs to 25.8% in August 2008 using only 4 µm thick GaAs layer which can be transferred from a wafer base to glass or plastic film.

Det stora problemet är att vi bara får in ca 1000w/m² energi i form av strålning från solen.

Vi behöver PV-celler som kan omvandla större bandbredder. Tänk om man kunde använda nanopartikel-teknologi för att tillverka ett material med antenner avstämda för ljus och infrarött där man kan ta emot vågrörelsen som vilken radiomottagare som helst, och sedan kanalisera energin till en ledare.

Over the past 30 years, solar cell efficiencies have continuously improved for all
technologies. Among the most important accomplishments to be noted ([20] – see below
for more detail about the specific technologies) are the 24.7%-efficient c-Si solar cell
(University of South Wales, Australia), the 18.4%-efficient CIGS solar cell (NREL), the
16.5%-efficient CdTe solar cell (NREL), and the 39%-efficient GaInP/GaAs/Ge triplejunction
solar cell under 241-suns concentration (Spectrolab) [21]. Research on dyesensitized
solar cells (DSSCs) and organic solar cells (OSCs) began only during the last
decade. The last reported record efficiencies are 10.4% for DSSCs (Ecole Polytechnique
Fédérale de Lausanne, Switzerland) [22], and 5.7% for OSCs (Princeton University) [23].

Despite the notable progress made in the improvement of the efficiencies of all these
technologies, achieved values are still far from the thermodynamic efficiency limits of
~31% for single junctions[6], 50% for 3-cell stacks, impurity PVs, or up- and downconverters,
and 54-68% for hot carrier- or impact ionization-based devices [24].
Furthermore, the efficiencies of commercial (or even the best prototype) modules are
only about 50% to 65% of these “champion” cells [20]. Closing these gaps is the subject
of ongoing research.

The solar-to-electric efficiency of solar thermal technologies varies largely depending
upon the solar flux concentration factor, the temperature of the thermal intermediary, and
the efficiency of the thermal cycle for the production of mechanical work and electricity.
Parabolic troughs and power towers reach peak efficiencies of about 20%. Dish-Stirling
systems are the most efficient, with ~30% solar-to-electric demonstrated efficiency. The
performance of these systems is highly influenced by the plant availability. In the case of
parabolic troughs and power towers, thermal storage increases the annual capacity factor7
from typically 20% to 50% and 75%, respectively.

paraboler med sterlingmotor/generator

“The cuts will drag module prices down and squeeze margins,” Henning Wicht, lead solar analyst for IHS iSuppli, said in Munich before the decision. “Module prices in Germany will have to come down at least 10 percent.”

Usel politik när EU vill stoppa Kinas solceller