Solar Concentrator

Solar energy is the basis for all life on our planet, and people have harnessed the energy of the sun for sustaining life, keeping warm, and most recently, power. With the nexus of economical, political, technical, social and global conditions bearing down upon us, solar energy has once again been brought to the forefront, a place of promise not seen since the energy crisis of the 70s. However, since the 70s, there has been tremendous progress in solar technology research and development for solar energy technologies.

Today, the world has a very clear realization of the problematic dependence on petroleum in terms of geopolitical stability as well as the negative environmental impact high carbon fuels pose. This realization has created a “tipping point;” a critical mass has formed – solar power production is absolutely how humans will generate a progressively larger percentage of power needs.

The OptiSol™ Solar Concentrator is a new generation disruptive nanotechnology-based plastic solar concentrator and solar film that is a first-of-its-kind in the solar photovoltaic (PV) industry. Traditional silicon solar cells absorb only a small fraction of the total incident solar radiation potential, with a majority of the light either reflected or changed to thermal energy (heat). Based on electromagnetic non-optical principles and using NanoShrink™ technology, the OptiSol™ enhances the capabilities and efficiency of existing solar cell designs by focusing and tuning the incident solar radiation from the sun for optimal silicon absorption, with less of the total spectrum lost as heat or reflection.

The Opt iSol™ technology represents a stand-alone potentially disruptive product for Shrink Nanotechnologies to be marketed and sold as a companion device to new or existing silicon PVs, or as a solar accessory that can be
manufactured and packaged by any major silicon PV manufacturer.

The U.S. electric generation system is roughly 1,000 gigawatts (GW) of generating capacity currently in place. However, the total solar generating capacity is only 0.9 GW or less than 0.1% of the total capacity. Yet, the solar energy available to be harnessed is enormous. In fact, if every home in America had a 3 kilowatt (KW) rooftop system more than 420 MW could be produced or more than 35% of our entire residential demand. The opportunity to add photovoltaic (PV) solar installations is large and growing. Of the current grid-connected solar generating installations, 480 MW or about half of the total solar generating capacity is PV. The global PV market is expected to reach 8-20 GW by 2011.

The global solar photovoltaic market jumped to an estimated $37 billion for 2008 (www.setenergy.org), with an estimated 51% compound annual growth rate (CAGR) through 2011. The cumulative global solar capacity is greater than 15 GW, with a doubling in solar installations in 2008 alone which added close to 6 GW of solar PV capacity. Although some estimates show 2009 to be a slow year for solar growth (20-25%), 2010 and beyond is predicted to be very promising.

The European market leads in total solar demand, with China and Taiwan rapidly gaining market share. German company, Q-cells, is the leading European solar PV manufacturer with over 760 MW capacity (2008); China’s Suntech and Taiwan’s Gintech peak at 1000 MW and 560 MW capacity (2008), respectively. The US-based First Solar reached 716 MW capacity in 2008, with Japan’s Sharp and Sanyo solar capacities around 1 GW combined.

The fastest growing segments in solar is represented by thin film PVs at 123% to 0.89 GW of manufacturing production, or 15% of total PV market. While silicon represents a vast majority of the solar PV installations (~43% in the US), new technologies are coming online that are showing promise in terms of energy efficiency and affordability. While cost and efficiency are major drivers for solar revenue, today’s solar PVs are priced installed at $6-$8/W, demonstrating that both factors can be further refined to increase adoptability as new technologies are introduced.

In terms of additional government support driving the solar market, the U.S. Department of Energy’s Solar Energy Technologies Program is a nine year program driven by the Solar America Initiative (SAI) launched in 2007. The program’s goal is to achieve grid parity for solar electricity produced by photovoltaic systems across the nation. This will be accomplished through the federal government role in research and development, demonstration and deployment of solar energy technologies. Shrink intends to seek grants and other research awards offered by the SAI program through National Renewable Energy Laboratory (NREL) and the California Energy Commission PIER program, among others to support ongoing research and commercialization of our solar cell, concentrator, and other applications of the Company’s platform technology.

With silicon approaching its limits in terms of efficiency, affordability, and lifespan, new disruptive technologies are poised to capture market share. Advances in manufacturing processes and nominal efficiency gains are keeping silicon PVs the market leader for time to come; however, new solar concentrator technology has the potential to markedly alter the economics of solar PV installations by lowering costs and boosting power output of new and/or existing silicon PVs, effectively reducing the “payback” period to one that is more investment friendly.

Our development team has been charged to have a scalable and optimized commercial OptiSol™ concentrator ready for UL certification submission by the Spring of 2011. Presently, we have prototyped five iterations of OptiSol™, achieving significant additional efficiencies at each iteration. We estimate that a strategic alliance with a major silicon PV manufacturer would markedly decrease the time-to-market once Shrink’s R&D team has completed final prototype development and testing, with concomitant knowledge transfer protocols.

OptiSol™ solar concentrator technology is compromised of a semiconductor Quantum Dot (QD) layer integrated into the NanoShrink™ substrate. The next iteration of our solar cells will integrate our QDs into the plastic creating a single thin film which can be processed using our proprietary technology to generate the nano-features that create the optimum performance our products are designed for.

About 48% of the energy of the spectrum is in the infrared range, 44% is in the visible range, 7% is in the ultraviolet range. Silicon PV cells have rather low efficiency for higher energy parts of the spectrum (See Figure 2 below). Solar cells utilizing a-Si (amorphous silicon) respond to light of a different wavelength (red curve) than c-Si (crystalline silicon) solar cells (blue curve). The c-Si solar cells are very difficult to manufacture despite the broader absorption spectra. The Company’s PV cells are designed to absorb over the entire spectra (black outlined area).

The flexible nature of the substrate allows for easy integration into new or existing silicon PV installations. However, unlike current silicon PV systems which require 12-15 years of use in order to pay for themselves, our systems, which are a fraction of the cost, would allow the consumer to take advantage of newer improved technology– think about the personal computer market and how one felt after they purchase a Pentium I processor and then the Pentium II and II and so on would come to market soon after purchase. OptiSol™ will be optimized to convert broadband UV-VIS photons to low energy IR photons, in the spectral region where silicon PVs have higher external quantum efficiency. The image below is of a commercially available glass solar concentrator (left); and our plastic-based solar concentrator (right). The cost of the glass cell is approximately $15.00. Our plastic cell costs less than $0.20 to make:

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Below are images of our prototype solar concentrator and solar films. Energy is being collected by the silicon PV (silicon photo-voltaic) cell attached to the cell at this edge. It is also noteworthy that the source of this bright emission is a white light that is only a tenth the power of the sun!

The solar concentrator on its own in direct sunlight (A) produces 124mA (milliamps, a unit of electrical current) as the light passes through the OptiSol™ prototype. When shaded (B) , the prototype is still able to absorb diffuse light in its surroundings to generate 20mA. silicon solar cells that have great difficulty absorbing diffuse light. A white diffuser is used beneath the OptiSol™ protoype in test (C) resulting in the current boosted back up to 146mA.