User:Teresatrow/Skyline Solar

Skyline Solar has developed High Gain Solar (HGS) Arrays to produce electricity for grid connected commercial, industrial and utility scale solar markets.

Economics of Photovoltaic (PV) Electricity Generation
Photovoltaic panels have been in production at low levels since the 1980s. The ramp in solar panel deployment is gated by cost, and the industry has been working on various schemes to decrease the cost. Simple economies of scale drive the cost down over time as bigger and more automated factories are built and the supply chain develops. At the same time, solar innovation is driving the energy production of PV products up. Local and Federal incentives are being put in place to push the industry towards the size and maturity needed to reach grid parity.

The cost of PV energy includes the panel cost, and the cost to install the system. The system installation cost includes racks, wiring, inverters, logistics and simplified installation. Reducing the cost of the PV Panel must be coupled with reduced system costs to reach grid parity where PV Electricity matches the cost of grid electricity generation.

The output of the PV System can be increased with improvements in cell efficiency, the use of trackers, concentration, and other more subtle engineering improvements. Tracking provides up to thirty percent more energy per peak Watt versus fixed tilt systems, and is starting to be implemented on a broader scale. Controlling the temperature of the cell is critical to high energy generation as increased cell temperature decreases the output of the panel. Skyline Solar uses a combination of tracking, heat sinks, and reflectors to focus light on a single string of silicon cells and maximize energy production.

Technical Details
Skyline Solar’s High Gain Solar product combines crystalline silicon cells with reflective racks, single axis trackers, and passive heat sinks to create a 10x concentration of sunlight on the cells. Trackers adjust the position of the reflective racks so that light remains concentrated on the solar cells while the sun passes through the sky. The arrays are oriented North-South and the tracker runs east to west to optimize the light capture.

The reflective racks concentrate light onto thin strips of solar cells, reducing the need for silicon and driving the cost of the PV Array down. The reflectors are made from standard materials like steel and aluminum. Skyline Solar is making use of automobile factory capacity to produce the reflectors. The patented system design reduces cost and ensures reliability.

Skyline’s Design
HGS Array -- The HGS Array contains a reflective rack, four rows of High Gain Solar panels running along the length of the system, a shared tracker, foundation, and coupling hardware attaching it to the next array in a column.

Reflective Rack – The reflective rack serves two functions. It provides structural support for the panels – similar to a traditional solar rack – and adds the additional function of collecting and reflecting light from a large aperture onto the much smaller surface area of HGS panels. Initial systems have a concentration factor of roughly ten times. Each Reflective Rack is constructed from four curved sheets of metal running along the top of the structure and a series of ribs and struts on the bottom. The top surfaces are covered with a thin reflective metal coating encased in oxide layers to ensure high durability. This technology was developed and tested over many years in the lighting industry. The overall structure forms a stiff, material-efficient space frame similar to structures used in the automotive and aircraft industries.

HGS Panels -- HGS panels are manufactured with the same materials and processes as traditional solar panels but are much smaller in size. They include a backing plate, silicon cells, encapsulant, glass cover plate and junction box. One feature of the HGS panels not found on other panels is a passive metal heat sink which allows passive convection cooling through open air channels. Traditional flat panels have no thermal solution and tend to lose efficiency during peak afternoon sun when heat trapped behind the panel drives cell temperatures up.

Columns -- Reflective racks are installed in long mechanically coupled columns with adjacent arrays sharing mounting poles and foundations. The system includes a single-axis tracking system which rotates long columns of arrays to follow the arc of the sun.

Target PV Markets
As the solar energy market evolves from residential rooftop and off grid installations towards a more diverse set of applications, different technologies will command advantages in different markets. Two key dimensions determining which technology is best suited are climate and system size. For example, space constrained roof-mount applications in sunny climates are best suited to high efficiency fixed tilt panels whereas roof and ground mount applications in less sunny environments tend to favor thin films which work well in low light conditions.

Thin film scales well into the tens of Megawatts but efficiency and energy density are much lower than high efficiency silicon. The market for large ground mount systems using silicon continues to evolve quickly, particularly (but not only) in distributed generation applications where land is valuable. The ability to drive higher energy density and lower energy cost makes tracking important in these areas. For example a large fraction of the PV system capacity installed in Spain in 2008 went into tracked systems and many of the large systems being installed in California, Southwestern US and Southern Europe are now being tracked. Other candidates regions for tracking include North Africa, the Middle East, Australia and parts of Asia.

Concentrating Solar Power (CSP) has attracted renewed interest for very large, utility scale deployments based on the prospect of low delivered energy cost and storage. If realized, this provides a measure of dispatch-ability, valuable to utilities. But obstacles to CSP include large up front capital investment, very high water consumption and long design and deployment cycles.

HGS combines the best aspects of tracked PV and tracked CSP making it the leading solution for sunny climates. HGS systems are optimized for 100 kW to multi-Megawatt tracked ground mount applications and are ideal for larger systems.

Skyline Solar, Inc. was recently launched with CEO Bob MacDonald, PhD and funding from venture capital firm New Enterprise Associates (NEA) and was a 2008 winner of a Department of Energy Solar Energy Technology Program grant.

Skyline Solar installed its first system for the San Jose-based Valley Transit Authority (VTA). The VTA System dedication was on May 15th, 2009.

Company Facts

 * Type		- Private
 * Founded	- 2007
 * Founders 	- Bob MacDonald, Bill Keating, Eric Johnson
 * Headquarters	- Mountain View, CA, USA