Resource World Magazine

58 www.resourceworld.com J U N E / J U L Y 2 0 1 8 Developments in Green Technology by Jane Bratun GREEN TECHNOLOGIES SUNPOWER PROVIDING MILITARY, COMMERCIAL AND HOME SOLAR POWER SYSTEMS Solar energy works by capturing the sun's energy and turning it into electric- ity. SunPower Corp. [SPWR-NASDAQ], based in San Jose, California, notes on its website, that every hour, enough photons impact our planet to generate enough solar energy to theoretically satisfy global energy for a year. These photons, or photovoltaic (PV), power accounts for only five-tenths of 1% of the energy consumed in the United States. But, solar technology is advanc - ing, and the cost of going solar is dropping rapidly, so our ability to harness the sun's energy is on the rise. A 2017 report from the International Energy Agency shows that solar has become the world's largest- growing power source – marking the first time that solar energy growth has surpassed that of all other fuels. PV solar panels generate direct current (DC) electricity. With DC electricity, elec - trons flow in one direction around a circuit. Alternating current (AC), where the current periodically reverses direction, powers the US electrical power grid, primarily because it is less expensive to transmit over long distances. A solar inverter takes the DC electricity from the solar array and uses that to create AC electricity. Inverters are like the brains of the system. Along with inverting DC to AC power, they provide ground fault protection and system statistics, including voltage and current on AC and DC circuits, energy production and maximum power point tracking. Central inverters have dominated the solar industry since it began. According to SunPower, the micro-inverter is one of the biggest technology shifts in the PV indus - try. Micro-inverters optimize for each solar panel, not for an entire solar system, as cen- tral inverters do. This enables every solar panel to perform at maximum potential. When the central inverter has a problem on one solar panel, such as it being in the shade or dirty, it can drag down the solar array performance. Micro-inverters, such as the ones in the SunPower ® Equinox™ home solar system, make this a non-issue. If one solar panel has a fault, the solar array still performs efficiently. A typical grid-tied PV system, during peak daylight hours, frequently produces more energy than one customer needs, so that excess energy is fed back into the grid for use elsewhere. The customer gets credit for the excess energy produced and can use that credit to draw from the con - ventional grid at night or on cloudy days. A net meter records the energy sent com- pared to the energy received from the grid. SunPower claims the world's highest effi- ciency solar panels, featuring SunPower ® Maxeon ® cell technology and more than 750 patents for solar technology. The company provides solar advisors to US federal gov - ernment agencies, deploying solar power systems at military facilities nationwide, including more than 28 megawatts (MW) at Nellis Air Force Base in Nevada and 10 MW of solar and 1 MW of energy storage at the US Army's Redstone Arsenal in Alabama. The company also provides 13.78 MW at Naval Air Weapons Station China Lake, as well as 5.6 MW at the Air Force Academy in Colorado Springs. At a ribbon cutting event on April 10, 2018, the US Air Force Civil Engineer Center, Vandenberg Air Force Base, and the Defense Logistics Agency, Energy marked the start of operations for a 28-MW solar PV system at Vandenberg Air Force Base near Lompoc, California. The power gen - erated by the system is expected to meet about 35% of the base's energy needs. "Access to reliable, resilient electricity to meet operational needs is a priority for the US Air Force, and this solar project enables us to increase our own energy security at Vandenberg with competitively priced, dependable solar energy from SunPower," said Ken Domako, Chief of Portfolio Optimization at Vandenberg Air Force Base. The base will purchase electricity under a 25-year power purchase agreement, pro - viding Vandenberg with competitive, fixed electricity rates, and the Air Force will retain all of the associated environmental credits. Alabama-headquartered Regions Bank provided the capital required for the solar project, eliminating the need for capi- tal expenditures by the Air Force. The onsite system is the largest Air Force solar project in which the Air Force consumes all energy produced. "The Air The 4.4-megawatt SunPower installation at Campbell Soup Company's World Headquarters in Camden, New Jersey. Photo courtesy SunPower Corp.

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