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    Health and Wellness & Saving the Planet

    Health-And-WellnessAmerican poet, Ralph Emerson, wisely stated, “The first wealth is health.” At Blue Oak Energy, we just completed a year-long health and wellness program to not only encourage staff members to take charge of their wellbeing but also to be positive role models in environmental responsibility and sustainable living.

    The concept of the program was simple: ride your bike to work, run at lunch, or drive a vehicle in that gets better than 40 miles to the gallon, and deposit money into our company wellness bank ($5 per activity; $1 for every gas efficient vehicle).

    Health and wellness dialog

    In addition to the focus on the physical aspect of our wellbeing, we wanted to promote dialogue in other areas of our individual wellness such as emotional, medical, and social aspects that are easily neglected in today’s corporate world.

    What we found was that being “healthy” doesn’t just require eating right and breaking a sweat on a daily basis. Having a balanced and thriving wellbeing requires scheduling those dreaded (but necessary) doctor check-ups, turning off the smart phone to spend quality time with loved ones, and making the effort to invest in friendships that encourage personal growth and establish community.

    Wellness in action

    So how did Blue Oak do?

    We biked, we ran races on the weekends, we started composting, and even held our first ever company kickball tournament. Metrics?

    • 75% staff participation
    • More than 14,000 miles of bike riding
    • Prevented over 186 metric tons of CO2 emissions
    • AND we invested $5,500 in our company wellness bank

    Only the beginning

    As we look forward and anticipate what 2012 will bring for Blue Oak Energy and the PV commercial solar industry, we are also excited to continue our endeavor to keep wellness at the forefront in the work place.

    We are gearing up for our 2012 wellness program with a refreshed focus, new goals, and inspired (possibly wacky) ideas.

    We all know that we live in a culture that requires us to work (more than we prefer most of the time). Blue Oak Energy’s ability to impact the world greatly depends on our staff’s health and wellness. There is much to be done and we definitely plan to have fun along the way!

    Here’s to wellness, happiness, and plenty of sunshine in 2012.

    Solar Farm – How to Avoid Alligators

    Sometimes the most challenging aspect of utility-scale solar or commercial solar installations is not getting the equipment running and connected to the grid. It’s where to put the equipment or how to fit it into a specific plot of land that is irregularly shaped while avoiding the alligators.

    solar-farm-gator

    This was the case with the recently launched 5.9MW Stanton Solar Farm we designed and engineered for OUC in Orange County, Florida.

    The challenge

    We were tasked with helping to define the useable area within the client’s property. There were numerous environmental challenges. The design incorporated the use of a single-axis tracker on an irregularly shaped parcel that is prone to flooding. The tracker blocks are large and highly constrained in terms of footprint.

    There were also interesting challenges that arose with the stringing plan. A “string” is the the trade jargon for a “Source Circuit”, which is a multitude of solar modules, wired in series, to achieve a desired voltage, nominally 600V. This voltage is limited by the National Electrical Code as well as the operating specifications of the inverter (temperature plays a big role in this limit as well). At Stanton, each panel or racking assembly is comprised of 10 modules, but there were 14 modules per string.

    The solution

    At first we proposed to break up the tracker blocks into smaller sub-arrays, but this was the least cost-effective solution. The team came up with an optimal block size and ways to trim panels off of the ends of the rows to create a “stepping” of the array that matched the curved edges of the parcel.

    stanton-solar-farm

    Within this optimal footprint, we had to consider the string size and ensure that each tracker was divisible by 14. And the parcel kept shrinking.

    As we learned more about the environmental conditions in and around our site, we learned the array would need to be moved as far to the west as possible to allow for a wetland buffer, flood mitigation measures, and possible tree shading along the east and south. This led to multiple adjustments to the layout of the array.

    Stringing 5.9 Megawatts in a single day also proved to be an interesting and exciting challenge. But we pulled together and made it happen.

    A job with teeth

    This is the first PV project that I worked on where alligator intrusion on the site was a factor. The array had to be designed to withstand hurricane force winds, possible flooding, corrosive salt air … and alligators. Not that alligators really pose a threat to PV systems, mostly just the people that are trying to maintain them.

    It might only be a small amount of instantaneous power compared to its neighboring coal-fired plant, but in the long term, this system will offset many tons of carbon, which could add up to a significant environmental contribution.

    Solar Energy Components UL Listed to 1000 Volts

    Is 1500V the new 1000V?

    In the second quarter of 2011, manufactures of inverters and combiners began receiving certifications for meeting the updated UL1741-2010 standard, bringing 1000V listed products to the US market. Previously, only utility and behind-the-fence projects were able to install 1000V systems by using European inverters.

    In addition solar panels, fuses, and disconnects have been UL listed to 1000V with their respective UL standards. European installations have been operating with 1000V systems for years, so it’s great to see the U.S. attempting to catch up.

    The drive for increases to the DC system voltage is to reduce costs of wire and other balance of system components. With a higher voltage and more modules connected in series, more power can be transmitted on a given wire size and fewer source circuits are needed. The result? More efficiency.

    Has the U.S. really caught up?

    To increase the cost savings some European manufacturers are beginning to develop components rated at 1500V. The TUV testing labs have already begun certifying products to the European IEC standards. There are still design issues to overcome, such as what will be the industry standard fuse size?

    The limiting factor will once again be how long it takes for UL to add provisions in the standards for intended system designs. As for the voltage limit on residential installations, NEC 690.7(C) still limits the system voltage to 600V.

    Commercial installations may still run into difficulty with the Authority Having Jurisdiction (AHJ) on the installation of systems over 600V. The AHJ would need to be brought into the design process early in the project to avoid possible rejection of the design.

    With increased ground mount projects and pressure from the solar power industry, 1000V systems will become commonplace and the desire for going to 1500V will grow.

    Questions of safety and reliability

    If all of the elements of product design, system design and safety come together to make 1500V systems a reality, further decreases in installed cost and return on investment will be achieved. But as with any new development, the testing process will determine when safety and reliability reach the point where certification makes sense. In the meantime, any step forward is greeted with cheers by those of us in the commercial solar design and installation business.

    Long Island Solar Farm Goes Live!

    Posted on: by Tobin Booth No Comments

    Blue Oak Energy was fortunate to attend the ribbon cutting ceremony on November 18, 2011 for a project we began designing in May 2009. There was an abundance of enthusiasm, community support and sunshine at this event to celebrate full operation of this awesome solar electric system.

    This project is known as the Long Island Solar Farm which is a 37MWp (32MWac) solar farm covering six distinct parcels of land within the confines of the Brookhaven National Laboratory property. Brookhaven National Laboratory’s role is to produce excellent science and advanced technology with the cooperation, support, and appropriate involvement of our scientific and local communities. As such, this solar electric system is an indicative example of their leadership in science and technology. Brookhaven is one of ten total national laboratories in the United States and is located in the center of Long Island in Upton, New York.

    When we started working on the Long Island Solar Farm, we knew there were some challenges which could significantly alter the intended outcome of the project. The items below are some of the challenges we expected from the onset or discovered during the design process:

    The Largest Solar Farm in the Northeast United States - the Long Island Solar Farm

    Long Island Solar Farm - 37MWp

    • Wetlands

    The site is surrounded by wetlands on two sides of the multifaceted perimeter. The required offsets from natural wetlands were considered and we took a conservative approach to ensure there was no encroachment on these important habitats.

    • Native Species

    A protected tiger salamander required zero disturbances in any native habitat areas. As a result of the tiger salamander habitat locations, there are several radii in the solar array property which allows designated setback.

    • Crossing the Long Island Rail Road (LIRR)

    Crossing a railroad easement with the electrical conductors which deliver the solar farm’s energy to the Long Island Power Authority’s substation was all new to us. We obtained a permit from the Long Island Rail Road to provide a path for the solar farm’s conductors.

    • Governmental Entity

    Ok, we have done governmental projects before but we did not know what it would be like to help secure easements and lease land from the US Department of Energy (DOE) and Brookhaven National Labs (BNL). In fact, the DOE and BNL turned out to be great partners.

    • Native Pine Barren Forestland

    There were trees and undergrowth removed from this site to accommodate the PV system. However the designated Central Pine Barrens forests were untouched. We worked diligently with the Pine Barrens conservancy group to ensure there was no harm to this native forestland. Boundaries were surveyed to ensure any development was within the land areas designated for development by the conservation.

    • Topographic Variation and Grading

    There was a major effort to remove the existing vegetation but not change the current topography of the site in order to ensure the same drainage patterns to the wetlands.  As a result the non-uniform site ranged from nearly flat to hilly across the field.  We were able to design the site in three dimensions in order to ensure the shading, ground clearances and spacing was properly accounted for in order to match the energy production & economic models remained valid.

    • Conductor design Based on Soil Resistivity

    The underground solar field electrical conductors were specifically sized for the soil resistivity, which is a measure of how much the soil’s properties will resist the flow of electricity. It is an important factor in designing an efficient underground electrical system. The soil resistivity and how it varies in the soil is also necessary to properly design the electrical substation’s grounding system.

    • AC Collector System: 34.5kV versus 13.8 kV

    The solar farm contains 25 each 1.25MVA inverter stations which covert the solar array direct current to alternating current. We had the opportunity to choose 13.8kV or 34.5kV voltage class electrical “collector” system gear. The higher voltage equipment is more expensive, but the high voltage requires less conductor area to transmit the current. A detailed engineering cost study revealed that the 34.5kV collector system was the best choice for this solar farm.

    • Step-up Transformer

    The solar farm’s alternating current collector system delivers electricity at 34.5kV. But the interconnection voltage to the Long Island Power Authority is at 69kV. We used a central step-up transformer at a median location in the array field to transform from 34.5kV to 69kV. This step-up transformer has a long delivery time and thus a potential failure of this critical component could shut-down the facility for months. Therefore, the development team chose to site a spare transformer at the site which allows for quick replacement in the event of a failure.

    • Transformer Oil Containment

    The transformers all use environmentally friendly and biodegradable mineral oil. However, we still chose to design an oil containment feature at each transformer to collect the oil in the event of a transformer failure.

    • NYISO System Impact Study

    The interconnection queue at the New York Independent System Operator required completing the interconnection process through a cluster study. This put the solar farm in the interconnection study process with other projects which change the major supply or demand of electrons to the state’s grid. The whole study process took about 12 months from initial application to final approval.

     

    Solar Energy Data Centers for IBM

    Posted on: by Tobin Booth No Comments

    How IBM is being smart and could be smarter
    A fabulous article on solar powered data centers has been blanketing the media recently. IBM intends to use the variable and intermittent solar energy produced on a rooftop solar photovoltaic system to provide Direct Current to power their data centers.

    This is an application for solar energy which has been underutilized over the years, in my opinion. Given the huge and constant energy demand which data centers require and the variable-rate structures from utility companies, solar energy folds nicely into an energy diversification portfolio and generally makes a healthy investment for a data center or server farm.

    Technology companies are smart in typically locating their data centers in areas where electricity is inexpensive; financially the returns could often still be even better. But, as the article notes, data centers run on Direct Current (DC). Electrical pioneer Nicola Tesla early on proclaimed the benefits of running electrical loads on DC (he was eventually trumped by the benefits of transmission and distribution of Alternating Current (AC) by Tesla’s colleague, Thomas Edison).

    Well, if solar energy directly powered a data center, then we remove one efficiency loss from the equation: the loss from the DC to AC inverter. Typically in a solar electric system, the Direct Current produced by the solar array is directly converted to Alternating Current and then distributed to loads. As proposed by IBM, the inverter has been eliminated from the solar electric system. While modern inverters are often 96-98% efficient, this is a peak or average peak efficiency under specific circumstances. In the real world, the losses from an inverter will amount to 5-7% of the energy produced by the solar array over the power ranges it will operate. Just like a transformer, an inverter operates at different efficiencies over a range of power levels.

    Here is how a data center is typically setup with a backup power system and uninterruptible power system (UPS) in the figure. Please note this is a simplified version of a UPS system and does not show all components which make this type of system functional.

    Backup power system with secondary solar source

    UPS Solar Power System

    If you add the solar energy to directly charge the very same battery bank which supports the data center loads, the variable and intermittent energy production from a solar array becomes stable. The solar array simply adds current into the battery bank which is used as needed to support the data centers.

    Now, here is where IBM can take it to another level and actually make their data centers into energy profit centers. If the solar array is sized large enough, this power system can become bidirectional and export power to the utility grid.

    The AC to DC power conversion equipment, which is usually only operated in a single direction, can become a path to an income stream. As utility companies are starting to increase Time of Use rates during peak periods (which correspond nicely with peak solar energy production) the financial return on a bidirectional system becomes attractive.

    In essence, IBM’s realization is brilliant. They are on to something here and we would love to see them take it to the next level with smart grid bi-directional energy integration. This is the future in terms of delivering energy security, energy diversification, eliminating waste, and ensuring peak financial performance for the company and its assets.