Commercial Solar Operations, Maintenance and Asset Management

Designing and building photovoltaic (PV) energy plants is a major focus for Blue Oak Energy. However, once the solar plant is operational, a watchful operation and maintenance (O&M) staff is crucial for realizing the long-term financial return and benefits you

Inspecting the electrical interconnection for the commercial solar array interconnection

Inspecting the electrical interconnection for the commercial solar array interconnection

expect. Commercial and utility solar facilities are excellent solutions for producing clean energy, but if not properly maintained potential revenues will lead to what we call the “expected disappointment”.

These are some of the unexpected events we have experienced while maintaining solar facilities across many geographies for more than a decade:

Rodent intrusion

Electrical equipment naturally provides a warm and dry habitat for creatures of many forms. Also fenced solar farms provide protected areas for rodents to multiply and thrive. It is essential to ensure the electrical equipment is sealed and out of reach for walking, crawling, jumping and slithering vermin.

Broken modules

Module breakage just happens. Galactic homerun fly balls and golf balls seem to have a magnetic attraction to solar modules in some locations. The occasional massive hailstorm has been known to cause problems in severe weather locations. A frequent visual inspection of the modules is important to identify natural breakage or manufacturer defects.

Inverter failure

Inverters are complex devices with many internal electronic components such as breakers, contactors, Insulated Gate Bipolar Transistors (IGBTs), Field Effect Transistors (FETs), resistors, capacitors, power supplies and more. The amount of heat moved through an inverter presents a challenge for the manufacturers of the amazing power electronics gear we deploy. Regular inspection, cleaning and inverter operational verification is essential to long term solar facility success.

Fence damage

We have seen fences damaged from adjacent trees, from the neighboring farmer, and from vandalism. Ensuring sound perimeter protection also ensures protection of the equipment inside the fence.

Vegetation growth

Regular management of vegetation growth is important to prevent interruption to the solar facility’s peak energy production. Vegetation can create shade on the solar array and grow into or around the electrical gear creating a fire hazard. Without proper vegetation management, a solar site operator is allowing an electrical hazard to persist.

 Theft / vandalism

Just as copper conductors have become a target for vandals, solar facilities have gained attention as well. A quiet solar facility at the end of a dirt road can be an enticing target to those who realize the equipment’s value. We have found that a relatively inexpensive security system with motion detection and video surveillance is a solid way to protect your solar asset.

Grid fluctuations

Occasionally, a voltage spike or disturbance on the utility power grid can cause damage on a solar facility. It happens once in a while and requires breakers to be reset and/or fuses to be replaced. An attentive solar system operator will receive an alarm and will respond to repairs at the site.

Module cleaning

For many sites, we provide an annual module cleaning service. Cleaning will remove dirt, grime and guano from the solar module glass. An immediate increase in energy production is a nice bonus after the annual module cleaning.

Blue Oak Energy has a vested interest in the continued efficient operation of photovoltaic systems because we are passionate about this technology and industry. We possess the knowledge of the many solar technologies deployed over the last decade and know many of the sites deployed across the US. There are general maintenance issues which need constant appraisal by a regularly visiting maintenance professional and the office supporting asset manager possessing a keen eye and deep understanding for these sites.

As Che Geiser, who heads up Blue Oak Energy’s O&M team points out, “There are a host of areas that you can predict and manage. Blue Oak Energy has great strengths, because we start as an engineering firm,” said Geiser. “We have a very strong expertise in this field, and coming from an engineering base, we really understand how these systems are built, so we know how to maintain them.”


Solar Energy Penetration on the CAISO Control Grid reaches 4093MW

CAISO is constantly making moves towards making renewable

energy part of the process that is transforming the lifestyles of people in California every day. On March 8, 2014, the company’s efforts were met with an incredible achievement. According to a recent press release by Steven Greenlee at CAISO, by reaching 4,093 megawatts of solar production power (the highest ever seen), this is a new record for solar generation in California. The previous record was almost a year ago at 2,071 MW of peak production, or nearly half of this year’s achievement!

CAISO Reaches 4GW of Solar

CAISO Reaches 4GW of Solar


Although solar power has recently become more affordable and accessible, Blue Oak Energy is still competing with new technologies, lower cost fossil fuels and other regional markets to offer the best solutions for its customers. California is the country’s leading producer of solar power and has given many businesses and industries the option to replace electricity with natural energy sources.


“Reaching commercial operation for utility scale projects California is a monumental task in itself. With so many requirements for permitting and interconnection, what Blue Oak has been achieving is a major accomplishment,” says Jacqueline DeRosa, Director of Regulatory Affairs at Customized Energy Solutions.


Communities can expect to see more breakthroughs like this in the future. DeRosa believes that with the CAISO interconnection already established, Blue Oak is on its way to more successful projects down the road.


“California’s progress in bringing renewable energy online has been nothing short of remarkable, stated Tobin Booth, CEO at Blue Oak Energy. He added, “The state’s ability to offer multiple energy market opportunities to produce energy and compete with conventional technologies has established California as one of the world’s clean energy leaders.”


With more solar projects coming on line, DeRosa emphasizes the need for the CAISO  to make changes to their metering and telemetry rules to facilitate accessibility of lower cost and up-to-date data acquisition technology for projects such as those being developed by Blue Oak. DeRosa also commented that the interconnection process is complex. Having successfully completed the CAISO’s interconnection process, Blue Oak has the highly valued experience that will enable it to move swiftly through the interconnection requirements as it pursues additional solar development in the state.

Commercial PACE Financing for Solar Energy Systems

A new type of financing is available to install commercial solar energy projects. It’s called Property Assessed Clean Energy, or PACE financing. PACE commercial financing makes commercial and industrial solar projects more affordable by spreading the cost out over a longer time period and lower interest rates than traditional bank or equipment financing.

Commercial PACE financing for Solar Energy Systems

Commercial PACE financing for Solar Energy Systems


City or county governments, who have elected to offer PACE financing, issue bonds to private investors. These investors, in turn, offer loans to commercial property owners for building clean energy projects in exchange for a property tax lien which pays for 100 percent of the solar energy upgrade. Repayment is usually over a 20-year period and is billed annually by the municipality as a line item on the property tax bill.

The increased property taxes pay for the initial cost of buying solar panels. The higher property taxes are counterbalanced by lower energy costs. Ultimately, the commercial or industrial entity employing PACE financing enjoys an annual energy savings greater than the increased property taxes. Municipalities benefit by sponsoring PACE financing, which creates jobs and lightens the load on our environment.

For commercial property owners, PACE benefits include:

    1. Full service financing, usually at lower rates and longer time periods than most banks will offer.
    2. Since PACE financing stays with the property, there is no payoff required if the property is sold or the tenant moves out.
    3. PACE is a property qualified financing, which is not credit based, rather it is based on the property’s valuation.
    4. There is an instant addition to the owner or tenants cash flow because of lower energy costs.
    5. Property owners also see an increase in both the efficiency and value of the property.

“Not only does this reduce greenhouse gases,” said CaliforniaFIRST Program Administrator H. Simón Bryce, “but it also contains a strong construction component. There are a number of jobs implemented with the retrofits involved with building these clean energy systems.”

Furthermore, CaliforniaFIRST lets property owners decide who installs the clean energy project. If the property owner doesn’t have a financing partner, CaliforniaFIRST helps in finding one from their list of private capital providers.

PACE is a relatively new phenomenon that began in Berkeley. California and Colorado passed the first PACE legislation in 2008. States adding PACE in 2009 included Oregon, Nevada, New Mexico, Texas, Oklahoma, Wisconsin, Illinois, Louisiana, Ohio, Virginia, New York, North Carolina, Vermont and Maryland. In 2010, Minnesota, Missouri, Michigan, Georgia, Florida, Maine, New Hampshire, Massachusetts and the District of Columbia joined the PACE list. Wyoming and Connecticut added PACE legislation in 2011, New Jersey came on board in 2012, and Arkansas added PACE in 2013. Hawaii permits PACE financing, because of an existing law. All told, 29 states and Washington, D.C. authorize PACE financing.

This type of innovative financing is one of the waves catching on in the commercial and industrial solar industry segment. Every commercial solar solution is customized to a specific site. We can help define a realistic solar solution for your commercial or industrial site while also laying out the financing options for your specific energy consumption profile.

Solar Energy Glossary of Terms

pv_VIWhen a solar electric energy system engineer or designer is matching the power electronics (DC/AC inverter) to a solar module there are some important terms and variables that need to be defined. The list below defines the common terms and provides commentary on the common solar photovotaic system variables. Also, we have taken the definitions a step further by showing how these variables are important in matching a solar module to the inverter’s electrical characteristics.

STC Rating: The Standard Test Condition (STC) is an instantaneous solar panel rating under controlled conditions. The Standard Test Conditions for a module are: solar irradiance of 1000 W/m2 , with the cell temperature maintained at 25°C and zero wind speed for cooling effect. These conditions are rarely, if ever, encountered in the real-world; therefore we are blessed with multiple other confusing terminologies.
PTC Rating: PTC (PVUSA or Performance Test Conditions) are defined as 1000 W/m2 plane-of-array irradiance, 20°C ambient temperature, and 1 m/s wind speed. PTC differs from standard test conditions (STC) in that its test conditions of ambient temperature and wind speed will result in a cell temperature of about 50°C, instead of the 25°C for STC. This rating was developed in an attempt to simulate real-world conditions. With elevated operating temperatures, the module/array produces less power, therefore the PTC rating of a module is typically 89% of the STC rating.
Inverter Efficiency: Efficiency for an inverter can be defined as power-out divided by power-in. The inverter efficiency varies with ambient temperature, DC input voltage, and inverter’s operating power level. As a result, defining inverter efficiency is an interesting game. The California Energy Commission has created a “weighted” inverter test procedure to create a level playing field. This weighted inverter efficiency is known as the CEC inverter efficiency.
CEC Rating: The California Energy Commission (CEC) has created the CEC system rating for determining rebate levels. This CEC rating for a solar array is simply the PTC rating of a solar array times the inverter’s CEC efficiency.
Inverter Power Rating: This is the maximum output power rating of the inverter, expressed in Watts (W) or kiloWatts (kW).
Inverter Maximum DC Input Current: This is the maximum input DC current that should be connected to the inverter at any time. It is important not to exceed the maximum input current of the inverter as this may damage the components and will void the warranty.
Inverter Maximum DC Input Voltage: This is the maximum DC voltage that can be applied to the inverter. Exceeding this value can damage the inverter. In the Selection Guide output results, the maximum input voltage is determined using the Open Circuit Voltage corrected for the user-selected minimum temperature.
Inverter Minimum Power Point Tracking DC Input Voltage: This is the lowest voltage at which the inverter can continue its maximum power point tracking routine, which optimizes the power production. The inverter will continue to operate at voltages below this value, down to Minimum DC Input Voltage, but will not maintain the maximum power production.
Inverter Minimum DC Input Voltage: This is the lowest DC input voltage for which the inverter can operate. In the Selection Guide output results, the minimum input voltage is calculated using the Max Power Voltage corrected for the user-selected maximum temperature.
Module Nominal Power Rating: This is the nameplate rating or nominal output power of the panel under Standard Test Conditions. At higher temperatures, the PV panel will produce less power than its nominal STC rating.
Cell Temperature: We typically use a standard 30°C above ambient temperature as the cell temperature for all calculations. This is the temperature of the cell while under illumination.
Lowest Ambient Temperature: The lowest ambient temperature selection should be conservative and as close to the 30-year record for the system’s geographic location. This temperature selection is used to adjust the open circuit voltage and ensure the inverter’s maximum voltage is not exceeded.
Highest Ambient Temperature: The highest ambient temperature selection should be conservative and as close to the 30-year record for the system’s geographic location. This temperature selection is used to adjust the maximum power (operating) voltage and ensure the inverter does not shutdown due to low voltage during the hottest part of the day.
Strings: A number of PV panels connected in a series circuit represent a “string”. The maximum number of panels in a string is determined by the Open Circuit Voltage at the lowest temperature selected. The minimum number of panels in a string is determined by the Maximum Power Voltage at the hottest temperature selected.
Module Open Circuit Voltage: This is an electronics term for the voltage between two points when they are not connected by a load circuit. This is typically the greatest amount of voltage that can be provided by a circuit to these two points.
Module Maximum Power Voltage: This is the operating voltage point where a solar module delivers maximum power. The Maximum Power Voltage changes primarily with sun intensity and cell temperature. A grid supplementing inverter has a maximum peak power tracking routine which tracks the changing Maximum Power Voltage throughout the day.
Module Short Circuit Current: This is an electronics term for the current between two points that are connected by load circuit with zero resistance. This is the greatest amount of current that can be delivered by a circuit.

Calculation Method All of the above terminology is essential for understanding how to matching a solar array with an inverter. The inverter will only operate when delivered a specific voltage and voltage varies significantly with temperature. Therefore, it becomes essential in solar engineering and design to understand the temperature variables in a specific location plus the electrical characteristics of the products you will be using. The solar array minimum and maximum voltages are calculated as follows:



Vmin=XSeries*(Vmp+(Htemp+∆V-25°C)Vtemp) Where:

Vmax = Maximum temperature adjusted open circuit voltage encountered
Vmin = Maximum temperature adjusted open circuit voltage encountered
XSeries = The number of modules in series
Voc = Open circuit voltage of the module, experienced by the array is subjected to sunlight or just before the inverter is starting, also known as the no-load voltage.
Vmp = Maximum power voltage of the module. This voltage exists when the array / inverter is operating and producing power in ideal sunlight conditions.
Ltemp = The design minimum temperature experienced in daylight conditions
Htemp = The design maximum temperature experienced in daylight conditions
∆V = The change in temperature between ambient temperature and sunlight soaked solar modules
Vtemp = The solar module manufacturer’s voltage drop due to temperature (expressed in V/ºC)


If you read this far you deserve a free Blue Oak Energy t-shirt!


Solar Health and Wellness

As an incentive to keep its employees in good health and top physical condition, Blue Oak Energy offers a health and wellness program, complete with an online exercise tracking service and monthly prizes. Blue Oak’s receptionist Victoria Adams manages this program and performs regular tracking and encouragement, which assists staff in their quest for maintaining optimum health, mental stamina and physical condition.

Our company-wide exercise tracking software provides Blue Oak Energy employees with a running record of health and wellness statistics, such as recording the number of miles jogged and routes taken by employees while running, jogging or walking. Employees can track food consumed and calories burned while exercising. Exercising goals can be set by employees with this online health and wellness tool. It can even suggest workout plans, based on these goals.WELLNESSBANNER

Adams said additional incentives are added for Blue Oak Energy employees with monthly prizes in five categories. To keep things interesting, the prize-winning categories change from month to month. For instance, for the month of January 2014, prizes were handed out to the Blue Oak Energy employee who exercised for the most overall days, the employee with the longest exercise event, the most consecutive days of exercise by an employee, the most unique event and the most active employee.Staff Ride 6-8-11

February 2014 prize categories include the most improved employee from the prior month, the employee with the longest single activity, the one who put in the most consecutive days of exercise, she or he who registered the most difficult exercise in one day and the employee with the most days of exercise, overall. Several wellness-friendly prizes are handed out. Winners choose from items such as Camelbak hydration packs, Ultimate Pro workout kits and Foot Locker gift cards to hiking backpacks, as well as bocce ball sets and Jamba Juice gift cards.

The main incentive of Blue Oak Energy’s health and wellness program is to encourage staff to get outside and exercise—to perform activities that they would not normally experience, break outside their comfort zone and think beyond their normal limits. Sometimes, the activities occur at work. Adams says twice a month an activity is planned, such as a bike ride or a lunchtime walk.

Other health and wellness privileges include discount gym memberships, monthly newsletters, along with a bulletin board detailing upcoming running, walking and interesting exercise events in the community.

Adams feels that the health and wellness program is just one more reason why Blue Oak Energy is a fantastic company to work for.

“We know that our ability to physically challenge ourselves and reach goals is directly related to our ability to meet and exceed our mental challenges as well,” said Adams.