Month: April 2017

Carefree Operations and Maintenance – Part 2 – Less Is More

Carefree Operations and Maintenance – Part 2 – Less Is More

Carefree Operations and Maintenance - Part 2 - Less is More

By Sun Action Trackers

In Part 1 of our Carefree Operations and Maintenance series, we discussed Land O&M and various solutions to lower costs and minimize financial risk, while maintaining an “eco-friendly” approach.  In Part 2 of our series, we will be discussing the complexity of system designs and how they affect your overall O&M costs over time.  There are a wide variety of issues to take into account when evaluating O&M costs during the lifecycle of your project.  These issues could include such variables as system design, environmental variables and materials used in the project.  In this article we will be focusing on System Design.

Keep it Simple Solar (KISS)

In previous articles, we have mentioned this approach which we have found to be most effective when tackling O&M costs over time.  By focusing on hyper-simple design, O&M costs of systems designed by major manufacturers are getting lower and lower as systems become more refined and efficient.  Though approaches vary widely, there are a number of innovative designs and options for your project.  Sun Action Trackers’ PST-1AX6 Single Axis Solar Tracking solution highlights a number of innovative additions to lower O&M costs initially and for the lifecycle of the project.

Linked vs. Independent Row Designs

Linked Row Solar Arrays or “centralized tracker designs” move multiple rows of solar trackers with a single motor or actuator, whereas Independent Row or “decentralized tracker designs” require 1 motor or actuator per row.  Though the decentralized tracker designs offer some flexibility for land usage, the centralized tracker systems are much more efficient with 25% of the moving parts than its counterpart.  Less moving parts lowers the potential for system failures, while also requiring less time to maintain the system overall.  In many cases, linked row systems will also require “leveling” of each row to allow the systems to work.  The Sun Action Trackers’ PST-1AX6 single axis solar tracker however does not require grading or leveling to make our system work properly.

Figure A

Replaceable Parts

Linked row and independent row systems also differ greatly in the number of motors that are needed to make the entire system.  Figure A highlights an 800Mw project using 8 actuators to run the entire system vs. 28 motors on the independent system as each row requires its own powered motor.   Each row also requires its own control box and sensor opposed to the linked row system that uses 1 control box and sensor for every 6 rows. This means a significant increase of energy usage to use the tracker system, and more moving parts to replace and fix moving down the road.  As another question, Which do you think would require more operations and maintenance attention?  1 actuator and 1 sensor, or 6 motors and 6 sensors?

Figure B

Ground Mounting

Even before tracker construction can begin, the pilings must be poured and secured before steel construction can begin.  Figure B illustrates linked row systems vs. independent row systems.  As you can see, the linked row system only requires 48 pilings per 100 Kw compared to 56 for the independent row system.  This makes a difference in future foundation maintenance and installation time.

Key Takeaways

When it comes to single axis solar tracking: Simple is King.  By limiting replaceable parts that could potentially fail during design and engineering, you will ultimately lower your Operations and Maintenance costs across the board.  Minimizing points of failure is going to lead to a system that consumes less energy thus maximizing total production of the system.  If you want to make your project more efficient, KEEP IT SIMPLE SOLAR.

Posted by Jonathan Bunting in Actuator, component, components, control box, Products, real time sensor, single axis solar tracker, solar tracking, 0 comments
Carefree O&M – Part 1 – Count Your Sheep

Carefree O&M – Part 1 – Count Your Sheep

Carefree O&M - Part 1 - Count your Sheep

By Sun Action Trackers

As Operations and Maintenance becomes a hotter topic in the Solar and Solar Tracking industry, there has been many approaches to lower costs and minimize risk in the design and installation of solar farms.  There have been a wide variety of approaches in each area of solar farm O&M costs and savings.  In this article, we will discuss a practice that is becoming more common amongst utility scale solar farm developers across the country.

Options for Land Operations and Maintenance (O&M)

During the development of utility scale solar farms, there are so many operational parts in motion that if the land had not been graded and trampled, that it will be before the installation is done.  The sites are often left looking bare and lacking grass as the project installation heads near completion.  Not too far after however, mother nature takes over and grass starts growing and spreading quickly.  This creates the need for landscaping services and workers to maintain the acres and acres of property to ensure proper functionality of the system.

The Old Fashion Way

Many developers choose to periodically mow the property which takes multiple days and workers, while creating risks that need not be created.  Some of the inherent risks include but are not limited to:

  • Flying Objects – While mowing properties this vast, it is likely that at some point something will be struck by the mowers. This could be something natural such as a rock, or something left behind from development such as a nut or bolt.  This creates a risk to workers, but also to the solar farm itself, by cracking or shattering panels that then would need to be replaced.
  • Dust/Sand – Mowers also kick up quite a bit of dust no matter what the condition of the soil and property is. This sand and dust settles on the panels, making them less efficient and creates the need for the panels to be cleaned more frequently.

Though this method is widely adopted many developers are looking for alternative methods to lower O&M costs and to minimize financial risk on each project.

Genetically Modified Flora

One of these alternative methods is to plant “low growing grass” which has been genetically engineered to grow to a certain height and stop.  This method has proven to be effective in some areas, but the major drawback is weeds.  As the grass grows, weeds become an inevitable part of the landscape.  Since the weeds will never stop growing, this again creates the need for human intervention on a constant and continuous basis causing a hike in O&M costs. Another option in modifying the landscape is using herbicides and chemicals to keep the grass and weeds at bay.  This option works but it is contrary to the “eco-friendly” passion that renewable energy harvesting is based on.  Though this may be a viable solution, it creates risk to the environment and surrounding areas.

Keep it "Simple Solar" (KISS)

The simplest solution in solar is usually the best.  Systems are designed with minimal moving parts and are highly engineered to maximize efficiency and lower O&M costs.  Why wouldn’t you look for the simplest solution when it comes to land O&M costs?  Many solar farm developers from California, Texas, North and South Carolina and even Europe are adopting a simple and hyper-effective solution that is lowering land O&M costs and providing opportunities for the local economy and is completely eco-friendly.

Send in the Sheep

The aforementioned solution that has been adopted globally is the use of livestock, preferably sheep to maintain your land for you during the harvesting of your solar energy.  Sheep are low maintenance requiring only water and food, which is the growing grass in most solar farms.  States like California and North Carolina have widely adopted this solution and are showing incremental decreases in land O&M costs, while creating a thriving industry for farmers in the local economies surrounding their solar farms.  In North Carolina, there are sheep farmers that will even offer their flock for free for use at the solar farms in return for the free food that their flock consumes.

Environmentally and Financially Symbiotic Relationships

Not only is this method environmentally friendly, but it also creates more revenue through shared resources and legal loopholes.  In many states developers are charged an Energy Tax for the land usage, whereas agricultural land is not subject to the same taxing.  This creates a revenue increase from the partnership between farmer and developer.  It also saves the farmers money due to a seemingly unlimited food source.  The marriage between farmer and developer is truly a symbiotic one as both parties have much to gain, while also lowering costs on both sides.  On the environmental side, both parties are allowing nature to run its course while causing no harm to the land or the surrounding areas.  It also allows the developer to “cut the cord” of reliance on fossil fuels for land O&M, which we are sure that mother nature welcomes.

Not Just a Developer Farmer Relationship

Since the development of these relationships major brands have gotten involved bringing the process full circle.  Whole Foods, a national organic grocery market started selling “solar farm sheep” when it started selling lamb chops of sheep that had been exclusively raised on Solar Farms.  Sun Raised Farms is the name of the company that landed the opportunity with Whole Foods, providing their lamb chops exclusively for the nation’s healthiest supermarket.  The buying motivation for Whole Foods is that the sheep are essentially free range, raised organically in expansive open spaces.

Key Takeaways

Many of the solar farm developers in North America are beginning to use sheep to graze and maintain their solar farms.  The sheep are low cost and even free in some cases, creating a relationship between farmer and developer where everyone wins.  Financially it makes sense to use sheep as there are available tax breaks, unlimited food for the animals and no need to O&M risks by using machinery, human labor, and chemicals.  In Solar Energy Harvesting, simplicity is key to lowering O&M costs and minimizing risk.

Posted by Jonathan Bunting in Community, home news, Products, Residential Solar Trackers, solar system benefits, solar tracking, 0 comments