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We deliver real-world energy solutions today to build a sustainable tomorrow. - See more at: http://www.blueoakenergy.com/blog/#sthash.XOerM0Fn.dpuf

We deliver real-world energy solutions today to build a sustainable tomorrow. - See more at: http://www.blueoakenergy.com/blog/#sthash.XOerM0Fn.dpuf
We deliver real-world energy solutions today to build a sustainable tomorrow. - See more at: http://www.blueoakenergy.com/blog/#sthash.XOerM0Fn.dpuf
We deliver real-world energy solutions today to build a sustainable tomorrow. - See more at: http://www.blueoakenergy.com/blog/#sthash.XOerM0Fn.dpuf

Optimizing Utility Solar and Commercial Solar through LCOE

February 19, 2015

Have you ever assumed that trackers weren't worth it in the Mid-Atlantic?  Have you ever requested no shading from 10am-2pm because it has always been the convention?  Have you ever specified a 1.3 or 1.4 DC-to-AC loading because… well, who knows why?  While these conventions will get your commercial solar or utility solar array in the ballpark you’re likely leaving money on the table by not optimizing your array.

Through its experience providing solar design of some of the largest arrays in the nation as well as its experience installing commercial solar arrays, Blue Oak Energy has developed a simple method to compare the upfront cost impacts of solar design changes to the long-term effects on  energy production and revenue.  Blue Oak Energy has successfully used this method to narrow in on the right solar design such as tilt, spacing, and size for a space-constrained array, the right racking or tracker technology for an array in a mid-latitude area of the country, the right spacing for trackers, and the right inverter loading ratio for countless arrays.

The optimization begins by developing an indicative cost for the array broken into approximately 200 categories.  Each category is then analyzed to determine what effect a change in a particular variable has on the overall cost.  For example, adding modules may affect 100% of the cost of DC output-circuits, 0% of the inverter cost, and 40% of the medium voltage collector cost as the array grows in one direction and not the other.  With the baseline cost and the amount that varies according to a variable, array prices for dozens of scenarios can be created and energy models executed for each through new options in PVSYST 6.

Blue Oak Energy primarily uses a Simple Levelized Cost of Energy Calculation (sLCOE) as the metric for evaluating the optimal solar design.  It considers the combination of capital costs, operations and maintenance (O&M) costs, and performance and in doing so provides value of the energy over the life of the system. This simple LCOE does not include many complexities of how a client may value a project but does work as a relative indicator of project optimization versus other scenarios.

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Sample Cost and Relative Sensitivity Summary for a Utility Solar Array

When comparing the change in a variable to LCOE Blue Oak energy typically finds a clear optimum as expected. Moreover the optimum is fairly robust.  While variations of 15% or more in fixed cost, O&M, or other variables can move the LCOE of all cases up or down, the point which is the optimum remains constant.

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Sample LCOE Optimization

The example below shows an optimization of a commercial solar or utility solar array in a specific location to determine if it is better to install more modules on in a particular space constrained area and sacrifice production or if it is better to install fewer modules, each performing better.  Aside from the pitch optimization, even just picking the wrong tilt could have resulted in an increase in LCOE of 30%!  That’s a lot of money left on the table.

 

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