May 29, 2024

The high cost of shade: quantifying the benefits of module-level optimization

We built a tool that calculates solar optimization benefits over time
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The high cost of shade: quantifying the benefits of module-level optimization

The Mismatch Menace

Shade and other forms of mismatch are significant factors impacting the performance of rooftop solar installations. Shading is a common issue, especially in rooftop settings where trees, nearby buildings, chimneys, HVAC units, can cast shadows that partially cover modules at certain times of the day or year.

The impact of shade varies significantly. For instance, even a small amount of shading can cause a substantial drop in energy output, depending on how modules and their bypass diodes are configured​ (GlobalS&P Report)​. These losses are like a continuous leak in your energy production. Although it may seem small, the value of lost production can add up to enormous sums over a solar project's 25+ year lifetime.


Tigo TS4-X-O Flex MLPE installed on a solar module

The Solution: MLPE (Module Level Power Electronics)

Systems that incorporate optimizers (a type of MLPE) can address these mismatches by allowing each module to operate independently, thus minimizing the impact of underperforming panels on the overall system performance. The impact of optimizers varies depending on the levels of mismatch at the site. For example, Aurora Solar, which specializes in PV production modeling, has quantified examples of DC optimizers increasing output from 5.5% to 17.3% here and here.​Tigo data shows a similar range across our fleet of installed systems, which average about 7% increased energy production. Some sites are less, some are more, even exceeding 20%. At Tigo, we call this increased production ”Reclaimed Energy” and show it for each site in the Tigo Energy Intelligence (EI) portal.


The Tigo Energy Intelligence (EI) portal showing Reclaimed Energy in green on the stacked bar chart

What’s Reclaimed Energy worth?

Compound interest is the eighth wonder of the world. He who understands it, earns it; he who doesn't, pays it.” –Albert Einstein (maybe)

Getting the benefit of Reclaimed Energy from a solar installation is like earning additional interest from the site every day the sun shines. However, it’s hard to grasp how much the benefits can add up overtime - especially because the annual benefit increases over time as utilities charge ever-increasing electricity rates in the future.

So, we built a tool to make it easier to visualize and adjust – it’s called the Solar Optimization Benefits Calculator. Here are some examples with benefits over 25 years:

Location Application Size (kW) Electric Rate ($/kWh) Capacity Factor Reclaimed Energy Total Benefit Benefit per Watt
Germany Residential 8 $0.40 13% 7% $12,174 $1.52
CA, USA Residential 10 $0.33 20% 7% $19,315 $1.93
TX, USA Residential 15 $0.14 17% 7% $10,448 $0.70
Italy Commercial 50 $0.20 17% 5% $3,537 $0.71
UK Commercial 100 $0.16 11% 5% $36,791 $0.37


As you can see in the results and assumptions, the value of electricity, % reclaimed energy, and capacity factor all have significant bearing on the value per watt. Full definitions and assistance for finding each of of the input assumptions are available inside the calculator.

The Solar Optimizer Benefits Calculator - plug your custom info into the tool and immediately see the results.

Value for solar EPC’s and installers

Opponents of optimizers will claim 10-15c/W savings as they chase the lowest possible cost per watt. Yes, that can enable a cheaper overall install, but forgoing optimization can reduce savings by 10x more than the costs that were ‘saved’. The decision to focus purely on up-front cost minimization can significantly hurt the overall returns of the project.

Understanding and deploying MLPE technology effectively can set you apart in a competitive market, offering your clients not just solar solutions but optimized solar solutions that promise maximum returns on their investment.

Moreover, the ability to offer enhanced safety features, such as rapid shutdown capabilities provided by MLPEs, adds another layer of value to your services, ensuring that installations are not only efficient but also adhere to the highest safety standards.


Closing thoughts.

He (or she) who understands how this value will accrue overtime will earn it. That’s what this optimization benefits calculator is all about.

If you’re interested in learning more about Reclaimed Energy or Tigo products that enable it, there are a bunch of resources including research reports and videos below the calculator on the same page here.

If you’re looking at a project today, get in touch with a member of the sales team here.


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