a guide to solar monitoring approaches (part 2 of 2)
TRANSCRIPT
Part 2: Good Cop, Bad Cop;A Guide to Solar Monitoring Approaches
(Part 2 of 2)
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Overview
In Part 1 of Good Cop, Bad Cop; A Guide to Solar Monitoring Approaches we defined solar plant monitoring
and two approaches; inverter-integrated monitoring and inverter-agnostic monitoring. Part of this
exploration was to pinpoint which data is needed to truly understand how well a solar plant is performing.
We wanted to better understand what functions are needed to maximize return on the solar investment.
In this Part 2, we will further explore data and diagnostics and discuss the extended role that monitoring
solutions will play in the not-so-distant future.
Content
Data and Diagnostics 6
Future of Monitoring 6
Conclusion
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Data and Diagnostics
A granular monitoring system can greatly reduce O&M costs by remotely pinpointing problems that would
otherwise go unnoticed or that would require costly site visits to identify. Identifying a problem quickly
allows field technicians to go directly to the problem area with the right tools and equipment.
Which factors truly affect the output and return on solar investment?
While inverter failures can be the source of yield loss, there are a number of other factors that could
negatively influence solar plant power production. Additional factors include cable damage, installation
errors, shading, or dirty modules. These types of errors are difficult to detect without a professional
monitoring device. According to GreentechMedia, although a significant portion of solar PV projects
currently have a monitoring system in place, few are synced in real-time with diagnostics tools. Plants might
have a basic monitoring platform in place but many factors can cause plant underperformance. Detailed
performance insight inclusive of all onsite components can make the difference between making money
and losing it.
Performance Analysis Examples
Figure 1: String level issues due to panel diode failure
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Figure 2: Temperature increase causing performance drop
Neutral and inverter-agnostic platforms like Solar-Log® aggregate substantial data from multiple devices
and display it in easy-to-analyze charts and graphs. We commonly refer to Solar-Log® as the Bad Cop:
the system will tell you when your plant is performing well, but more importantly, when there are issues.
However, advanced monitoring can provide an excessive amount of detailed performance data. Analyzing
and pinpointing failure areas can be tiresome and an O&M team can be easily overwhelmed. Missing
key information is an easy mistake to make. Inverter-agnostic monitoring manufacturers specialize in
developing ways to detect these solar plant errors and report them, as quickly as possible, in a prioritized
view.
Figure 3: Fleet view on Solar-Log WEB Enerest™ 4.0.
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Future of Monitoring
Simple and basic monitoring has become a commodity. As solar is not maintenance-free, inverter-agnostic
monitoring systems need to offer much more than data logging. Ensuring minimum outages and downtime
with a continuous incident management platform is just the beginning.
As incentives decrease or change, consuming solar power becomes more valuable than feeding-in to
the grid. This shift creates a even stronger use case for additional array components including batteries,
consumption meters, smart relays and plugs. Inverter-agnostic monitoring platforms are in an ideal
position to track and control devices from varying manufacturers. Energy control technology provides a
way to optimize the use of self-produced power. Inverter-agnostic monitoring platforms will ideally be
able to monitor performance, production and consumption, and control usage based on the production
forecast. Having all of these features and future solutions in one system is one of the reasons why
companies select an inverter-agnostic option.
In the Global Energy Storage Outlook 2019 report, Wood Mackenzie Power & Renewable’s projects that
storage deployments will grow from a 12 gigawatt-hour market in 2018 to a 158 gigawatt-hour market
in 2024. A solar plus storage solution is an excellent way to future-proof the plant owner’s investment,
even after the death of net-metering. Making use of self-produced power eliminates the need to purchase
electricity from the grid, and therefore increases solar plant ROI.
Disparate inverters and varying devices create a headache for solar O&M providers when it comes to
monitoring their customer’s assets. Performance monitoring matched with storage monitoring and control
provides a complete picture of what is happening with the solar plant. The operator can determine how
and when it makes the most sense economically to use, store, or distribute power with detailed insight
views on energy flow.
Figure 4: Example of solar plus storage visualization on the Solar-Log® monitoring platform.
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Active and reactive power management will be a big topic in the upcoming years as a way to maintain grid stability.
According to the SEIA/Wood Mackenzie Power & Renewables U.S. Solar Market Insight™ report, total
installed U.S. PV capacity will more than double over the next five years. An increase in installed solar plants
of course means an increase in energy production. An increase in energy production can mean more grid
issues. Managing the increased energy production will be critical.
Power management creates a dynamic platform for grid companies and smooth management of surplus
power. Most inverters installed are set to produce real power only (versus reactive power). This can be a
problem for commercial sites that have a poor power factor. If a solar inverter supplies only real power
then the power factor at the site may drop significantly. This not only causes voltage regulation problems
at the site but could also trigger utility penalties or surcharges. Balancing active and reactive power along
with power factor control enables more operating flexibility and increased system reliability. Power factor
control can benefit solar plant owners and operators by increasing load capacity and reducing power
losses, improving voltage and deferring upgrades.
Figure 5: Using a beer mug as a visualization for reactive power, active power and total system capacity.
How can Solar-Log® inverter-agnostic monitoring achieve active and reactive power control for solar plants?
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Controlling active power and regulating reactive power is typically a serious technical challenge. Most inverters
are not capable of dynamically injecting or absorbing reactive power in response to local voltage measurements
automatically. Solar-Log® creates a flexible solution for utility operators by providing a dynamic platform capable of
injecting or absorbing reactive power in response to local voltage measurements. The system can maintain voltage
levels within their normal ranges and improve efficiency through the addition of I/O’s and energy relays. Solar-Log®
allows grid operators to control the active and reactive power based upon generation, load and self-consumption.
This solution, in turn, balances power flow (active and reactive power) and provides power factor control during
high peak demand. Other functions such as the fixed value, cos phi shift factor or performance-related cos phi
functions can be implemented without additional measurements with the solution provided.
Conclusion
In general, the software sector is concerned with the automated and intelligent collection and evaluation of data
from a multitude of sources. The challenge is preparing this massive amount of data in a comprehensive way.
Whichever monitoring and energy management system a company selects, it should be innovative, flexible and
proven: innovative enough to improve efficiency, flexible to reduce costs and proven to increase performance. It is
important not only to give the customer hints about errors, but to also point out solutions. This allows daily busi-
ness processes to be automated and minimizes the efforts needed to ensure the health of the solar fleet.
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