Renewable Energy Monitoring Systems – The Next Big Thing?

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If micro-inverters are the current craze in the solar industry, then I predict that solar energy monitoring systems will be the next big thing.

Micro-inverters (and other parallel technology) are given lots of attention because they can increase the efficiency of a system by up to as much as 10%-20%. Similarly, solar electricity systems that are hooked up to monitoring systems have a 10% energy production increase over systems that are not hooked up to monitoring systems, according to Will Shortt, CEO of Deck Monitoring.

PV solar panels last at least 25 years, where as inverters only come with an 8-10 year warranty. That means that sometime in the 8-10 year range the inverter will die and the system will stop producing energy. With a monitoring system in place the installer or homeowner will know immediately that the system has been compromised. Otherwise it could be weeks or months before the homeowner looks at their energy usage statement from their utility company and realizes that their solar electricity system is not longer producing energy.

Monitoring systems currently cost around $1,000, which seems like a small price to pay for installers to be able to ensure that a homeowner’s system is working properly. With a monitoring system in place an installer could offer a “performance assurance”, and that may be just the differentiator needed to close the deal.

All California installers are required to give a 10-year warranty, but this might compel them to give even longer warranties. Similarly, it may motivate installers to offer warranties in other states.

Combine a warranty with monitoring systems and I can see how a solar installer could proactively call a homeowner to say that they’re going to drop by to clean the panels when they see the productivity drop rather than the other extreme of having a system fail for some reason, then have a furious customer calling because their $20,000 solar energy system has not been producing electricity for the past month. I’d much prefer to read stories on yelp about how great an installer is because they called a customer to say there was a problem that they were going to come out to fix before the customer even knew there was an issue.

Thomas Dinkel, CEO of SunReports said that SunPower, SunRun, Solar City, and Sungevity all offer monitoring with any systems they install, and therefore to be competitive with them other installers will likely start offering monitoring as well.

The most compelling feature of monitoring systems is the ability to measure performance against what was promised and what is expected of the system. Not only is it fun to see, but it also serves as a great indicator if something goes wrong with the system.

Lastly, when homeowners are able to view their solar energy production or energy usage in a clear, easy to view fashion, they inevitably will adjust their behavior and start using less energy, which is a great positive side-effect.

*Clean Power Finance recently hosted a webinar with SunReports and Deck Monitoring, which is where I learned much of what I just reported. However I’m sure there are other monitoring solutions out there, and I’d be interested in hearing about them too.

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8 Comments

  1. You may be onto something.

    Note, however, that an 8-10 year warranty for an inverter does not necessarily correlate with expected lifetime. In fact, there are also many modules with 10 year product guarantees – and some with 10 yr guarantees and 20-25 year production warranties.

    The majority of inverters should last well beyond the warranty period.

    Soiling is likely a more compelling reason to consider monitoring – especially when it can affect output by up to 30% and the solution to more energy is simple.

  2. Hi David,
    Great point. I would be very interested in seeing data on the actual lifespans of both traditional inverters and micro-inverters.

    We often hear talk of panels lasting well beyond their 25 year warranty, but I have not heard nearly as much about that being the case with inverters. Although it certainly could be the case. Similarly, I’ll be very interested to see how long micro-inverters last. Each one is dealing with a lower voltage, so maybe they won’t wear out as fast, although there are many more per installation, which means more chances for one to fail. Similarly, guys like eIQ Energy and Tigo and others are making parallel technology that supposedly evens out the voltage being sent to the central inverter and can help it last longer as well.

    I would be that some of the solar lease or PPA guys like SunRun or Sungevity might have data on that since they own so many installations, and therefore could potentially compile some interesting data on the field performance of their systems.

    Thanks for the comment!
    David
    President
    Residential Solar 101

    • David,

      I am writing for Building and Innovation magazine, set to be the first magazine in the United Kingdom to focus entirely upon innovation. The magazine is set to be read by over 10,000 decision makers such as architects and MDs. Our launch issue, early September, features contributions from Vince Cable, Minister of Business and Innovation, as well as the MDs of Technology Strategy Board and BRE Innovation Park.

      The unique aspect of this magazine is that it focuses upon innovation in the construction sector. Currently, I am trying to compile an innovation showcase which highlights new innovations set to have an impact upon the construction industry. I’ve read your blog with interest and was wondering where you found your information from? If you have any more details about the technology, would you be kind enough to send me details to philip.jordan@finitecommunications.com

      I would be very grateful for any information you could send me. Keep up the good work!!!

      Thanks for your help,

      Philip

    • Hi David,

      It would be great to get more “data on the actual lifespans of both traditional inverters and micro-inverters”.

      – And thanks Bert, for the great discussion on failure issues.

      There are at least two things we need to look at with micro-inverters – population impacts as well as the potential for micro-inverter induced module failure.

      1. Population impact

      One of the arguments that is being provided to promote micro-inverters is that there is reduced risk of (catastrophic?) failure by having a distributed architecture. Yet the likelihood of a failure at a specific site is actually higher due to the higher population. (if the failure rate is 1%, then the likelihood of a unit failing is 1%, but the likelihood of a single failure within a population of 100 is 100%.)

      At any given time, there may be multiple failing micro-inverters in a single installation. This may only affect a small portion of the system output at any given time, but it does not necessarily mean that the system will have higher output or lower maintenance costs. The maintenance costs of continual service may be much higher than dealing with – the small likelihood – of a single catastrophic failure with a central inverter.

      2. Influence of micro-inverter on module lifetime

      Since the micro-inverter is a heat source that is in direct – and non-uniform – contact with the module, it may represent a potential for induced module failures. It would be interesting to see lifetime data on this potential impact.

      Summary:

      Rather than being ‘better’ than a central inverter, micro-inverters may well be inferior on average. But, the simplicity and convenience factor may outweigh robustness advantages of a central inverter – particularly for residential installations. Even so, it would be nice to have a bit more data on this.

      Regards, David (http://d-bits.com)

  3. When PVpowered sold to Advanced Energy for a 4-1/2 multiple of sales it became clear that the market values reliability. However, warranty periods do not equal actual operating service life. It may be longer, it may be shorter. It’s a law of averages for the mass producer, insured by expensive product liability policies, which have little data to go by, as of today.

    Neither does MTBF translate into actual operating life in a complex, high-stress environment. A calculation determining Mean-Time-Between-Failures, it is a great engineering tool to compare similar design next to each other under the same operating assumptions. Assumptions. None does justice to the fact that operating conditions and human sloppiness can lead to fatal compromise of the power system. Sandia National Laboratories has published a report in 2008 that studied numerous failure mechanism for inverter failure – in the field. Albeit progress has been made, at the expense of $/W, NREL has also published statements made by leading brand inverter manufacturers that conclude that it is not economically feasible to extend the theoretical, average, life of the inverter much beyond 10 years. Inverters are the second most expensive cost item and the heart of the system that convert power from the solar panels to power our grid can readily accept. The cost of “congested heart failure” in the solar power domain comes with an expense of an average of $1,000 per service call – the word on the street at the Solar Power International conference, with respect to large commercial and utility-scale solar applications. This could put OEMs in a disadvantaged position, satisfying response time commitments stipulated in Power Purchase Agreements – under stiff, 5-digit penalties for their customer, the energy service provider. While the micro-inverter market is clearly addressing consumer needs for scalability, control, and incremental cost, and come with monitoring features, the bulk of the global market (77% commercial, 15% utility scale by New Zealand’s Ministry of Economic Development), is much concerned about maintenance costs over the (20-year) life of the solar plant. So is monitoring the next big thing? That depends on the application and its actual ability to reduce cost, so all of us can afford green power. It does become a critical component of the Balance-of-Systems in large installations. While monitoring today reports catastrophic events after the fact and may limit loss of revenue, we believe that failure prediction rather than failure reporting is the key to economic significance. This has been successfully demonstrated for decades by oil&gas and energy firms, such as Schlumberger, GE, and ABB, demonstrating Condition-Based Maintenance effectiveness in the operation of large scale energy production plants. Until now, this technology has been limited to mechanical and electro-mechanical power systems, such as cooling pumps, pipelines, transformers and wind turbine generators based on gear-box designs. infiniRel has developed fundamental signal-processing know-how to transform this known practice to power electronics. This impacts Billions of Dollars in unexpected maintenance costs. In June, Dell took a reserve for $100 Million Dollars because of bad capacitors in desktop and server power supplies. That is avoidable – but only in high-rel, high Dollar applications it is affordable. Capacitors are the buffer to safeguard more sensitive electronic components. Higher reliability capacitors can be as much as five times as expensive and yet exhibit their own temperature sensitivities – and only addresses one in over 30 failure mechanisms in the life of the inverter. Smart Sensor technology can distribute the cost across all inverters, plants, in any given service territory. The Law of averages at work in our favor. When Dallas Emergency Services have placed ambulances at the most likely time and place of reported past incidents, their response times have gone down dramatically! The same concept applies to solar emergencies. Failure prediction, similar to a check-engine-light in an automobile, can offset emergency costs, as anyone would attest to after being stranded far away from home.

    During the translation from potential maintenance cost savings to $ per kilo Watt hour (kWh) of energy produced, it makes a huge impact on the profit margins of energy service providers, operating at a fraction of a cent per kWh – let alone the de-risking of subsequent damages of unexpected failures. That’s big!

  4. Interesting concept and discussion – I’ve spent a lot of time researching alternative energy and the options that it provides for both consumers and businesses. As someone passionate on the topic, I find that monitoring energy use is one of the most important pieces in a “green” transformation. Many of us are still in the dark on how much energy we consume, and those of us making the leap into photovoltaic technology can still continue to decrease our energy use by being more aware of what we utilize. The opportunities with this type of technology are endless! To increase awareness of energy use, we’re having a sweepstakes for the month of September where we are giving away a free TED 1001 Energy Meter. If you’re interested check it out.

  5. Hi Dave,

    You are right it is already a big thing. The gosolar website lists no less than 80 monitor service providers.

    What is important though, merely reporting how many KW or KWh being produced is

    not enough. Average Joe can’t tell if the system is working well, or under-performing.

    A sufficient monitoring service should tell how well a system is working, and

    perhaps offer some diagnostic information when something is wrong.

    I encourage you to dig deeper.

    -Steve

    • Hi Steve,

      I certainly agree with you. My understanding is that both Deck and Sun Reports, the two monitoring companies I mention, are actually tools for installers, not for homeowners. Therefore both have “alarms” and the like since they will be monitoring tens, if not hundreds or thousands of installations at once. It would require a whole lot of manpower to comb over reports for 100 installations daily to be sure all are working properly. Whereas with their alarms and notifications and installer won’t have to look at a customer’s specific reports unless something has gone wrong.

      As for the customer facing monitoring, I don’t know if tools like the TED Energy Meter and the like have any sort of alarms built in, or if they just present the data in a pretty way and you have to then decide what you want to do with that data. Mark T, any idea?

      Thanks for the comments.

      -David

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