Renewable Energy Monitoring Systems – The Next Big Thing?

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

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!

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