Sentient Energy: smart grid breakthrough?

This data-file is a technology review for Sentient Energy, assessing innovations in smart grids. Its technology can achieve energy savings via a combination of “Conservation Voltage Reduction” and “Volt-VAR optimization at the grid edge”. This also helps to integrate more solar and EV charging into power grids. We will explain the technology below and in the data-file.

Sentient Energy is as an “intelligent sensing platform for grid utilities”, helping power utilities to identify and remediate grid issues. It has “the largest mesh network line sensor deployments in North America”. It is a private company. It was founded in 2009, headquartered in Frisco, TX and employs around 150 people. Its products are used by over 25 of North America’s largest utilities, and have helped reduced outage time by 20%, patrol costs by 60% and clocked up 1bn+ intelligent sensor hours in the field.

Volt-VAR optimization at the grid edge is the focus in about one-third of Sentient’s patents, and the focus in our technology review. So what does this mean?

Why does Volt-VAR optimization matter? Imagine a group of houses, all connected to a single grid loop. Nominally, all of them “draw power at 120 Volts”. But in practice, voltage falls off slightly, as you get further from the sub-station (look at the green dots in the chart below). This is because the inevitable creation of electro-magnetic fields “consumes reactive power” (VARs). Park this thought for now.

Sometimes the grid is strained, power prices are very high, and there is a risk of load-shedding. In times like this, it is common for a utility to save energy via “Conservation Voltage Reduction”. If you remember that Power = Voltage x Current, then clearly you can save power by lowering the voltage at the sub-station by 1-5%. It might take a little bit longer for the kettle to boil. But basically nothing is going to break.

What limits Conservation Voltage Reduction is that there is a minimum acceptable voltage. No customer should see their voltage fall below this level. And thus in our image below, we can only lower the voltage at the sub-station by 4 Volts before the ‘pink dots’ below, which tend to be customers furthest from the sub-station, hit the lower limit. But most of the time, a utility is simply guessing here. It has data about the sub-station, which it owns and operates. But it may have hardly any data at all about what is happening downstream of the sub-station.

Technology review for Sentient Energy

Enter “Volt-VAR optimization at the grid edge”. The idea is to place dozens of smart optimization devices around the grid. They can detect the voltage in real time, and they can “inject reactive power” to boost voltage at the critical places where voltage is becoming unacceptably low. There have been several studies and over 10,000 deployments of these devices to date. They can typically increase the power savings during Conservation Voltage Reduction by 2-3x. I.e., during times when power grids are under-supplied, total energy savings of 3-5% can safely be achieved, by safely lowering the sub-station voltage, almost imperceptibly for customers.

This also helps smooth the volatility of solar. One study has shown a 72% reduction in voltage volatility from installing a swarm of grid-edge optimization devices. In turn, this kind of improvement in a grid’s ability to tolerate voltage fluctuations can unlock something like 45% more solar hosting capacity. If smart inverters and dynamic voltage controllers are employed together, than the solar hosting capability can be improved by 60%.

Related research, which may be helpful in explaining the terminology in this short note includes our overview of how power grids work, overview of reactive power compensation, long-distance power transmission, transformers and how hot temperatures strain power grids. We think optimization of the power grid is going to be a $1trn pa opportunity in the energy transition.

In conclusion, our technology review for Sentient Energy finds 3-5% energy savings and great solar penetration can be achieved using smart energy systems. Our assessment on Sentient Energy’s technology, the moat in its patents, and further data-points gleaned from its white papers can be found in the data-file below.

Copyright: Thunder Said Energy, 2019-2023.