Voltage management: technology that can optimise solar PV usage

Regulating voltage to prevent spikes can significantly improve the performance of residential solar panels and domestic appliances.
Published: Wed 08 Aug 2018

The uptake of solar photovoltaic (PV) systems is increasing on a global scale.

An ever-growing number of customers is eager to convert to residential solar PV installations as a way to lower their energy bills, sell excess energy generated back to the grid and reduce their carbon footprint.

Evidence of that is shown in the figures of PV installations - for example, the UK reached 1.5m panels installed in 2018.

In addition, in Australia, 3.5m solar panels were installed throughout 2017, bringing a power capacity equivalent to one medium coal power plant.

The country reached a record 1,057MW of capacity in small-scale systems.

"The solar revolution is happening very quickly,” says Richard McIndoe, Executive Chairman at Edge Electrons.

“We've seen rapid uptake of solar in Australia over the past 10 years.

 

"We've seen the closure of a number of large coal-fired power stations and greater uptake of solar in the residential level than anywhere else in the world. Close to 30% of Australian homes now have solar panels."

However, this surge in solar PV uptake also has significant effects on the grid in terms of grid stability, maintaining voltage levels and frequency levels.

In an Engerati webinar, ‘Selling solar services: How voltage regulation optimises rooftop investments’, Richard McIndoe talks us through the major issues experienced by network operators and customers alike concerning controlling voltage levels, and how Edge Electrons’ EdgeIQ platform can tackle these problems appropriately.

High voltage issues in the grid

According to McIndoe, voltage levels can fluctuate significantly throughout the day according to energy consumption.

"At 8 in the morning you can see the voltage start to move up. As more solar kicks in towards the middle of the day, the draw from the grid goes down but the voltage moves up above 260V,” he describes.

“This causes major problems for customers in terms of performance of the solar - solar panels run at significantly reduced efficiency when they run at very high voltages, just like any other electrical appliances.

"Electrical appliances consume significantly more energy when at higher voltages and they don't last as long."

The graphic shows the progression of voltage levels and power flow throughout the day in Australia.

This inability to regulate voltage levels thus causes considerable problems for customers, as they cannot make the most out of their solar PV installations.

When running on higher voltages, customers’ solar harvest can be reduced by up to 15% and their solar inverters may disconnect.

"The most efficient level of voltage to run appliances is around 225V,” explains McIndoe. “When we're running the grid at 250 or 260V in Australia, that's around 10% to 13% higher voltage than required. For every 10% additional voltage, customers are then being forced to consume more than 9% more kWh than required."

EdgeIQ - a solution to voltage issues

Edge Electrons has devised a solution to such problems in the form of EdgeIQ, a small-form device that contains a patented AC-AC voltage regulation technology.

“Essentially we read the voltage around 18,000 times a second on the network, and through a combination of electronics and software, we regulate that voltage down to a constant output of 220 to 225V,” explains McIndoe.

“It attaches to either side of the meter, so it can be a network device or a household device. It regulates the voltage into the house so that all the appliances inside the house only ever see that flat 225V. They operate more efficiently, they consume less energy and the appliances last longer.

“Regarding solar - and here's where the application is particularly exciting - it reduces the consumption of electricity in the house by 9% to 10%, but also, because the device is bidirectional, it allows the voltage to be stepped up again to go back onto the grid. If the solar exports, we can continue to export at the voltage level of the grid.

“The device isolated the house and makes it as efficient as possible from a voltage perspective and then any excess energy, if there's more solar generation available for the grid, is exported onto the grid.”

The device clearly also results in considerable energy savings for customers. “It depends on the tariff levels, but we see generally between 12% to 15% improvement in household savings. It generates value for the customers of around AUD$800 a year [around USD$ 590], which is a combination of reduced consumption at the appliance level, improved PV generation and the protection that this provides to the household by keeping its voltage at a constant level," says McIndoe.

Richard McIndoe, Executive Chairman at Edge Electrons, explains in detail the use cases of EdgeIQ to customers and utilities.

Controlling voltage - the utility perspective

McIndoe adds that EdgeIQ also presents significant benefits for the utility as well as for the consumer. For instance, its high operating speed means that utilities have at their disposal real-time, in-depth analysis of customer energy consumption.

"From a network perspective and a retailer perspective, there's a lot more interest in that granular data that we provide from each customer, both in terms of customer usage profiles and in terms of those technologies that lend themselves to peak demand management and appliance monitoring and control."

In addition, the device allows for a voltage management flexibility that can be extremely useful for grid operators. “The Edge IQ device helps networks manage voltage by stepping that voltage down to a flat 225V. However, the flexibility in the technology allows us to move voltage in real time up to 280V or down to 160 or 140V,” McIndoe explains.

“This particular application for networks is of great interest, because in the event of interruption of supply or issues in the grid, we have the ability to switch all of the household voltages down to below the regulated level."

The applications of EdgeIQ are not limited to solar installations, but the device can also be used to manage the voltage on battery storage systems. “By protecting the house at a constant voltage level, the battery performance is significantly improved and it reduces any events of voltage lockouts,” says McIndoe.

“In addition, for non-solar houses, the benefits are still strong. Savings from voltage regulation are still there and customers still have visibility over their consumption in real time, and by protecting the house and its appliances there is still an economic benefit for them to be protected from voltage surges and spikes."

"It’s all about putting the customer at the heart of the equation. What we're doing here is giving the customer more energy independence, ensuring that their solar and batteries perform better than previously and giving more visibility and control of the voltage at the utility level, given the current challenges in terms of integrating solar, batteries and distributed generation in the grid."

Watch the webinar

To find out more about how voltage management and control can benefit your utility, watch the webinar ‘Selling solar services: How voltage regulation optimises rooftop investments’, presented by Richard McIndoe.