New Behind-The-Meter Data Guidelines Could Reduce Solar Export Restrictions

To integrate solar power into the grid more efficiently, the grid operators need to know what’s happening with your solar system. That means looking behind your meter.

With 9GW of solar PV installed, Australia’s enthusiastic embrace of household renewables is starting to bump into system capacity issues. As I wrote last week discussing the advent of the two-sided market, the time is coming where the energy sector will need to be able to reach behind the meter and manage the consumer-side resources such as rooftop generated solar electricity.

AEMO predicts that if we get it right, Australia could be generating as much as 45% of its electricity behind the meter – and to get it right, it’s clear that consumers’ supply assets (solar power, standalone batteries, and EV batteries) have to become more visible to the network.

What does ‘behind the meter’ actually mean? It means all the energy flows that happen in your house between your solar power system, battery and appliances. All the grid knows is whether you are importing or exporting to the grid. It has no idea how much solar energy you are generating, the state of your battery or even the voltage at your switchboard.

Vendors, industry associations, regulators, governments, generators and distributors, and universities have gathered to create “The Distributed Energy Resources (DER) Visibility & Monitoring Best Practice Guide” to help make what’s behind the meter more visible.

Project member and CEO of Solar Analytics Stefan Jarnason told SolarQuotes the project, which will go live at the start of May, is designed to establish what data from household PV systems is needed upstream by generators and distributors so vendors can put the telemetry into inverters.

Jarnason told us the genesis of the project was installers of quality systems were becoming frustrated at the number of low-cost, low-quality systems being installed.

“Installers want their customers to have both consumption data and system monitoring, so [customers] can see what they’re getting – and those companies last longer than people installing rubbish.”

The increasing desire from the network side to “see past the meter” created a good opportunity to bring lots of organisations together, he said. While the core of the group is ten vendors (GreenSync, Enphase, Redback Technologies, Edge Electrons, Fronius, Sonnen, switchDin, Tesla, Watt Watchers and SMA) plus Solar Analytics, the project had input from more than 50 organisations including network operators, regulators, industry associations, universities, and installers.

Jarnason said DER already helps maintain grid resilience.

“However, they could be doing a lot more.”

Since DER will become the biggest single generator on the network, it’s going to need to be managed just like every other generator.

“We need to see what [DER generators] are doing, and find the best way to orchestrate this.”

For example, he said, nobody knows yet whether DER needs to be managed in real-time or not.

Making the data available to the regulator will benefit everyone, he told us – including the owners. He said today some system owners find their PV export-limited to zero,

“because the generators and regulators don’t know what’s going on.”

 

“Ninety-nine percent of the time, DER can export at full whack,” stated Jarnason. “Only one percent of the time would they need to turn off completely to better support the grid – that’s clearly a better outcome for the solar owner.”

What the participants in the guide set out to create was to define the minimum data set needed to give regulators and grid generators the visibility and control they need. To get to the required data, the group first defined the use cases shown below.

Behind the meter data use-cases. Source: DER best practice guide

The required static and dynamic data fields defined in the guide are shown below.

Best practice guide – static data types. Source: DER best practice guide

Best practice guide dynamic data. Source: DER best practice guide

Optional static fields include:

• national meter identifier (NMI);
• AC connection ID;
• equipment details;
• equipment settings;
• device ID; and
• device details.

Optional dynamic fields include:

• site active/reactive energy imported/exported;
• DER active/reactive energy consumed/generated;
• battery SOC; and
• frequency.

The Money Question …

Having harmonised the data everyone needs or wants, Jarnason said, the other important question to answer is

“who pays for it?”

He doesn’t expect the costs to be too onerous, but there will be a cost – vendors who don’t gather all the data in the table will have to write the data collection into their firmware and get it into customers’ hands; the infrastructure (such as servers) to gather the data is another part of the cost; and so on.

Jarnason said contributors to the best practice guide represent about 80 percent of the market, and they recognise the

“need to be cautious about where that cost is imposed.”

The data collection capabilities in the guide will be voluntary at launch. Even so, Jarnason said between 40 and 50 percent of the market is already installing hardware that collects this data. The authors of the guide aren’t in a position to make the guide a standard, but hope that regulators will adopt the data set in the guide for their future standards.

That points to another important reason for getting the best brains together to create the guide: since visibility is mandatory for virtual power plants, and for retailers to create the right tariff offers, it’s better to work out what should be in a future standard than to have a standard imposed without input from the vendors and solar installers.