“The whole is greater than the sum of its parts” may be a cliché — but it is apt for describing the principle of virtual power plants”

As more and more rooftop solar PV is built and connected to the grid, utilities are coming under immense pressure to maintain grid infrastructure and quality of supply, provide good levels of service and continue to expand the network’s generation and supply infrastructure as electricity demand rises, especially peak demand.

Virtual power plant technology turns rooftop solar and other types of distributed assets from the problem into the solution.

While networking and aggregating smart inverters connecting rooftop solar PV systems to the grid can provide grid support, such as voltage regulation and reactive power support, connecting solar-plus-storage systems can benefit the individual customer and provide unique grid benefits, such as peak shaving, frequency response and spinning reserves.

As these fleets expand, utilities can defer costly expansion works, be it new distribution equipment or even peaking plants. Everyone benefits, from the energy customer at the ends of the grid to utilities and operators, as investment in expanding the grid can be administered more cost-effectively.

Like conventional generation plants, a virtual power plant is always on and always available but is much more efficient and cleaner, as well as being less expensive.

The hardware in virtual power plants, such as solar PV, smart inverters, batteries, even loads — appliances and devices that use electricity such as heating and air conditioning units in demand response initiatives — are brought to life using advanced software, automatically dispatching and optimizing these hardware units that are linked to the wholesale power markets.

Elements needed for a virtual power plant include connectivity between the platform running the virtual power plant and the customer sites as well as computing power close to the devices being controlled, according to virtual power plant software vendor Enbala Networks.

With Enbala’s Symphony platform, the field devices are distributed computing nodes that interface with distributed energy resources, like solar-plus-storage systems, to optimize routines and relay information to the platform’s server. The server consists of three software components that serve different functions. One handles forecasting and optimization, another manages the distributed energy resources, and a third handles resource control and dispatch for energy market interface and interaction.

This market interaction is how virtual power plants derive their value.

By providing a comprehensive interface to grid operations and market systems, a virtual power plant opens up the means to incentivize customers to take part in the programme and generate revenues from market participation.

Virtual power plant technology should include, according to Enbala:

• A dynamic bidding and market interface that can provide market bids, forecasts and operational network information

• Evaluation of all available market opportunities and grid service requirements for the network

• Real-time measurement, verification and evaluation capabilities

• Support for web service interfaces

Cutting-edge virtual power plant software can deal with a mix of demand response loads and distributed energy resources of different sizes and descriptions. The technology needs to be robust and rapid enough to accommodate customer constraints.

The system understands the flexibility and ramping characteristics of each distributed energy resource or demand response load and dispatches them within customer-defined constraints as needed.