Electricity systems were traditionally designed around a relatively simple model.
Large power plants generated electricity, transmission networks transported it over long distances, and distribution networks delivered it to consumers.
That model is changing.
Solar installations, wind generation, battery storage, electric vehicles, flexible loads, and other smaller energy assets are increasingly becoming part of the electricity network.
Instead of electricity flowing only from large centralized plants toward consumers, modern networks can have generation and storage connected at different points across the system.
This broader shift has increased interest in distributed energy resources.
But distributed generation is not simply about installing smaller renewable plants.
It changes how engineers need to think about electricity flows, voltage, protection, control, forecasting, and grid integration.
What Are Distributed Energy Resources?
Distributed Energy Resources, commonly called DERs, are energy resources connected relatively close to where electricity is consumed or connected within distribution-level networks.
Depending on the system and definition being used, DERs can include:
- Rooftop solar
- Commercial solar installations
- Small-scale wind
- Battery energy storage
- Combined heat and power
- Flexible loads
- Electric vehicle charging
- Other controllable distributed assets
The important characteristic is that these resources are distributed across the electricity system rather than being concentrated in one large generating facility.
A distribution network can therefore contain multiple generation and storage resources operating alongside traditional electricity consumers.
The Solar Example
Solar photovoltaic technology is one of the most visible forms of distributed generation.
Solar PV can be installed on:
- Residential buildings
- Commercial properties
- Industrial facilities
- Warehouses
- Institutions
- Large ground-mounted sites
The technology converts sunlight into electricity using photovoltaic modules and associated electrical equipment.
At larger scales, solar PV plants can include extensive arrays of modules, inverters, transformers, electrical collection systems, monitoring equipment, substations, and grid-interconnection infrastructure.
The engineering requirements change depending on the scale and location of the installation.
Why Solar Generation Is Different From Conventional Generation
Solar generation is dependent on sunlight.
Output changes during the day and can be affected by:
- Solar irradiation
- Clouds
- Temperature
- Shading
- Soiling
- Module characteristics
- System losses
This creates a different operating pattern from conventional generators that may be dispatchable within their operating constraints.
For a grid operator, a large amount of solar generation can therefore change the timing and magnitude of power flows.
This needs to be considered when planning the network.
Wind Adds Another Variable
Wind power has a similar renewable-energy characteristic but behaves differently from solar.
Wind turbines generate electricity based on the available wind resource.
Wind conditions can vary due to:
- Wind speed
- Wind direction
- Air density
- Turbulence
- Terrain
- Weather patterns
A wind project also has significant mechanical and structural considerations because turbines operate in changing environmental conditions.
For developers working on wind power projects, resource assessment, turbine selection, micrositing, electrical design, civil infrastructure, and grid integration all need to be considered together.
Solar and Wind Are Complementary Technologies
Solar and wind should not always be viewed as competing technologies.
Their generation patterns can differ.
Solar generation is strongly associated with daylight hours.
Wind generation depends on local wind conditions and can occur during different periods.
This creates opportunities for hybrid renewable projects that combine different generation resources.
A combined project can potentially produce a more diversified generation profile, although the actual benefit depends on the site, resource characteristics, technology configuration, and grid conditions.
The Grid Has to Adapt Too
One of the biggest changes caused by distributed generation is that power flows become less predictable and more dynamic.
A traditional distribution network was largely designed around power flowing:
Grid → Distribution Network → Consumer
With distributed generation, the flow can become:
Grid ↔ Distribution Network ↔ Consumers + Generators + Storage
At certain times, a consumer may take electricity from the grid.
At another time, that same site may generate more electricity than it consumes and export the surplus.
This changes the electrical behaviour of the network.
Voltage Management Becomes Important
Distribution networks are designed to operate within specified voltage ranges.
When distributed generation is connected to the network, electricity may flow in directions that were not originally expected by the system design.
Depending on the network configuration and generation level, this can create voltage-management challenges.
Engineers may therefore need to evaluate:
- Voltage rise
- Voltage drop
- Reactive power
- Transformer settings
- Inverter behaviour
- Network loading
- Power flow
The appropriate solution depends on the specific network.
Protection Systems Also Need to Evolve
Protection systems are designed around expected fault conditions and power-system behaviour.
Adding distributed generation can alter fault-current contributions and the direction of power flow.
This can affect the assumptions behind existing protection arrangements.
Engineers may therefore need to evaluate:
- Fault levels
- Protection settings
- Relay coordination
- Breaker ratings
- Directional protection
- Islanding considerations
The exact requirements depend on the generation technology and point of connection.
What Happens When Solar and Wind Are Combined With Storage?
Energy storage can provide another layer of flexibility.
A battery can absorb electricity during one period and discharge it during another.
This can change how renewable generation interacts with the grid.
For example, excess solar generation during a period of high solar output could potentially be stored and later used when generation falls.
Similarly, storage can be used for applications involving grid support, peak management, renewable integration, or other project-specific objectives.
But storage introduces its own technical requirements.
A BESS project may require consideration of:
- Battery technology
- Power conversion systems
- Battery management
- Thermal management
- Fire protection
- Control systems
- State of charge
- Degradation
- Grid interface
So adding storage does not eliminate the need for careful engineering.
The Importance of Forecasting
As renewable generation becomes more distributed, knowing how much electricity will be produced becomes increasingly useful.
Solar generation forecasts can consider expected weather and irradiation.
Wind forecasts can consider expected wind conditions.
Forecast accuracy is not perfect, but better information can help system operators and energy managers plan around expected generation.
Forecasting can become particularly important when renewable penetration increases.
Distributed Energy Does Not Mean “Simple Energy”
A smaller installation may have less total capacity than a utility-scale power plant.
That does not automatically make it technically simple.
A distributed solar installation may still need to coordinate with:
- Local voltage conditions
- Inverters
- Protection
- Metering
- Communication systems
- Grid requirements
A larger distributed-energy portfolio can also involve thousands of individual assets.
Managing them collectively introduces additional control and communication requirements.
From Individual Assets to Virtual Power Plants
One interesting development in distributed energy is the aggregation of multiple resources.
Instead of managing each asset completely independently, software and control systems can coordinate multiple distributed resources.
For example, an aggregated portfolio could potentially include:
- Solar systems
- Battery storage
- Flexible loads
- Electric vehicles
- Other controllable resources
The individual assets remain physically distributed, but their operation can be coordinated.
This concept is sometimes associated with virtual power plants.
The underlying idea is that many smaller resources can collectively provide useful grid services when appropriately controlled.
Why Site Selection Still Matters
Distributed generation does not eliminate the importance of location.
For solar, site conditions can influence energy production, installation requirements, shading, access, and system design.
For wind, resource quality is particularly important.
Wind projects may require detailed assessment of:
- Wind speed
- Wind direction
- Turbulence
- Terrain
- Wake effects
- Accessibility
The electrical network also matters.
A location with an excellent renewable resource may still face challenges if suitable grid capacity is unavailable nearby.
This is why resource assessment and grid assessment need to be considered together.
Technical Studies Help Before Connection
Before connecting significant renewable generation to an electrical network, engineers may need to study how the proposed system will behave.
Depending on the project, studies can include:
- Load flow
- Short-circuit analysis
- Voltage analysis
- Protection coordination
- Harmonic assessment
- Reactive power analysis
- Dynamic or stability studies
The required studies depend on the size, technology, voltage level, network characteristics, and applicable grid requirements.
The purpose is to identify potential technical issues before the system is commissioned.
What Developers Should Evaluate
For a distributed solar project, useful questions include:
- Is the solar resource adequate?
- Is the site suitable?
- Can the local network accept the proposed generation?
- Is the inverter configuration appropriate?
- Are voltage conditions acceptable?
- Is protection coordination addressed?
For wind:
- Is the wind resource adequately assessed?
- Is the turbine suitable for the site?
- Has micrositing been evaluated?
- Are wake effects considered?
- Is the grid connection suitable?
For a broader DER portfolio:
- How will the individual assets communicate?
- How will generation be controlled?
- Can storage be coordinated?
- How will the resources respond to grid conditions?
- What data is required for monitoring?
The Future Is More Distributed, But Also More Coordinated
The growth of distributed energy does not necessarily mean that electricity networks will become fragmented.
In many cases, the opposite may happen.
The individual resources can become more coordinated through:
- Smart inverters
- Energy management systems
- Advanced metering
- Automated controls
- Battery systems
- Forecasting
- Digital monitoring
This creates an electricity network where generation, consumption, and storage can respond more dynamically to changing conditions.
Frequently Asked Questions
What are distributed energy resources?
Distributed Energy Resources are energy resources located across the electricity network, often close to consumers or connected to distribution systems. Examples can include solar, wind, batteries, flexible loads, and electric vehicle resources.
Is rooftop solar a distributed energy resource?
Yes. Rooftop solar is a common example of distributed generation because electricity is produced close to where it may be consumed.
Are utility-scale solar plants considered distributed energy resources?
Not necessarily. The classification depends on the system and definition being used. Large utility-scale plants connected directly to transmission networks are generally treated differently from smaller distribution-connected resources.
How does distributed solar affect the grid?
Depending on its size and location, distributed solar can influence voltage, power flow, protection behaviour, and network loading. The actual impact depends on the local network.
How does wind generation differ from solar generation?
Solar generation depends primarily on sunlight, while wind generation depends on wind conditions. Their generation profiles, equipment, resource assessments, and site requirements are therefore different.
Can solar and wind be combined?
Yes. Hybrid renewable projects can combine solar and wind generation. Whether this provides a practical benefit depends on resource characteristics, site conditions, system design, and grid requirements.
Does battery storage help distributed energy?
Battery storage can provide flexibility by storing electricity and supplying it later. Depending on the project, it can support renewable integration, peak management, backup, or other grid-related applications.
Why are power-system studies needed for renewable projects?
Studies can help determine how generation will affect voltage, power flows, fault levels, protection, and other electrical characteristics of the network.
What is a virtual power plant?
A virtual power plant is a coordinated collection of distributed energy resources managed through control and communication systems. The resources remain physically separate but can be operated collectively.
What is the biggest challenge with distributed energy?
There is no single challenge applicable to every project. Technical considerations can include voltage management, protection coordination, variable generation, communication, forecasting, grid capacity, and coordination of multiple assets.
Conclusion
Distributed energy resources are changing the structure of modern electricity systems.
Solar PV can place generation close to consumers or distribute generation across larger areas. Wind projects add another variable renewable resource with different site and operating characteristics. Storage and digital controls can further change how these resources interact with the grid.
But installing renewable generation is only one part of the transition.
The electrical network must also be able to accommodate the generation safely and reliably.
That requires appropriate resource assessment, technology selection, electrical design, grid studies, protection, control, monitoring, and system coordination.
The future electricity system is therefore not simply about more solar and more wind.
It is about creating a network in which generation, consumption, storage, and grid infrastructure can work together intelligently and reliably.