Utility Scale: what it means and how a large-scale energy project works
‘Utility Scale’ is a term used in the energy sector to describe generation or storage facilities developed on a scale large enough to operate primarily as assets within the electricity system; they are usually connected directly to the grid and designed to supply, store or manage large quantities of energy.
The concept is particularly associated with utility-scale solar photovoltaic plants, wind farms and grid-scale BESS systems, although it can also be applied to other large-scale electricity generation infrastructure.
Translating ‘utility scale’ simply as ‘large-scale’ is useful, but incomplete. What characterises these projects is not only their capacity in MW, but also the way they are connected, their role within the electricity system, and the model through which they sell the energy or services they provide to the grid.
Furthermore, a utility-scale project does not have to be owned by an electricity company or utility. It may be owned by an independent power producer, an infrastructure fund, an energy company, a developer, an industrial firm or various investment vehicles.
What does ‘utility scale’ mean in the context of energy?
Generally speaking, a utility-scale facility generates or stores energy primarily to supply the electricity grid, rather than being designed solely to meet the consumption needs of the building, home or industrial site where it is located. This characteristic distinguishes it from distributed generation and numerous behind-the-meter systems, where generation or storage takes place behind the consumer’s meter and is primarily aimed at reducing or managing their own demand.
In the case of photovoltaics, the IEA PVPS generally describes utility-scale plants as ground-mounted (or floating) facilities that usually feed their electricity directly into the grid. Consequently, examples within the energy sector include:
- Utility-scale photovoltaic solar power stations.
- Onshore and offshore wind farms.
- Systems BESS at network level.
- Hybrid solar + storage projects.
- Large hydroelectric power stations.
- Thermal power stations and other centralised power generation facilities.
From how many MW is a project considered to be utility-scale?
There is no universal threshold that determines when a project can be classified as utility-scale. The threshold depends on the technology, the country, the regulatory framework, the connection voltage level and the methodology used by each organisation. For this reason, defining ‘utility-scale’ solely by means of a figure (for example, 1 MW, 5 MW or 10 MW) may be technically incorrect. The IEA PVPS itself states that there is no specific power rating that allows for a consistent distinction between centralised and distributed photovoltaic systems across all markets.
As a benchmark for the sector, SolarPower Europe In its methodology for the European market, it uses a segmentation in which the utility-scale photovoltaic segment corresponds to ground-mounted installations with a capacity exceeding 1,000 kW. This figure constitutes a methodological definition for its statistics and is not a universal rule applicable to any energy project. In practice, to identify a utility-scale asset, it is more useful to analyse several factors together:
- Installed capacity: these are typically installations of several MW and, in large-scale projects, of hundreds of MW or even greater capacities.
- Grid connection: they are usually connected directly to high-capacity distribution networks or transmission networks.
- Use of the energy: its production is primarily directed towards the electricity market, a buyer under a contract or the grid, and not solely for local self-consumption.
- Revenue model: this may depend on wholesale markets, auctions, PPA, capacity markets or balancing services.
- Systemic function: generation, storage, energy arbitrage, capacity, balance, frequency control or grid support, depending on the technology.
Utility-Scale Solar: what a large-scale photovoltaic plant is like
The term ‘utility-scale solar’ is probably one of the most common uses of the term. It describes large photovoltaic plants designed primarily to generate electricity and feed it into the grid. These facilities can range from a few MW to several hundred MW, or even exceed the GW scale in certain markets. A utility-scale solar plant typically comprises:
- Thousands or millions of photovoltaic modules.
- Central inverters or string inverters.
- Fixed structures or solar trackers.
- Processing centres.
- Internal medium-voltage networks.
- Step-up substation.
- Grid export line.
- SCADA systems, communications, protection and control.
- Production forecasting systems and power plant controllers (PPC).
Design is not simply a matter of installing as many modules as possible. Engineers must optimise variables such as the DC/AC ratio, electrical losses, orientation, pitch, Ground Coverage Ratio (GCR), shading, clipping, availability, degradation, curtailment and connection point capacity.
For example, a 100 MWac plant may have a significantly higher DC photovoltaic power output. This oversizing allows the inverter to be utilised more fully for more hours of the year, although it also increases the frequency of certain clipping events. The optimal design depends on solar resource, electricity prices, component costs, grid constraints and the financial model. In projects of this scale, small percentage differences in generation, availability or losses can represent significant amounts of energy and revenue over the asset’s 25, 30 or more years of operational life.
Utility-Scale BESS: grid-scale storage
The term ‘utility-scale’ is also becoming increasingly important in energy storage. A utility-scale BESS is a grid-connected battery system designed to store and deliver significant amounts of power and energy to the electricity system. Unlike a domestic or commercial battery installed primarily to manage a user’s consumption, a utility-scale BESS can participate directly in electricity markets and provide multiple services simultaneously. Its applications include:
- Energy shifting: storing electricity during certain hours and using it later.
- Energy arbitrage: charging when prices are low and discharging when the price of electricity rises.
- Balancing services: a rapid response to help maintain the balance between generation and demand.
- Frequency control: rapid injection or absorption of power in response to system deviations.
- Congestion management: storage and offloading at strategic points in the network.
- Capacity: to provide power during periods of peak demand.
- Renewable integration: shifting solar or wind power generation from periods of high output to times of peak demand.
The International Energy Agency (IEA) Points out that approximately 80 per cent of the new battery storage capacity installed globally in 2025 was accounted for by utility-scale projects, as opposed to behind-the-meter storage. In these projects, it is particularly important to distinguish between power (MW) and energy capacity (MWh). For example, a 100 MW / 400 MWh BESS can deliver its rated power of 100 MW for approximately four hours, which is why it is commonly described as a four-hour system.
Utility-scale versus distributed generation and behind-the-meter generation
One of the best ways to understand what ‘utility scale’ means is to compare it with distributed generation and behind-the-meter systems.
| Feature | Utility Scale | Distributed generation / Behind-the-Meter |
|---|---|---|
| Standard scale | MW to hundreds of MW or more | From kW to several MW, depending on the application |
| Main objective | Generating, storing or managing energy for the electricity system | To focus primarily on serving or managing local consumption |
| Connection | Electricity distribution or transmission network | Usually associated with the point of consumption |
| Economic model | Market, PPA, auctions, capacity and network services | Energy saving, self-consumption and demand management |
| Solar example | 200 MW solar power station | Photovoltaic installation on an industrial building |
| BESS example | 100 MW / 400 MWh grid-connected BESS | Battery installed behind the meter in a factory |
However, this classification does not depend solely on power output. A large-scale industrial facility could have tens of MW of generation or storage capacity and still fulfil a primarily behind-the-meter function. For this reason, the point of connection and the economic use of the asset are just as important as its size.
How does a utility-scale project generate revenue?
Utility-scale projects typically require high CAPEX, so their viability depends on converting electricity generation, capacity or flexibility into sufficiently predictable revenue streams over the life of the asset. Among the most common models are:
Power Purchase Agreement (PPA)
Through a Power Purchase Agreement, the project enters into an arrangement to sell electricity to a buyer under contractually defined terms. A long-term PPA can reduce direct exposure to market volatility and be significant for the project’s financing and bankability.
Merchant sales
A merchant project sells all or part of its output directly to the electricity market. Its revenue therefore depends on hourly prices or on other products traded on the market. In the case of solar and wind power, it is not enough to analyse the average price of electricity. It is necessary to examine the capture price – that is, the average price actually achieved during the hours when the technology is generating electricity.
When there is a high level of solar power penetration, many plants generate electricity simultaneously during the same hours. This can drive down prices during periods of high solar output and lead to price cannibalisation, thereby increasing interest in storage and hybridisation.
Auctions and regulated mechanisms
Some projects are developed through public auctions or other schemes that provide for specific terms regarding remuneration or energy procurement.
Network services and flexibility markets
Utility-scale BESSs can combine different sources of revenue through a strategy known as ‘revenue stacking’. Depending on the regulatory framework and design, a single asset can generate revenue from arbitrage, balancing services, capacity, congestion management or other products on the electricity market.
The economics of a utility-scale project: CAPEX, LCOE and economies of scale
One of the key economic characteristics of utility-scale projects is their ability to capitalise on economies of scale. Increasing the size of the project can reduce certain unit costs because elements such as engineering, development, equipment, construction, operation and infrastructure can be spread across a larger installed capacity. For this reason, it is common to express specific CAPEX using indicators such as:
Specific CAPEX = Total investment / Installed capacity
For example, a power station with an investment of 70 million euros and a capacity of 100 MW would have:
70.000.000 € / 100.000 kW = 700 €/kW
In the field of energy storage, analysis typically involves examining both the cost per watt and the cost per unit of energy capacity:
- €/kW: relating to the power that the system can deliver.
- €/kWh: relates to the amount of energy it can store.
A reduction in unit CAPEX does not, in itself, guarantee that a project will be better. Other factors must also be taken into account, such as output, losses, degradation, availability, financing costs, O&M, service life, curtailment and the price realised for the electricity. In power generation, all these variables ultimately influence metrics such as the LCOE, whilst from an investor’s perspective, NPV, IRR, DSCR, cash flow and other profitability and financing metrics are also used.
Development and construction of utility-scale projects
The development of a utility-scale installation is usually considerably more complex than that of a small distributed system. Before construction can begin, the project must pass through various technical, administrative, environmental and financial stages. Among the most important elements are:
- Availability, site management, construction and commissioning.
- Measurement and analysis of energy resources.
- Environmental studies, permits and authorisations.
- Adverse weather conditions, geology and climate
- Identification of the connection point, access studies and network capacity.
- Conceptual and detailed engineering.
- Estimation of CAPEX, OPEX and the financial model.
- EPC contract.
- Construction and commissioning.
- Commercial operation of the asset.
In projects running into hundreds of MW, the transmission infrastructure can become a critical part of the investment. The asset may require its own substation, kilometres of power lines and various other facilities needed to reach the authorised connection point. For this reason, the availability of grid capacity, connection times and the risk of curtailment are key factors in determining the bankability of a utility-scale project.