Load shifting changes when electricity is consumed or drawn from the grid. A facility might schedule a flexible process for a different hour, charge vehicles overnight or use stored energy during a preferred period. The objective is timing. Load shifting does not necessarily reduce total energy consumption, and it does not always lower the highest demand reading.
Its value depends on the electricity arrangement and on whether the operation can move without creating a different problem.
Two ways to change the timing
The first approach moves the activity itself. A flexible process can run earlier or later, or a building can schedule eligible loads around operating needs. The equipment still consumes electricity when it runs.
The second uses storage. A battery charges at one time and supplies electricity at another, allowing the underlying business activity to continue on its normal schedule. Thermal storage can change the timing of electricity used for heating or cooling through a different physical process.
The DOE solar and storage overview describes storage as a way to use generated electricity later. The distinction between stored energy and generation is essential: storage moves availability and introduces losses; it does not create extra electricity.
Load shifting, peak shaving and efficiency
| Concept | Primary objective | Question to ask |
|---|---|---|
| Load shifting | Change the timing of use or grid import | When will the energy be consumed or supplied? |
| Peak shaving | Reduce demand during relevant peak periods | How high will grid demand become? |
| Energy efficiency | Reduce energy needed for a given service | How much energy does the task require? |
A project can pursue more than one objective, but the effects need separate evaluation. Moving several processes to the same cheap-rate period might reduce an energy-charge component while creating a new demand peak.
A simple financial illustration
Suppose a hypothetical battery delivers 90 kWh during one period after using 100 kWh to charge earlier. If the relevant energy prices were $0.20/kWh during discharge and $0.10/kWh during charging, the simplified avoided purchase would be $18 and the charging purchase $10.
The $8 difference is an illustrative energy-charge calculation only. It excludes equipment costs, degradation, standby use, demand charges, tariff restrictions and other charges. It also assumes the delivered energy offsets purchases that would actually have occurred. These invented rates are not Maryland, Virginia or DC tariff quotes.
This example shows why comparing rate differences without storage losses and operating costs overstates the benefit. For a real project, use the applicable tariff and measured interval load data.
Operational flexibility is the limiting resource
Before buying controls or storage, identify which activities can move. A process with a strict completion deadline has a different scheduling window from optional charging. A school, clinic or production facility may have loads that must remain available regardless of price.
An owner can classify loads as fixed, flexible within a window, or interruptible under defined conditions. Record the person responsible for approving each operating change. A technically feasible schedule is of little use if it conflicts with production or occupant needs.
For a solar-equipped site, shifting a flexible load into solar-producing hours can increase on-site use of generation. The value still depends on what exported electricity would otherwise receive and whether the schedule creates additional costs.
Controls need measurable objectives
A proposal should identify the measurement boundary, scheduling rules and operating constraints. Explain what happens when a forecast is wrong, an activity runs late or the battery reserve is needed for backup.
DOE’s battery evaluation methodology helps frame performance measurement. For load shifting, the owner also needs before-and-after timing records so the project can be assessed against its intended use, not just total battery throughput.
Map the activity before moving its electricity use
A load belongs to an activity: charging a vehicle, producing a batch, conditioning a space or running another service. Moving electricity use requires understanding that activity’s constraints. A schedule that looks attractive on an energy chart can fail if it conflicts with a completion deadline, occupancy requirement or production dependency.
Start by recording when the activity can begin, when it must finish and which conditions must remain satisfied. Identify whether it can pause, restart or change its operating rate. These are business and technical questions that the responsible operating team must answer together.
For an illustrative facility, a cleaning process might move within an evening window while a refrigeration function must remain available continuously. Both use electricity, but only one offers the same scheduling flexibility. A model should reflect that distinction rather than applying a uniform percentage of flexibility to the whole building.
The most useful initial output is a list of specific movable activities and their limits. That list provides a realistic foundation for evaluating controls, storage or changes in operating practice.
Moving a load is different from reducing its service
A successful shifting strategy preserves the required outcome while changing the timing of the associated electricity use or import. If a facility simply completes less work or accepts poorer service, the energy result should not be presented as an equivalent-service improvement without explaining the change.
This distinction matters in measurement. A lower daytime energy total could result from moving a process, canceling it or changing its output. Those outcomes have different commercial meanings. The performance report should identify which occurred.
For an illustrative charging operation, vehicles may need the same total energy before departure even if charging moves to another period. The schedule must still deliver that energy within the available window. A control that reduces charging during one period but never completes the required service has not met the original objective.
Define the service requirement alongside the energy target. That makes it possible to evaluate both the electrical result and the operating outcome, instead of declaring success from one favorable meter reading.
Storage separates the activity from the charging schedule
A battery can charge during one period and discharge while the underlying activity continues at another time. This can be useful when the business cannot move the activity itself. The trade-off is that storage adds equipment, losses, operating limits and maintenance responsibilities.
DOE’s solar and storage overview describes storage as capturing energy for later use, with losses along the process. The financial analysis therefore needs the energy required to charge as well as the energy delivered during discharge.
A storage proposal should define the useful output boundary. If a calculation uses energy delivered to AC loads, the corresponding charging input must be described consistently. A battery-only efficiency figure should not silently stand in for the complete system’s operating result.
Also identify the required duration. A resource that can supply substantial power briefly may not cover a long operating period. Conversely, a large energy store may lack the output capability needed by the activity. Both the energy and power requirements belong in the assessment.
Solar self-consumption is a timing question
A solar-equipped property can examine whether flexible activities can move into periods when generation is available. This may increase the amount of solar energy used on site, but the value depends on the electricity arrangement and the cost of changing the activity.
For an illustrative workshop, a flexible task may move from an evening period into the middle of the day. The commercial analysis needs to account for the electricity purchases and exports that change. It should not count the same solar energy once as avoided export and again as an independent additional saving without explaining the baseline.
Production is also variable. A schedule that assumes a fixed amount of solar energy every day needs a plan for conditions when actual output differs. The relevant control and operating approach should preserve the required business function.
Increasing self-consumption is an operating metric, not a complete investment conclusion. The owner still needs to compare the benefits with the equipment, control and operational costs required to achieve it.
A cheaper energy period can still create a costly demand pattern
Energy timing and maximum demand are related but different. Moving several activities into one period may concentrate their power requirements. The resulting demand can matter where the applicable electricity arrangement includes demand-related charges or where the electrical infrastructure has a relevant constraint.
An illustrative facility might move vehicle charging and a flexible process into the same overnight window. Each change appears reasonable when evaluated separately. Together, they may create a new period of high simultaneous demand. The combined schedule should therefore be analyzed at the relevant time resolution.
Do not assume that the word “off-peak” describes every charge or capacity condition affecting the site. Use the actual tariff, customer class and electrical arrangement. A commercial analysis should identify which charges change and which remain unaffected.
The practical design may spread activities within the available window rather than starting them together. Whether that is possible depends on the process requirements and supported controls. Evaluate the full schedule before selecting the equipment.
Forecast errors and exceptions need an operating plan
A schedule may rely on expected occupancy, production, electricity use or solar generation. Actual conditions can differ. The operating plan should identify which priorities control when the forecast is wrong or an unexpected requirement appears.
For example, an urgent production order may require a process to run during a period normally avoided. The control should not prevent the business from meeting an authorized priority, but the resulting energy and cost consequences should be visible. A useful system records exceptions rather than hiding them inside an unexplained performance shortfall.
Clarify who can override the schedule and which limits remain mandatory. Routine business scheduling should not be confused with the authority to change electrical protection or capacity-related controls. The equipment and site requirements determine those boundaries.
The owner should also know what happens if communications or data are unavailable. The selected system’s supported behavior needs to be documented so staff understand whether an interruption affects scheduling, monitoring or the underlying operation.
Evaluate economics with a complete boundary
A simple energy-price comparison can identify an opportunity, but it is not the whole business case. Depending on the strategy, the analysis may need to consider storage losses, equipment cost, controls, ongoing support, operational effects and other applicable electricity charges.
Separate measured facts from assumptions. Current interval data and bills provide evidence about the existing site, while a future dispatch schedule is modeled behavior. The proposed tariff treatment must be verified for the account, and any future rate assumption should be labeled as an assumption.
Ask how the result changes if fewer activities can move, the available window becomes shorter or the modeled price difference changes. These sensitivity checks help identify whether the project depends on a narrow set of favorable conditions.
Avoid a false precision problem: a spreadsheet can produce an exact-looking annual total from uncertain inputs. A useful report explains the range of outcomes supported by the assumptions and the factors that would cause the owner to revisit the decision.
Confirm performance without confusing activity with benefit
A control platform may show that energy moved from one period to another. That establishes an operating observation, but the owner also needs to know whether the required service was preserved and whether the intended economic or grid-import outcome occurred.
Compare relevant time-based records and note changes in occupancy, production or equipment. If the facility’s use changes substantially, a simple before-and-after comparison may not isolate the effect of load shifting. The evaluation should explain its baseline and any adjustments.
DOE’s battery evaluation method supports structured measurement of storage performance. For a shifting project, add the operating records needed to connect that performance with the site’s objective.
Assign responsibility for reviewing the strategy over time. A schedule that suited last year’s operations may no longer fit a new tenant, revised production pattern or expanded charging requirement. Periodic review should ask whether the flexibility still exists, whether the controls use it appropriately and whether the resulting service remains acceptable. That keeps load shifting tied to a real operating need rather than an unattended schedule.
Common questions
Can load shifting work without a battery?
Yes. Scheduling flexible equipment or charging changes consumption timing directly. Storage is useful when the activity cannot move or when another operating objective justifies it.
Does a time-of-use rate guarantee savings?
No. Savings depend on the energy that can actually move, the applicable charges and the cost of making the change. A rate difference is an input to the analysis.
Can shifting affect comfort or production?
It can. Define acceptable operating conditions before changing schedules and measure whether those conditions remain satisfied.
Is load shifting suitable for outage backup?
The same battery may support both uses, but energy allocated to one purpose may be unavailable for the other. Backup reserve and dispatch priorities must be explicit.
Evaluate the schedule before the equipment
Bring operating schedules, interval electricity data and the current tariff to a discussion with Soleil Energy’s renewable energy team. If storage is part of the concept, its battery service is the relevant next step.
Project requirements depend on the site, equipment and applicable rules. Confirm design and installation decisions with the appropriate qualified professional.
