BESS & MicrogridsLesson 3 of 5FOUNDATION LESSON
Sizing from interval data and dispatch behavior
Monthly energy totals hide the shape that storage must control.
- READING TIME
- 15 minutes
- OBJECTIVES
- 3 learning objectives
- SELF-CHECK
- 3 check questions
- INTENDED FOR
- Utility, facility, energy, engineering and project-finance teams
Educational lesson. Confirm project-specific requirements before application.
01LEARNING OBJECTIVES
After this lesson, you should be able to:
- 01Use interval load data rather than monthly consumption alone
- 02Connect dispatch logic to power and energy requirements
- 03State efficiency, reserve and degradation assumptions transparently
02EXPLANATION
What is physically and operationally happening?
Monthly energy totals hide the shape that storage must control. Two facilities can consume the same monthly kWh while one has a sharp fifteen-minute demand peak and the other has a flat profile. Peak shaving depends on the magnitude, timing and duration of the peak; resilience depends on the selected load and outage duration; solar shifting depends on simultaneous generation and demand.
A credible sizing model replays a defined dispatch rule against interval data. It applies charge and discharge limits, state-of-charge (SOC) bounds, efficiency, auxiliary consumption, reserve and degradation. The output is a comparison of feasible configurations, missed targets and sensitivity to assumptions.
- 01
Load profile
Validated interval demand reveals peaks, duration, variability and critical-load behavior.
kW by time - 02
Dispatch rule
A defined algorithm charges, discharges and preserves reserve.
Setpoint - 03
SOC model
Energy balance applies efficiency, limits and auxiliary loads each interval.
% SOC - 04
Sensitivity
Tariff, degradation, outages and operating changes test decision robustness.
Range of outcomes
Illustrative peak-shaving dispatch
The BESS discharges above a site limit and may recharge when headroom is available.
Sizing and dispatch: illustrative profile
Site demand and target limit. Values are educational, not Metro Power project-performance claims.
04OPTIONAL ENGINEERING DEPTHEngineering reasoning for this learning pathThe same design relationship, checks and evidence apply across every lesson in this path.
- Separate PCS power from battery energy
- Resolve reserve versus commercial dispatch priority
- Include losses, degradation, auxiliaries and downtime
- 01Simulate the complete interval sequence and SOC
- 02Coordinate battery management system (BMS), power conversion system (PCS), energy management system (EMS), protection and transformer states
- 03Test tariff, warranty and availability sensitivities
Peak cap fails during long events
Energy depletes despite sufficient PCS power
Replay interval load and SOC
Outage reserve is unavailable
Commercial dispatch consumed reserved energy
Compare command history with EMS policy
- Interval load and generation data
- Dispatch and SOC simulation
- Approved single-line diagram, controls and protection basis
05WORKED EXAMPLE
Energy needed to cap a peak
Demand exceeds a 700 kW limit for three intervals: 820 kW, 940 kW and 780 kW, each 15 minutes.
- Required powers are 120, 240 and 80 kW
- Energy = (120 + 240 + 80) × 0.25 h = 110 kWh
- Maximum discharge power is 240 kW
- Then add losses, reserve, degradation and repeat across the full data period
06COMMON FAILURE OR MISCONCEPTION
“The monthly bill is enough to size a demand-management BESS.”
Monthly kWh and even billed peak do not reveal the shape, duration and recurrence that determine power, energy and recharge behavior.
Check what you can explain without looking back.
Choose an answer and report your confidence. The confidence signal is stored only until you submit this page.
What is most important for peak-shaving simulation?
A 200 kW discharge lasts 30 minutes. Delivered energy is:
Which assumptions affect usable delivered energy?
08SOURCE NOTES
Sources for further study.
International references support further study. They do not replace Philippine laws, regulations, utility requirements or project specifications.
- 01US DOE Energy Storage HandbookSandia National Laboratories and US DOE
Technology, system engineering, safety, procurement and commissioning.
Open source ↗ - 02DOE/EPRI Electricity Storage Handbook in Collaboration with NRECASandia National Laboratories
Utility planning and implementation context.
Open source ↗ - 03Grid-Scale Battery Storage Frequently Asked QuestionsSandia National Laboratories
Foundational grid-storage concepts and project questions.
Open source ↗