REopt — The Complete Guide: Optimal Sizing of Solar, Storage and CHP

REopt is an optimisation tool from NREL, now the National Laboratory of the Rockies. Instead of manually testing a few sizes of PV array and battery, you enter the load profile, tariff and costs, and the tool works out which combination of technologies, at which size, gives the lowest total cost.

REopt

National Laboratory of the Rockies (formerly NREL)

Online tool for the economics and optimal sizing of PV, wind, storage and CHP for a building, campus or microgrid.

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What you get

Technology mix — solar PV, wind turbines, batteries, combined heat and power (CHP) and thermal storage.
Optimal size and dispatch — including how storage charges and discharges through the year.
Economic analysis — net present value and savings against the business as usual case.
Resilience — how long the system can sustain critical loads during an outage.
API and open source — the engine is available to developers under a BSD licence.

A note for readers outside the US

The built-in tariff database and climate data focus mainly on the United States, but you can enter your own load profile and tariff, including seasonal and time-of-use rates, and get a result relevant to a project in Israel or elsewhere. It is a screening tool for the feasibility stage: detailed design and accurate yield calculations are done in other tools.

Related tools

For detailed solar performance and finance modelling — SAM. For PV yield modelling in Python — pvlib. For open-source energy system optimisation — oemof.solph.