Units

The engine works in kW, kWh, a fraction for the SOC (0.62, not 62), and the prices' currency per kWh. A source gives what it gives: watts or kilowatts, a percentage, a price per MWh. So every series carries its unit (Series.unit), and microgrid.engine.units converts it once, at the edge:

Quantity	Units it knows	Becomes
power	W, kW, MW	kW
energy	Wh, kWh, MWh	kWh
fraction	%, or no unit	a fraction (no unit means it already is one)
price	<currency>/Wh, <currency>/kWh, <currency>/MWh	the same currency per kWh

from microgrid.engine import units

units.convert(42.0, "%", "fraction")          # 0.42
units.convert(85.0, "EUR/MWh", "price")       # 0.085, EUR per kWh

units.normalise(series, quantity) converts a whole series. A dataset's units are converted when it is read; a Python client converts its own inputs before handing them over (the engine reads the numbers as given).

A unit it does not know is refused (UnitError), never guessed: a reading in an unknown unit is not used, rather than used wrongly by a factor of a thousand.

Currency

Prices may be in any currency, and the library never converts one. Every money figure out of the library is in the prices' currency. EUR/MWh becomes EUR/kWh; ¢/kWh passes through as a currency named ¢, a hundredth of what a dollar price would say.

No name says a currency: per_kwh in valuation/2, the battery's wear (wear_charge_per_kwh, wear_discharge_per_kwh) in plant/2. Give the wear in the prices' currency too. The command's tables head their money columns with the dataset's currency (cost EUR, EUR/kWh), and a dataset whose prices name two currencies is refused, never mixed. A recorded price in a per-MWh unit is converted like a forecast's.

Signs

Each meter's sign convention is in plant/2 (meters[].sign), the one place it is stated.