3E Research Incorporated

This calculator estimates the household potential for generating power from alternative sources. The power calculated is the average over the year: most alternative sources have daily or seasonal variations, requiring excess capacity, energy storage, and/or multiple types of source. This is an approximate estimate: a much more detailed assessment is needed to make an accurate estimate.

For wind power, the power-weighted average wind speed requires some knowledge to calculate at all accurately: the mean wind speed is not the correct value to use; if you have access to wind speed data (time or fraction of time for each speed), the power-weighted average can be estimated as the cube root of average of cube of wind speed.

We have included an entry for micro hydro, though this would be an unusual energy source for an individual household. Micro-hydro and wind power are more cost-effective at the community level.

Enter constants or simple expressions in each of the input boxes, then press the "Calculate" button. This calculator uses metric units - conversions can be performed by entering the conversion factors in the boxes, e.g. "250/10.8" to convert 250 sq ft to m².

Environment and local energy sources
Latitude		degrees
Fraction of sunny hours in daytime
Possible solar collector area		m² (= sq ft / 10.8)
Solar collector angle		degrees from horizontal
Solar collector direction		degrees from south
Power-weighted average wind speed		m/s (= mph / 2.24 or km/h / 3.6)
Max wind turbine diameter		m (= ft / 3.28)
Water stream flow		m³/s (= cu.ft/s / 35.3)
Water head		m (= ft / 3.28)
Wood		tonnes dry per year for stove burning (= cords * 1.8)
Manure/compost		tonnes dry per year for biomass heating

Source	Power potential	Energy to produce	Installation cost	Running cost
	(average kW)	(kWh)	(US $)	(US $/year)
Solar-electric
or Solar-heat
Wind power
Hydro power
Wood heat
Biomass heat
Total (solar-electric)
Total (solar-heat)