Lowtech Graph lists low-tech options for every need of a home. Here you can compare them, find tutorials to build them, and link them together into a circular system. Why low-tech?
Small petrol or diesel engine (direct drive)
Needs the grid
One of 8 ways to meet this need. Cost, carbon, footprint and rankings are relative to other solutions for the same need, not absolute.
A small petrol or diesel engine that drives a pump, a log splitter or a winch straight off its shaft. It does heavy work away from any wiring, and keeps running when the grid does not. But it needs delivered fuel, is loud, cannot run indoors and needs regular servicing.
Build it
This solution is not buildable as a DIY project.
Cost
Medium
Upkeep
Seasonal
Skill to build
None
Lifespan
Long if serviced; the servicing schedule is the whole determinant
Embodied carbon
Medium
Space / material use
Low
Output timing
On-demand/controllable
Skill to repair
Intermediate
Regulation (FR example)
Noise from garden and site equipment is restricted by prefectoral and municipal orders, typically by time of day and day of week.
Levels are relative to the other options for this need, not absolute. Fewer dots is lighter.
Small petrol or diesel engine (direct drive) (This page) Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: Medium · Skill to build: None · Upkeep: Heavy · Change to daily life: Occasional · Works without the grid: No Choose it if you need heavy work done far from any wiring, even when the grid is down.
Solar PV array Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: Medium · Skill to build: Intermediate · Upkeep: Light · Change to daily life: None · Works without the grid: Yes Choose it if you have a sunny roof or patch of ground and want free electricity with no moving parts.
Small wind turbine Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: Medium · Skill to build: Intermediate · Upkeep: Regular · Change to daily life: None · Works without the grid: Yes Choose it if your site has steady wind and you want power at night and in winter.
Micro-hydro turbine Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: Medium · Skill to build: Intermediate · Upkeep: Regular · Change to daily life: None · Works without the grid: Yes Choose it if water flows all year on or next to your land and you want power day and night.
Mains electricity Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: Low · Skill to build: Specialist · Upkeep: None · Change to daily life: None · Works without the grid: No Choose it if the grid reaches you and you want the most reliable supply in normal times.
Pedal / hand-crank generator Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: Low · Skill to build: Basic · Upkeep: Light · Change to daily life: Daily · Works without the grid: Yes Choose it if you want a little emergency power, for a phone, a light or a radio, from your own muscles.
Water motor for direct mechanical drive Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: Low · Skill to build: Intermediate · Upkeep: Regular · Change to daily life: Occasional · Works without the grid: Yes Choose it if you have a stream and want it to drive a pump, a mill or a tool directly, with no electronics.
Electric motor (mains or battery driven) Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: Low · Skill to build: None · Upkeep: None · Change to daily life: None · Works without the grid: No Choose it if you want quiet, controllable drive at the flick of a switch.
Sources
Project engineering judgement: the conventional source of shaft power
Limitations of this page
We don’t list sizing or quantities, as the yield of each technique depends on the quality of its build. The catalogue compares options but doesn’t dimension them. Regulatory notes are indicative, with a French example, and need to be confirmed locally.