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?
Backup generator
Passive
One of 2 ways to meet this need. Cost, carbon, footprint and rankings are relative to other solutions for the same need, not absolute.
An engine burning petrol, diesel or propane that drives a generator. It is started when the sun and wind have been too weak for too long and the batteries run low. It gives power on demand in a long dull spell, but runs on bought fuel and is noisy.
Build it
This solution is not buildable as a DIY project.
Cost
Medium
Upkeep
Seasonal
Skill to build
Intermediate
Lifespan
15-25 years for the engine/alternator with regular maintenance and periodic exercise-running
Embodied carbon
Medium
Space / material use
Medium
Output timing
On-demand/controllable
Skill to repair
Intermediate
Regulation (FR example)
Fixed electrical installations must meet NF C 15-100, and a Consuel certificate is required before a new connection is energised. Grid-connected generation requires an Enedis connection agreement.
Levels are relative to the other options for this need, not absolute. Fewer dots is lighter.
Backup generator (This page) 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: Occasional · Works without the grid: Yes Choose it if you want power on demand through long, dull spells.
Oversized battery bank for extended autonomy Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: High · Skill to build: Basic · Upkeep: Regular · Change to daily life: None · Works without the grid: Yes Choose it if you want several days of autonomy with nothing to burn and no noise.
Sources
General backup-generator industry durability consensus
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.