Checkthisout
Solar Wizard
- Joined
- Nov 14, 2021
- Messages
- 4,848
Well maybe... I think it is a key aspect to all this is that the generator isn't the only thing in the system.
Hard to prove (and highly situational), but I suspect the embodied energy of a given off-grid system would be way worse if it had tons of tiny "engines" that burned fuel directly to apply the chemical energy at the point-of-use as heat or mechanical energy.
Another interesting aspect that is a bit more on-topic is what's the total fuel efficiency (or fixed cost efficiency) of folks' off-grid systems. i.e. if you have an off-grid system that produces/consumes 4 MWh/yr but uses 200 kWh of generator-derived power at 10% chemical conversion efficiency and $1.50/kWh to get through the year, how well are you doing overall?
Code:0.2 (MWh / yr) / 10% (conversion efficiency) / 4 (MWh) = 50% effective chemical conversion efficiency 200 (kWh / yr) * $1.50 (USD / kWh) = $300 (USD / yr) $300 (USD / yr) / 4000 (kWh / yr) = $0.075 (USD / kWh)
Obviously, the above doesn't include up-front equipment or ongoing maintenance costs.
Heat recovery for heating in the winter which happens to coincide with reduced insolence I think could make it a win.
That is one thing that I haven't seen on this site. Someone with a gen in their system who has come up with a nifty and SAFE way to recover engine cooling and exhaust heat.