• 0 Posts
  • 156 Comments
Joined 2 years ago
cake
Cake day: June 10th, 2023

help-circle









  • LA batteries don’t “only trickle charge”, but a) the cost per kW of UPS equipment is usually significantly higher than the generator, and b) the generator has a much higher surge current capability than inverter-based sources, and c) the power that actually goes through the battery loses anywhere from 10-30% in the round trip, so you get less usable output by routing power that way. If the cost issue becomes a smaller obstacle and you can be clever about bypassing the battery when appropriate, then like hybrid cars you can overcome those challenges… but not everyone or all affordable equipment can do that.






  • If you convert the chemical energy in a unit of coal to heat (burn it) you can calculate how much energy exists in that coal, measured in appropriate units (e.g. kWh). That is evidently what this author is trying to dumb down as “invested energy”. The amount of energy extracted as electricity is typically 40% of that… the rest ends up as heat which is much less useful than electricity.

    I agree that this is not particularly useful in discussing the merits of different energy sources because good design tends to do as well as is practical and the supply of fuel and negative impacts of that process can’t vary dramatically.