Vorpal wrote:As for other combustion engines... most of them have electric substitutes. Felling a large tree needs a petrol chain saw, but the other stuff can be done with electrics, unless you have a large lawn. Of course, that's not necessarily ideal. If your power comes from coal plants, for example the combustion engine is probably a better choice, as it's more efficient and less polluting.
That's not usually true. The efficiency of an internal combustion engine is around 30%. The efficiency of a steam turbine as used in a power station is around 60%. And the efficiency of an electric motor is about 90%. So converting coal to electricity is actually more efficient, in most cases, than burning petrol or diesel (which, of course, both consume electricity in the refinery).
A few things...
First, thermal efficiency (use of heat energy) in a turbine is not the same thing as mechanical (work) efficiency; transferring quantities of stuff into work such as cutting grass, trimming trees, etc.
Secondly, there are many losses in the system outside of a turbine that make the process of coal energy to something useful at a house somewhat less efficient than doing the same thing with a combustion engine held in my hand. Most electricity generation in the UK comes from combined cycle plants, which are rather more efficient than the few aging coal power plants still running.
If we were comparing an electric car to a combined cycle power plant, I would agree (although 60% is still a bit high)
However, a two cycle engine (the small petrol engines used for chain saws, lawn mowers, etc) are very much more efficient than large IC engines, like those used in cars. The thermal efficiency is double (2 cycle versus 4 cycle engine) and the mechanical efficiency is typically 60 or 70% better.
That said, if we compare everything in the system from O&G /coal extraction & refining, emissions, etc. to work done in my garden, they are probably fairly comparable.
The solution is not to do it at all.
“In some ways, it is easier to be a dissident, for then one is without responsibility.”
― Nelson Mandela, Long Walk to Freedom