I see in the Press that DOC have placed a Mitsubishi Outlander plug in hybrid at Stewart Island. They charge it with a diesel generator, kind of defeats the purpose wouldnt you think.
skull,
May 14, 10:25am
Bloody half wits, what sort of plank would think that's saving anything.
martin11,
May 14, 10:39am
Donot you realise that Stewart Island power is all generated by big diesel Generators ,they are not connected to the national grid .
john1623,
May 14, 2:14pm
I do know that,what is your point.
ronaldo8,
May 14, 2:27pm
It would be interesting to see the numbers, given that a generator that runs at constant load and speed is always significantly more efficient than a vehicle engine of the same displacement in doing useful work. Even with the loss of moving the energy from one domain to another the comparison would be interesting.
tony9,
May 14, 2:47pm
Generator losses (windage and resistance), roughly 10%. Battery charging losses, about 10%, battery discharge and controller losses, roughly 10% and motor losses (same as generator) about 10%. Ok, you can get some regen saving, but this is proven to be low.
Modern diesel auto would be about 30% more efficient use of fuel than generator, battery, motor traction power. Exception is if waste heat from generator is captured for process heating.
marte,
May 14, 2:47pm
Well if anything, its sound pollution would have dropped by a substantial amount. On Stewart island this would be a factor.
It surprises me that they hadn't set up a solar power generation system just for this single situation. The island hasn't got much roading & a EV would do particularly well there.
Ps - when i was there as a kid(60-70's), every house had its own diesel generator, no idea how many still do, or if most or all now on a common one? But certainly back then, you could hear many of them running.
gph1961,
May 14, 3:44pm
a good place to be when the revolution comes
gpg58,
May 14, 3:49pm
Except where will food and supplies come from? oh well, survive on fish i suppose. Must admit a 5 hectare property(bare land) with a stream thru it, had a bit of appeal initially.
tony9,
May 14, 4:03pm
No, the losses I quote are in addition to the ICE engine losses which apply in both cases.
Ships and Rail locos used to be diesel-electric when fuel was cheap and no one cared much about pollution. Now they tend to be direct drive.
ronaldo8,
May 14, 4:17pm
Hmm
average auto diesel = ~30% stationary diesel = ~55% loss due to conversion from your numbers =40%
40% of 55% = 22%
22 vs 30, 8% difference.
ronaldo8,
May 14, 4:18pm
Yes I saw that, hence why I deleted that post.
ronaldo8,
May 14, 4:42pm
Doh That should be 60% (the remainder, not the loss) of 55%. Meaning 30% vs 33%
Or there about, given some flex in the numbers. I.E. they are very close and could go either way depending on the details.
tony9,
May 15, 10:03am
Your stating point of 55% for the stationary diesel is about the best achievable of a ship type two stroke diesel of 30+ Mw. Stewart Island has 5 industrial engines of around 300Kw, likely below 40% efficiency depending on load.
gazzat22,
May 15, 10:25am
Whats the level of Air Pollution down there? Does it compare with Queen St/Willis St or whatever in CHC?
ronaldo8,
May 15, 3:48pm
All right, lets assume that's the case without checking or knowing for sure.
So 60% of 40% = 24% vs 30%. I.E. a 6% difference, maybe. And so, difficult to understand how you arrived at this conclusion.
"Modern diesel auto would be about 30% more efficient use of fuel than generator"
alowishes,
May 15, 4:53pm
Don’t forget the cost to ship the diesel over there:-)
marte,
May 15, 6:48pm
With only 28kms of road, the engines not likely to get warm anyway. If theres a place that would suit a EV, Stewart island would be it. But as a self solar powered setup, it would make a great proving ground to test it out, given the noise pollution aspect alongside the possibly most expensive electricity in NZ.
tygertung,
May 16, 2:48am
Wind turbine? Should be fairly windy down there.
martin11,
May 16, 3:00am
Stewart Island council is looking at wind turbines , Solar would probably not be cost efective there for them
scuba,
May 16, 8:42am
You would think wave / water generation would be a good direction to look at For NZ . Surely some of that technology is available or can be improved upon.
ronaldo8,
Aug 8, 11:15am
A bit more simple math using the loss numbers from post 7 and remembering that they aren't simply additive but multiply the result of each successive step. So
100 % - 10%= 100*0.9 90 - 10% = 90*0.9 81 -10% = 81*0.9 72.9 -10%=72*0.9 65.61%. Thats what remains after those stacking, not additive, losses.
So An average 30% efficient vehicle diesel vs 45% efficient stationary diesel (eg Cummins 300kw genset) with a loss that leaves 65.6% to use is 45*0.656= 29.5%
30 vs 29.5 efficient.
Suddenly the wails sound a bit shrill
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