Q's on commercial emergency diesel leccy generation.

WIAWSNB

Hi.
On the off-chance that anyone on here has insights to such a topic
What price ppl would a commercial operator be able to buy red diesel at, compared to domestic? No idea of quants involved, but I guess 30k litres or more.
Rough efficiency of 1950's generators, and how this improved in the 60's?
Thanks.

Robin9

Isn't   Red Diesel specifically for agricultural use ?    and illegal for any other purpose ?

doodling

Hi,

Robin9 said:

Isn't   Red Diesel specifically for agricultural use ?    and illegal for any other purpose ?

It is more complicated than that - see https://www.gov.uk/guidance/using-rebated-fuels-in-vehicles-and-machines-excise-notice-75 .

WIAWSNB

Robin9 said:

Isn't   Red Diesel specifically for agricultural use ?    and illegal for any other purpose ?

It's essentially for non-road use, other than agri. It's the usual 35-second oil, as used for heating and stationary engines, things like that. 

DullGreyGuy

WIAWSNB said:

Robin9 said:

Isn't   Red Diesel specifically for agricultural use ?    and illegal for any other purpose ?

It's essentially for non-road use, other than agri. It's the usual 35-second oil, as used for heating and stationary engines, things like that. 

Its more nuanced than that per the link shared:

2.4 Machines and appliances for heating and electricity

Machines and appliances being used primarily to generate heat and electricity for premises that are not used for commercial purposes can use red diesel.

A kerosene heating system is an excepted machine when it is being used to generate heat for any premises.

No expert on red diesel, though had plenty at home growing up given my father's job, but the above would say that you cannot use it for commercial purposes. 

WIAWSNB

DullGreyGuy said:

WIAWSNB said:

Robin9 said:

Isn't   Red Diesel specifically for agricultural use ?    and illegal for any other purpose ?

It's essentially for non-road use, other than agri. It's the usual 35-second oil, as used for heating and stationary engines, things like that. 

Its more nuanced than that per the link shared:2.4 Machines and appliances for heating and electricityMachines and appliances being used primarily to generate heat and electricity for premises that are not used for commercial purposes can use red diesel. A kerosene heating system is an excepted machine when it is being used to generate heat for any premises. No expert on red diesel, though had plenty at home growing up given my father's job, but the above would say that you cannot use it for commercial purposes. 

Thanks. But I'm not looking for clarification on the legalities - it is used for leccy generation - but just the figures. 

Cheers.

QrizB

WIAWSNB said:

Rough efficiency of 1950's generators, and how this improved in the 60's?

It does depend on scale.

Modern small generators make around 1kWh per litre (which is terrible, when you think that a litre of diesel contains 10kWh of thermal energy). Medium-sized ones (tens of kVA) are better and might make 2kWh per litre.

1950s-60s ones might not be much different?

WIAWSNB

QrizB said:

WIAWSNB said:

Rough efficiency of 1950's generators, and how this improved in the 60's?

It does depend on scale.

Modern small generators make around 1kWh per litre (which is terrible, when you think that a litre of diesel contains 10kWh of thermal energy). Medium-sized ones (tens of kVA) are better and might make 2kWh per litre.

1950s-60s ones might not be much different?

Large scale. MW - enough to keep a town running.

QrizB

WIAWSNB said:

QrizB said:

WIAWSNB said:

Rough efficiency of 1950's generators, and how this improved in the 60's?

It does depend on scale.

Modern small generators make around 1kWh per litre (which is terrible, when you think that a litre of diesel contains 10kWh of thermal energy). Medium-sized ones (tens of kVA) are better and might make 2kWh per litre.

1950s-60s ones might not be much different?

Large scale. MW - enough to keep a town running.

Here's a modern 2MVA genset. It burns 424 l/h at rated output, which is gettingon for 5kWh/litre. I don't think a 50s/60s generator would manage that.

https://www.hampshiregenerators.co.uk/generators/diesel-generators/agg-p2030d5-2000kva-diesel-generator/

doodling

Hi,

The old rule of thumb was that with a diesel engine you get one third of the fuel energy out of the shaft, one third out of the exhaust and the other third out of the cooling system.

Modern diesels will achieve low 40s percent efficiency out of the shaft.  Of course you then have the alternator efficiency (around 98%, less on a small machine) and the parasitic load of the cooling system to take into account.