From Gas to Electrons...

TiggerToo

TiggerToo

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Has anyone considered converting their on board cooking facilities from gas to electric?
Induction hobs are now chap. Microwave ovens are quite efficient. Toasting can also be rather fast and homogeneous.

Just a thought.
 
I have a small microwave that will run from a 2kw inverter when not on shore power.
Packet curries, rice, etc pouches take 2 minutes on low power.
I always run tgecengine while it is on.
 
Boater Sam said:
In relation to charging a battery, burning a bit of gas wins hands down for cooking. Every pro kitchen I have ever been in cooks on gas too.
Click to expand...
don't get me wrong. I am a gas "fan" at home. But even there, we are about to convert to induction hobs. And I have now noticed that some "Profis" are doing the same.

But on the boat, we are not into Haute Cuisine. More like High Seas Cruising. And gas storage is an issue. And I am getting really impressed with the ability to capture wind and solar energy efficiently. As AT (above) states, microwaves are really fast as well.

Does anyone have any DIRECT experience about how long it really takes to toast a slice of bread with something like this?
toaster

Then, I could try and work out how long I would need to charge my battery...
 
TiggerToo said:
don't get me wrong. I am a gas "fan" at home. But even there, we are about to convert to induction hobs. And I have now noticed that some "Profis" are doing the same.

But on the boat, we are not into Haute Cuisine. More like High Seas Cruising. And gas storage is an issue. And I am getting really impressed with the ability to capture wind and solar energy efficiently. As AT (above) states, microwaves are really fast as well.

Does anyone have any DIRECT experience about how long it really takes to toast a slice of bread with something like this?
toaster

Then, I could try and work out how long I would need to charge my battery...
Click to expand...
Made a tested sandwich with something similar this lunch time. Probably about 10 minutes all in...
 
We've been cooking electrically since last year. Left the gas cooker in place and occasionally still use it e.g. after a few days of dull weather.
We have 1kw of solar (plus another 200w which can be deployed at anchor). A 270Ah DIY lithium battery (cost less than equivalent lead acid capacity). A 3kw inverter (total overkill, but should be long lived as it doesn't work hard).
The hob is a Vango Sizzle, 2*800w which sounds puny but it's actually fine most of the time. We don't need to cook in a tearing hurry like we did when we lived in a house. The only time we feel that it's underpowered is for steaks or large stir fries. We could always get a more powerful single burner. For an oven, we use a Remoska, drawing about 500w. Also have a toaster.

Very pleased with the project. We've used one bottle of gas since moving aboard last summer. There's noticeably less condensation from electric cooking, and less background heat. And yes I do feel a bit of smug going weeks on end living entirely off solar power. It's just one less thing to worry about, especially changing countries and having to deal with different gas bottles.
 
We’ve just fitted a small flat bed microwave, needed to upgrade inverter which was plan anyway, used it over the last few weeks both on shore power and battery with no issues, we ore using it for short periods as we would at home. Induction hob would be a bit more of a struggle so keeping gas for hob and oven.
 
TiggerToo said:
Does anyone have any DIRECT experience about how long it really takes to toast a slice of bread with something like this?
toaster

Then, I could try and work out how long I would need to charge my battery...
Click to expand...
We have a panini press like that - once it is up to temperature the toastie cooks in 4-5 minutes. Getting to temp is probably another couple of minutes but it is higher power than the one you show. Once at temperature it has a thermostat so won't be drawing full power for the entire cooking time.

I wouldn't dream of trying to make toast with it but I suppose it might work.
 
It can be done, but is hardly green.

Let's make calculations of the relative CO2 emissions from three means, assuming 1 kWhr is required to make your daily meals (approximately one burner for one hour). 1kWhr is 3.6 MegaJoules. Even if this number is way OTT for your cuisine, since it's relative efficiencies we are calculating the absolute number isn't important.

ELECTRIC COOKING WITH INDUCTION HOB POWERED FROM A GENERATOR
Assume efficiency of energy in to energy imparted to the food is 90% for your induction hob (probably it's a bit less).
Generator's use (pretty much all of them, from 3kW to 35MW) about 210g of diesel per kWhr (see for instance Brake-specific fuel consumption - Wikipedia) so to get 3.6MJ into the food one needs to use 210 / 0.9 = 233g of diesel.

In terms of CO2 emissions, that's 233 / 142 = 1.64 moles of Decane, C10H22, so 1.64 * 10 * (12 + 2*16) = 722g of CO2.

ELECTRIC COOKING WITH INDUCTION HOB POWERED BY SHORE-POWER
Same induction hob at 90% efficiency.
In 2020 the UK average - so including renewables and nuclear as well as gas - for electricity generation was 233g of CO2 per kWh (btw, this has to fall to below 50g by 2030 to meet our climate commitments - which gives an idea of the scale of changes we still need to make).

In terms of CO2 emissions, that's 233 / 0.9 = 259g of CO2.

BURNING LPG ( PROPANE)
Assume only 50% efficiency of enthalpy of combustion into the cooking pots (probably pessimistic).
Enthalpy of combustion is around 50MJ per Kg, so to get 3.6/0.5 = 7.2MJ you have to burn 144g.
Propane is C3H8, molecular weight 44g, which when burnt converts to 3 x (12 + 16) = 84g of CO2.

So 144 / 44 * 84 = 275g of CO2.

CONCLUSION
Cooking by propane is pretty much a wash with using shore-power in terms of CO2 emissions, and emits only 38% as much as cooking with an induction hob and a generator.

As shore-power gets greener (less emissions per kWh) the advantage of using induction hobs will increase, and for those with sufficient solar and batteries it's already better, but no way is it green if you have to use an engine or generator to power it. Finally, Propane can be made from renewables anyway; it's a by-product of bio-diesel manufacture.

CONTEXT
What is 275g of CO2 compared to motoring? Suppose your motoring uses about 3 litres of diesel an hour.
That's 3 * 0.85 = 2.55Kg, which makes 7.9Kg of CO2. Hence a day's cooking on gas is the equivalent of motoring for all of 275 / 7900 * 60 = 2 minutes. And I assume you do bicycle to the boat...
 
jdc said:
It can be done, but is hardly green.

Let's make calculations of the relative CO2 emissions from three means, assuming 1 kWhr is required to make your daily meals (approximately one burner for one hour). 1kWhr is 3.6 MegaJoules. Even if this number is way OTT for your cuisine, since it's relative efficiencies we are calculating the absolute number isn't important.

ELECTRIC COOKING WITH INDUCTION HOB POWERED FROM A GENERATOR
Assume efficiency of energy in to energy imparted to the food is 90% for your induction hob (probably it's a bit less).
Generator's use (pretty much all of them, from 3kW to 35MW) about 210g of diesel per kWhr (see for instance Brake-specific fuel consumption - Wikipedia) so to get 3.6MJ into the food one needs to use 210 / 0.9 = 233g of diesel.

In terms of CO2 emissions, that's 233 / 142 = 1.64 moles of Decane, C10H22, so 1.64 * 10 * (12 + 2*16) = 722g of CO2.

ELECTRIC COOKING WITH INDUCTION HOB POWERED BY SHORE-POWER
Same induction hob at 90% efficiency.
In 2020 the UK average - so including renewables and nuclear as well as gas - for electricity generation was 233g of CO2 per kWh (btw, this has to fall to below 50g by 2030 to meet our climate commitments - which gives an idea of the scale of changes we still need to make).

In terms of CO2 emissions, that's 233 / 0.9 = 259g of CO2.

BURNING LPG ( PROPANE)
Assume only 50% efficiency of enthalpy of combustion into the cooking pots (probably pessimistic).
Enthalpy of combustion is around 50MJ per Kg, so to get 3.6/0.5 = 7.2MJ you have to burn 144g.
Propane is C3H8, molecular weight 44g, which when burnt converts to 3 x (12 + 16) = 84g of CO2.

So 144 / 44 * 84 = 275g of CO2.

CONCLUSION
Cooking by propane is pretty much a wash with using shore-power in terms of CO2 emissions, and emits only 38% as much as cooking with an induction hob and a generator.

As shore-power gets greener (less emissions per kWh) the advantage of using induction hobs will increase, and for those with sufficient solar and batteries it's already better, but no way is it green if you have to use an engine or generator to power it. Finally, Propane can be made from renewables anyway; it's a by-product of bio-diesel manufacture.

CONTEXT
What is 275g of CO2 compared to motoring? Suppose your motoring uses about 3 litres of diesel an hour.
That's 3 * 0.85 = 2.55Kg, which makes 7.9Kg of CO2. Hence a day's cooking on gas is the equivalent of motoring for all of 275 / 7900 * 60 = 2 minutes. And I assume you do bicycle to the boat...
Click to expand...
Although if it's from a large Solar array / Wind power and battery bank....
 
Daverw said:
We’ve just fitted a small flat bed microwave, needed to upgrade inverter which was plan anyway, used it over the last few weeks both on shore power and battery with no issues, we ore using it for short periods as we would at home. Induction hob would be a bit more of a struggle so keeping gas for hob and oven.
Click to expand...
Solar power provides normally what we need to use to put back into battery's so not having to run engine to use
 
Yes rewired the boat to suit the 2kw the Multiplus microwave 700 watts, pulls 1100w max, we’ve found most stuff only needs med power for 60 secs etc. the flat bottom microwaves need slightly less power than turntables ones, also don’t rattle

no different on shore power as all goes through Multiplus as we have limit of 6amp for shore power, it handles split between shore power, solar and batteries
 
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I have all electric galley - coffee maker, toaster, microwave, induction hob and air fryer/pressure cooker

Needs no shore power and I don't have or want a generator - I have a decent solar array (its a 50 foot cat after all) and 500 ah LifePo4 and in the UK need no shore power input for 8 months of the year including making electric heated hot water every day and running computers, tv, fridge and freezer etc. We are lucky enough to be on the South Coast in the sunniest place in the UK but its very much doable.

The only thing solar can't really do is heat the boat in winter months which is done by diesel heater
 
jac said:
Although if it's from a large Solar array / Wind power and battery bank....
Click to expand...
Correct, as I said in my conclusions section: "...for those with sufficient solar and batteries it's already better [ie less CO2 than using gas]..."
 
Alan S said:
In this case you are actually cooking (rather inefficiently) by diesel.
Click to expand...
Yes but curry and rice takes 4 minutes.
So not really significant. I would probably run the engine for that long or longer to warm it up...

But I do take your point.

By the way I have PV on the roof of my house, an air source heat pump and an electric car that gets charged overnight on cheep surplus electricity.
So I do try my best. :cool:
The boat uses about 40 to 50l of diesel a year so less than one tank full for most ICE cars...
 
Just to add to what I already wrote, we cannot charge the lithium system from the engine- it is strictly solar only (and shore power if we're alongside, which isn't often). So no inefficient engine charging in order to cook.
I was quite sceptical of how much we would be able to rely on solar power, which is one of the reasons why I left the gas in place. But in real life it works very well.
I should also add that I'm not in the UK, although it's not exactly been wall to wall sunshine here either.
 
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