Is iBoost really worth it?

psamatt

So we've recently had 4.8kw worth of Solar Panels fitted on our South facing roof, in addition to this, we have had iBoost fitted.

We are just about to sign up for Outgoing Octopus which pays 15p per KWH of exported Electricity, we are on the standard variable for gas (10.24p per KWH) and therefore am wondering if its any point in having iBoost? I know you can't quantify 1 KWH of Gas vs 1 KWH of Electricity, however, on the naive view, heating water (in a tank) is cheaper via the Gas boiler if you export the Electric to Octopus then to use the iBoost to heat the water?  

Thoughts?  

QrizB

Devices like the iBoost are "worth it" at times when gas is worth more than exported electricity. But at the moment, when gas is subsidised by the EPG and Octopus are paying 15p/kWh for export, you're better off exporting the power and heating with gas.

In a year or two, prices might have swung back the other way (or they might not).

Petriix

It's important to do the calculations. Work out what you would spend on hot water without the iboost rather than assuming every kWh diverted has saved you money. If you can earn 15p for export then it's almost certainly not worth it. Maybe if you were on Go and limited to 4p exports (or whatever it is now). 

RealtimeBlues

So its about cost savings etc and not about saving the planet lol

thevilla

RealtimeBlues said:

So its about cost savings etc and not about saving the planet lol

It is offsetting gas somewhere so might as well save the most money.  Have you invested in saving the planet?

ispookie666

I used to have iBoost in my old house, works well. I set the thermostat to high (70ish)  but again I was getting FiT.
This time I have installed it along with batteries, I don't think there is any economic sense but at least I'm doing my bit for the environment, I do have oil heating.

Reducing carbon foot print seems to be very popular. 

Magnitio

psamatt said:

So we've recently had 4.8kw worth of Solar Panels fitted on our South facing roof, in addition to this, we have had iBoost fitted.

We are just about to sign up for Outgoing Octopus which pays 15p per KWH of exported Electricity, we are on the standard variable for gas (10.24p per KWH) and therefore am wondering if its any point in having iBoost? I know you can't quantify 1 KWH of Gas vs 1 KWH of Electricity, however, on the naive view, heating water (in a tank) is cheaper via the Gas boiler if you export the Electric to Octopus then to use the iBoost to heat the water?  

Thoughts?  

You might find this debate of interest:

https://forums.moneysavingexpert.com/discussion/6374313/hot-water-debate/p1

I still use the immersion most of the time, but have recently used gas when solar generation has been poor and electricity rates have been high.

QrizB

RealtimeBlues said:

So its about cost savings etc and not about saving the planet lol

I suspect @RealtimeBlues won't be back, but if they are they might like to consider that a kWh of gas has a carbon footprint of just over 200g CO2, while a kWh from the grid has a typical carbon footprint of ... about 200g CO2.

Whether you replace a kWh of gas with your own electricity, or export the kWh to the grid and displace a kWh of grid electricity, the net effect on carbon emissions is similar.

Petriix

QrizB said:

RealtimeBlues said:

So its about cost savings etc and not about saving the planet lol

I suspect @RealtimeBlues won't be back, but if they are they might like to consider that a kWh of gas has a carbon footprint of just over 200g CO2, while a kWh from the grid has a typical carbon footprint of ... about 200g CO2.

Whether you replace a kWh of gas with your own electricity, or export the kWh to the grid and displace a kWh of grid electricity, the net effect on carbon emissions is similar.

It's more complicated than that though... 

A kWh of electricity exported can only offset the CO2 of the very last generator to spin up rather than the whole grid mix. Usually that's a gas power station, which tend to have a round trip efficiency of about 60% vs your boiler's 80% +. Your exported solar power will be used locally so avoids all the major grid losses. 

It would have to be quite unusual circumstances for it not to be 'greener' to burn the gas at home and export the solar. I'd say it's fairly clear that an iboost or similar actually reduces the environmental benefits of a typical solar PV installation; where there is mains gas at least.

If you only have electric water heating it's probably far greener (much of the time) to export during the day then use overnight electricity to heat the water when demand is lower.

It seems very strange to me that people would assume a solar diverter has any environmental benefits. 

Niv

For me the diverter will reduce the number of loads of oil I need to buy so in my case has 'some' env benefit. But, being honest, I will be doing it to save money, env benefits are nice but money saving is the driver.

RealtimeBlues

QrizB said:

RealtimeBlues said:

So its about cost savings etc and not about saving the planet lol

I suspect @RealtimeBlues won't be back, but if they are they might like to consider that a kWh of gas has a carbon footprint of just over 200g CO2, while a kWh from the grid has a typical carbon footprint of ... about 200g CO2.

Whether you replace a kWh of gas with your own electricity, or export the kWh to the grid and displace a kWh of grid electricity, the net effect on carbon emissions is similar.

Surely a kWh from the sun has zero g of CO2