Noob Solar / battery questions and confusion about potential cost savings?

Reed_Richards

marchesini46 said:
... how much of our gas bill is for heating and how much is heating our hot water? I don’t suppose you know of how I can find out that split?

If your house has an Energy Performance Certificate that should give an estimate.  

arty688

Also they have longer on this planet than us. Having said that I also have 2 teenagers and am surprised by their complete apathy about climate change. I try to do my bit but the education system in this country in my mind is so backward. They seem to waste lessons on RE or more controversial forced to do a modern language , but barely touch something that destroying the planet.

shibli

I have a similar quote with Light Renewables but requested a "iboost" for my megaflow, this will save gas costs in heating the water, which current rate has made it worth the investment

marchesini46

Magnitio said:

marchesini46 said:

I’m as a father of two teenage sons, whereby they think light bulbs and switches automatically turn themselves off and a house runs on fresh air so it’s ok to leave your TV and PS5 on while you pop out to the park for 2/3 hours 😂, I didn’t want to be a grumpy dad and berating them at every opportunity. So if I can get my bills down significantly, I’ll be a happy bunny. If we do decide to go down this solar / battery route, we can also be more mindful of when we use the power hungry appliances ie tumble dryers etc. 

Can I ask how much you managed to save on a monthly basis to give me a real world comparison?

When they next go out and leave the TV and PS5 on, go into the settings of each to put them in eco mode, or to automatically go to sleep when not in use. On PS5, it's something like: System Settings > System > Power Saving and Rest Options

They will need to understand the cost of energy when they go to Uni or leave home, so it's worth educating them.

I can’t even get the older one to close his cupboard door after he’s got something out 😂. They are good kids though so I’m not going to be down on them too much. 

When I moved in 20 years ago, I changed all the single ceiling pendants to halogen downlighters - over a 100 on the whole house and couldn’t work out why my electricity bill had risen so much 😂😂😂.  Best eco saving I did was change all the lamps to LEDs. 👍

marchesini46

shibli said:

I have a similar quote with Light Renewables but requested a "iboost" for my megaflow, this will save gas costs in heating the water, which current rate has made it worth the investment

I think armed with all this new info, I’m going to give them a call and get a revised cost with more battery, panels and the iBoost. 

Thanks

arty688

I don't know if your quote included bird protection , when I mentioned it to them they included it for no extra cost.

Alnat1

Noticed I put that the solar was installed in March 21 in my previous post, should have been March 22, so only a couple of months to go on.

We previously used around 11kwh a day, 4000kwh a year, similar usage monthly though the year. Since solar this has gone down to an average of 9.1kwh per day but in the first month when we didn't get paid for export were trying to use as much as we could ourselves. Hubby was encouraged to jet wash the patio/wash and vacuum car etc. and I was washing the washer (doing a 90C cleaning program) on sunny days. We're now on Octopus Outgoing Agile so don't mind exporting to the grid so much, paid an average of 16.7p per unit so far.

We've imported just under 1khw on average from the supplier for each day since installation This is made up of many days of tiny little watts only (battery can take a couple of seconds to kick in when you flick kettle on) , then a few of dull days when batteries didn't fill and we used 3-4kwh overnight and the following morning. We've exported 42.8% of the solar generation and we're home all day.

Winter will be very different but so far I'm happy with our decision to install the system. One regret, wish we'd got a bit more than 4.8 of battery, might have to add another 2.4 soon.

feelingsuelawley

QrizB said:

You'll see that in December you used 582kWh but a 4kWp system will only generate, on average, 154kWh in that month. You'd need a much bigger system, 15kWp, to generate as much electricity in an average December as you use.

• Adding a battery lets you use your solar electricity in the dark. For most average households, using 3000kWh/yr (8-10kWh/day) a battery of 6-8kWh is the "best" size at current prices. In your case you're such a large user that a larger battery might be worth considering but a larger battery will only benefit you on those days of the year where your panels are generating that much excess power. The time taken to pay back the cost will extend accordingly.
  

Reading this has slightly terrified me.

Over the past 6 months my average monthly electricity consumption has been:

• Oct 686 KWh
• Nov 724 KWh
• Dec 795 KWh
• Jan 784 KWh
• Feb 718 KWh
• March 974 KWh
• April 734 KWh

Using PVGIS to drop a pin on my roof and using approximately the right azimuth suggests I will generate about 80KWh from a 4KWp system in December, so barely 10% of my needs. Although by the looks of this, I'm going to need a minimum 8KWp system to meet my needs even in sunnier months!

And that is before I consider:

1. moving my main car from diesel to EV

2. moving my water heating from gas boiler to smart electric immersion

both of which will substantially increase my consumption.

I know there is a strong argument for "how on earth are you using that much electricity? Turn some stuff off!" (but this is 2 adults WFH plus 1 child home educated & second child in A-levels so home quite a bit - so we're paying for a lot of energy that schools & employers would normally provide and saving money/carbon emissions by very low travel)

But I feel like my bottom line here is that it's not even worth me considering moving to solar because I don't have more than 10m2 of roof space and there is no point considering buying enough battery to keep things going.

Which begs the question - if I'm motivated by green-ness more than money saving here (and accept that not travelling/going to an office or school makes sense on this basis) - what are my best ways of reducing the environmental impact of my energy consumption?

Do I use green electricity tarrifs and still move water heating to electric immersion?

Magnitio

feelingsuelawley said:

QrizB said:

You'll see that in December you used 582kWh but a 4kWp system will only generate, on average, 154kWh in that month. You'd need a much bigger system, 15kWp, to generate as much electricity in an average December as you use.

• Adding a battery lets you use your solar electricity in the dark. For most average households, using 3000kWh/yr (8-10kWh/day) a battery of 6-8kWh is the "best" size at current prices. In your case you're such a large user that a larger battery might be worth considering but a larger battery will only benefit you on those days of the year where your panels are generating that much excess power. The time taken to pay back the cost will extend accordingly.
  

Reading this has slightly terrified me.

Over the past 6 months my average monthly electricity consumption has been:

• Oct 686 KWh
• Nov 724 KWh
• Dec 795 KWh
• Jan 784 KWh
• Feb 718 KWh
• March 974 KWh
• April 734 KWh

Using PVGIS to drop a pin on my roof and using approximately the right azimuth suggests I will generate about 80KWh from a 4KWp system in December, so barely 10% of my needs. Although by the looks of this, I'm going to need a minimum 8KWp system to meet my needs even in sunnier months!

And that is before I consider:

1. moving my main car from diesel to EV

2. moving my water heating from gas boiler to smart electric immersion

both of which will substantially increase my consumption.

I know there is a strong argument for "how on earth are you using that much electricity? Turn some stuff off!" (but this is 2 adults WFH plus 1 child home educated & second child in A-levels so home quite a bit - so we're paying for a lot of energy that schools & employers would normally provide and saving money/carbon emissions by very low travel)

But I feel like my bottom line here is that it's not even worth me considering moving to solar because I don't have more than 10m2 of roof space and there is no point considering buying enough battery to keep things going.

Which begs the question - if I'm motivated by green-ness more than money saving here (and accept that not travelling/going to an office or school makes sense on this basis) - what are my best ways of reducing the environmental impact of my energy consumption?

Do I use green electricity tarrifs and still move water heating to electric immersion?

With that level of usage, I would suggest doing a very detailed audit of where all the electricity is being used and work out what improvements can be made. We have 2 adults at home most of the day and the highest month in the past year before installing solar was 251kWh. The quickest and most effective environmental impact you can make is working out how you can use less. Out of interest, do you know what your gas usage is over the same period?

feelingsuelawley

Magnitio said:

With that level of usage, I would suggest doing a very detailed audit of where all the electricity is being used and work out what improvements can be made. We have 2 adults at home most of the day and the highest month in the past year before installing solar was 251kWh. The quickest and most effective environmental impact you can make is working out how you can use less. Out of interest, do you know what your gas usage is over the same period?

Gas:

• Oct 2363 KWh
• Nov 3845 KWh
• Dec 3999 KWh
• Jan 4737 KWh
• Feb 4110 KWh
• March 2713 KWh
• April 1433 KWh

It's a 1930s built semi where most of the house has no cavity in the walls. And 4 people at home every day meaning at least 4 rooms need to be heated.

There's some modern extension with cavity wall insulation, but one of the rooms we were heating is a loft conversion which isn't great.

And to swing back round to your point on reducing consumption, I'm not saying I'm perfect and I do need to get much more granular with monitoring the usage per activity but realistically I'm going to shave 10% off my usage (as a guess) not 50% so for now I am focussing on how to reduce my environmental (and financial) impact at this level of consumption.