electricity savings

asturdy2

coming upto my one year anniversary, I have used 2100 units in the last year, and used over 3000 units the year before with no solar panels. looks like I have saved about £135 on electricity if you say 15p per kwh. How much have others saved ?

Martyn1981

My kWhs have gone down from approx 3,000 to 1,600 (1,550 last year) so around £180+.

Mart.

Sterlingtimes

Thank you both for the interesting figures. It will be another 9 months before I have my own view.

I am inclined to think that the following types of people will save more:

[A] those who are greedy on their use of their appliances; and/or

those who have lower efficiency devices.

Let's say that I have the choice between two tumble dryers

B rated vented costing £140 per annum in energy (capital cost £150)

A+ rated heat pump costing £70 per annum in energy (capital cost £450)

Without solar the A+ would have a 300/70 = 4.25 payback on the incremental expenditure over the B. However, the solar contribution starts to make the payback period much longer.

Solar changes the payback equation. A solar user (putting ethics aside) may even prefer financial to invest in cheaper products with a lower efficiency rating.

The_Green_Hornet

The year prior to my Solar PV installation I used 2888 kWh. Last year I used a miserly 838 kWh. Now I would love to say that this is all down to my panels but as I only have a small system it obviously wouldn't be true.

A lot of savings have been made by replacing older electrical appliances with newer more efficient models - for example my current TV uses a fifth of the electricity than my previous one did - and on changing usage habits.

legoman62

Pre solar I was using over 5000kWh a year.:eek:

Last year I paid for 2233kWh from the grid:)

Wattson say's I used 4122kWh last year:T Saving me over £200.00:beer:

As I have stated before, after fitting SPV/Watttson i am more aware of where my

electricity is being used/wasted and have tried to modify/lower usage where possible;)

System

Another factor is whether or not people are at home throughout the day. I have a 2.15kWp PV solar system and my electricity use has fallen from 3,400 kWhs/pa to 2,400kWhs/pa. We are using about 55% of what we generate. This percentage will increase as I have just bought an EV. As I write, my panels are pumping out 1.6kWs. Just sticking the car on charge for a couple of hours at a 1.5kWh charge rate would cost nothing and give me 12 miles more range (4 miles per kWh). Or, put another way, I will have spent nothing to save about £1.25 in petrol costs.

Before this gets people going on the cost/benefits of EVs compared to ICE cars then I would just point out that for 6000 miles annual usage then, even without PV solar (i.e.; that is, charging from the mains at 11.1p/kWh) my running costs will be £850 pa less than they are today. Adding back free rapid charging thanks to my local Council, PV solar gains, and free charges on the Electric Highway, I am hoping to see a reduction in my motoring costs of nearly £950 per year.

zeupater

Hengus wrote: »

.... for 6000 miles annual usage then, even without PV solar (i.e.; that is, charging from the mains at 11.1p/kWh) my running costs will be £850 pa less than they are today. Adding back free rapid charging thanks to my local Council, PV solar gains, and free charges on the Electric Highway, I am hoping to see a reduction in my motoring costs of nearly £950 per year.

Hi

That's odd .... let's have a quick look. I guess that the £100(950-850) is road tax, so £850 is fuel savings ? .... so £850 buys somewhere around 772 litres(850/1.1), that's 170gallons, so wiping out all fuel consumption would mean that the replaced vehicle would need to have averaged 35mpg(6000/170) ...

Now, let's look at the cost of electricity using the supplied figures .... 6000miles at 4miles/kWh is 1500kWh (leaving natural discharge and charging/usage inefficiencies aside) .... if you're paying for all of the electricity that's somewhere around £180/year ....

Considering that you could have a £0 rated car tax on a petrol/diesel fuelled car, we now have a maximum saving of somewhere around £670/year (850-180) against an anticipated replacement cost of the battery pack of £4k after 10 years, on a vehicle which initially costs around (/well over) £10k more than a directly comparable ICE vehicle ....

So, next, pv provision .... for many people the EV will be parked on a car park at work for 5 week days when it's bright enough for pv to be generating any serious amount and at weekends it'll be outside a shopping centre/supermarket ... then there's the odd really dull days when there's little generation, the consecutive run of dull days when you just about cover base load, 3 or 4 poor generation winter months and on decent generation days there's the competition with other high demand requirement such as washing machines, dishwashers, cookers etc ... If you are at home most of the time and only use the vehicle for short trips, with a 2kWp system from which around 1000kWh/pa is already consumed, you'll be doing well to provide anything more than 300-500kWh towards the EV charge ...

As for charging points on public car parks, around here, when you've found where they are & they're not already being used or aren't out of order, or haven't been decommissioned in order to make space for disabled or mother/toddler spaces they're okay .... apart from that, make sure that you're never more than 50% charge from home or have hybrid generation ...

Ah, nearly forgot .... then there's the requirement to not forget to plug the car in when it's sunny because you'll probably be using again in a minute (which happens more often than you'd think!) .....

I'm not against EVs, MrsZ uses hers in EV mode as much as possible, but can't see any logic in anyone claiming any form of monetary saving over a similar specification internal combustion engine vehicle (unless it's personal saving on a company car .... )

HTH
Z