Solar explained to clever people by people who are not trying to be clever

Solar Panels in SS8 (Castle Point)

See if solar pays off for you in Castle Point — price, savings and payback in under a minute (official UK data).

Solar Calculator

Change the settings below to see how costs and savings work for your situation.

System Size

Roof Direction

Battery Storage

Export Value

Your Numbers

Break-even
11.8 years
After this, it's pure profit
Upfront Cost
£10,173
What you pay to get started
Annual Benefit
£863
What you save every year
Profit Over 25 Years
£11,390
After paying itself off, you're this much ahead

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How we calculate this

Solar generation: Based on typical south-facing roof at 35° angle. We account for weather, dirt, and system losses (14%).

How much you'll use directly:

  • Without battery: You'll use about 40% of what you generate. The rest gets sold back to the grid.
  • With 5 kWh battery: You'll use about 70% (battery stores extra for evening use).
  • With 10 kWh battery: You'll use about 75% (more storage means less exported).
  • Panel-only payback: Bigger systems don’t shorten payback—cost and savings rise together per kW.
  • Battery & payback: Batteries raise self-use and cut bills, but added hardware cost often lengthens break-even at typical UK rates.
  • When a battery can still make sense:
    • Evening-heavy usage patterns
    • Time-of-use tariffs / cheap night rates
    • Low export rate vs. high unit rate
    • Heat pump or EV charging synergy
    • Optional backup/resilience (system-dependent)
    • Lower evening-hour CO₂ vs. grid

Costs: Battery prices are typically £700 per kWh. Export tariffs vary by supplier (usually 5–15p per kWh).

Grid connection: Systems up to about 3.7 kW typically need just a notification (G98). Larger systems may need permission (G99).

These are typical values based on average usage patterns. Your actual results will vary based on your roof, shading, and how you use electricity.

Your area in context

Read the full story

A typical roof here lands around 5.0 kW, with most eligible homes comfortably fitting within 3–6 kW. Each kilowatt of panels produces roughly 1038 kWh per year on a south-facing roof. We value self-used electricity at 26.5p and exported surplus at a baseline 10p via SEG. Use the calculator above for your exact tariff.

Unit rate
26.5p/kWh
Standing charge
48.2p/day
Sunshine yield (south)
1038 kWh/kW
Export price (baseline)
10p/kWh

Browse the scenarios below. Each battery size has its own expand — open the one that matches your plan (or just explore). For each system size (2–8 kW) we show annual output, how much you use directly, what gets exported, annual benefit, upfront cost, break-even, and a 20-year net. Negative numbers are possible — that’s the honest trade-off when adding more battery than your usage profile justifies.

No battery 5 kW example → Annual benefit: £863, Upfront: £10,173, Break-even: 11.8 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2077 kWh 831 kWh 1246 kWh £220 £125 £345 £4,069 11.8 yrs £2,831
3 kW 3115 kWh 1246 kWh 1869 kWh £331 £187 £518 £6,104 11.8 yrs £4,247
4 kW 4154 kWh 1661 kWh 2492 kWh £441 £249 £690 £8,138 11.8 yrs £5,662
5 kW 5192 kWh 2077 kWh 3115 kWh £551 £312 £863 £10,173 11.8 yrs £7,078
6 kW 6230 kWh 2492 kWh 3738 kWh £661 £374 £1,035 £12,207 11.8 yrs £8,493
7 kW 7269 kWh 2908 kWh 4361 kWh £771 £436 £1,208 £14,242 11.8 yrs £9,909
8 kW 8307 kWh 3323 kWh 4984 kWh £882 £498 £1,380 £16,276 11.8 yrs £11,324

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 2,035, battery £/kWh = 700.

3 kWh battery 5 kW example → Annual benefit: £1,034, Upfront: £12,273, Break-even: 11.9 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2077 kWh 1246 kWh 831 kWh £331 £83 £414 £6,169 14.9 yrs £2,104
3 kW 3115 kWh 1869 kWh 1246 kWh £496 £125 £620 £8,204 13.2 yrs £4,206
4 kW 4154 kWh 2492 kWh 1661 kWh £661 £166 £827 £10,238 12.4 yrs £6,308
5 kW 5192 kWh 3115 kWh 2077 kWh £826 £208 £1,034 £12,273 11.9 yrs £8,411
6 kW 6230 kWh 3738 kWh 2492 kWh £992 £249 £1,241 £14,307 11.5 yrs £10,513
7 kW 7269 kWh 4361 kWh 2908 kWh £1,157 £291 £1,448 £16,342 11.3 yrs £12,615
8 kW 8307 kWh 4984 kWh 3323 kWh £1,322 £332 £1,655 £18,376 11.1 yrs £14,717

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 2,035, battery £/kWh = 700.

5 kWh battery 5 kW example → Annual benefit: £1,120, Upfront: £13,673, Break-even: 12.2 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2077 kWh 1454 kWh 623 kWh £386 £62 £448 £7,569 16.9 yrs £1,391
3 kW 3115 kWh 2181 kWh 935 kWh £579 £93 £672 £9,604 14.3 yrs £3,836
4 kW 4154 kWh 2908 kWh 1246 kWh £771 £125 £896 £11,638 13.0 yrs £6,282
5 kW 5192 kWh 3634 kWh 1558 kWh £964 £156 £1,120 £13,673 12.2 yrs £8,727
6 kW 6230 kWh 4361 kWh 1869 kWh £1,157 £187 £1,344 £15,707 11.7 yrs £11,172
7 kW 7269 kWh 5088 kWh 2181 kWh £1,350 £218 £1,568 £17,742 11.3 yrs £13,618
8 kW 8307 kWh 5815 kWh 2492 kWh £1,543 £249 £1,792 £19,776 11.0 yrs £16,063

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 2,035, battery £/kWh = 700.

7.5 kWh battery 5 kW example → Annual benefit: £1,146, Upfront: £15,423, Break-even: 13.5 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2077 kWh 1516 kWh 561 kWh £402 £56 £458 £9,319 20.3 yrs £-153
3 kW 3115 kWh 2274 kWh 841 kWh £603 £84 £687 £11,354 16.5 yrs £2,395
4 kW 4154 kWh 3032 kWh 1121 kWh £804 £112 £917 £13,388 14.6 yrs £4,944
5 kW 5192 kWh 3790 kWh 1402 kWh £1,006 £140 £1,146 £15,423 13.5 yrs £7,492
6 kW 6230 kWh 4548 kWh 1682 kWh £1,207 £168 £1,375 £17,457 12.7 yrs £10,040
7 kW 7269 kWh 5306 kWh 1963 kWh £1,408 £196 £1,604 £19,492 12.2 yrs £12,589
8 kW 8307 kWh 6064 kWh 2243 kWh £1,609 £224 £1,833 £21,526 11.7 yrs £15,137

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 2,035, battery £/kWh = 700.

10 kWh battery 5 kW example → Annual benefit: £1,163, Upfront: £17,173, Break-even: 14.8 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2077 kWh 1558 kWh 519 kWh £413 £52 £465 £11,069 23.8 yrs £-1,766
3 kW 3115 kWh 2336 kWh 779 kWh £620 £78 £698 £13,104 18.8 yrs £851
4 kW 4154 kWh 3115 kWh 1038 kWh £826 £104 £930 £15,138 16.3 yrs £3,468
5 kW 5192 kWh 3894 kWh 1298 kWh £1,033 £130 £1,163 £17,173 14.8 yrs £6,085
6 kW 6230 kWh 4673 kWh 1558 kWh £1,240 £156 £1,395 £19,207 13.8 yrs £8,702
7 kW 7269 kWh 5452 kWh 1817 kWh £1,446 £182 £1,628 £21,242 13.0 yrs £11,319
8 kW 8307 kWh 6230 kWh 2077 kWh £1,653 £208 £1,861 £23,276 12.5 yrs £13,936

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 2,035, battery £/kWh = 700.

13.5 kWh battery 5 kW example → Annual benefit: £1,180, Upfront: £19,623, Break-even: 16.6 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2077 kWh 1599 kWh 478 kWh £424 £48 £472 £13,519 28.6 yrs £-4,079
3 kW 3115 kWh 2399 kWh 717 kWh £636 £72 £708 £15,554 22.0 yrs £-1,393
4 kW 4154 kWh 3198 kWh 955 kWh £849 £96 £944 £17,588 18.6 yrs £1,293
5 kW 5192 kWh 3998 kWh 1194 kWh £1,061 £119 £1,180 £19,623 16.6 yrs £3,979
6 kW 6230 kWh 4797 kWh 1433 kWh £1,273 £143 £1,416 £21,657 15.3 yrs £6,664
7 kW 7269 kWh 5597 kWh 1672 kWh £1,485 £167 £1,652 £23,692 14.3 yrs £9,350
8 kW 8307 kWh 6397 kWh 1911 kWh £1,697 £191 £1,888 £25,726 13.6 yrs £12,036

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 2,035, battery £/kWh = 700.

Figures are illustrative and use the same method as the calculator above. For exact results, adjust your roof direction, tariff, and usage in the calculator.

Your Area at a Glance

Your Electricity Rate
26.53p/kWh
Daily Fixed Charge
48.25p/day
Local Sunshine
1038kWh/kW
A 1 kW system generates ~1038 kWh per year. A typical home uses ~2,700 kWh per year.
Typical System Size
5.0kW
For houses & bungalows in this area

Local Property Data

Property Types

Houses: 48% • Flats: 12% • Bungalows: 34% Based on 8,416 properties

Coverage

Castle Point (100%)

Areas Covered

Canvey Island South, Canvey Island East, Canvey Island Central, Canvey Island North, Canvey Island Winter Gardens

Data Sources & Assumptions

Solar yield: PVGIS (EU Joint Research Centre), January 2025 data

Electricity rates: Ofgem price cap, Q4 2025

Installation costs: MCS certified installer data, March 2025

Property data: EPC open data (Open Government Licence), aggregated

All estimates are typical values. Actual results vary based on your specific situation, roof characteristics, and usage patterns.