Carmarthenshire
Solar panels in Carmarthen, designed on a free call.
A 12-panel roof in Carmarthen makes about 6,230 kWh a year and costs £6,360 installed; a free 30-minute video call sizes it to yours.
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How much a Carmarthen roof makes, month by month
PVGIS puts Carmarthen at 980 kWh per kWp a year, 5% above our Carmarthenshire county estimate. 68% of it arrives between April and September, peaking in May.
Generation per kWp, month by month
Show the monthly figures
| Month | kWh/kWp |
|---|---|
| January | 34.9 |
| February | 53.1 |
| March | 87.2 |
| April | 116 |
| May | 123 |
| June | 121 |
| July | 117 |
| August | 105 |
| September | 88.6 |
| October | 61.4 |
| November | 42 |
| December | 30.5 |
Source: PVGIS v5.2 (European Commission JRC), SARAH3 database, 1 kWp, 14% system loss, 35 degree pitch, due south, checked September 2026.
Against Great Britain as a whole: Carmarthen makes 980 kWh per kWp a year, and the mean of our 85 county PVGIS estimates (our GB average) is 925, so Carmarthen is 6% above it.
How Carmarthen compares
Small towns rarely get published solar figures, so here are the numbers for Carmarthen. It is one of 3 Carmarthenshire towns we track, and it ranks 2nd of 3 for solar yield, a town of 16,875 people in the House of Commons Library settlement data. PVGIS gives its roofs 980 kWh per kWp a year, 2.68 peak sun hours a day averaged across the seasons, and the standard 12 panel model turns that into £883 of year one benefit, £247 of it from your own generation and £636 from export at 12p.
Treat these as calibration rather than a quote. The calculator below runs the same model, opened on Carmarthen's own yield, and prices a 12 panel system at £6,360 installed before any battery. Your free design call reworks every number for your actual roof, its shading and your usage.
Planning applications here go through Carmarthenshire; nationally, the House of Commons Library classes Carmarthen as a small town.
The charger is in the installed price but left out of payback: charging savings depend on your mileage and tariff, which the design call models properly.
Your real roof and usage, worked through on a free 30-minute video call. Use the full form or leave three details below.
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Three details. We call or text within one working day to book your free 30-minute design call, on video or by phone if you prefer.
Modelled for Carmarthen at 51.8562, -4.31165 on PVGIS data, with imports valued at 26.32p/kWh and solar at £1,000 per kWp installed. Sources and assumptions: help page.
The network operator for Carmarthen
On NESO's licence-area map, Carmarthen is in South Wales, which National Grid Electricity Distribution (NGED) operates. That makes NGED the network operator for any system fitted here.
Below 3.68kW per phase of inverter and battery output, the G98 route applies: the installation is notified to NGED within 28 days of commissioning, with no prior approval.
Above that, G99 means applying before the work is booked. NGED's guaranteed standards give 45 working days for a low voltage generation quotation, with £80 paid for each working day late.
Sources: NESO DNO licence areas (3 May 2024); NGED, guaranteed standards of performance table, checked 25 September 2026. G98 vs G99, explained.
Heat pumps and EV charging in Carmarthen
A heat pump in Carmarthen
Heating demand peaks when solar is weakest. In Carmarthen, a 12-panel system makes about 190 kWh in December and 220 kWh in January, a fraction of its 780 kWh in May, which is why a heat pump here is costed on its tariff first.
Grant support in Wales comes from the Boiler Upgrade Scheme: £7,500 for an air source or ground source heat pump, £2,500 for air-to-air, and an extra £1,500 until March 2027 where the home is heated by oil or LPG off the gas grid (gov.uk, checked 28 September 2026).
Charging an EV in Carmarthen
Carmarthen's May output, about 780 kWh from 12 panels, is several times the 70 kWh or so a typical home uses in daylight that month on our calculator's settings. Daytime charging turns that surplus into miles.
The calculator above includes a 7.4kW smart charger from £1,100 installed. Renters and flat owners with off-street parking can claim 75% of a chargepoint's cost, up to £500 per socket, until 31 March 2027 (gov.uk, checked 28 September 2026).
What the named kit costs, installed
Every system is designed around your roof on the free call before anything is fitted.
Solar panel servicing and repair in Carmarthen
The same sourced benchmarks apply in Carmarthen as everywhere we cover: honest repair pricing and what a service should include.
Solar in Carmarthen: your questions answered
How much electricity do solar panels make in Carmarthen?
About 6,230 kWh a year from 12 panels (6.36 kWp), on PVGIS satellite data for Carmarthen: 980 kWh per kWp, or 2.68 peak sun hours a day on average. May is the strongest month, at about 780 kWh.
Is solar more expensive in Carmarthen?
Prices on this site are the same everywhere: £1,000 per kWp installed, which puts a 12-panel system at £6,360 in Carmarthen, and a Duracell Dura16 installed with solar at £4,450 on top. The local part is generation, about 6,230 kWh a year here, which is what drives payback.
Which DNO covers Carmarthen, and what does it need from me?
National Grid Electricity Distribution (NGED) covers Carmarthen. A home system of up to 3.68kW per phase is notified to NGED within 28 days of commissioning under G98, and nothing waits on approval. Larger outputs need a G99 application before work starts. NGED's guaranteed standards give 45 working days for a low voltage generation quotation, with £80 paid for each working day late.
What could I earn from exporting in Carmarthen?
On the 12p export scenario, a 12-panel system in Carmarthen sends about 5,296 kWh a year to the grid, worth around £636. The export rates table compares what each supplier pays.
How much solar does Carmarthen get in December?
December is the low point: about 190 kWh from a 12-panel system in Carmarthen, on PVGIS data, rising to 780 kWh in May. From November to February the same system makes about 1,020 kWh in total, which is why a battery charged off-peak does more of the work in winter.
How Carmarthen compares with its neighbours
How the towns nearest Carmarthen compare on the same PVGIS settings, closest first.
| Town | kWh per kWp a year | vs Carmarthen |
|---|---|---|
| Carmarthen | 980 | this town |
| Llanelli | 1,064 | +84 kWh |
| Ammanford | 969 | −11 kWh |
| Gorseinon | 1,040 | +60 kWh |
| Gowerton | 1,063 | +83 kWh |
| Clydach | 981 | +1 kWh |
| Swansea | 1,023 | +43 kWh |
Each row is a PVGIS v5.2 run at that town's centre with the same settings. Treat gaps of a few kWh as noise and gaps over about 30 kWh per kWp as real differences in sunshine.
Also for Carmarthen: Solar panels in Carmarthen from OVO Solar & Battery
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Reading for Carmarthen homeowners
Sourced, dated and written by us. The same ground we cover on your free call.
Do solar panels need direct sunlight? Not really, and here is why
No. Solar cells respond to light hitting them, not to a clear line of sight to the sun.
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Read the guide →What MCS certification actually is, and why your export payments depend on it
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Read the guide →Get my free quote
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