What would a 500 kWp array produce on a farm near Hemel Hempstead?

Yes, and the figure matters more than the sunshine. At 895 kWh per kWp a year, a 500 kWp array on a Hemel Hempstead holding models at around 448,000 kWh. What changes the answer is how much of that the farm uses itself. Source: EU PVGIS v5.2, SARAH3, 10 degree pitch, 14 percent system loss.

Which network operator handles the connection around Hemel Hempstead?

Applications go to UK Power Networks, who run the network across Hertfordshire. On a farm the incoming supply matters as much as their answer: a single phase supply caps what can be installed whatever the roof would take.

What does Dacorum require for solar on an agricultural building?

Roof-mounted panels on an agricultural building often fall under permitted development, subject to limits on projection above the roof plane and to the building not being listed or in a conservation area or National Park. We confirm the position with Dacorum before the design is finalised.

Has anyone near HP2 already done this?

The planning database records 0 ground mounted and 5 roof mounted solar schemes in this postcode district. That matters less as proof it works and more as evidence of how the local network has treated export applications. Roof arrays under a megawatt often never appear in the database, so the real figure is higher. Source: Renewable Energy Planning Database, Q1 2026.

Solar panels for farms in Hemel Hempstead

Most holdings around Hemel Hempstead already own the best generating site they will ever have, and it is the roof of the shed they built for something else. Each survey records the sheet type and condition, the usable area once rooflights and vents come out, and whether the supply is single or three phase.

895 kWh per kWp a year at this latitude, so a 500 kWp array models at about 448,000 kWh. Source: EU PVGIS v5.2, SARAH3, 10 degree pitch, 14 percent system loss.

Book a roof survey in Hemel Hempstead

Drawing Hemel Hempstead unit

Roof 96 x 62 m

Array 500 kWp

Yield 448,000 kWh/yr

Scale 1:500 / Rev A / HP2

Illustrative layout for a unit of this size. Your own figures come from the roof survey.

Hemel Hempstead / Hertfordshire

Eastern arable farmland with solar arrays on farm buildings — Industrial stock of the kind we survey across East of England.

Farm building solar PV across Hertfordshire

What a farm roof near Hemel Hempstead generates

Modelled irradiation at this latitude is 1146 kWh per square metre a year in the plane of a shallow-pitched roof, which works out at 895 kWh for every kWp installed (EU PVGIS v5.2, SARAH3, 10 degree pitch, 14 percent system loss). That sits within a few percent of the mean across the areas we cover, so what decides the scheme is your own demand pattern rather than the latitude.

5 roof mounted schemes are on record nearby. Roof arrays under a megawatt frequently never reach that database at all, so the real number of farm roofs generating around Hemel Hempstead is higher than the record shows.

We survey holdings across the HP postcode area, starting from HP2.

Dacorum is the planning authority for most holdings here, and it is the authority that decides whether an array on an agricultural building falls inside permitted development.

FIG. 1 What a Hemel Hempstead roof makes, month by month

Jul produces 6.0 times what Dec does on the same roof. A 500 kWp array here models at about 448,000 kWh across the year, but it arrives unevenly, which is why we size against your summer daytime load and then look at whether storage is worth adding for the shoulder months.

Monthly figures as a table

Month	kWh per kWp	500 kWp array
Jan	25	12,500
Feb	39	19,500
Mar	73	36,500
Apr	104	52,000
May	119	59,500
Jun	123	61,500
Jul	125	62,500
Aug	105	52,500
Sep	82	41,000
Oct	51	25,500
Nov	30	15,000
Dec	21	10,500

Source: EU PVGIS v5.2

FIG. 2 Hemel Hempstead against the rest of Hertfordshire

Stevenage901
St Albans901
Hatfield901
Hertford901
Welwyn Garden City899
Watford898
Harpenden896
Hemel Hempstead895
Borehamwood895

Hemel Hempstead ranks 9 of 10 towns we cover in Hertfordshire on modelled yield, against a national mean of 886 kWh per kWp. The county runs from 895 to 911, a spread of 16 kWh per kWp. Within Hertfordshire that difference is small enough to ignore: where the building sits is not what decides this scheme, your consumption pattern is.

Bars are zero based, so length is proportional to the figure. Where a county is flat, that is the finding: location is not the lever, consumption is. Source: EU PVGIS v5.2, modelled per town

Grid connection through UK Power Networks

Connections around Hemel Hempstead are handled by UK Power Networks, which sets the export limit for the site. Above 3.68 kW per phase the connection runs under G99, so the export limit is agreed in advance rather than assumed. Where the local network is constrained, an export-limited connection usually still makes the scheme work, because a farm uses most of what the roof makes during the working day.

Across Hertfordshire the planning database records 119 solar schemes totalling 844 MW, of which 12 are operational (REPD Q1 2026).

Solar already consented near HP2

From the government's Renewable Energy Planning Database, Q1 2026. These are the schemes on record in this postcode district, which is a fair guide to how the local network has been treating export applications.

Scheme	Operator	Capacity	Mounting	Status
Iron Mountain Site	Iron Mountain	0.3 MW	Roof	Operational
Amazon Boundary Way	Amazon UK Services / Push Energy	2 MW	Roof	Planning Permission Expired
G Park Maxted Road - Solar Panels	BBUKPF	1.25 MW	Roof	Awaiting Construction
Century House, Maylands Avenue - Solar PV Panels	Smiths Detection Limited	0.72 MW	Roof	Awaiting Construction
G Park, Maxted Road - Solar Panels	ABRDN	0.77 MW	Roof	Awaiting Construction

Book the survey

Send us the postcode

Tell us where the unit is and roughly how big the roof is. We come back with what it can carry, what it would generate against your consumption, and the three ways to pay for it.

Lenzie Consulting Ltd arranges the survey and passes your details to our MCS-certified installation partner so they can quote.

Questions about solar in Hemel Hempstead

What would a 500 kWp array produce on a farm near Hemel Hempstead?: Yes, and the figure matters more than the sunshine. At 895 kWh per kWp a year, a 500 kWp array on a Hemel Hempstead holding models at around 448,000 kWh. What changes the answer is how much of that the farm uses itself. Source: EU PVGIS v5.2, SARAH3, 10 degree pitch, 14 percent system loss.
Which network operator handles the connection around Hemel Hempstead?: Applications go to UK Power Networks, who run the network across Hertfordshire. On a farm the incoming supply matters as much as their answer: a single phase supply caps what can be installed whatever the roof would take.
What does Dacorum require for solar on an agricultural building?: Roof-mounted panels on an agricultural building often fall under permitted development, subject to limits on projection above the roof plane and to the building not being listed or in a conservation area or National Park. We confirm the position with Dacorum before the design is finalised.
Has anyone near HP2 already done this?: The planning database records 0 ground mounted and 5 roof mounted solar schemes in this postcode district. That matters less as proof it works and more as evidence of how the local network has treated export applications. Roof arrays under a megawatt often never appear in the database, so the real figure is higher. Source: Renewable Energy Planning Database, Q1 2026.

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