Harrow’s private drivers are switching to plug-in cars at a steady clip. DVLA records about 7,524 privately kept plug-in vehicles across Harrow borough at the end of June 2026, up from 5,934 a year earlier, a rise of roughly 27% in twelve months (our arithmetic on the Department for Transport’s table). For a Harrow household with an electric car, or one on the way, the question is how a car, a home battery and solar panels fit together, and which one does which job. This guide answers that with Harrow’s own figures. For storage on its own, see our page on battery storage in Harrow.
What the DVLA figures do and do not say
The figures count licensed plug-in vehicles, battery electric and plug-in hybrid together, by the registered keeper’s address. We use the privately kept count because company-registered cars can sit at a fleet’s address rather than an employee’s home; in Harrow, about 9,695 plug-in vehicles were licensed in all, so private keepers account for most of them. The figures cover the whole borough, from Harrow Weald to South Harrow, and they count cars, not chargers or households with a car.
Three devices, three jobs
Solar panels generate. A battery moves electricity from when it is made, or bought cheaply, to when you need it. An EV is the largest flexible load most homes will ever have. The common mistake is to expect the battery to fill the car. The Energy Saving Trust describes a typical home battery as perhaps 10 kWh, which is small next to a car’s battery, so in most Harrow homes the car charges either directly from surplus solar on a sunny day or from the grid on a cheap overnight rate, while the home battery looks after the house in the evening.
The cost of grid charging gives a sense of scale. At the October to December 2026 price-cap average of 26.32p per kWh, putting 60 kWh into a car costs about £15.79 (our arithmetic); off-peak EV tariffs price overnight units well below that average.
Summer and winter in Harrow
PVGIS estimates that a 4 kWp due-south array in Harrow makes about 3,965 kWh a year, but the year is lopsided: about 477 kWh in June and 480 in July, against about 140 in December and 159 in January. The nearest Met Office station with a sunshine record, at Northwood, averaged about 209 hours of sunshine in July and about 51 in December over 1991–2020.
That shape decides how the three devices share the work. On a summer weekday a car parked at home in the daytime can soak up surplus solar directly, and a battery takes what is left for the evening. In December there is little surplus for either, and the car and the battery both lean on the overnight rate. A battery sized for the house’s evening use, rather than for the car, is the one that earns its place across the whole year. Our guide to what size home battery you need covers that sizing.
Where Harrow households charge
Semi-detached houses are the largest housing type in Harrow, home to 37.1% of households, and they lead in North Harrow (54.0%) and Kenton West (64.7%), where owner-occupation reaches 74.8% (Census 2021). Owners of houses decide for themselves, but they get no OZEV grant: the scheme that covered them closed in April 2022. The town centre is different. In Greenhill ward, 69.0% of households live in purpose-built flats and 47.5% rent privately, and there OZEV’s grant of 75% of the cost, up to £500 per socket, is available to renters and flat owners with private off-street or allocated parking, through an OZEV-authorised installer. Households with on-street parking only can get up to £500 towards a chargepoint with an approved cross-pavement solution, subject to the council’s rules.
Fuse, network and paperwork
A 7.4 kW charger draws 32 A continuously. Most homes have a 60 A, 80 A or 100 A main fuse, and load management, a current sensor on the incoming supply, usually avoids an upgrade even with a battery in the mix. Our guide to whether your fuse will take a 7 kW charger goes into the detail. Harrow town centre sits in UK Power Networks’ Eastern Power Networks area. The installer notifies UKPN of a new chargepoint, and a battery goes through the G98 or G99 route like solar: up to 16 A per phase (3.68 kW) is notified, anything larger needs approval before work starts.
VAT and costs
The VAT treatment differs between the devices. A residential battery installation carries 0% VAT until 31 March 2027 and 5% from 1 April 2027, but a home chargepoint is not on the energy-saving list and is standard-rated at 20%. On the Energy Saving Trust’s figures a home battery ranges from £1,500 to £10,000, with a 5 kWh system around £4,600; your own figure comes from a survey. Some suppliers also offer export tariffs that require both solar panels and a home battery, with a half-hourly smart meter and an MCS certificate; those terms are set by each supplier.
Next step
For the roof side, see our solar panels in Harrow page, which covers Harrow on the Hill’s conservation areas, and our solar panels in North London hub for the wider area. If the network paperwork is your main question, our Edgware guide to G98, G99 and power cuts goes through it. When you are ready, ask for a survey through our contact page.
Sources: Department for Transport and DVLA, VEH0142 licensed plug-in vehicles by local authority (2026 Q2 and 2025 Q2, published 23 September 2026); PVGIS 5.3, European Commission Joint Research Centre (PVGIS-SARAH3 2005–2023, Harrow run 15 October 2026); Met Office, Northwood location-specific long-term averages 1991–2020; Ofgem, energy price cap October to December 2026; Energy Saving Trust, Battery storage (updated 19 August 2026); HMRC, VAT Notice 708/6; GOV.UK, Changes to electric vehicle chargepoint grant schemes from 1 April 2026 (updated 7 July 2026); ONS Census 2021, TS044 and TS054, Harrow borough and Greenhill, North Harrow and Kenton West wards, via Nomis; London Borough of Harrow, Living Harrow: Climate and Nature Strategy 2023–2030; UK Power Networks, licence boundaries dataset and EV and fuse guidance; Energy Networks Association, EREC G98 Issue 2; Octopus Energy, export tariff eligibility page (7 October 2026).