What is power factor correction?
Power factor correction reduces the apparent power needed to supply a given active load by managing reactive current or current distortion [S1]. It can matter to your connection capacity and bill. UK Power Networks publishes a minimum 0.95 power factor condition unless otherwise agreed, with further qualifications [S2]. Check your connection terms and measured demand before buying equipment. Checked October 2026.
What does power factor correction mean?
Power factor correction is the use of electrical equipment to reduce reactive current or current distortion and improve the relationship between active and apparent power [S1].
Why it matters for your site: a poor power factor can increase the current needed for your working load and affect network charges [S3]. Before adding chargers, establish whether the issue is actually present. Use the business electricity data for context, alongside your own bill.
A kilowatt (kW) measures active power; a kilovolt-ampere (kVA) measures apparent power. For the conversion and supply headroom calculation, read kVA, kW and power factor.
How do capacitor banks and active correction differ?
Capacitor banks supply reactive power locally to offset inductive loads, such as motors. Automatic banks switch stages as demand changes. Active correction uses power electronics to shape current rather than simply adding capacitance [S1].
Chargers and solar inverters therefore need an equipment-specific assessment. Ask for measurements across operating loads and an explanation of any harmonic distortion. Adding capacitors alone does not resolve every distorted current waveform [S1].
When could poor power factor affect your bill?
National Grid Electricity Distribution identifies excessive reactive power charges for relevant high- and low-voltage half-hourly metered customers [S3]. Your actual exposure depends on the applicable charging schedule and how those charges appear in your contract. Ask for the affected bill lines before calculating a saving.
UK Power Networks’ published conditions specify at least 0.95 power factor unless otherwise agreed, alongside restrictions on reactive energy flows [S2]. Ask your distribution network operator (DNO), the local network company, to confirm your conditions. Check contractual interpretation with your solicitor.
Next step
Gather your bills and survey findings for the site-power tool and cut energy costs hub, then get matched with an installer that covers your area.
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Common questions
Does correction generate electricity?
No. It changes reactive current or current shape; it does not create the active energy your equipment uses [S1]. Request measurements rather than a promised reduction in consumption.
Is a capacitor bank suitable for every charger?
No. Capacitors compensate inductive reactive demand, while active correction can address distorted current. Ask the designer to measure the load and harmonics before specifying either [S1].
Is 0.95 a universal UK requirement?
No. It is a condition in the cited network guidance, subject to agreement and operational qualifications. Obtain the conditions for your own connection [S2].
What should an inverter proposal disclose?
Request its reactive-power operating range and how the proposed settings meet your connection terms. The cited guidance calls for equipment capable of operation from 0.95 lead to 0.95 lag [S2].
Which billing information should you request?
Ask for the reactive-energy line, applicable network charging schedule and measured demand. The network identifies excessive reactive power charging for relevant half-hourly metered customers [S3].
Ask about your site
Sources
- Power factor correction, IEEE,Last checked 19 October 2026
- Power factor connection responsibilities, UK Power Networks,Last checked 19 October 2026
- Electrical losses and reactive power charging, National Grid Electricity Distribution,Last checked 19 October 2026