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OVO Energy Ltd

OVO Logo

Reducing energy consumption by 30%

“The results speak for themselves but the process and experience of achieving them was smooth and, dare I say it, enjoyable."

Justin Dekoszmovszky, Head of Sustainability

OVO energy is a leading independent energy supplier offering keen pricing and exceptionally good customer service.  Founded in 2009, it is growing rapidly and has 460,000 domestic customers and 850 employees.  OVO believes in being a good corporate citizen and has a serious and practical approach to all aspects of sustainability.

The challenge

OVO Building

To facilitate its rapid growth, OVO leased a new 6,500m2 headquarters at Temple Quay in Bristol. OVO’s objective was to maximise energy efficiency as part of the office refurbishment.  As it is likely to outgrow the twelve year old building within three years, significant capital investment was ruled out.  OVO also needed support to develop internal systems, procedures and legal compliance.

Maximising energy efficiency

The Green Consultancy (TGC) carried out an energy audit to identify cost effective improvements to the refurbishment and a second, after occupation, to investigate the behaviour of energy-consuming central plant and other equipment at night.

We advised on the selection of suitable metering, monitoring and targeting hardware and software.  Key to OVO’s selection criteria were the drill-down and analytical functions – to quickly identify energy-savings opportunities and verify the results of implementation. Submeters were installed to give a sufficiently detailed breakdown of energy consumption without spending a fortune and “over-measuring”.

TGC worked closely with our Building Management Systems (BMS) partner Demma to optimise the Building Management System (BMS).  For example, BMS sensors were located in the void above false ceilings where they would not function properly and they were relocated.  Advice was also provided to identify and implement low cost improvements to the lighting controls.

30% energy saving with payback under 2 months

The above improvements enabled OVO to achieve a 30% reduction in energy consumption – that’s a saving of around £120,000 pa with a payback of less than 2 months.  Here are a few examples of the opportunities implemented.

  • Chiller and air handling had never been correctly scheduled and this was causing the entire building to be filled with chilled air every night.  Not only was this a waste of electricity running the fans, pumps and chillers, but the boilers were having to run overtime to reheat the building the next morning.  Heating and cooling for the building were both set to 22oC, and so fighting each other and running all day.  Fixing those problems saved nearly £100,000 and reduced gas consumption by 49% as shown below.

OVO chart 1







  • Turning the central plant from “in hand” (manual) to auto instantly saved £10,000.
  • Control routines were added to the servers to centrally switch off all the PCs and printers once everyone had left the building.
  • Time control was optimized on hot water taps and added to the water coolers.  This only cost a few hundred pounds and saved over £1,000 per annum.
  • Switching off electric heaters in gym change rooms when not needed saved 71% or £10,000 as illustrated below – and made for much happier, less sweaty gym goers.

Average savings chart for switching off heaters

Systems, procedures and legal compliance

TGC provided OVO’s Energy Savings Opportunity Scheme (ESOS) Lead Assessor and worked with OVO to prepare management systems to be compatible with ISO 14001 and ISO 50001.

The Reaction

Justin DeKoszmovszky

"I have been very impressed with TGC's pragmatic, flexible and effective approach and results.  In the year we started working with TGC we grew roughly 300% and doubled our staff numbers while moving to a new building.  TGC was able to strike the right balance of applying proven process while leaving room for innovation to match OVO's culture and situation.  The above results speak for themselves but the process and experience of achieving them was smooth and, dare I say it, enjoyable."
Justin Dekoszmovszky, Head of Sustainability


Put us to the test NOW!  To discuss your requirements please call John Treble on 01761 419081 or email John@GreenConsultancy.com

John Treble

Put us to the test NOW!

For over twenty five years we have been delivering superior outcomes for thousands of commercial, industrial and public-sector clients.

You need not take our word for it – hundreds of their comments are at the foot of these pages.

To discuss your requirements please call John Treble on 01761 419081 or email


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