What is Voltage Optimisation?

What is Voltage Optimisation? Quite simply, it is to reduce the voltage applied to electrical equipment. If the reduction in supply voltage is careful...
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What is Voltage Optimisation? Quite simply, it is to reduce the voltage applied to electrical equipment. If the reduction in supply voltage is carefully matched to the needs of the electrical equipment it is possible to make a substantial energy saving and extend the equipment's life expectancy.

The Voltage Supplied to Sites in the UK: Above 250v

240 to 250v

230 to 240v

Very high supply voltage, very high energy wastage, with premature equipment failure.

High supply voltage, high energy wastage, with reduced life expectancy of equipment.

Medium supply voltage, reduced equipment efficiency which wastes energy.

230v

220v

Standard voltage range across Europe. Maximum equipment efficiency and life expectancy.

220 to 207v Low supply voltage, may be problematic with certain types of equipment.

Why can we reduce our Voltage? • There is a legal requirement for the National Grid to maintain the UK mains voltage. This is known

as the “statutory supply voltage” in the UK, it is set at between 216V and 253V: The average voltage supply being around 242V.

• The reason for the “statutory supply” being in a wide range is because of increased electricity

demands at different times of the day. The amount of power being used at any one time will cause the grid voltage to fluctuate.

• The supply voltages in the European Union are lower than the UK.

In 1993 supply voltages across the EU were harmonised, resulting that all electrical equipment supplied within the EU (CE mark) must work at voltages as low as 207V.

• So, in the UK, where supply voltages are traditionally much higher, equipment made for

the European Union is oversupplied with significantly higher voltages than it is designed for and this leads to higher running costs, unnecessary energy consumption and a shortened lifespan.

By adopting voltage optimisation technology, your electricity will be supplied at a functional voltage of around 220V.

The equipment on site… Below illustrates the hierarchy of energy savings for the same reduction in voltage. Very High

Mains frequency lighting

High

None thermostatically controlled heating

Very Good

Good

Moderate

Modest Low Very Low

Fixed speed motors (lightly or intermittently loaded) White goods Office & IT equipment Continuously heavily loaded fixed speed motors Other electronic equipment Variable speed, DC or servo controlled motors

SON, Metal Halide, Mercury Switch start fluorescent Compact fluorescent Tungsten halogen Towel rails Hand dryers Hair dryers Frost protection Air conditioning, Presses Air compressors, Pumps Refrigeration, Fans Conveyors, Machine shops Fridges & freezes Microwaves Washing machines Dishwashers VDUs Desktop PCs Photocopiers Printers Applications similar to fixed speed motors (above) HF lighting LED lighting Laptop PCs UPS equipment Applications similar to fixed speed motors (above)

Typical Saving Best Saving

Supply Voltage 245V High Savings

8%

10%

12%

12%

15%

19%

With the right type of equipment, for every 1% reduction in voltage, you will see roughly a 2% reduction in energy consumption! Therefore with a typical mix of equipment and an average supply voltage a 10% energy saving is possible in most instances.

Voltage Optimisation at Belton House

Belton House mansion, owned by The National Trust, Grantham

ECO-MAX Voltage Optimiser as installed on site at Belton House.

Belton’s electricity supply (2013) The National Trust worked with GWE to assess the site, and profile the existing energy usage for further analysis. It was recorded that the voltage at Belton House was very high and fell outside of the ideal range for maximum efficiency. The voltage fluctuation also caused numerous problems on site in terms of power quality. 270

260

250 Incoming Grid Voltage 240

230

220

210

Optimum Voltage (220V)

This graph shows the incoming fluctuating grid voltage at Belton House as recorded during the logging period 9/8/13 – 19/8/13 by GWE.

The Solution It was decided that implementing a voltage optimisation project would effectively reduce the incoming voltage to a more desirable level, minimising stresses on site equipment, reducing overall energy consumption and reducing the costs of electricity bills. A careful site equipment load analysis was completed and it was established that the voltage could be safely reduced by 7.9%. 270

260

250

240

230

220

210

Incoming Grid Voltage Optimised Voltage (7.9% Reduction Optimum Voltage (220V)

This graph shows the incoming voltage at Belton House recorded during the logging period 9/8/13 – 19/8/13 and the 7.9% proposed voltage reduction by the ECOMAX Voltage optimiser.

The Project Summary GWE give a thorough and accurate business case breakdown for each site, highlighting realistic expectations for savings, ROI and payback periods.

Current electricity consumption and particulars All inclusive electricity tariff Annual expenditure Annual consumption Maximum demand provided Supply voltage provided Anticipated savings based on an optimised voltage of 223v Percentage saving of current kWh kWh saving Reduction in harmful Carbon Dioxide emissions Reduction in CRC Tax payment, (based on £12/tonne CO2) Financial saving -- excluding CRC tax reduction Financial saving -- including CRC tax reduction Expenditure Total Estimated Cost Payback Excluding CRC tax reduction Including CRC tax reduction Return on investment Excluding CRC tax reduction Including CRC tax reduction

£

8.7p/KWh £33,231 381,970 KWh 121 Kva 242v Typical 10.6% 40,337 kWh 21.2 Tonnes CO2 £254

Maximum 15.1% 57,624 kWh 30.2 Tonnes CO2 £363

£3,509 £3,763

£5,013 £5,376

Typical

Best

29 Months

20 Months

27 Months

19 Months

41.4%

59.1%

44.4%

63.4%

8,484.00

The Savings and Benefits The ECO-MAX optimiser came into operation at 19:30 on Tuesday the 3rd December 2013. The graph below compares the kWh consumption for Monday the 2nd December against Wednesday the 4th December, (full day before against full day after installation). This comparison should rule out any differences in ambient temperature differences which may affect consumption. The average kWh consumption for Monday 2nd was, 20.4kWh compared against 18.4kWh for Wednesday the 4th, which equates to a saving of almost 10%.

The graph below compares the kWh consumption Dec 2012-Feb2013 against Dec 2013-Feb2014. The average kWh consumption for Dec 2012-Feb2013 was, 24.1kWh compared against 21.1kWh for Dec 2013-Feb2014, which assuming ambient temperatures and visitor numbers are similar, equates to a saving of 12.6%.

To be able to accurately test the effects like for like (as we can’t be certain there are an equal number of visitors as last year), live switching tests were carried out. This meant, switching the VO between ‘savings mode’ and ‘bypass mode’ and monitoring the difference. – The graph below demonstrates a 12% saving. kW Consumption 9th April 120

100

60 With ECO-MAX Without ECO-MAX

40

20

0 2:27:19 PM 2:29:57 PM 2:32:35 PM 2:35:13 PM 2:37:51 PM 2:40:29 PM 2:43:07 PM 2:45:45 PM 2:48:23 PM 2:51:01 PM 2:53:39 PM 2:56:17 PM 2:58:55 PM 3:01:33 PM 3:04:11 PM 3:06:49 PM 3:09:27 PM 3:12:05 PM 3:14:43 PM 3:17:21 PM 3:19:59 PM 3:22:37 PM 3:25:15 PM 3:27:53 PM 3:30:31 PM

kW

80

Other Benefits The property team at Belton House noticed a number of other benefits regarding the installation of the ECO-MAX equipment: Since the installation: - Light bulbs aren’t blowing as frequently so there is a lower ongoing maintenance cost - The fire and security alarms don’t trip as often so there are less disturbances and ‘false alarms’ - Due to the reduction in voltage spikes and fluctuations, electrical equipment on site will now have a longer operational life and will work more effectively at the reduced voltage. The equipment was installed at a convenient time, minimising the disruption to site and business continued uninterrupted as normal.

The Installation Before

After

1 year on In the year since the VO installation, in Dec ’13, Belton has used 11.4% less electricity. If you discount the months of Oct ‘14 and Nov ‘14 where the property was busier, because of a very warm half-term and Christmas offer, then the savings over the 10 month period are 14.8% At Hardwick Hall a VO on the Stableyard electricity supply has so far used 12.5% less in the 8 months since installation.

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