St John’s School & Sixth Form College, a Catholic Academy in County Durham was opened in 1964 and has seen extensive redevelopment and extension since. The school has been continually maintained and improved to a high standard which has enabled the school to retain its essential character while adapting to the changing demands of education.

The Challenge

Whilst the school is proactive in looking at ways to reduce their energy a primary concern was that 5-10 PC monitors were failing every week and the school network was going offline. Other issues were the air handling unit in the sites kitchen intermittently going into reverse which shut off the gas supply causing major problems with the food preparation. Food mixer motors were also burning out and the pumps for the swimming pool failing prematurely.

The Solution

A three phase logging equipment was installed to analyse the incoming and site power quality. The analysis showed excessive 3rd harmonics causing the site failures. The EMS designed Powerstar unit was specifically wound to correct the 3rd harmonic issues. Post installation the power quality issues have now been resolved and the correct voltage applied to the sites electrical equipment. A secondary benefit through voltage optimisation is the site is now saving £8,125 in annual electricity costs.

Savings & Benefits

Key Figures

Actual reduction in energy consumption: 8.8%
Guaranteed reduction in energy consumption: 7.9%
Annual financial savings: £8,125
Carbon reduction savings per annum: 42.8 Tonnes


The lifespan of equipment on site has now returned to normal with 3rd harmonics issues resolved and 81,614 kWh saved per annum.

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