Testing Times

Resilience testing of standby power equipment ensures that vital electricity supplies are maintained in the event of an emergency. However, routine ‘on-load’ testing can be expensive while ‘off-load’ testing can potentially damage valuable equipment. Yoav Zingher, director and co-founder of KiWi Power, explains (as an example) how several hospitals throughout the UK are incorporating resilience testing regimes into their demand response programmes, providing NHS Trusts with lower energy bills, optimised standby power equipment and substantial risk-free recurring revenue streams.

Facilities managers working in NHS-run hospitals will undoubtedly be familiar with health and safety legislation and guidance surrounding the issue of resilience. Resilience management refers to:

‘All activities undertaken to give NHS facilities the capacity to anticipate, prevent, prepare for, respond to and recover from disruptive challenges that would otherwise prevent the organisation from meeting its primary duties.’ - (HBN 00-07) .

Essentially, resilience is the ability of a building and its services to withstand the impact of an incident or emergency. Such emergencies might include acts of terrorism, civil disturbances, storm damage and unplanned interruptions to utility supplies.

Emergency planning measures and detailed risk assessments are carried out in order to prevent loss of power. Furthermore, hospitals are legally required to ensure that systems must be reliable, available, maintainable and economic (in terms of efficiency) under the Health and Safety at Work Act 1974.

Safe supply

A hypothetical example of a resilience requirement developed from a risk assessment listed in HBN 00-07 states that hospitals should have:  “Provision for an electricity supply system that is capable, in the absence of mains electricity, of sustaining the essential load of the facility for a period of not less than 200 hours.”

Due to historically high levels of grid reliability, disruptions to electricity supplies are rare. To mitigate against loss of power, all healthcare premises are connected to the public electrical supply (PES), which is provided and operated by a local distribution network operator (DNO). It’s recommended, where possible, that larger healthcare premises should be supplied with a dual PES from separate DNO substations. These, in turn, should ideally be fed from separate parts of the National Grid in order to avoid having a single point of mains failure - (HTM 06-01)².

In addition to a dual PES, hospitals are also equipped with emergency standby power generators, which are designed to offer significant power capacity in the event of a supply interruption or outage.  

Standby generator set at the Lister Hospital




Critical power

The increasing use of power-hungry devices within hospitals can result in electrical infrastructure running at full capacity. IT equipment, air conditioning and vital electronic diagnostic and monitoring medical equipment all require a constant supply of uninterruptible power. Without this, patient health is put at risk, particularly in departments such as operating theatres, cardiac wards, A&E and radiography, where life support equipment is used. Non-clinical and support departments also rely on secure power supplies to maintain vital services and provide continuity of care.

Legal obligations, reducing clinical and non-clinical risks and business continuity are important reasons why a thorough resilience testing regime is essential for hospitals. Recent events in the US demonstrated how inadequate standby power contingency plans forced several hospitals and medical centres to close and evacuate patients following Hurricane Sandy. Closer to home the failure of a 500 kVA standby power generator at Watford General Hospital in November 2004 was caused by an excessive electrical load.

Demand response

Recently, several NHS-run hospitals throughout the UK have improved their standby power resilience testing regimes through a programme called ‘demand response’ (DR).

The Colchester General Hospital


Demand response is an increasingly popular green alternative to the expensive carbon-heavy ‘peaking power stations’ that the National Grid relies on during times of grid stress. The process involves electricity demand management whereby participants temporarily switch off or turn down non-essential power. Alternatively, companies can switch over to their existing independent standby power generators for a short period of time - usually around an hour. This reduces electricity use and helps National Grid to meet the needs of the country at times of grid stress without having to fire up expensive and dirty coal-fired power stations, or to import electricity from abroad.

Carrying the load

Like a car engine, generators require frequent use to keep them working efficiently and, in order to ensure emergency preparedness, should be tested at least once a month. Testing ‘off-load’ can cause poor combustion, soot formation, clogging of injector rings and unburnt fuel creating oil contamination. Fuel kept in storage for extended periods of time can lead to further deterioration and damage. Demand response allows standby generators to be tested ‘on-load’ and at full capacity, making it an ideal way to prove engine resilience and optimise performance. Generators are most valuable in DR programmes where they are able to synchronise with the mains grid supply because they can support significant site electrical loads.

Recurring revenue

The National Grid is willing to pay organisations to use less electricity at times when it is struggling to meet peak demand. It is able to do this because it is cheaper than paying for polluting coal-fired power stations to be kept ‘warm’ or on standby in order to meet this occasional extra demand for energy. Larger organisations, such as NHS-run hospitals, can earn up to £100,000 per year by participating in a DR programme with no upfront costs to pay. The installation of smart grid metering equipment and, if necessary, integration with existing building management systems, is carried out with no upfront cost by some DR aggregators such as KiWi Power.  

Smart hospitals

Increasing numbers of facility management staff working in hospitals are beginning to see the value of utilising their existing standby power assets for DR, or are incorporating DR measures when planning upgrades to electrical infrastructure.

Case example 1:  Lister Hospital is an acute NHS-run hospital in Hertfordshire that is currently participating in a DR programme. The hospital recently upgraded its electrical systems, which included a new combined heat and power plant (CHP). To help ensure the hospital had a reliable standby power solution in the event of a power failure, it installed new on-site generators and duplicate electricity feeds. Together with lower carbon CHP technology, Lister Hospital is provided with 4.5MW which can be dispatched to provide short-term operating reserve (STOR) and is able to avoid peak energy tariffs through TRIAD management.

Aerial view of The Lister Hospital


KiWi Power, was responsible for the project management and support for the deployment of four newly installed 2MVA, LV diesel standby generators, which provide full backup for a new 5MVA, duplicate 11kV feed from UK Power Networks. Controlling and monitoring these generators remotely allows facility managers to be contacted immediately should any problems arise.

Case example 2: Colchester Hospital University NHS Foundation Trust provides healthcare services to around 370,000 people from Colchester and the surrounding area of north-east Essex. The hospital’s electrical services have been upgraded and its load capacity increased: a DR programme also facilitated a remotely automated start procedure that has improved the Trust’s resilience testing regime, achieved savings on the energy bill and generated a new revenue stream for the hospital.
Emission control

A DR programme mitigates the risks associated with poorly managed backup energy supplies. The advantages of such a scheme are:

- costly load bank testing is reduced;
- an improvement in generator reliability at times of mains failure;
- hour-long run times so no alteration to generator cooling is required;
- and the replacement of a normal testing schedule with a revenue-generating load test exercise.

Through DR aggregators, such as KiWi Power, hospitals are now reducing their energy consumption from the grid at peak demand times while getting paid by National Grid. In this way, hospitals are earning significant recurring revenue streams, gaining visibility into their real-time energy use, improving resilience testing regimes as part of their emergency preparedness and decreasing their carbon footprints. 

Not only hospitals, but any industrial or commercial organization, where continuity of power supply is critical to their operation, can adopt these testing procedures for their standby power equipment.

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