ELECTRICAL INFRASTRUCTURE
How energy-resilient is your estate?
The electrical infrastructure of many major healthcare sites was designed in a different era, and has evolved over decades in reaction to changing circumstances and advances in technology. Ed McNaught, Healthcare specialist at TGA Consulting Engineers, discusses some of the key steps to take to ensure that such infrastructure can provide resilient standby power supply to 100% of clinical facilities, and, increasingly, can also accommodate embedded renewable generation.
With over 40 years’ electrical engineering experience, of which much of the last 20 have been spent advising NHS Estates managers, it’s clear to me that there are wide variations in the condition of healthcare estates. Some estates have modernised, but there are many where critical resilience relies on the performance of 40- or 50-year-old electrical equipment. While this equipment was well designed and built, and has remained reliable well beyond its designated life, the availability of spares and the skilled personnel to maintain it are becoming scarcer, and the risk of critical failure increasing. This in turn presents a greater risk to staff and patient safety, that is fast becoming untenable. As we move towards Net Zero Carbon, and become
ever more reliant on electricity, the grid will come under growing pressure countrywide, so it is essential that healthcare estates can cope with the increased electrical loads that come with decarbonisation, as well as with power supply disruption. The increasing risk of more frequent cyberattacks on hospitals, such as the incident on 3 June which severely affected services at some major London hospitals – described as ‘one of the most serious in British history’ – reinforces the need for hospital infrastructure to be self-sufficient, resilient, and resistant to such attacks. So, what can be done? The modern hospital estate needs electrical infrastructure that: n Can provide resilient standby power supply to 100% of clinical facilities (historically this was only 30%);
n Can ensure resilience in times of disruption to the primary supply;
n Has the capacity to accommodate embedded renewable generation (e.g. solar PV);
n Has capacity to supply electric powered plant installed to achieve decarbonisation of heating and cooling, and
n Has the capacity to supply EV charging systems for operational vehicles, and possibly staff and visitor vehicles.
Determining the capacity of the electricity supply that will be required to meet these various drivers requires a number of steps, which are closely linked into the stages of a decarbonisation plan. Let’s look at each of these points in turn.
1: What must be done to provide a resilient standby power supply to 100% of clinical facilities?
Historically, hospital electricity distribution has been classified as essential and non-essential – the latter supplied from the incoming grid supply, with the capacity
to supply 100% of the load. This would provide the normal supply to the essential distribution, which could supply 30% of the load, and would have a changeover arrangement to a secondary supply, typically standby generators sized only for this purpose. However, this no longer offers sufficient resilience for modern clinical care requirements, where there is increasing reliance on electrically powered systems and devices. NHS England’s Health Technical Memorandum (HTM) 06-01 provides good clear guidance on governance and risk management steps that Trusts should adopt to determine risk to patients from supply loss, and the appropriate clinical risk grade for each department within the hospital. It also addresses and grades risks to business continuity due to supply loss.
The role of the Electrical Safety Group The HTM advocates the Electrical Safety Group overseeing the governance of this. Some Trusts have established a standing Electrical Safety Group, whereas others form one as needed. While the group’s membership can be adjusted to address circumstances at hand, it is certainly beneficial to maintain a standing group that regularly reviews all matters set out in the HTM.
Figure 1: The solution for the University Hospital of North Tees in Stockton- on-Tees comprised two ring main units connected by a cable, with the DNO routinely using this as the open point on its interconnector between two primary substations.
DNO switched alternate supply
Hospital intake switchboard
Standby generation system
Further area substations connected in ring
Area substation
Clinical department section boards
October 2024 Health Estate Journal 55
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104 |
Page 105 |
Page 106 |
Page 107 |
Page 108 |
Page 109 |
Page 110 |
Page 111 |
Page 112 |
Page 113 |
Page 114 |
Page 115 |
Page 116 |
Page 117 |
Page 118 |
Page 119 |
Page 120 |
Page 121 |
Page 122 |
Page 123 |
Page 124 |
Page 125 |
Page 126 |
Page 127 |
Page 128 |
Page 129 |
Page 130 |
Page 131 |
Page 132
