Page 56 - Energize May 2022

TECHNICAL

All of this is driven by data. Modern microgrid solutions produce data points which are include UPS power for the cooling system
analysed by AI and machine learning engines. This data can be used to provide information as well if needed, so there is no longer
about the abnormal behaviour of system components, maintenance needs, unexpected a need for a multiplicity of smaller UPS
power fluctuations, or even security metrics. This information allows the microgrid to systems. The primary requirement of
become predictive and prescriptive. Leaders in the space do not just operate one or two cooling makes trigeneration with gas
microgrid solutions but have multiple sites that all aggregate management data. turbines or gas engines as a primary
source attractive. Data centres generally
Examples of C&I microgrids do not have space for renewable energy
Health care systems on site, but in some cases where
Hospitals and healthcare centres have the highest energy consumption per square metre land is available, especially outside of
of all non-industrial buildings. Healthcare facilities are distinct from other occupancies, CBDs, incorporation has been possible.
and this affects both their power needs and the systems that operate and supply power.
While healthcare facilities have always had some form of on-site energy generation, rapidly Commercial buildings
emerging new technologies and the growing desire for reliable power and cleaner energy Commercial buildings such as shopping
sources have put a renewed focus on more developed microgrids, particularly those using malls, have the great advantage of large
renewable energy components. roof space and open parking areas which
Many inpatient healthcare facilities are “defend-in-place” facilities, so they cannot lose could accommodate solar panels. Many
power for an extended duration of time. A healthcare microgrid is essentially a microgrid malls already have rooftop solar systems
on steroids. While there have been systems in the past which might meet the loose installed, making the conversion to
definition of a traditional microgrid, the intelligence and access to multiple new sources microgrid operation easier. Such buildings
adds a considerable amount of complexity to the system. The ultimate goal with healthcare are usually only equipped with standby
microgrids is no single point of failure. power and no primary source. The large
Hospital energy requirements are more complex than other buildings as there is a amount of rooftop solar makes large ESS an
requirement for heat (in the form of steam) for sterilisation as well as electrical power. This option as well. Some have found that peak
is normally supplied by either coal or gas boilers. CHP plant as part of the microgrid could be period consumption can be reduced by
used for this function. CHP plant can consist either of gas engines using trigeneration, or fuel using storage and could also use arbitrage
cells with heat recovery. Small gas turbines in combined cycle mode with HRSG have also as demand is low at night, allowing cheap
been used in larger installations. electricity to be stored for next-day use.

Data centres Manufacturing facilities
With their need for large amounts of continuous, clean and affordable power, data centres are Similar to commercial buildings, factories
excellent candidates to benefit from microgrids. These are receiving increased attention as a usually have large roof space and open
means to power data centres. Data centres have two critical components: servers and coolers. ground for PV installation. There are many
The data centre cannot run without a cooling plant and a reliable power supply because cases, though where the need for low
the cooling plant is just as important as reliable power for the servers. Data centres grade heat or steam makes CHP plant
traditionally have two stages of standby power: first-line diesel generator sets and standby an attractive option for primary power.
batteries (UPS systems).The purpose of the UPS system is to provide power to the server Some examples of industrial microgrids
systems during the start-up period of the gensets. Typical back-up periods would be 5 to 15 include the Guinness brewery in Dublin,
min. There is no UPS power for the cooling system. ABB’s facilities in Longmeadow and Eaton’s
A data centre microgrid provides both features and could vary the size of the ESS to factory in Germiston.

References
1. C Baumann: “How microgrids for data
centres increase resilience, optimise costs,
and improve sustainability”, Schneider
Electric White Paper 289, 2020.
2. P Asmus: “Plug-and-pay modular
microgrids gain market momentum”,
https://microgridknowledge.com,
30 December 2019.
3. Veckta Insights: “Commercial & Industrial
(C&I) Microgrids”, www.veckta.com

Send your comments to
Figure 3: Healthcare microgrid (Schneider) rogerl@nowmedia.co.za

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