ENERGY MANAGEMENT


hospitals in the New York area were closed to patients for at least three weeks after the storm, many due to power loss and even loss of emergency back-up generators that were damaged, flooded or ran out of fuel. At Bellevue Hospital, the national guard formed a ‘bucket brigade’ to get fuel to the generators in an attempt to keep them running.3 A blackout in 2003 saw half of New


York City’s 58 hospitals experience failures in back-up power generation.4


When back-


up power fails, patients must be moved to other facilities, causing upheaval to caregivers and families. During emergency events, a hospital’s resources can be overwhelmed as they may be inundated with patients from other hospitals as well as other medical facilities, walk in clinics, nursing homes and retirement care facilities. When a power failure occurs during an emergency like Hurricane Sandy it adds complication and resource depletion at a time when urgent care needs spike.


Cost implications Severe weather related power outages in the US cost the economy between $18 billion and $33 billion between 2003 and 2012.5


Overwhelming scientific


evidence shows that climate change is set to increase the frequency and magnitude of storms and additional pressure on the electricity grid is expected as urban populations continue to increase. Current levels of US urban living are 83 per cent and this is figure is expected to rise to 90 per cent by 2050.6


These combined


elements are spurring the push towards reliable critical infrastructure resilience through on-site generation and other strategies.


In addition to the growing need to


mitigate against grid based electrical power failure, hospitals are seeking to improve sustainability, reduce carbon emissions and better manage resources. Energy management is becoming


4.6 MW


gas turbine- powered CHP


1m gallon


chilled water thermal energy storage tank


200 kW of solar panels


Princeton healthcare system generates 100 per cent of its heating and cooling from CHP.


IFHE DIGEST 2018


The overall cost of producing energy is set to increase from 10.6 cents/kWh in 2017 to 23.5 cents/kWh in 2050, putting even greater demand on hospital budgets


and when to use on site power, all without any action from the user. The Fort Bragg military base microgrid


Army microgrid.


increasingly important. Thus, the goal for hospitals should be to invest in energy systems that ultimately help reduce energy use and the environmental impact associated with the energy they must use and increase the resilience of their energy systems to achieve reliable operation during severe weather or other critical events. Used effectively, among other strategies, microgrids can assist hospitals in meeting these goals. Microgrids are commonly seen as back-


up replacement for diesel generators, but this does not scratch the surface in terms of the functionality and benefit these systems can provide for critical infrastructure. Microgrids are essentially an energy management system that links multiple sources of energy supply, matching supply with building demand. Sources of energy include utility energy, on site generation such as CHP and solar energy and on site storage. Microgrids are intelligent systems that are controlled by highly advanced software that optimises and synchronises various pieces of equipment and energy transmission elements. This brings maximum intelligence and efficiency to building energy planning and management. Additionally, the system can determine what combination of energy resources to employ at any given time and when stand alone operation is required, all based on hospital management goals such as budget goals or sustainability targets. According to the US Energy Information


Administration, the overall cost of producing energy is set to increase from 10.6 cents/kWh in 2017 to 23.5 cents/kWh in 2050, putting even greater demand on hospital budgets. With intelligent switching, a microgrid can employ peak saving, leveraging on site against that of utility energy to determine when to buy


saves $4 million each year by taking advantage of a real time pricing tariff, and an additional $1.2 m by operating generators in peak saving and energy demand management modes.7 Disconnecting from the grid or ‘islanding’ with a microgrid can happen instantaneously with back-up storage to support local generation and this occurs seamlessly without disruption of service. This means that in the event of sudden utility grid collapse, the microgrid can switch to on site generation and storage instantly and without any interruption in equipment function. Maintenance and performance testing can also be conducted under normal operating conditions without system shutdown, which can find deficiencies that otherwise would only have become apparent during an outage. If one generator does fail, other units on the microgrid can easily pick up its load. Back-up diesel generators are also stranded assets, sitting idle until use, while microgrids work 24/7, using all elements constantly and at the peak of efficiency. This offers great resiliency and flexibility over a large range of circumstances and conditions. If on site generation ever exceeds demand, excess energy can also be sent back to the grid to produce a revenue stream. For example, the Princeton Healthcare System generates 100 per cent of its heating and cooling from CHP, so when the 200 kW solar array generates power during peak rate periods or when storage is full, this can be sent back to the grid to generate supplementary income.


Energy system efficiency The microgrid monitors and diagnoses every element in the system constantly and as an integrated whole for maximum efficiency. Historically, when a new wing or building was added to a hospital, a new set of equipment would be added to provide energy for the new section. The new equipment would not communicate with the old building, leaving isolated units of energy generation. Microgrids consider the whole building system with an integrated approach so that adding new sections or loads involves simply calculating to adjust for this new input. The system can operate for


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