Page 38 - Energize May 2021

TECHNICAL

Demand reduction around 20 percent of the total power supply, the control and optimisation of the power system
Reducing an installation’s electricity, becomes a significant challenge. Centralised transparency into all devices, from the power
natural gas and water consumption generation assets to the devices that consume electricity, enables proactive management of
requires a change in customer behaviour the power system. With automated monitoring and controls, power system supply and demand
combined with the implementation of can be optimised and balanced in real time and faults can be quickly detected, isolated and
conservation measures. Some examples repaired. Advanced controls allow systems to operate based on performance metrics such
of widely commercialised solutions include as economics, carbon footprint or reliability. Advanced demand response systems enable
programmable thermostats, occupancy automatic peak load shedding and participation in the energy markets (where allowed by
sensors, efficient lighting, building envelope local regulations), a key revenue generating opportunity. In addition, storage assets can be
improvements, chiller and boiler upgrades/ automatically deployed to sustain mission critical loads. The key challenge is the integration of
retrofits, VFDs for HVAC units, building the disparate systems to optimise the total system.
management systems and advanced
metering. The cost savings that result from Grid independence
conservation measures can be leveraged A fully evolved microgrid is the culmination of the previous three phases and the ability to
to fund advanced on-site generation operate independently from the main grid for an extended period of time. Automated controls
and storage solutions. While electricity know when, how and why to be grid independent, or connected to the main grid. Grid
conservation is the primary focus of this independence can be accomplished in two ways. First, if the microgrid has internal combustion
phase, water conservation will improve engines with reactive power compensation within the system to provide voltage and frequency
project payback. regulation, the power system can connect or disconnect via relays, switches and breakers – this
is the more developed method and commercially available today. Alternatively, the microgrid
On-site generation and storage generation and storage assets can connect to the main grid via a series of inverters, allowing for
Implementation and integration of on-site more advanced control of power in both directions between the main grid and the microgrid.
generation (renewable and conventional)
and storage solutions is the next level of What drives a consumer to consider a microgrid solution?
microgrid development. The goal is to deploy Microgrids are not for every type of end user. The investment can be significant. The simple
power generation that is cleaner (lower GHG) payback will likely be more than 15 years, but for certain organisations it is well worth the cost.
and more efficient for the end user than what
is generated by the main grid. Renewable, Reliable and secure power system
on-site electricity generation options include Hospitals, universities, refineries, pharmaceutical manufacturing, data centres and the
solar photovoltaics and small wind turbines. military are dependent on having a continuous, uninterrupted supply of power. Today, these
Given the relatively low cost of natural gas organisations maintain on-site generators (mostly diesel) for emergencies because even a
and efficiency of modern combined heat and modest loss of power can have negative consequences. The automated controls in a microgrid
power (CHP) solutions, end users can deploy will better balance the demand in the system with a supply of energy from backup generation,
small gas turbines (under 50 MW) to provide the main grid and local storage assets.
an economically viable generation capability.
To lower the total carbon footprint, locally Physical and cyber security
produced biomass or methane from landfills Some federal installations, particularly the military and security agencies, place a high value on
can be used as fuel for the turbines instead physical and electronic security. Hacking sponsored by foreign governments or online activists
of natural gas. Storage of energy, whether adds an additional degree of risk and the need for an advanced, secure power system solution.
thermal or electric, may be high- or low-tech.
Batteries, flywheels, compressed air and Planned transformation
pumped hydroelectric storage are among Organisations in growth or transformation mode are ideal candidates for a microgrid solution.
the more high-tech (and higher cost) options. Expanding a university, building a new factory or the military’s base realignment and closure
Relatively low-tech storage solutions include process (BRAC), which consolidates personnel onto fewer, expanded bases, are good
chilled water or ice storage. Electric vehicles candidates for microgrid solutions. In each case, there will be a significant increase in baseline
offer another alternative for energy storage. energy consumption. Similarly, a planned replacement of on-site power generation is a perfect
Although experts are split on the feasibility time to consider future power system needs and conduct a lifecycle cost assessment to
and business case of using electric vehicles determine the best path forward.
as storage, what is universally accepted is
the attraction of recharging vehicles at night, Regional drivers
when the demand for electricity and the cost Government regulations and incentives that affect the microgrid business case are at the local,
of electricity is lowest. state, regional and federal level.
• Local: The Database of State Incentives for Renewables & Efficiency (www.dsireusa.org)
Advanced controls provides an expansive and dynamic list of local, state, utility and federal incentives and
Control systems, such as distribution policies that support green energy initiatives.
supervisory control and data acquisition • State: Certain states have established renewable energy targets or Renewable Portfolio
(SCADA), building management and demand Standards (RPS) for power producers, making some degree of renewable or alternative fuel
response, are all parts of an intelligent adoption mandatory.
microgrid network. As the percentage of • Regional: Independent system operators (ISOs) and regional transmission organisations
on-site renewable generation approaches (RTOs) vary on whether and how energy consumers may participate in energy markets.

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