 Their intermittency creates problem

 Improve integration and enhance utilization of energy generated from photovoltaics and wind
turbines using BES
 Through distributed microgrids, you can monetize assets through new revenue stream,
increased asset utilization, improve yields and reduce operating costs
 Asset Monetization involves creation of new sources of revenue by unlocking of value of
hitherto unutilized or underutilized assets.
 Revenue streams are the various sources from which a business earns money from the sale of
goods or the provision of services.
 Improve safety by reducing fault current up to 5 times due to the utilization of electronic devices
that allow for lower fault current contribution to the rest of the electrical grid
 Renewable smoothing: orange line is the intermittent production of PV throughout the day, by
including ESS and filling the gaps (in blue), the energy produced will be smooth.
 Handle ramp or duck curve: this is when energy consumptions increased dramatically in a
predefined time. Every country or city has somewhat of a duck curve and the ability to handle to
load ramp cannot be done through conventional generation but it can be handled very quickly
be ESS
 Firming renewable production: Firming up supply means guaranteeing supply from other
sources in the event of poor sun or wind generation. While renewable energy sources have
become cheaper than coal, the issue lies with intermittency, in other words, they do not
generate energy when the sun is not shining or the wind is not blowing
 Stabilizing the electric grid
 Controlling energy flow
 Optimizing asset operation
 Creating new revenue
 Mitigate demand charges of commercial and industrial applications or time of day ToU (Time of
Use) energy charges
 Utilize the additional energy generated by PV which was not utilized
 Maintain constant voltage: by injecting reactive power as much as possible
 Black start: when conventional generators are not available or not possible to utilized
 T&D congestion relief: when supply and demand is served locally
 EV: when EV is act as a source
 LiFePO4: Lithium Iron Phosphate
 Usable capacity: it is typically considered wise to use just 30 to 50 % of the rated capacity of LA
deep cycle batteries, e.g., 600 Ah can only provide 300 Ah at best
 AGM: Absorbed Glass Matt
 The final 20% of Lead Acid battery cannot be fast charged.
 The first 80% is bolt charged by a smart, multistate charger but then the absorption phase
begins and the charging current drops off automatically making the last 20% a slow charge
process or trickle charge.
 Lead acid batteries suffer inefficiency issue, they waste around 15% of energy you put into them
due to inherent charging inefficiency. So, if you provide 100A power into lead acid battery, you
actually only storing 85 Ah effectively.
 The faster you charge any lead acid battery the less energy you get out of it. This is also known
as Peukert’s loss
 When the battery is applied to large current load, there will be voltage sag.
 Here is a typical BESS architecture, it consists of:
 LiFeSO4 battery
 Connected to the grid through a converter electronics and governed by a battery management
system
 Converter electronics is bi-directional allowing the battery to charge and discharge through the
BMS using supervisory control
 Supervisory control can be communicated through ICT to a microgrid controller or to a SCADA
system
 Information and communication technology (ICT)
 The BMS may have its local supervisory control that makes decision on when to charge and
discharge the battery based on state of the power grid
 The BMS also allows for data acquisition
 It allows the SCADA or external system to gain knowledge about the health of the battery, stage
of charge etc.

What is State of Charge (SoC)?

 The charging current, in blue, usually it is a constant up to a certain state of charge and then the
current decays exponentially
 Correspondingly, the battery voltage rises as the charging current is applied and it remains fairly
constant voltage till the charging current starts reducing after reaching preordain SoC and the
battery voltage starts climbing and becomes constant
 This is where we have reached 100% state of charge and the battery is ready to take on some
load.
 What is C-rate: it is a measure of the rate at which the battery is being charged or discharged. It
is defined as the current through the battery, divided by the theoretical current draw under
which the battery would deliver its nominal rated capacity in 1 hour.
 Simply, C-rate is used as a rating on the battery to indicate the maximum current that the
battery can safely deliver on a circuit
‘‘C’’ Rate *: A common method for indicating the discharge, as well as the charge current of a
battery, is the C rate, expressed as:
 Could be Voltage of individual cell, min and max voltage etc.
 Current flowing in and out of the battery
 BMS can also monitor temperature, coolant temperature or temp of individual cell
 Monitor State of charge SoC, Depth of Discharge DoD
 Monitor the State of Health SoH
  Monitor State of Power
 Monitor State of Safety
 Coolant flow for air or fluid cooled batteries

ETAP capabilities

https://www.youtube.com/watch?v=8wJUHxQcUQw
What are the Three D’s? Decarbonization, Decentralization, Digitalization
With the National Grid ESO confident it can operate on 100% renewables by
2025, the 3 D’s (decarbonization, decentralization and digitalization) become
even more prominent in paving the pathway towards this goal.

These 3 Ds are the pillars to creating the green energy economy of the future.
But what do each actually represent and mean? We’ll explain all…
Decentralization

Decentralization refers to the reduction in reliance on just a handful of large

generation plants. This means dispersing generation across many smaller
plants. It also refers to the increasing amount of embedded generation coming
online, for example, CHPs on business sites or solar panels on residential
properties.

Current carbon-based plants that feed power onto the grid, whilst bad for the
environment, do carry a certain level of what we call ‘system inertia’. This
essentially means that if a power plant breaks down then there is a small
amount of continued generation – typically just enough to enable the grid to
start up another power plant. Renewables do not tend to have the same levels
of inertia, and it is difficult to instruct another renewable source to start up.

It is important that there are lots of small renewable generators in order to

dilute the risk. As older, carbon emitting plants reach the end of their lives,
replaced with wind farms, solar fields, hydro/marine generation and biomass,
decentralization is increasingly prevalent.

Decarbonization

Decarbonization refers to eliminating carbon-based fuels for electricity

generation. Whilst the influx of renewable energy sources means that the grid
is more sustainable, renewable generation can be highly intermittent. The
weather is unpredictable, solar and wind cannot be relied upon, which creates
problems with the balance of supply and demand, and in turn affects the
frequency stability.

However inconvenient these fluctuations may be, it is imperative we meet our

green goals. The IPCC’s warnings on climate change, along with our
commitment to the Paris Agreement, mean our grid must be cleaner for future
generations.

The Intergovernmental Panel on Climate Change (IPCC) is an

intergovernmental body of the United Nations responsible for advancing
knowledge on human-induced climate change. It was established in 1988 by
the World Meteorological Organization (WMO) and the United Nations
Environment Program (UNEP), and later endorsed by United Nations General
Assembly. Headquartered in Geneva, Switzerland, it is comprised of 195
member states.

That’s where our next point comes in…

Digitalization

The energy market is undergoing complex changes. Therefore, effective

management and monitoring is imperative, and is achievable with state-of-the-
art digital technology when implemented across all areas of the electricity
system, from generation to transmission, distribution, supply and demand.

The technology for the elements on the grid has come along way. For
example, the demand-side technology on industrial and commercial sites,
battery technology (both behind-the-meter and in front) and residential
systems. However, the core infrastructure of the grid is still using similar
switches to those used in the 1940s, and so requires some further upgrades
in order to realize the full potential of digitalization.

 We can use intelligent battery parameter estimation inside ETAP BSS implementation
 We can use BSS modeling and simulation in ETAP for frequency, voltage, ramp & demand
response simulations
 Implementation of battery management system

 Some of the modeling challenges and the need for some of these capabilities
 One of the modelling challenges of battery storage is the complex non-linear behavior of the
charge and discharge curves, various C-rates that may be possible provided by the battery
manufacturer that follow different charge and discharge profiles.
 Hysteresis depends on battery chemistry
 Other modeling challenges may include:

 CC: constant current can be variable

 CV: constant voltage can be variable
 The battery it self is a load and a source
 When we look at the mathematical modeling inside ETAP, we essentially use the manufacturer
datasheet to begin with and we prepare parametric model of the battery. This parametric model
utilizes various parameters provided by the manufacturer to estimate the charge and discharge
characteristic of the battery.
 State of the art intelligent is used to convert manufacturer datasheet and the parameters into
optimized parameters and the corresponding charge and discharge curves that will be utilized
during the simulation
 In ETAP you can develop a battery inside the battery library and use battery parameter
estimation to estimate charge and discharge curves if they are not provided by the
manufacturer
 If they are provided by the manufacturer, you can also use parameter estimation to compare
the manufacturer as well as the estimated curves

 In DC arc flash, we may want to vary the State of Charge of the battery to see the DC short
circuit current contribution
 SC Current contribution decreases as the battery SoC decreases
 Based on Battery model and parametric model current contribution is decided
 At lower SoC the time takes for protection devices to react will increase, increasing I^2 t and
therefore the damage curve and eventually arc energy
 Ability to model various state of charge while conduction DC arc flash is very important feature
 DC short circuit
 DC Arc Flash
 Notice that the short circuit current from the battery is less than what we observe from short
circuit because what it is shown here is in fact the arcing current and not the bolted fault (zero
impedance fault current)
 Controlled rectifier allows regulation on input and output terminal depending upon the flow of
power
 Uncontrolled rectifier means that as the current output demand increases, the output voltage at
the rectifier also starts reducing.

 Time domain load flow is when we are varying loading or generation as a function of time and
including controls such as tap changers, switched capacitor banks and BMSs as well.
 Time domain allows you to define various events (define event that occur at a particular time
and include action e.g., circuit breaker open/close)
 Each component such as PV array, generator or source, can have time profile associated with it
 PV panel can you excel file for irradiance profile
 You can vary irradiance on pv panel as a function of time and observe the power flow of the
entire system as a function of time
 In time domain load flow, you are not limited to hourly step or minute step. For example, if you
use external data, you can go to the second time frame
 You can run computations for a whole day, an hour, a week, a month, a year and even multiple
years depending on the target and the objectives


 Time domain load flow has application in renewable power plants as well as microgrid systems
in order to perform time varying power simulation
 So far, we looked at steady state lets turn our attention to the dynamic side.
 In ETAP, you can actually model the dynamics of BESS together with their controller using UDM
 ETAP include BESS models based on WECC

 UDM is a graphic logic editor that allows you to model the transfer functions of various control
systems
 One you have built the TF you can then compile it and create a black box model of this control
system diagram
 For situations where control blocks are insufficient, you can add a script block using C# syntax to
define any kind of logic that can not be defined using the standard control blocks
 Using UDM we can build the complete battery energy storage system transfer function that not
only includes the plant level controller but it also includes the stat of charge logic
 State of charge logic has already been defined, it includes certain variables such as max and min
state of charge as well as some initial state of charge.
 Its output is driven into an electrical controller which includes various modes of operations
(defined) like voltage control, pf control, reactive power control and so on

 The dynamic stability has a time slide to observe:

o User defined actions like events
o Program defined actions
o Automated actions such as relay trips
 The difference between EMT and RMS is that EMT always considers instantaneous values of
voltage and current, whilst RMS only considers the fundamental frequency values. This means
that EMT simulations can also be used to model very high frequency phenomena (such as
lightning or switching surges).

 The system on the right, PSCAD, represents a full fidelity of the green boundary in ETAP(Left)
 PSCAD will solve the system in micro second step
 ETAP will solve the system in 0.1 ms step
 ETAP is connected to PSCAD
 You can include what PSCAD solves in micro second step in ETAP (co-simulation)
What is ‘behind the meter’? – An introductory
guide for businesses

Behind the meter: the way forward

A recent survey has revealed that nearly two thirds of companies with large
energy bills are planning to invest in battery storage technology. The news is yet
another example of how organizations are increasingly taking steps ‘behind the
meter’, in order to control their energy costs and improve their carbon footprint.
Without doubt, the idea of operating behind the meter has been one of the most
talked about subjects within the energy industry in recent years. But what does it
mean in practice and how can businesses benefit from doing it?
What does behind the meter mean?
Any gas or electricity user – whether they are big or small, a domestic user, or a
commercial or industrial organization – will have meters on their premises that
calculate how much energy has been taken from the grid and consequently how
much is owed to the utility provider.
In simple terms, behind the meter refers to anything that happens onsite, on the
energy user’s side of the meter. Conversely, anything that happens on the grid
side is deemed to be in front of the meter.
So, why all the hype?
Until recently there was not much you could do behind the meter, bar turning off
lights and equipment when they weren’t needed, in order to save money and
reduce carbon emissions. The world, however, has changed and there are now a
whole host of possibilities.
Renewable Energy
Investing in some form of renewable generation is increasingly popular. Solar
photovoltaic (PV) panels and other power-generating renewable technologies,
such as wind turbines and biomass, can all be used behind the meter, to reduce
how much power needs to be taken from the grid.
The return on investment from such technologies can be significant. A good
working example of this is Premier Inn, the chain of hotels owned by Whitbread.
Premier Inn has invested in installing solar panels on more than 180 hotel
rooftops across the country. In doing so, it has cut the amount of electricity it
takes from the grid and reduced its carbon footprint substantially.
Battery Storage
Major technological advances, particularly in lithium-ion systems, have
seen battery storage shoot up in popularity for anyone looking to benefit from
activity behind the meter. With battery prices at an all-time low it makes
commercial sense to install this type of technology, either to store excess energy
that is being generated by a renewable source, such as an onsite solar scheme,
or simply to use the battery to store electricity from the grid when prices are low
and discharge it when prices are high.
Demand Side Response
Demand Side Response (DSR) provides a way to earn additional revenue by
helping to balance demands being placed on the grid. It can be carried out in a
number of different ways. High energy users may reduce their demands at peak
times, or when requested by National Grid. As an example, a manufacturer may
avoid carrying out an energy consuming activity during peak times of demand,
and instead move it to a different time of the day. In the case of battery storage, a
business may also support grid stabilization by storing electricity and then
discharging it back into the grid at peak times, to help meet supply and demand.
Additional Revenues Streams
National Grid is required to provide electricity at 50Hz, plus or minus 1%. This
strict regulation means it needs flexibility to balance the system. It does this in
several ways, including through the Firm Frequency Response (FFR) market.
Battery owners can offer a fast, reliable response, either on their own, or if
they are big enough, through an aggregator. By taking part in the FFR market, a
regular stream of revenue can be secured.
Other Benefits
Taking steps behind the meter also offers many other benefits. For instance, an
Electrical Energy Storage System (EESS) can act as an uninterruptible power
supply (UPS), providing a backup in the case of a blackout or power cut. This
resilience is particularly important for power critical operations, such as hospitals
and production lines.
Similarly, an EESS can help with power conditioning if a brownout strikes and
National Grid needs to reduce the voltage of supply. A less common benefit, but
a significant one nonetheless, is the opportunity behind the meter storage offers
for large energy users to reduce their connection charges. These vary depending
on peak import and export volumes. What a battery storage system allows an
organization to do, it is to smooth out its peaks.
Why behind the meter should be on the agenda
When done effectively, taking steps behind the meter can provide many benefits.
With energy prices on the rise and growing demands being placed on
organizations to be ‘greener’, it also makes sense to take as much control over
energy use as possible.