What is the Electric Grid and how is electricity produced?
The Electric Grid is simply the transportation network of cables, power sub stations and storage devices connecting production facilities to consumers and industries utilizing the electric power produced from generators. Electric power production is done by converting a non-electric form of energy to electrical energy by the use of a generator. Such heavy duty generators work in conjunction with turbines to spin a permanent magnet device in a between a sets of conduction wires. Applying Flemings Law, we can infer that a such a rotating magnet in a will induce current in the wires. However due to the fluctuation between north and south poles at each set of wires, an alternating current (AC) will be induced inn which the electrons constantly change direction with a certain voltage and frequency (hz). In industrial generators typically supplying power for households consist of three different phases, or sets of wires that induce current. These 3 phases are usually spaced by 120 degrees in the US to minimize the effect of fluctuating alternating current on devices using the power. 3 phases are supplied through the grid system and to consumers at around 60 hertz in the US and a single phase effective 120 volts.
Below are the steps taken to transmit power across the electric grid and to households and cities:
1.Generators produce AC current
2.AC current is fed through transformers to step up voltage
A 3 phase AC generator/motor is a device where three separate sets of coiled wires induce an electric current through the rotation of the permanent magnet in the middle. Each set of cables will be supplying an alternating current to a transformer that will step up the voltage while reducing the effective current of the electric power. This is done primarily to tackle long distance cable resistance and allow for more efficient power transmission.
3.Transmission Lines transmit current long distances (~500 kilovolts)
4.AC current oscillates at 60 hertz, 120 volts power through 3 phases
5.Sub-stations distribute power and step-down voltage for commercial use
Problems with this modern Electric Grid System?
The following are two primary problems faced by the modern electric system:
1.Electric supply needs to meet consumer’s peak demand curve
- High electricity demand during day time
- Low electricity demand during night time
2.Different types of generators have varied power outputs
- Solar and Wind power can be inconsistent depending on natural conditions
- Long distance electricity transmission is inefficient
These problems can overwhelm the grid system at times and can increase the inefficiency of power transmission and increase running costs of equipment in generating facilities as supply has to be ramped up in the day due to excess demand and ramped down during the night due to oversupply. Hence to avoid such issues, a buffer between supply and demand is needed to be created that will store excess energy for later use during high demand hours of the day(peak demand). Energy storage has been the most popular method of tackling the aforementioned issues in the grid system and have various benefits as mentioned below:
What is Energy Storage?
To store electric energy when low in demand and supply it when high in demand
- Integrated to electrical transmission grid
- Balance electrical grid system
- Storage is practical and reduces peak demand costs for end-users
Energy Storage Integration Methods:
- Electricity Rate Optimization (Time of Use)
- Store electricity when the market price is low an consume it when the market price is high
- Use storage in isolated grids or communities in conjunction with renewable energy sources
Store energy during off peak hours and distribute power supply between storage device and direct power suppliers.
- Save money on peak demand rates through controlling when energy is used directly from the grid
- Reduce energy utility charges from the grid
- Help power generation equipment last longer
The Future of Energy Storage and the Electric Grid?
-As of 2017, US has implemented over 24 GW of energy storage
-Over 600 projects are currently under development in the US, popular ones are flywheels, pumped-hydro and battery packs.
- Automation and EVs can allow for a stronger and smarter grid:
- In the “Smart Electric Grid” consumer electric cars could communicate with the grid and supply energy back to the system or utilise excess energy with their batteries at charging stations
- DC transmission lines integration could allow for more efficient electric grid and quicken demand response
- Grid storage technologies are allowing for developments in greener transportation technologies like more practical electric cars and vehicles like the Hydrogen Fuel Cell Vehicle (HFCV):
- Buses and cars can use Fuel Cell technology to produce electricity on the go using Hydrogen and power an electric powertrain (95% produced from natural gas reforming)
- US D.O.E has announced a $15.8 million for 30 hydrogen fuel cell implementation projects
- Hydrogen is expected to rise in demand drastically through the next 30 years and has already grown 3.5% through 2018