The Electricity Grid 101: From Elementary to Conversational in Grid Comprehension
Watt’s up with the grid? Demystifying a modern scientific miracle
Ever wondered how charging your phone actually works? Behind the plug is a complex but marvelous system that powers our lives.
I didn’t know how our electricity grid really worked up until very recently. I thought this would be a great opportunity to share my learnings and lay a foundation for future posts.
Los geht’s!
What is the Electricity Grid?
The electricity grid is responsible for delivering electricity to places like your home, favorite restaurant or the cinema. It is a network of synchronized electricity producers and consumers. They are connected through transmission lines and distribution centers. The coordination takes place in one or more control centers.
Most often when talking about the “grid”, people mean the transmission of electricity from the producer to its destination.
There are three main steps related to electrical grids:
Step 1: Electricity Generation
Step 2: Electricity Transmission & Distribution
Step 3: Electricity Consumption
Hold on a Second. What Exactly is Electricity?⚡️
Electricity is the flow of electrons through a conductor. It is one of the most common forms of energy. It is a secondary form of energy. Coal, nuclear, wind, solar, hydro, and gas are all primary sources we use to produce electricity.
Electrons move between atoms through the conductor from point A to B. The flow is possible because electrons from the outermost shell of one atom are pushed to an adjacent atom’s shell. The receiving atom now needs to give away the excess electron to another adjacent atom and so on. This results in the flow of electric current.
For electricity to flow, it needs to have a full electric circuit. If the circuit is interrupted, no electricity flows.
Wow, I’m glad we got this one out of the way. Back to the grid.
Step 1: Electricity Generation 🏭
Electricity can be generated in different ways. Mainly, we rely on burning fossil fuels such as coal, oil, and natural gas. Thankfully, we are in the process of changing that. Burning fossil fuels is the single biggest driver of climate change. Alternatives such as hydroelectricity, geothermal, solar, and wind are picking up.
The so-called renewable energy sources occur naturally (heat, sun, wind) and can be harnessed to create electricity as well. For now, let’s focus on how we have been creating electricity through conventional power plants.
I’ll try to keep it simple while covering the main aspects.
How Does Burning Fossil Fuels Yield Electricity? Four Key Steps
Power plants burn chemical energy in the form of one of the aforementioned fuels to create high-pressure steam - that results in thermal energy
The created steam powers a steam turbine - mechanical energy
The turbine rotates a coil wire through a magnetic field to generate electricity - electromagnetic energy (#electromagnetism)
The produced electricity is exported to the grid via transmission lines.
Let’s look at these steps visually to help us understand what’s going on:
Let’s also look at a more intricate visualisation on how the steam generator works:
All power plants except for solar photovoltaic plants generate electricity this way. But I’ll save the details for an upcoming post. Once the electricity is generated, it needs to be transmitted to the location where it’s needed.
Transmission here we come.
Step 2: Electricity Transmission & Distribution 🏭 ➡️ 🏠
Power plants create electricity far more potent than regular household appliances can use. But for the purpose of efficiency, the electricity created at the power plant is sent through a step-up converter to increase its voltage. This way, more power can be transmitted through the transmission lines while minimizing power loss. Important note: The voltage at one end of the transmission line is not the same as on the other.
Once the electricity reaches a local distribution center, it enters a step-down converter to break it into more manageable chunks. From there, lower-voltage transmission lines distribute the electricity even closer to its final destination. Before hitting industrial, commercial, and residential consumers, the voltage is stepped down one more time.
Now you can turn on your light at home.
Step 3: Consumption 🔌
Every house or apartment has a meter that measures the electricity consumption. This is necessary so that electricity bills are based on actual consumption data. A lot of appliances in buildings are using electricity. A TV requires electricity. A washing machine does. And so does a fridge. And so many other devices we plug in to run or charge.
With electrification being one of the key strategies for the green transition, our demand for electricity will only increase from here. And it has to be as clean as possible.
So let’s just build a bunch of solar and wind parks and celebrate our achievement!
If it would only be so easy…
Electricity is just like many things in life. It needs to be balanced. To be precise, energy supply and demand must be exactly matched. This is where we should take a look at grid balancing.
Grid Balancing: The Yin and Yang of Electricity ☯️
Electrical production and consumption need to be matched at any given time. Oversupply in voltage can cause damage to electric devices. Undersupply can result in blackouts because too much electricity is demanded from the grid.
Storing electricity is difficult by nature and as of now not economically viable on a large scale. But we are getting there. Daytime, weather, season, and electricity supply all affect the grid balance. The entire ordeal is very complex.
Electricity demand is forecasted on a daily basis. According to the forecast, supply is scheduled and then generated. The forecast is based on historical consumption and weather data as well as additional information related to the grid. That’s the job of the electricity grid system operator.
Electricity generated can only be added to the grid but cannot be sent to a specific location. Devices connected to the grid (i.e. plugged in to charge) are consuming electric loads.
To be able to schedule the supply accurately, we need to understand demand patterns and how each different type of power plant can serve different needs.
Demand Forecasting: Looking at the Past to Predict the Future of Loads 🔮
To ensure enough reliable supply throughout the day, electricity generation from power plants is split into three main categories:
Base load = minimum electricity demand over a 24-hour period, e.g. nuclear/coal power plants (low cost & low flexibility)
Intermediate load = medium electricity demand that fluctuates during daytime hours, e.g. natural gas engine/solar/wind (mid to low cost & medium flexibility)
Peak load = highest electricity demand that requires flexible power plants (“peaker-plants”), e.g. natural gas turbine/hydro (high cost & high flexibility)
Each of these loads varies in costs to generate electricity, flexibility, and electricity-generating capacities. To spare you from all the details, the main cost driver to operate a power plant is the fuel input to run it a.k.a. variable operational costs.
For instance, once turned on, a nuclear power plant will run for at least 100 hours before the plant can stop generating electricity. It already takes more than 12 hours to go from cold start to fully operational. Therefore nuclear power plants serve as base load power plants due to their inflexible but reliable operating characteristics.
On the other side, natural gas turbines are much more flexible and hence generate electricity for peak demand. Modern peaker-plants can be turned on and off within 15 minutes. This flexibility comes at a higher price for the electricity generated.
And in between all of that are renewables. Some of them exist in the form of large solar or wind parks that power the grid. In other cases, they can also be installed on-site where electricity is consumed.
Renewable Takeover 🔋💨☀️💧
Renewables are getting more price competitive and increasingly more affordable as time passes by. Why?
It’s simple.Renewables follow learning curves. They also have no variable operational cost to generate electricity. Both the sun and wind are free the last time I checked. Renewable energy sources are taking over. It’s inevitable.
So with their inevitable takeover, we need to ensure they can be effectively integrated into the grid. Currently the main problem is long-term storage of electricity that was generated from renewable sources on a grid scale. Once we achieve that, renewables can be brought into the conversation about who serves the base load of our future electricity mix.
Electricity storage has tremendous potential to improve today's grid and energy supply. It can help take demand off the grid during peak times, can store excess energy when it’s opportune, can serve as a backup in case of grid failures, and reduce emissions by lowering the peak demand. And more which I will write about soon.
Battery storage is the next big thing. Industry experts expect the battery storage sector to go through the same growth phase as solar did in the past decade. It’s expected to 8-fold by 2029. I am thrilled to see what’s going to happen here.
Due to the intermittent nature of renewables, grid balancing becomes more complex. And as a result, grid balancing becomes even more important. And long-term storages will play a key role.
What’s next?
One important aspect that I have not covered are the electricity markets. They are used for buying, selling, and trading electricity. Through financial incentives, they help ensure grid balance. How, you might wonder?
Stay tuned for next time.
If you are interested in learning more deeply about electricity and how it works, I highly recommend taking this course from Duke University. It helped me tremendously in understanding all this.
I hope you learned something along the way.
If you liked this post, please print it out and give it to a family member for Christmas. I’m sure they’ll love it!
If you feel like I didn’t do a good job getting the basics across: please call me out publicly in the comment section below.
Stay electric,
Basti
Loved it! Very articulate and so easy to understand for a topic so complex, although common to all of us. Looking forward to reading more like this. 😊
Loved this one! Very interesting to learn how the grid works and explained well for the ignorant :)