The Grid 03 January 2018
The Grid is a book by Gretchen Bakke about the American electrical grid. Overall I found it pretty informative, though it’s very American centric and spends a lot more time delving into the history and politics of the American grid than I was interested in knowing. To be fair it’s a tricky balance to get right as this complex history goes a long way to explaining the grid in America in its current form and why it will be so hard to change.
These origins also go a long way to explaining why it’s not well suited to the variable renewable sources that are being added today. There are regulations and laws in place that complicate the addition of these new sources even further; ranging from laws to protect the environment to rules intended to ensure public investment is used as intended, often with unintended and detrimental consequences. Overall it’s a balancing act to try to keep the supply in balance with the demand and a very limited timeframe in which to respond to changes to either. The addition of a reliable and large scale energy store would greatly relieve many of the issues that exist today but nothing at the scale required currently exists.
An electric grid works by separating electrons (negative) from their atoms (positive) and providing them a route over wires to get back together. We add resistance into this route:
- Produce heat
- In an electric motor to produce rotation in a magnetic field which is then connected into mechanical power
Voltage gives us a measure of the potential a circuit has, the work that electrons can reliably perform as they make their way through the circuit. Our machines expect a constant voltage. Too much voltage will cause everything in the system to overheat and destroy itself, too little and it will fail to perform.
Direct Current uses a set voltage set at the dynamo (converts mechanical energy into electrical) and can’t travel far. AC on the other hand can be stepped up to a much higher voltage using a transformer allowing it to travel much further. AC uses bidirectional waves while DC only travels in one direction. This means that AC briefly stops when changing direction but this is typically so fast that it’s not noticed. AC can also be sent in phases meaning that more than one wave can be travelling at the same time.
Micro and Nano Grids
Micro grids are a relatively new concept where larger institutions run their own grids, that during normal times act as part of the greater macro grid. The advantage is that because they are self contained, during a crisis when the macro grids goes down, they can be disconnected to operate independently. Thus the main grid continues to operate as normal during the good times but the micro grids add resiliency during times of crisis.
Nano grids on the other hand are small privately owned power sources, such as PV attached to a house, that potentially allow them to be entirely disconnected from the macro grid.
“Demand side” refers to the ability to control consumption by the consumers. Enabled by smart metres, it can be performed by adjusting the thermostat or turning off power intensive appliances during peak load.
Smart metres provide a number of useful functions:
- Help utilities know when they need to deploy linemen because of an outage
- Predict energy usage and peaks
- Enable “demand-response”
I enjoyed the early chapters the most where the basics of the grid were covered. The middle chapters were focused mainly on the history of the American grid and dragged on for a bit. It picked again towards the end when looking to the future and how the grid might look and the types of opportunities and technologies that are becoming available.
The chapter on storage was interesting. I particularly liked the idea of using electric cars as a means of storage, even if it’s not practical with the current technology you can see the potential.
Overall it’s a worthwhile read full of useful information that makes you think about where the future of energy is going and the opportunities that are becoming available.