Power is such a profound part of our everyday lives, yet few of us really think about where electricity comes from and how it ends up in our homes. The way electricity is transported is actually a super important part of the whole process. We’ve talked about the grid before here at MPE Group. It's that big, complex system that ensures the electricity generated gets to you, the consumer. But, did you know that one tenth of all electricity is lost in the grid?
How is the electricity lost?
The current grid loses around 10 percent of the power generated as heat. At the moment, the grid uses high voltage transmission lines which are relatively cheap.
But this kind of transmission loses a lot of power as heat. A survey of 140 countries found the electricity currently wasted in transmission accounts for a staggering half-billion tonnes of carbon dioxide — each year. These unnecessary emissions are higher than the exhaust from all the world's trucks, or from all the methane burned off at oil rigs. Inefficient power transmission also means countries have to build extra power plants to compensate for losses on the grid.
What can we do about it?
Superconduction is where electrons can flow without resistance or loss. Built into power cables, it holds out the promise of lossless electricity transfer, over both long and short distances. That's important, given Australia's remarkable wind and solar resources are often located far from energy users in the cities.
A single 17-centimetre cable can carry the entire output of several nuclear plants. Cities and regions around the world have done this to cut emissions, increase efficiency, protect key infrastructure against natural disasters and run power lines underground.
High voltage superconducting cables would allow Australia to deliver power with minimal losses from heat or electrical resistance and with footprints at least 100 times smaller than a conventional copper cable for the same power output.
Even more important, a typical superconducting cable can deliver the same or greater power at a much lower voltage than a conventional transmission cable. That means the space needed for transformers and grid connections falls from the size of a large gym to only a double garage.
So, what’s the downside? One problem is that superconductors must be cooled to work. But rapid progress in cryogenics means you only need to cool modern superconductors to -200℃, which can be done with liquid nitrogen — a cheap, readily available substance.
Superconducting cables can be laid underground with minimal footprint and requiring vastly less land. A conventional high voltage overhead cable requires an easement of about 130 metres wide, with pylons up to 80 metres high to allow for safety. By contrast, an underground superconducting cable would take up an easement of six metres wide, and up to 2 metres deep.
This has another benefit: overcoming community scepticism. At present, many locals are concerned about the vulnerability of high voltage overhead cables in bushfire-prone and environmentally sensitive regions, as well as the visual impact of the large towers and lines. Communities and farmers in some regions are vocally against plans for new 85-metre high towers and power lines running through or near their land.
Climate extremes, unprecedented windstorms, excessive rainfall and lightning strikes can disrupt power supply networks. While superconducting cables may cost more up front, you save by requiring fewer substations (as the power is at a lower voltage) and by avoiding the need to repair and replace following natural disasters.
Australia is at a crucial point in our sustainable planning right now to consider this long-term solution for our grid and the impact on our climate.