What Are Supergrids?
May 30, 2023 7:01 am
What Are Supergrids?
3 min read
Today’s grids are not equipped to handle large amounts of renewable energy and transmit them to where they are needed, so a new kind of grid needs to be formed – the supergrid. “The idea of a supergrid is a grid that connects nations, not just different parts of a country. The goal is to maximise the use of renewables wherever they are generating electricity.” says Akshat Rathi, a senior reporter for Bloomberg News.
The main case for supergrids is to help transport large amounts of renewable energy over long distances. Renewable energy plants such as solar and wind farms are usually outside of cities, a long distance away from developed areas. This is different from coal plants which are usually close to or within developed areas. This makes it difficult for the large amounts of energy to be transported across long distances, as there are no powerlines to do this. Supergrids are equipped with such long-distance powerlines, spanning up to 4 000 km in length. This would help connecting solar farms in deserts and wind farms in farmland areas, to major cities without losing too much energy.
This is where another aspect of supergrids come in. We currently use AC (Alternating Current) to move electricity through powerlines, but when moved over long distances, hundreds and even thousands of kilometres, much of the electricity is lost. The proposal is that supergrids will use High-voltage Direct Current (HVDC). HVDC still loses power of long distances, but not as much as AC.
How do we benefit from supergrids?
- Allow for clean energy to be transported over long distances. Solar Capital De Aar in the Northern Cape is South Africa’s largest solar power plant. It can produce 175 MW, enough to power 75 000 homes per year. However, the closest town to the plant is De Aar, which only harbours roughly 7 780 households. This means that the excess solar power essentially goes to waste. With the use of supergrids, this power would be transmitted to cities with much higher demand such as Kimberly, Bloemfontein and Beaufort West, 241 km, 325 km, and 295 km away respectively.
- Allow efficient energy trading between countries. Iran is a country that experiences about 36 rainy days a year, about 7 hours of sunshine a day on average and 340 000 km² of desert land. With supergrids, they could transmit energy to India, number 3 in the world in terms of electricity consumption.
- Allow countries to take advantage of each other’s renewable energy systems. If one country is having a windy day, they can share excess wind power with their neighbours. ElecLlink is a project that allows the UK to transmit surplus power to France through cables inside the Channel Tunnel. According to Philip O’Gorman, operations and maintenance manager at ElecLink, they transmit up to 1 000 MW either way, which is enough to power between a million and a million and half homes.
Challenges of building a supergrid
- Politics – many countries are still competing with each other in terms of economic power, resulting in tensions, which cause plans like this to stall. This is seen with the tensions between Japan and China stalling the Asia supergrid proposals.
- Land use rights. Local landowners refuse to allow transmission lines to be built on their land. The proposed Transwest Express is a project that seeks to transmit 3 000 MW of renewable energy from Wyoming to Vegas, a 1 126.54 km distance. After 17 years of being in development, the project has still not materialised due to having to secure legal permission from over 400 landowners along the route. Several other transmission lines such as Sunzia, Cascade Crossing, B2H, Energy Gateway West, Soo Green Renewable Rail and Champlain Hudson Power Express are all examples of long-distance transmission line projects that have been halted for the same reason.
Asia also has a proposed supergrid plan of their own. The Asia supergrid plans to connect far east Asian countries with 36 000 km of transmission lines. They plan to use Mongolia to construct renewable energy plants to feed these transmission lines. Wind and solar energy from Mongolia’s Gobi Desert can produce as much as 2.6 TW of electricity, more than double that of the US capacity (1.17 TW). China is also gearing up for a global grid, to connect the most renewable energy rich countries to the ones that consume the most energy.
Supergrids could be a major factor that helps us hit net-zero goals by transmitting clean energy over long distances. Do you think supergrids are the solution to clean energy transmission? Do you think the world will get them right by 2035? Share your thoughts by replying to this email!
For more information on supergrids, or any other energy related articles, view the blog posts on my website and be sure to open my weekly emails every Tuesday at 9am CAT.
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