SuperGrids: How to Join the Solar Power Grids of Entire Continents

India gained notoriety when it finished November’s COP26 climate summit by weakening a move to end the use of coal. Less widely recognised is that the country also started the Glasgow summit in a more positive fashion, with a plan to massively expand the reach of solar power by joining up the electricity grids of countries and even entire continents. Indian prime minister Narendra Modi has talked about the idea before, but the One Sun One World One Grid initiative launched in Glasgow now has the backing of more than 80 countries, including Australia, the UK and the US. The alliance is just one example of a growing movement to create regional and, eventually, globalsupergrids”: long-distance, high-voltage cables linking each country’s growing renewable power output.

The supergrid movement is being driven partly by the need to maintain a smooth flow of power onto electricity grids. Local weather makes the amount of power generated by wind and solar variable, but this becomes less of an issue if the grid is larger and distributed over a wider geographical area. What’s more, supersized green energy projects are often sited far from the cities or industrial areas demanding their energy, be it wind farms in the North Sea or solar farms in the Australian outback. Supergrids offer a solution to this problem by connecting large renewable energy sources with the people who use the power.

The Indian government is keen on links to the Middle East, to help India decarbonise using imported renewable energy,” says Jim Watson at University College London. The UK, one of India’s partners on the One Sun One World One Grid initiative, is also considering new long-distance cables.

Last September, the UK started importing hydropower from Norway via a 724-kilometre subsea cable. In the coming years, the cable is expected to be used mostly to export electricity from the UK’s growing number of offshore wind farms so that it can be stored in hydropower facilities in Norway and released onto grids as needed. In 2022, UK start-up Xlinks will try to persuade the UK government to guarantee a minimum price for electricity generated at a mega wind and solar farm to be built in Morocco that could power UK homes via a 3800-kilometre subsea cable. “I will very confidently predict that over the next 15 years the world will see a huge number of interconnectors,” says Simon Morrish at Xlinks of such cables.

Xlinks is also working with Australian firm Sun Cable on its proposal to build the world’s largest solar farm in the north of Australia and connect it, via Darwin, to Singapore through a 4200-kilometre cable, to supply it with low-carbon electricity. In September, Sun Cable gained approval to route the high-voltage cable through Indonesian waters. 2022 may also see progress on efforts to build an “energy island” in the North Sea, which would act as a vast hub for offshore wind farms that can supply several European countries. UK company National Grid recently told New Scientist it is in talks about the pioneering project.

Source: https://www.newscientist.com/

Highly Efficient Grid-scale Electricity Storage at Fifth of Cost

Rows of huge tanks full of chemical solutions storing energy generated from massive solar and wind farms and powering whole cities: It’s a landscape that millennials might very well equate with the new normalBatteries will power this new paradigm, and they won’t necessarily all be lithium-ion batteries. The flow battery is staking a claim in the renewable energy world of the future. Flow batteries are definiively the future of energy storage, or at least an important part of it.

What are flow batteries? They are systems of two connected tanks, both containing electrolyte liquids: one with a positively charged cathode and the other with the negatively charged anode, just like a lithium-ion battery. Electricity passes from one electrolyte liquid to the other via a membrane between the tanks.

 

Rechargeable like lithium-ion batteries, flow batteries have longer lives because the electric current flowing from tank to tank does not degrade the membrane. True flow batteries are also called redox flow batteries, after the two reactions they utilize: reduction, or a gain of electrons, and oxidation, or loss of electrons from electrolyte liquid to electrolyte liquid.

Now researchers in WMG at the University of Warwick, in collaboration with Imperial College London, have found a way to enhance hybrid flow batteries and their commercial use. The new approach can store electricity in these batteries for very long durations for about a fifth the price of current technologies, with minimal location restraints and zero emissions.

The scientists enhanced three hybrid flow cells using nitrogen doped graphene (exposed to nitrogen plasma) in a binder-free electrophoresis technique (EPD). Wind and solar power are increasingly popular sources for renewable energy. Unfortunately, intermittency issues keep them from connecting widely to the National grid. One potential solution to this problem involves in the deployment of long-duration battery technology, such as the redox flow battery. Despite its great promise the current costs of this system are a key determining factor to real-world adoption. An affordable grid battery should cost £75/kWh, according to the US Department of Energy. Lithium-ion batteries, which lead the charge for grid storage, cost about £130/kWh. The hybrid flow battery’s total chemical cost is about 1/30th the cost of competing batteries, such as lithium-ion systems. Scaled-up technologies may be used to store electricity from wind or solar power, for multiple days to entire seasons, for about £15 to £20 per kilowatt hour.

https://warwick.ac.uk/