VW will double investment in zero-emission vehicles to 20bn euros (£18bn) as it seeks to put the diesel emissions scandal behind it. The German firm plans to offer 80 new electric cars across the group by 2025. It comes as Mercedes-Benz also promised electric versions of all its cars. Mercedes chief Dieter Zetsche said the entire range would have electric or hybrid versions by 2022.
The Scottish island of Eigg has a precarious connection to the outside world – which I experienced first-hand when a storm forced the cancellation of my ferry and I had to wait two days for the next boat. But largely because of that fragility, the tiny island – 15 miles (24km) west of the mainland – has learned how to be self-sufficient. Remarkably, even in terms of energy.
Storage methods currently being used around the world include batteries, flywheels, geothermal plants, compressed air and hydrogen - even ice. But the the most popular method is hydro power - water pumped to the top of a mountain and then released to power turbines at the bottom. According to research company Navigant, global energy storage capacity is going to rise from about 1,750 megawatts (MW) in 2016 to nearly 11,000 MW by 2020.
Chief executive Elon Musk announced the firm would build batteries that store solar energy and serve as a back-up system for consumers during blackouts. The device would allow consumers to get off a power grid or bring energy to remote areas that are not on a grid. Tesla plans to start shipping the units to installers in the US by this summer.
Renewables have the power to transform not just the world's energy markets, but global economics and geopolitics. But wind and solar alone cannot deliver a world of clean and free fuel. Both are, by their very nature, variable, so to realise their true potential other technologies need to be harnessed. Improving connectivity to other countries is one relatively simple solution, but in a world where governments are becoming increasingly preoccupied with energy security, its attractions are somewhat limited. Managing demand more effectively using smart grids and appliances is another. But the technology with the most revolutionary potential is energy storage.
Electric subway trains draw on a huge amount of energy to accelerate away from the platform. A typical train might draw 4MW for 30 seconds to get up to speed. A few minutes later, the train sheds all of that kinetic energy when it brakes to pick up its next load of passengers.