The Wired West

[kristopher]

This is one of the most complete articles I've seen explaining the new concept for carbon free electrical grids. There is a small amount of confusion towards the end where the overall future potential of V2G is brought up and then it is juxtaposed against near term limitations (high price and serviceability to the grid) that will exist while market penetration is ramping up. In spite of that it is well worth the read - especially if you are just hearing about either the "smart grid" or "vehicle to grid (V2G)".

...The whole landscape of electricity is changing, from the way it's generated to the way it's used, in industry and in our homes; and the infrastructure that makes up the distribution network is also going to have to change. It's not so much the technology that's outdated, because that has been updated regularly and steadily over the years. It's the paradigm that underpins the way the distribution system was designed, back in the early 1960s. The old grid is on its way out. Say hello to the smart grid.

Currently, electrical distribution grids reflect the centralised, supply-led nature of power generation. Their job is to get big lumps of current from multi-megawatt power stations — generally located on the coast or in the countryside — to the consumers, who are generally in towns. On the way, the voltage is stepped down in several stages until it's finally transformed into the familiar 230V, 50Hz AC.

But we are now starting to see changes to this system. Renewable energy sources are making bigger contributions to the grid and, of course, their contribution is set to grow considerably in coming years, with the European Union's target of 20 per cent renewable energy by 2020. Renewable energy doesn't contribute to the system in the same way as major power stations, however. The voltage is lower; they produce less electricity and, crucially, they don't produce consistent amounts of energy all the time.

This is one of the reasons that electricity generation is going to have to become 'smarter'. Rather than a one-way conveyor-belt system, the grid is going to have to accept flows of current at different voltages from different places at irregular intervals.

<big snip>

One of the major advantages of a smart grid is that it could be used to phase the charging of battery-powered electric vehicles. Imagine a suburb with a large number of electric cars, all of which can be plugged in to recharge from their owners' domestic electricity supply. One set of sensors in the supply system detects when the vehicle is plugged in, while the domestic communications system switches power into the battery when prices are low; that is, at night. Local intelligence ensures that all the cars within a particular area aren't all charging at the same time, to avoid overloading the grid. The result is that, in the morning, all the cars in the area are fully charged from off-peak electricity; demand has been smoothed out; and everyone's happy.

Extend this system a little, however, and the cars take on a dual role. Stop thinking of it as a car, and think of it instead just as a battery. Its stored power needn't just be used to run the vehicle; it can be used for anything. As long as the vehicle is plugged in, power can be diverted out of it, onto the grid, as well as into it for charging.

Although each individual car would not be able to store a huge amount of charge, the cumulative effects could be huge. According to Jasna Tomic, new fuels programme manager for Californian low-carbon transportation advocate Calstart, if a quarter of car owners in the US switched to battery-powered electric vehicles, their storage capacity would total some 750GW — more than the country's entire generation capability. And with the UK government's major drive to promote the development and take-up of plug-in hybrids, the figures could well be similar here....

http://www.theengineer.co.uk/Articles/311944/The+wired+west.htm

[havocmom]

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