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Friday, June 15, 2018

Electric vehicles make solar power mobile

Solar PV systems can reduce electricity bills for many families and businesses.

Unfortunately this isn't the case for families who rent because properties available for rent rarely have solar panels installed.

Even for families who do have solar PV systems, the savings aren't that great when everyone is at work or school during the the day when the sun is shining and the solar energy output is mostly being fed into the grid.

There is another way to supply solar energy to these households and help them cut their electricity bills.

Many businesses are saving on their power bills by installing solar panels, but the savings would be greater if they had batteries to provide power early in the day and late in the afternoon when the output of the solar system is below the midday peak output.

Solar PV system output varies during the day
Suppose a business with a solar PV sysytem buys 4 or 5 electric vehicles that can deliver electricity from their batteries - the Nissan Leaf with a 40 kilowatt-hour battery is one electric vehicle designed for this role -  and leases them to its workers to be used in the following way:
  • The worker drives the electric vehicle to work each morning and plugs it into a power exchange socket where it provides electricity to the business whenever electricity use is greater than the output of the solar PV system AND has its battery recharged whenever there is excess solar energy being produced. 
  • The worker drives the car home each day after work and plugs it into a power exchange socket where it powers the home - with solar energy stored during the day while at work - during the evening peak period when electricity prices are at their greatest. 
  • By late evening or early morning, if the car battery charge has fallen below the level that is needed for the morning peak period to prepare breakfast and for the commute to work, some additional energy from the grid is stored in the battery - again at off-peak rates.
  • ...and so on, each day.
This may make electric vehicles a better investment than just assessing their value as a replacement for a simple petrol-fueled vehicle. They can provide electricity as backup generators for businesses when solar energy output is less than the amount of electricity used and they can let workers take solar energy home. This is especially valuable for anyone who lives in rented accommodation and/or lives in one of the many households where all the members are away from the home during daytime.

The following video uploaded in 2013 describes the process in 2 minutes. At that time, the Nissan Leaf had only a 24 kilowatt-hour battery. The recently released model has a 40 kilowatt-hour battery. 

One application of the technology is described in Adam Vaughan's the article published in The Guardian on October 3, 2017:

Electric car owners 'can drive for free by letting energy firms use battery' 

Electric car owners will be paid for letting an energy company use their vehicle’s battery in a pioneering scheme to increase take-up of the cleaner vehicles and help power grids manage the growth in green energy.

Nissan and one of the UK’s biggest challenger energy suppliers, Ovo, will offer the “vehicle-to-grid” service to buyers of the Japanese carmaker’s new Leaf from next year.

After installing a special charger in a customer’s home, the supplier will take over the management of the car’s battery, with owners able to set a minimum amount of charge they want for driving the next day. Ovo will then automatically trade electricity from the battery, topping it up during off-peak periods when power costs about 4p per kilowatt hour (kWh), and selling it at peak times for about four times as much.