Electric cars

Although electric cars are really a separate thing to renewables I think it is important to say something about them.

First of all, your domestic solar pv will never be sufficient to provide enough electricity to power up your car. You will have up to a 4kW pv installation. Most car powerpoints are around 6kW. That means that even if your solar pv is blasting out at 100% capacity that it still won’t be enough to not bring in anything from the grid. I’m not saying this to put you off-I think electric cars are amazing-I just don’t want you to go in with false expectations.

That’s not to say that solar and electric cars do not work together. An electric car is a great way to make sure a large proportion of your generated electricity is effectively used. A friend with solar pv installed at her house owns two electric cars and she has been measuring her exported pv generation. It is down to 7%. This is amazingly efficient.

So, electric cars: which one? There are basically two types. All electric and hybrid (i.e. with a petrol reserve for when you run out). Some examples of electric are the Nissan Leaf, Tesla and BMW i3. These all come in at around £30,000 new. A good review of the cars can be found here: http://www.carbuyer.co.uk/reviews/recommended/best-electric-cars

As for hybrids you’ve got Mitsubishi Outlander, BMW i3 Range Extender amongst others. Check out  http://www.autoexpress.co.uk/best-cars/86211/best-hybrid-cars-sale for a run down on the different models.

The first thing about electric cars which is absolutely amazing is that there is a pretty significant network now of car chargers around the UK which are absolutely free to use. Yes, you read right they are free to use. When you think for a moment about how much you spend on petrol and diesel this is a potentially phenomenal saving.

Hold on though. It’s not all good news. Getting an electric car means a shift in thinking. The current petrol/diesel mindset is fill your car up, drive until you notice its getting a bit low, fill it up again. If you have an electric, you need to think about charging. There are several different types of chargers and they all work slightly differently.

A slow charger is just a 3-pin 13A plug which can be fitted to your house and taken off your main board. This is the one in which solar comes in. Obviously, if you want to make the most of your solar on this you must charge during the day when the sun is shining. This will take 6-8 hours to fully charge your car. For most people then overnight or at the workplace is the best option. This means that solar and electric vehicles aren’t necessarily a great fit.

The next is a rapid charger. This doubles the current to 32A and halves the charge time. You will find plenty of these at shopping centres and supermarkets around the country. Very handy for topping up the car whilst doing the shopping.

The best chargers are the rapid ac and rapid dc chargers. These have important technical differences but the headline figure is that they can get cars up to 80% capacity in 30-60 minutes (dc chargers are a bit quicker than ac). The important thing to remember is to check whether the car you are interested in is ac or dc and then make sure you have an access to the relevant kind.

So in conclusion, electric cars are great and surely the future is going that way but you need to think carefully about how you are going to use it and charge it. Answering these questions will help:

  1. Will I (or more importantly my car) be at home during the day to take advantage of my solar generation?
  2. Will I regularly need to travel further than the range of the car? If so, is there a convenient charging point on the way and am I willing to wait while it charges?
  3. Is there an ac/dc (whichever is relevant) charging point nearby for rapid charging?
  4. How much am I currently spending on fuel and is the high price of the car justified by the savings that I will make?