Could street lamps become the next way to charge an electric car?
Using street lights to double up as an electric car charge point sounds on the surface to be a lucrative opportunity. Think of all the existing electrical supplies that are conveniently dotted around our cities and suburbs for street lighting. If a technical solution could be found to charge a car using these supplies, then this could be a simple solution to EV charging in residential areas.
I know that there are a number of manufacturers developing lamp post charge points and trials are happening in the UK, in London specifically. The key benefit that these trials highlight is that lamp post charging is a way to avoid expensive civils works by connecting to an existing supply. I really want to find out more about the results of these trails as I have some major questions when it comes to retrofitting lamp posts:
The main, fundamental issue of making these trials a success will be where the lamp post has been installed on the pavement. Typically, especially in terraced areas, street lights in residential areas are installed away from the kerb, towards a wall, to minimise street clutter and keep the pavement as clear as possible for pedestrians. However, what this means is that if a charge point is then attached to a lamp post, a cable would need to be stretched across the footpath onto the road. This would cause a potential trip hazard and I can’t imagine any local authority being comfortable with that.
In areas where the lamp post is mounted close to the kerb, the next biggest challenge will be the amount of power available. My gut feeling is that I don’t think that a lamp post will have the available power to offer even a 3kW charge. So in effect somebody could be plugged in all night and only get a small amount of charge. As the future evolves towards bigger batteries and faster charging, slow charging at a lamp post seems to be going in the wrong direction. There is of course a solution to this. It is entirely possible to upgrade the power and install more circuits to a lamp post to facilitate this dual use. But this is not the most cost-effective solution.
Having been involved in the IET Code of Practice for EV charging equipment installation, I also have to mention the question mark over earthing. Depending on the design of the lamp post supply circuit, it is possible that it could be fed from a TT, TN-S or TN-C-S earthing system. The BS7671 wiring regulations prevents connecting EV charging infrastructure to a TN-C-S supply (unless certain conditions are met) meaning that many lamp posts may not even be suitable for charging equipment – it’s definitely something that installers of this equipment need to be aware and knowledgeable about.
The other big unknown is how these charge points would be able to be metered. The electricity supply would be paid for by the landowner who quite likely would not wish to be paying for residents to charge their cars. Separate meters can be an option but again, this comes back to cost.
The final challenge is one that we have talked about a lot in the office – and is covered in an earlier blog on residential charging. If lamp post charging is to be installed in residential streets, how fair would it be for residents if those bays were to be reserved for EV charging only? There’s little point in investing in charging infrastructure of any type if the bays aren’t then reserved but how do you do this outside people’s homes especially where parking spaces are at a premium.
For now, I think lamp post charging should not to be dismissed. Dual use lampposts will no doubt have a place in the charging mix – but these would logically make more sense in new developments such as housing estates and car parks where the engineering challenges can be easily overcome. However, in the case of existing streets of lamp posts I am not convinced how feasible and cost effective this will will be.
Zero Carbon Futures is an electric vehicle consultancy which manages and delivers projects which help towns and cities increase EV uptake. If you think we could help your organisation to develop charge point networks or would like to learn more about our electric vehicle projects, please get in touch.