The way that the UK wire up our homes has not substantively changed in generations, and it is beginning to show. The practice of fitting a “single-phase” supply has its roots in the Victorian era when homes were largely fitted with connections that would support simple lighting systems. This system involved running “three phases and neutral” paper insulated and lead covered cables down a street. Each home in turn was connected with one of the three “phases and neutral”. The most significant change to how this has been done was in the 1930s when the voltage levels were more strictly regulated.
This electrical system has kept the UK in good stead for generations. On it the average home has incorporated a host of new applications and heat demands. So why change it if it isn’t broken?
Well, in the interest of meeting the government’s Carbon Budget and Industrial Strategy objectives a steep decarbonisation and becoming global leader in “clean growth”, we at the REA believe that how we think about homes in the future is going to have to change. The advancement of new power, storage, transport and heat technologies will drive the need for change and looking forward we should be preparing for all new houses to be built with solar, energy storage, heat pumps and EV charging points included, potentially as part of the new build package.
Home technologies
In fact, homes are already becoming more than passive takers of power – with around eight hundred thousand domestic rooftop solar installations across the country one of the first steps is progressing. By and large people appreciate self-generation, and for many this is the first step in adopting power storage and smart EV charging. Recent polling released by Client Earth indicates exactly how popular these home technologies are; 62 per cent of the British public would like to fit solar on their rooftop, 60 per cent would buy a home energy storage device, and nearly half would switch their car to electric.
Between the market demands and the policy drivers, to REA it is clear that there is a role for more solar, for more storage, for more EV charging and, as time goes on, more renewable heat technologies such as heat pumps in the home. This could be very easily applied in the planning stage of new housing sites by the councils simply applying the Merton Rule.
As a nation we should be preparing ourselves for this shift. DNOs such as Western Power Distribution (WPD) are trialling the additional costs of wiring a new homes in the UK with a three phase supplies. This involves running all three phases and neutral cable into each home. This is standard practice in many countries on the continent and beyond. Discussions so far indicate that the cost of opting to install a three phase over single phase supply could fall and that one of the main costs is in installing a larger and slightly more expensive distribution board (DB). Discussions within the sector indicate that these DBs can be redesigned to be smaller, and with scale, become significantly cheaper.
New standard
The benefits of three phase into the home would be to treble the allowable amount of distributed generation i.e. solar and energy storage that could be generated per home (presently there is a functional cap of 4kW for single phase installations), it would also allow people to opt for a larger, hence faster EV charging (particularly as car battery ranges extend, due to higher capacity batteries) and would provide supply capacity in the future as people opt to install heat pumps. Three phase house service connections have also been identified as a means of reducing electricity losses on the Low Voltage network, something now incorporated into WPD’s long term loss reduction strategy. Ultimately, such losses are passed on to consumers via their electricity bills.
Managing this transition would require Ofgem and the networks to agree to uniformly introduce three phase as a new standard. Currently the networks are bound to provide “lowest cost solutions” to the consumer, regardless if it is not preparing the home adequately for the demands of a changing technological future. We’re not talking about throwing the existing book of wiring rules away – we can continue to wire homes in a similar manner but balance the load over the three-phase connections and then have the ability to supply the higher-demand units, such as the EV charger and heat pumps.
We’re also not saying that people can’t install solar right now on a single phase supply – the issue is that it is restricted to 4kW. Nor are we saying that a 7kW EV charger can’t be connected, it can. The key point of our proposal is that each home on a single phase supply effectively caps one’s ability to connect no more than 4kW of distributive generation and also caps home EV recharge rate at to 7kW. By installing three phase the distributive generation can increase to 12kW and EV charging can increase to 12kW. The UK need to see these technologies as all part of a single, growing system and look ahead to future-proof the housing stock we’re building today, thus reducing the long-term carbon emissions in line with the government’s decarbonisation vision to 2050.