Solving Split Phase Power Challenges
In late summer 2026, Proterra Energy has been working on a project to solve a long running challenge involving split phase power for a customer we have had for the past 8 years.
The Customer’s property is not isolated but is rural and has suffered from a number of challenges. Like a number of rural properties in the Highlands and places like Dumfries and Galloway, it is serviced by a rarely used type of grid connection these days: Split Phase power. This is where the distribution network operator (DNO) runs two single phase supplies to the property to provide more power where a normal single phase domestic supply is not big enough.
The challenge with this is that modern electrical appliances, like heat pumps or renewable energy systems, need to be configured to operate in this way, which is rare or expensive. The cost of upgrading the grid supply to 3 phase was huge, and only got more expensive with time as costs for such projects increase.
When we first started working with the Client in 2018 we developed a unique hydro control system to enable us to renovate and bring back into service a 90-year-old hydro turbine at the property to provide renewable energy. The Client invested in a special heat pump system that would operate with this type of grid connection. However, challenges with the heat pumps after 8 years of operation and regular power outages through the winter mean that the status quo was not acceptable.
As with other similar sites across the Highlands, we have brought our “Taking Off-grid – On-grid” thinking to bear, and in a similar approach to Scaliscro Estate in Lewis, we will be going one step further! Taking off-grid on-grid, and then off-grid again…
We will take the site completely off-grid. By doing this we can build a 3 phase power supply system, reconfigure the hydro to 3 phase, and add a standard non modified backup generator. The Client will be looking at adding solar in the coming year or so.
It also means that in the future the Client will not be purchasing their electricity but maximising the use of their own. By integrating renewables with battery storage, and using intelligent control with the new heat pump system, means that almost 90% of the power consumed onsite can be generated locally. The remainder will be provided by the backup generator, which was becoming a requirement anyway because of the grid outages the Client was already experiencing.
The installation costs are commensurate or less than the last grid upgrade quote, but in this way the Client owns the asset, rather than paying the DNO to develop theirs.
We have built the main offgrid and backup system in our workshop and it will be deployed at the end of September for commissioning in October 2026. Watch our video on YouTube to see our progress!
