Case Study – The Corriegrennan Farmhouse

Overview

The Corriegrennan Farm House has a history spanning hundreds of years and is located in the Queen Elizabeth Forest Park in the Trossachs National Park, Scotland. The remote location of the farmhouse, located amongst 50,000 acres of woodlands, rivers, lochs, moorland and mountains, means the provision of a mains supply is economically prohibitive.

Despite an electrical mains supply not being practical, the apparent abundance of renewable energy provided hope for the owners. On closer examination, it was found that the location of the farmhouse was too sheltered for a wind turbine, and the cost of installing a hydro-electric facility was prohibitive.

The owners found themselves having to search for an alternative solution that would provide them with the reliable electricity supply that they required – they discovered the Powerguard PS Power System. In such a remote location, all of the electrical power has to be generated onsite using the fully integrated Powerguard PS System. The integrated system uses a set with auto-start control – by far the most efficient option. The fully-integrated PS System comprises of a diesel generator set, a battery bank and a power inverter.

Unlike normal generators which would run all of 24hrs, the PS System only needs to turn on the generator during periods when the electrical demand is high e.g. for a power shower, cooker or heating. This high demand period usually equates to less than 8hrs per day and if these periods are regular, the PS System can be programmed to turn on the generator automatically.

According to the owners, the system is programmed to run the generator for two periods every day; the ‘must run’ period between 6-9 am, and the ‘can run’ period between 5-7 pm. The must run period recharges the batteries from overnight use as well as being timed when people are getting up, the can run period simply tops up the batteries and is timed so that most high demand appliances can be run i.e. the cooker for dinner and the washing machine etc.

The clever part of the PS System is that during periods when the demand is high, any unused power is used to recharge the batteries. This stored energy then provides AC mains power to the farmhouse for the remainder of the day and night i.e. when the demand is low. The payback on an integrated PS System over a stand-alone generator is usually around 3 years. For even more fuel savings, the system can also handle imports from renewable generation sources to recharge the batteries, and the CHP option can provide free hot water whilst increasing efficiency to over 80%.