Going Tregreener – The Decarbonisation Project

Our goal is to be as eco-friendly as possible, and preserve the planet for future generations.  Over the last few years, we’ve been making big changes and have introduced new initiatives across the Resort to reach our carbon zero goals. Our hard work is paying off and we are awarded with the Gold Green Tourism Award for our continued commitment to sustainability.

In 2023 and into 2024 we have invested over £1.5 million in combatting the energy crisis and ensuring a greener future.  This project is currently underway with stage 1 complete.  The first stage was to install a 250 KW Solar Farm. This was successfully installed and completed on 2 May 2023 and in June 2023 produced approximately 50% of the energy needed to fulfill Tregenna's energy requirements.

This year (2024) we launch stage 2 - our new CHP (combined heat and power) turbine that will produce electricity at the same time as producing heat. The turbine will only be utilised at times of poor weather and at night-time when the solar power will not be working.

What is a CHP turbine and how will it work for Tregenna?

A CHP is a combined heat and power unit which runs on Gas. The unit to be installed at Tregenna is a Capstone C65. These units operate a micro turbine generator which uses the gas to create electricity. The main benefit of Capstone CHP over traditional internal combustion CHP’s are the lack of moving parts, therefore meaning less downtime for maintenance, thus it will run longer, with a higher level of reliability, throughout its life and offer better cost savings as directly compared to a traditional CHP. As the turbine spins, its produces heat, a heat exchanger unit sat on top of the microturbine, in turn heats water and this water is used for the hotels heating and hot water demand.

The CHP at Tregenna has been sized specifically to match the hotels base electrical load. This means that, when the hotel requires electricity, the CHP will run to match this load (up to 65kW). Thus, reducing the amount of electricity the hotel is required to import from the grid, easing burden on the local electricity network and in turn will lower Tregenna’s energy bills.

The new heating and hot water system has been designed with an 8000L energy storage vessel which will allow storage of the hot water produced by the CHP, until a time at which, it is required by the hotel. This storage vessel is a vital part of the newly designed system in ensuring that all energy produced by the CHP is utilised by the site, reducing energy consumption from running separate boilers.

The new heating system has been designed with a trio of Hamworthy Modumax high efficiency condensing boilers which are installed to pick up excess thermal load when required and in times when the CHP is offline. The heating and hot water circuits will then be fed using the water form the CHP and Boilers (where required) via plate heat exchangers.

At current Tregenna Castle has a 250kW PV array installed on site which is allowed to export up to 100kW back to the grid. As part of the CHP and Heating project, we are integrating control of the new heating system and PV array to allow for utilisation of this ‘excess’ electric. To do this, immersion elements have been installed in hot water and heating storage tanks. These will be brought in via the new Building management system installed as part of the project, via a complex immersion schedule, to utilise as much of this ‘free’ electrical energy as possible rather than sell it back to the grid.

The Controls element of this project is very complex and controls the CHP and PV to ensure the hotel is benefiting from utilising excess electricity provided by the PV and also thermal energy provided from the CHP. The Optimisation of these systems will lead us (Tregenna) to  lower our carbon footprint, reduce energy costs and to help us to become a more self-sustainable Resort.

This infrastructure will also be paramount to when the technology improves.  In the future we hope to add batteries to store the solar energy and then look to change the turbine with a hydrogen replacement.

We will continue to work hard towards becoming more sustainable and carbon zero in the future.