A Scottish Case Study: Can 5th Generation District Heating and Cooling Facilitate Holistic Decarbonisation in Clyde Gateway?

Achieving a decarbonised thermal grid that balances cost, environmental impact, and security of supply requires a holistic approach that integrates sector coupling and energy storage. A system that allows for energy sharing between heating and cooling and an interaction with the electricity grid through heat pumps is 5th Generation District Heating and Cooling (5GDHC). An ambient network is connecting decentralised water source heat pumps, allowing energy sharing and low temperature waste heat utilisation.

However, the economic viability of such schemes relies heavily on demand co-occurrence and energy trading to offset the increased capital and operational costs. Current efforts to quantify energy trading potential in these networks primarily rely on energy flow analysis, without considering the hydraulic effects of the system, which can be complex due to bidirectional mass flow and hydraulic sub-cycles. This is due to a lack of a coherent hydraulic design and control philosophy that allows bidirectional flow without hindering hydraulic stability. Understanding the boundaries of beneficial operation of the system against energy supply alternatives requires a complete technoeconomic assessment.

This work presents a complete analysis of a 5GDHC system, integrating heating, cooling, and energy storage, for a real-world application in Clyde Gateway, Scotland. The analysis, using experimentally validated open-access tools, quantifies the economic and environmental benefits of 5GDHC compared to counterfactual supply options. A detailed data analysis identifies the key 5GDHC design opportunities and pitfalls as well as key sensitivity variables for the proposed design and operational methodology. It sheds light on the potential impact to the electricity grid, the space constraints and interactions with other utilities, phasing of construction and operational challenges.

The results of this work can inform decision-makers, energy planners, and stakeholders in the development and operation of ambient district heating and cooling systems, supporting the transition towards decarbonised and sustainable thermal grids.