Use of heat pumps to provide flexibility to power systems
In this project for the German Federal Ministry of Economics and Technology, we assessed the potential for flexibility that a building stock equipped with heat pumps can offer to power systems with significant penetration of wind power. The thermal performance of buildings offers the opportunity to use heat pumps as a type of energy storage, while maintaining comfort for the building users. This potentially has benefits for the heat consumers, as lower cost electricity can be used but also for system operators in helping manage demand. We developed a dedicated model which incorporated the equivalent energy storage provided by the thermal behaviour of building stock into our electricity market model.
The approach allowed us to look at the difference between the market-driven operation of heat pumps and the business-as-usual thermal-driven operation. We applied the model to evaluate portfolios of high heat pump deployment in conjunction with high wind penetration scenarios for the future German electricity system.
Market driven operation of heat pumps leads to a reduction to the overall system operating costs through improved integration of renewable energy sources and a reduction in peak load leading to more efficient system operation. It also leads to a reduction in the system CO2 emissions compared to the business-as-usual case because of the more efficient operation of power plant. The cost savings per heat pump are in a range between 25€ and 40€ per year.
Although overall there are cost savings, operating heat pumps according to the electricity market rather than thermal demands means that there is a small loss of efficiency in heating the building and a consequent increase in electricity demand. However, this loss of efficiency only reduces the cost savings by around 10%. The cost savings from the use of heat pumps in this way are greater than those realized by building a new pumped storage plant, which is the main alternative used now.