Electrification of domestic heating on the island of Ireland to reduce emissions and enhance system stability

Abstract

This thesis has investigated if the use of electric heating methods could be used to replace fossil fuel methods in the domestic sector in order to reduce emissions with the added benefit of using them as a demand side management (DSM) source in order to provide grid stability and efficiency, while reducing wind curtailment.

The current grid CO2 intensity was examined, and the point of use emissions were calculated for comparison purposes. With the use of some basic household heating demand assumptions and degree day scaling, it was shown that currently, electric heating methods are not better in terms of emissions than fossil fuel central heating methods, apart from heat pumps due to their high coefficient of performance (COP).

To achieve a more realistic household heating demand, a Simulink model of a typical Irish household was developed. This showed that the method of heating can have a significant difference on the amount of heating demand required and emissions produced. As different methods of heating also produced different levels of temperature and had different response times. A methodology was set up to compare the methods which achieved a determined heating comfort level. This resulted in electric heating preforming better than when basic assumptions were made, but was still significantly worse than fossil fuel methods in terms of emissions.

In order to see the potential for electric heating in the future, as the fuel mix of electricity generation continually changes, projections for 2025 were made. These were based on transmission system operator (TSO) predictions and the scaling of 2015 data. They showed that by that time, the increase in system non-synchronous penetration (SNSP), wind capacity and closure of coal plant, the CO2 intensity of the grid will be significantly less. The 2025 data was put into the Simulink household model and showed that by this point, basic electric heating methods will produce less emissions than oil heating, which is the main method across the island. The use of DSM to increase the system SNSP was then considered, with the amount for DSM load estimated across the island. This resulted in a further reduction of emissions produced by off-peak electric heating and a small reduction in the overall system emissions.

Dispatch-down was then discussed in detail and the need for DSM was shown, along with the correlation of off-peak electricity tariffs and the amount of dispatch-down of wind, displaying that night-time storage heaters would be an ideal method to help reduce this.

The potential for distributed DSM was investigated using a modified version of the “New England IEEE 39-Bus System” on DIgSILENT PowerFactory. This was adjusted twice to reflect the dynamics observed on the Ireland all-island power system, during both a large loss-of-load event and a large loss-of-generation event. The simulation was set up in such a way that it represented how a large number of night-time storage heaters may react to an event with the use of four stage frequency relays (two over-frequency settings, two under-frequency settings). With the development of a scoring scheme, it was shown that real benefits in restoring the system’s frequency back to nominal can be achieved. However, it also showed that to attain the full benefits of distributed DSM and prevent any unwanted response reactions, the incorporation of a communication network will be necessary in future.

Date of Award	Dec 2020
Original language	English
Awarding Institution	Queen's University Belfast
Sponsors	Engineering & Physical Sciences Research Council
Supervisor	David Laverty (Supervisor) & Robert Best (Supervisor)