UK Energy series in the UK show changing seasonal patterns that need to be considered in energy use models. Ignoring these patterns can lead to inaccurate estimates and forecasts. Structural Times Series models help create more accurate models by allowing for evolving seasonal components. By using dynamic models, researchers can estimate elasticities and test the impact of fixed seasonal effects. Incorporating evolving seasonal effects into causal regression equations provides more flexibility in modeling seasonal variation than using ordinary dummy variables.