Authors deliberately avoid a single headline (whole-paper thesis: 'a range of techniques should be used where there is no clear statistical rationale for favouring one over another'). The two estimates with VALID inference on price are Johansen and STSM: footnote 20 'the two approaches where the coefficient on p is significantly different from zero (Johansen and STSM ... find a negative coefficient for p; supporting the assumption that an electricity demand relationship is estimated)'. || 'estimated long-run income and price elasticities of 1.96 and -0.06, respectively' (p.733)
Amarawickrama, H., & Hunt, L. (2008): "Electricity demand for Sri Lanka: A time series analysis." Energy, 33(5), 724–739.