Paper's proposed/advocated estimators are the between (BE) and long-run difference (DE) estimators; FE is the conventional benchmark they compare against. Conclusion headline for electricity own-price references the DE value. || 'we use between and long-run difference estimators to provide estimates of interfuel ... elasticities' and 'demand for coal and electricity in China is very inelastic (own-price elasticities less than -0.4)' (p.128-129)
Ma, C., & Stern, D. I. (2016): "Long-run estimates of interfuel and interfactor elasticities." Resource and Energy Economics, 46, 114-130.