Affiliation: Gillings School of Global Public Health, Department of Environmental Sciences and Engineering
The flow regime of rivers is a complex, but important measure of environmental quality, and one that can be significantly impacted by conventional hydropower generation. While traditional hydropower scheduling creates a periodicity in downstream flows that corresponds to daily and seasonal demand patterns, the advent of de-regulated electricity markets introduces new influences. In these markets, hydropower utilities have financial incentives to alter generation schedules on a real-time basis, as hydropower is uniquely well suited to take advantage of sudden, and less predictable, variation in supply and demand. This study explores the potential for market dynamics to impact flows downstream from hydroelectric dams, as well as the financial cost and efficacy of efforts to mitigate the environmental effects of unnatural flow regimes under de-regulated market conditions. Three operating scenarios are explored, including (i) multi-market participation; (ii) current operations; and (iii) run-of-river operations. Results suggest that, in most cases, the scale of any differences in flow regime resulting from the pursuit of revenue in new markets is dwarfed by the additional revenue generating potential of such a strategy. Moreover, while implementing a run-of-river policy frequently yields `more natural' flow regimes than current operations, these improvements appear modest in most cases and come at a substantial cost in terms of foregone hydropower revenue.