Riverine ecosystem services and the thermoelectric sector: strategic issues facing the Northeastern United States

Abstract

Major strategic issues facing the global thermoelectric sector include environmental regulation, climate change and increasing electricity demand. We have addressed such issues by modeling thermoelectric generation in the Northeastern United States that is reliant on cooling under five sensitivity tests to evaluate losses/gains in power production, thermal pollution and suitable aquatic habitat, comparing the contemporary baseline (2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010) with potential future states. Integral to the analysis, we developed a methodology to quantify river water availability for cooling, which we define as an ecosystem service.Projected climate conditions reduce river water available for efficient power plant operations and the river's capacity to absorb waste heat, causing a loss of regional thermoelectric generation (RTG) (2.5%) in some summers that, compared to the contemporary baseline, is equal to the summertime electricity consumption of 1.3 million Northeastern US homes. Vulnerabilities to warm temperatures and thermal pollution can be alleviated through the use of more efficient natural gas (NG) power plants that have a reduced reliance on cooling water. Conversion of once-through (OT) to cooling tower (CT) systems and the Clean Water Act (CWA) temperature limit regulation, both of which reduce efficiencies at the single plant level, show potential to yield beneficial increases in RTG. This is achieved by obviating the need for large volumes of river water, thereby reducing plant-to-plant interferences through lowering the impact of upstream thermal pollution and preserving a minimum standard of cooling water. The results and methodology framework presented here, which can be extrapolated to other regional assessments with contrasting climates and thermoelectric profiles, can identify opportunities and support decision-making to achieve more efficient energy systems and riverine ecosystem protection.

A regional assessment of the water embedded in the US electricity system

“…For example, California has implemented 316(b) by establishing cooling system technology-based standards aimed at reducing withdrawals of ocean and estuarine surface water, which has tended to shift once-through ocean water cooling to non-water cooled or recirculating systems in the state [39]. Through section 316(a), the Clean Water Act also sets operationally relevant limits on temperature increases due to water use for cooling [40,41], which influences choices about cooling system technologies. Although variability in regional consumptive water intensity for electricity is related to circumstance (e.g.…”

Planning for Algal Systems: An Energy-Water-Food Nexus Perspective

“…11,[79][80][81] In response, environmental regulations in the US (Clean Water Act 1972) and Europe (European Fish Directive, Water Framework Directive) have set limits on water intake volumes and river temperature increases that result from power plant thermal loads. 82,83 In recent summers, warm river temperatures have triggered regulatory temperature limit thresholds, forcing some power plants to shut down or curb electricity generation, sometimes resulting in blackouts and costing consumers in the US tens of millions of dollars.…”

“…Vulnerability studies have shown this could constrain electricity generation in Europe and the US. 81,98 In addition, droughts worldwide have already resulted in lower crop yields and higher food prices. A changing climate is projected to intensify such extreme events causing further constraints on the agriculture sector and crop growth for both biofuel and food production.…”

Thermal pollution impacts on rivers and power supply in the Mississippi River watershed

“…In addition, OTbased plants rely on sufficiently cool river temperatures to maintain optimal thermal efficiency [13,14]. Previous electricity generation vulnerability studies have concentrated on climate and water resource change impacts, while thermal pollution assessments have had a unitary focus on determining the temperature rise on receiving waters [5,[15][16][17][18][19][20][21][22]. In regions where power plants are closely populated along rivers, thermal pollution from upstream plants may cause plant-toplant thermal interference and increase condenser inlet temperatures at downstream OT-based plants, potentially lowering thermal efficiencies and triggering CWA curtailments [23].…”

“…The importance of incorporating higher spatial and temporal resolutions to reliably assess thermal pollution is also yet to be addressed. Thermal pollution and electricity generation vulnerability assessments across large domains are typically executed at a 0.5 • spatial resolution, although few have used higher resolutions (0.05 • , 0.125 • ) [5,16,17,20,21,[24][25][26]. Studies that use coarse spatial resolutions may misgauge the extent of thermal pollution as it forces placement of multiple plants inside a single grid cell and fails to capture finer-scale variations in river discharge, temperatures and thermal equilibration rates.…”