or gas with carbon capture and storage), and energy efficiency. Battery storage cannot cost-effectively replace hydro capacity in the Northwest due to charging limitations during energy shortfall events." "Replacement power would cost several times as much as the lower Snake River dams costs," according to the publication. Modeling studies calculated the costs of replacing the power from the dams comparing several scenarios, favoring two "deep decarbonization" ones. Deep decarbonization was defined as "zero carbon emissions by 2045 [and] high electrification of buildings, transportation, and industry to reduce carbon emissions in other sectors." Two scenarios that aimed for deep decarbonization compared costs when adding only baseline technology capabilities, with costs when at least one "emerging" technology substituted for some of the baseline technology. Baseline technologies were "solar, wind, battery plus pumped storage, energy efficiency, demand response, [and] dual fuel natural gas plus hydrogen combustion plants." "Emerging technologies such as hydrogen, advanced nuclear, and carbon capture can limit the cost of replacement resources to meet a zero emissions electric system, but the pace of their commercialization is highly uncertain." For reducing cost, the study particularly favored adding new small modular nuclear reactors as a cheaper alternative to baseline technologies. With at least one emerging technology in a deep decarbonization scenario, net present value annual costs of replacing the services of the dams was modeled to be $415 million in 2035 to $428 million in 2045. This would lead to public power retail costs increasing by 8% (on average an extra $100 per year per household) in higher bills by 2045. In a purely baseline technologies deep decarbonization scenario, extra annual costs would range from $496 million in 2035 to $860 million in 2045, leading to 18% higher bills ($230 more per year) by 2045. Other scenarios were within the same cost range, except for deep decarbonization with no new combustion, which would be much more costly because of difficulties in creating firm capability solely with wind and solar power. Tributaries The Salmon River is the second largest tributary. Although the Salmon has larger drainage than the Clearwater, the Salmon drains much drier country and therefore has a smaller discharger than the Clearwater, about annually compared to about annually for the Clearwater River. The Snake River has over 20 major tributaries, most of which are in the mountainous regions of the basin. The largest by far is the Clearwater River, which drains in