Alternative solutions to power oversupply in the Pacific Northwest.

Author:Rietmann, Emily

    The Pacific Northwest is uniquely blessed with an abundant supply of electrical power. In fact, power oversupply events can occur when large amounts of wind generation combined with large amounts of hydropower produced by dams on the Columbia River generate electricity in excess of total demand. (1) Oversupply events are likely to occur when power demand is low, and in the springtime when river flows and wind generation are high. (2) Dam operators on the Columbia River can respond by spilling water over the dams without generating electricity, but too much spill exceeds water quality standards (3) and can harm fish and other aquatic species. (4) If dam operators cannot spill water, the water must pass through hydropower turbines, thus generating electricity. (5)

    When dam operators must put water through hydropower turbines to protect aquatic life, the Bonneville Power Administration (BPA) (6) displaces non-hydropower generation to maintain system reliability. (7) In response to the oversupply problem, BPA proposed several policies (8) to the Federal Energy Regulatory Commission (FERC). (9) Each attempted solution cut off wind generation from the transmission grid to make room for excess hydropower generation. (10) Unsurprisingly, each attempted solution met opposition--first from wind generators whose power sales were cut off without compensation, (11) and then from transmission customers charged with the costs of compensating curtailed wind generators. (12) The fight over how to allocate wind displacement costs is ongoing, (13) but the best solutions to oversupply avoid compensating wind generators altogether by keeping wind generators online during oversupply events.

    One alternative to curtailing wind generation is to store surplus power generated during oversupply events. (14) Power storage facilities like aquifer recharge and pumped hydropower projects could enable wind generators to stay online during oversupply events by using excess wind generation to pump water out of the Columbia River and storing the water and power for later use. (15) In this way, aquifer recharge and pumped hydropower are more efficient and more aligned with important policy goals than curtailing wind generation, because they support increased renewable power generation. (16) Wind generation is currently an intermittent source of renewable energy with the potential technical capacity to power the world. (17) In the Pacific Northwest alone, wind power has the potential to satisfy all of the current electricity consumption in the region four times over. (18) But wind will remain an intermittent, niche energy source without the capacity for storage. (19) Aquifer recharge and pumped hydropower are storage options for wind energy that could enable the integration of wind power in any area where there is great energy capacity and significant water storage concerns. (20)

    In addition to being more sustainable, long-term responses to oversupply than curtailing wind generation, aquifer recharge and pumped hydropower projects present a host of other benefits. (21) Aquifer recharge projects can restore critical groundwater areas, which can yield significant environmental and economic benefits in groundwater-limited regions. (22) Pumped hydropower facilities have the potential to return flexibility to the federal hydropower system, because they can store large quantities of water. (23) This gives dam operators more choices when it comes to deciding when to spill water over the dams or generate hydropower, thereby improving the capacity for fish management and ensuring the reliability of the power grid. (24)

    While aquifer recharge and pumped hydropower could expand the use of low-cost, low-carbon hydropower and wind energy, and could reduce the severity of excess energy events, they are not free of complications. (25) Permitting processes at the state and federal level can make it difficult for proposed aquifer recharge and pumped hydropower projects to receive authorization. (26) Both aquifer recharge and pumped hydropower must receive state permits to withdraw surface water from the Columbia River. (27) Moreover, aquifer recharge projects must receive authorization to inject appropriated water into underground aquifers, and pumped hydropower projects must receive dam approval by the state. (28) Finally, pumped hydropower projects face the additional hurdle of completing the federal licensing process, which can take decades and ultimately make such projects too daunting to finish. (29)

    In addition, both aquifer recharge and pumped hydropower projects are costly to implement. (30) Aquifer recharge projects could strain the capacity of the existing infrastructure used to pump water out of the Columbia River, such that costly improvements must be made. (31) Pumped hydropower projects are even more costly to implement than aquifer recharge projects; moreover, the current regulatory treatment of the costs of pumped hydropower adversely affects the feasibility of these projects. (32) Despite the challenges facing proposed aquifer recharge and pumped hydropower projects, over time, these alternative solutions to oversupply arguably will prove more efficient than curtailing wind generation.

    This Comment uses the oversupply problem in the Pacific Northwest to illustrate the benefits and complications of integrating excess energy supply and water storage in a sustainable way, ultimately concluding that solutions to oversupply that avoid curtailing wind generation are preferable to BPA's chosen alternative. Part II explains the oversupply problem in the Pacific Northwest and details BPA's proposed solutions to oversupply thus far. Part III explains aquifer recharge and pumped hydropower and why they are more attractive solutions to oversupply than curtailing wind generation. Part IV outlines the project authorization process for aquifer recharge and pumped hydropower projects at the state and federal level. Part V explains some of the complications associated with implementing aquifer recharge and pumped hydropower projects. Finally, this Comment concludes with an explanation of why aquifer recharge and pumped hydropower are, nevertheless, more attractive solutions to oversupply than curtailing wind generation.


    Oversupply occurs when the minimum generation of the power system--supply--exceeds firm load and secondary sales markets-- demand. (33) In the Pacific Northwest, this typically happens in the spring and early summer when demand for power is low and the supply of hydropower and wind-generated power are high because of seasonal storms and annual snowmelt runoff from tributary rivers. (34) Under normal conditions, when power supply exceeds demand, generators in the Northwest sell power to utilities in the Southwest over the Pacific Northwest/Pacific Southwest Intertie. (35) But during oversupply events, supply might exceed demand in both the Northwest and Southwest electricity markets. (36)

    When oversupply events occur in the BPA balancing authority (37) area, BPA curtails production of the electricity it cannot sell by spilling water over dams on the Columbia River instead of running water through hydropower turbines and generating electricity. (38) But BPA can spill water over the dams only to the extent that spilling does not harm fish and other aquatic species. (39) When BPA must put water through the turbines to protect aquatic species--and therefore generate electricity in excess of load and export amounts--BPA must curtail other sources of generation to protect against the reliability problems associated with overgeneration. (40)

    To maintain reliability on the electrical grid, supply and consumption of electrical power must be balanced at all times. (41) Power overgeneration threatens reliability, because too much electricity on the transmission grid causes electrical lines to heat up and sag, thereby forcing grid operators to reroute electricity, which can result in the overuse of other electrical lines and create a domino effect on the whole system leading to blackouts. (42) BPA prevents blackouts and maintains reliability during periods of overgeneration by initially curtailing thermal generators (43) to the lowest possible generating level without threatening reliability. (44) If BPA determines additional generation relief is needed, it curtails variable energy resources, such as wind, which may result in moving wind generators completely offline. (45)

    Oversupply is not a new problem in the Northwest, but it has become problematic as more wind power is added to the power supply. (46) BPA added about 1,000 megawatts (MW) of wind power to its transmission system in 2012, which brought the total wind capacity within its balancing authority to 4,300 MW. (47) In 2011 and 2012, oversupply totaled about 97,500 megawatt-hours (MWh) (48) and 49,744 MWh, (49) respectively. Oversupply is likely to continue to be a problem in the Pacific Northwest. (50) BPA projected the cost of reimbursing curtailed wind generators would total $10 million in 2013, but noted that because conditions can change quickly, wind displacement costs could exceed $50 million in 2013. (51)

    In 2011, BPA made its first attempt to address oversupply through its Environmental Redispatch and Negative Pricing Policies (Environmental Redispatch), (52) under which BPA curtailed wind generators in the BPA balancing authority area during oversupply events, and delivered federal hydropower to wind generator customers. (53) Under Environmental Redispatch, BPA provided federal hydropower for free or at low cost to wind generators, but wind generators did not receive...

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