03.21.08Harry Valentine, Commentator/Energy Researcher,

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Advances that are occurring in energy conversion technologies and in the marine shipping industry could strengthen the case for high capacity pumped hydraulic energy storage at Niagara Falls. At the present time the United States leads the world in the number of pumped hydroelectric installations of over 1,000 megawatts, followed closely by Japan. America’s largest such installation at Bath County, Virginia transfers water over a vertical height of 1,262 feet and is rated at 2,100 megawatts. The Ludington installation on Lake Huron in Mason County, Michigan, uses a vertical height of 363 feet and is rated at 1,872 megawatts.

The largest installation in New York State that is located 30 miles southwest of Albany involves a vertical height of 1,200 feet and is rated at 1,200 megawatts. By comparison, the pumped hydroelectric installations at Niagara Falls are relatively small, with the Lewiston pumping station in New York being rated at 240 megawatts and the Adam Beck pumping station in Ontario being rated at 174 megawatts. Lake Erie covers an area of 9,900 square miles and its water level is 326 feet above the adjacent Lake Ontario that covers an area of 7,300 square miles. Some 185,000 cubic feet of water per second flows through the Niagara River from Lake Erie into Lake Ontario.

The water flow rate over Niagara Falls is controlled so as to assure the economic viability of the tourist trade at Niagara Falls, to maintain hydroelectric power generation capacity downstream at the Moses Saunders and Cedar Rapids power dams on the St. Lawrence River where the marine shipping depends on sufficiently deep water levels. The hydroelectric power stations at Niagara are rated at 2,500 megawatts for New York and 1,600 megawatts for Ontario where generation capacity is being expanded by boring a new tunnel.

It may be quite possible to modify the exit of the new Beck tunnel to allow for the installation of reversible turbines. At different times such turbines drive electrical generation equipment and also pump water over greater vertical height (363 feet) that between Lakes Ontario and Erie (325 feet). The tunnel boring machines can that produce passages of up to 50 feet in diameter through the solid rock at Niagara could be used to bore many more parallel tunnels in that vicinity over a period of several decades. Such action would gradually increase pumped hydraulic capacity and related power generation capacity. A slightly lower water volume flow rate that flows into Lake Erie could flow over Niagara Falls during the day to preserve the tourist trade and be reduced overnight.

Water levels in Lake Ontario would drop by 1.1 inches if 800,000 cubic feet of water per second were pumped uphill through multiple tunnels into Lake Erie between 12 a.m. and 6 a.m. Lake Erie’s water levels would rise by 0.81 inches during that period. The sheer capacity of the two lakes can allow for 18 trillion cubic feet of water to be pumped to the higher elevation with minimal change in the height of either lake. That water would return to Lake Ontario during the same day during peak generating periods when up to 14,000 megawatts may be possible for up to 8 hours duration, or up to 11,000 megawatts for up to 10 hours. That power would be shared between New York and Ontario. This cyclic movement of water at Niagara should barely register across the large expanse of Lake Ontario in the shipping channels of the St. Lawrence River or at the Moses Saunders hydroelectric power station.

Possible Sources of Energy to Place into Storage

New York State is projected to have a possible shortfall of electrical power within the next two decades during which time Ontario will rebuild much of their generation capacity. The Manley report recommended using proven generation technology at the time when it was written. It suggested that wind turbines of 200 feet in diameter with the hubs at 80 meters or 262 feet above ground could produce up to 5 megawatts output each and account for up to 15% of Ontario’s future generation capacity. A more recent design of vertical axis wind turbine from the UK extends to a height of 470 feet to 490 feet above ground and is rated up to 9 megawatts output.

An advanced design of vertical axis wind turbine from China can ride on magnetic levitation and generate over 50 megawatts in a wind speed of 30 miles per hour. Research, development and initial testing have already been undertaken on airborne wind turbines that could generate up to 100 megawatts of power from high altitude winds. There are numerous locations across eastern Canada as well as the northeastern and south central USA where several designs of wind turbines could generate power at different elevations and from where off peak power may be transferred into storage including at Niagara.

There is renewed interest in the U.S. and in Ontario to increase nuclear electric generation capacity. Nuclear and other thermal power plants achieve optimal efficiency and cost effectiveness when thermal components operate at constant temperature and pressure. They would run at constant output and require access to high volume energy storage capacity. The presence of massive storage capacity at Niagara could prolong the service lives of many thermal power stations. It would also allow the purchase of massive amounts of off peak power at low cost that would be re sold at a higher price during the peak periods.

Power could be generated from ocean tides at regular intervals including outside of the periods of peak market demand. Variable amounts of power could be generated intermittently from ocean waves. Having access to high capacity energy storage could enhance the economic case of ocean tidal and ocean wave energy conversion. A portion of the off peak oceanic electric power that may be generated along America’s Atlantic coastline and also along Hudson Strait could be transferred into storage at Niagara in the distant future.

A group of American researchers recently examined the future possibility of generating electricity from concentrated solar photovoltaic and concentrated solar thermal technologies in the desert area of the Southwestern U.S. That group proposed to store energy using compressed air in emptied subterranean salt domes. Solar electric power from the Southern U.S. could be carried along UHV DC power lines into storage at Niagara at a future time. Mega hydraulic storage would exceed the capacity, efficiency and operating cost of compressed air storage technology. The evolution and development of cost competitive renewable energy technologies strengthens the case for mega capacity pumped hydraulic storage between New York and Ontario.

Marine Operations

There are long term plans to widen and deepen the shipping channel to allow longer and wider ships that have a keel depth of 45 feet to sail into Lake Ontario and possibly into Lake Erie. Wider and deeper channels will increase water flow rate through the St. Lawrence River and even through the locks that are located adjacent to the power dams. Side reservoirs and pumping equipment would have to be installed at several locks so as to maintain a constant water flow rate through the shipping channels.

Allowing ships with a keel of 45 feet in depth into Lake Erie would require that water levels be maintained at a higher level in that lake as a way of maintaining water depth in the Detroit River and St. Clair River. It would also require a massive rebuilding of the locks and shipping channel between Lakes Ontario and Erie. Pumped hydraulic storage could be installed at the larger locks in the future to save water and assist the energy industry while ships are transferred in between elevations during the overnight hours.

Conclusions

There have been growing concerns about dropping water levels in the Great Lakes. The use of pumped hydraulic storage would increase the efficiency by which water is used. It may be possible to install mega scale pumped hydraulic storage technology at Niagara with little or no adverse effect on either the region’s ecosystem or the tourist trade that depends on Niagara Falls. The falls could still be a spectacular tourist attraction even if the water volume that goes over the falls is significantly lower than the water volume that flows into Lake Erie from the Detroit River. Ecosystems would likely be unaffected.

Pumped hydraulic storage could offer major long term economic benefits to both New York State and to Ontario. Ontario could install reversible turbines in a modified exit of the new tunnel that is being constructed at Niagara so as economize on water. New York State and Ontario would both realize economic benefits in power generation after additional hydraulic tunnels are drilled on both sides of the border at Niagara and reversible turbines installed. The International Joint Commission and the International St. Lawrence Board of Control are the tribunals that will ultimately decide as to whether or not to allow for the installation of mega hydraulic storage technology between the upper and lower sections of the Niagara River.

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Reader's Comments

Date	Comment
Roger Arnold 3.27.08	The potential pumped hydro capacity between lakes Erie and Ontario is large enough to supply power buffering for a most of south central Canada and the north central US. What's missing, however, is the transmission capacity to take advantage of it. Perhaps new HVDC or superconducting lines could help to make the job feasible. But it's an issue that would need to be examined carefully before turning the TBMs loose around Niagrara.
Len Gould 3.27.08	Hmmm... So Ontario, by investing $25 billion in pumped storage at Niagra, could gain a load shift from peak to off-peak of about 5,000 megawatts. (presuming typical hydro facility costs of $5 million / megawatt) I would just point out that by investing perhaps $500 / customer in an IMEUC smart meter market system, assuming each customer could then load-shift 1 kw for the 10 hr period from day to night (smart appliances doing laundry and dishwashing at night, thermal storage water heating / space cooling, etc.) it would need only 5 million customers to accomplish the same outcome, at a cost of ony $2.5 billion dollars in meters, leaving "as much as" $22.5 billion in the budget to subsidize the appliance installs, central databases, training etc. if necessary. And such subsidy shouldn't be necessary if the market incentives are simply designed properly, as in my articles on this site describing the system.
Kenneth Kok 4.1.08	Harry: Study your map. Ludington is on Lake Michigan and not Lake Huron.
Joseph Somsel 4.3.08	The economics of pumped storage strongly favors the input of the lowest cost, most reliable generation possible. Given the energy losses in storage and recovery, low input price is leveraged - that is, any input price difference going in is multiplied as a difference of the output price. Likewise, the large first cost of a pumped storage plant makes the reliability and availablity of the input power even more important. Any downtime of the pumped storage facility due to lack of input power just adds to the annual net cost of the facility. Both factors lead to the conclusion that adding pumped storage favors coal and nuclear and disadvantages renewables on the system. In other words, fans of renewables (wind and solar) can not claim that pumped storage will make their favorite electric sources more acceptable in the market place. On the contrary, more pumped storage will increase the advantages of coal and nuclear over wind and solar.
Roger Arnold 4.5.08	Joseph, I'm afraid I don't see your logic. A pumped hydro facility never pumps and generates at the same time. It's a time shift machine for electrical energy. I can't see that it makes any difference whether the energy it's shifting is surplus from a baseload system or from an intermittent system. All that matters is the cost spread between input and output and the total throughput. Am I missing something?
Len Gould 4.6.08	Joseph make a very good point. If a pumped storage facility is cost-justified on the basis of accepting XX MWH of power every night from the grid, but some nights only 1/2 XX MWH of excess generation is available because the wind is not blowing that night, then the unit cost of the energy the pumped storage setup does put out the next day goes up significantly. Pumped storage, (and any other bulk central electricity storage except heat in a solar CSP install) are currently so expensive that they MUST be fed by absolutely reliable sources of electricity during off-peak hours. The same would NOT apply to grid-smart PHEV's which could fall back to stored fuel sources if the electricity became unreliable off-peak. Implementing an intelligent and comprehensive advanced electricity market system would enable this.
Roger Arnold 4.7.08	Len, I think pumped-hydro facilities are normally justified on the basis of regulation service and avoided costs for peaking units. Both pumping and generating rates are highly variable, depending on the instantaneous level of power surplus or deficit. There may be a design expectation that they will absorb x MWH and supply y MWH daily (with 'y' hopefully not too much less than 'x'), but the timing is discretionary. The capacity factors for both pumps and generators are, by design, relatively low. I.e., they're oversized for typical loads, so that they can handle larger maximum loads. That doesn't usually have a big cost impact, because the major cost is usually in the associated storage reservoirs and tunnels, rather than the pumps and generators. Bottom line: pumped hydro facilities do NOT expect or require absolutely reliable sources of electricity during off-peak hours.
Joseph Somsel 4.7.08	The output unit cost of electricity X from a pumped storage unit can be expressed as a simple equation: X = Y/e + Z/T Y = input unit cost of electricity e = efficiency of pumping and generation or kW-hr output divided by kW-hr input Z = annual capital + operations/maintenance cost of the facility (assume non-variable) T = annual kW-hr output The usual run-of-thumb is 4 kW-hr go in to a plant and 3 kW-hr come out for e = .75. Therefore, the costs differences in inputs are magnified by the inefficiencies of the process making cheaper input power a priority - hence coal or nuclear are preferred. The term Z/T is simple amortization of the plant costs against total output - the less output, the fewer kW-hr to amortize the costs against. If your fixed costs are $10 million and you output one billion kW-hr per year, the Z/T = one cent. Curtail operations because of limited wind resources to 500 million kW-hr a year and the Z/T term is now 2 cents per kW-hr. Even if Roger's point is correct, more expensive, less reliable input power raises the cost of regulation service.
Roger Faulkner 1.6.09	It is important to note that the viable time scale for energy storage is in this case well above a day. In round numbers, if max output is around is around 10 GW, then this system could run at full capacity for 4.5 days before increasing the lake level of Lake Ontario 30 cm. No other pumped storage setup would have this kind of ratio of storage capacity/power output (GW-hours, about 1075)/(power output 10 GW, 14.29 GW input, assuming 70% total efficiency). I am applying for a NYSERDA grant to study this scenario. Avoidance of capital cost for new generation capacity is part of the benefit. Allowing non-dispatchable energy sources to make a large contribution to the energy budget, and to displace even baseload capacity; I agree that this only makes sense in the context of an enhanced grid.

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