Professor Jacobson and his team have performed analyses for large interconnected grids and conclude that, for electrical power provision, we can go to 100% solar/wind/hydro within the next generation, with significant investments of course. This article should be studied. A few comments.
The better grid interconnectivity you have, the more efficiently you can use available hydro power as an energy storage medium rather than a base load power provision medium. This means substantially more efficient and effective use of the hydropower capacity of North America.
East-West (EW) grid connectivity in North America is a great aid to efficient energy use because the ‘peak demand periods’ are off-set in time (up to 3 hours in the US, 4.5 hours in Canada). This has the effect of ‘smoothing the demand curve’, reducing the height of the peak demand spikes, and increasing the efficiency of base load power use. All good! Texas would have benefitted considerably from much better interconnectivity during the winter storms that led to The Great Texas Blackout of 2021. Balancing power cost and power provision reliability is a delicate and complicated issue. Solar power alone, in Nevada, is far cheaper than any other source, but it lacks reliability: it has to be stored when in excess for use later. The more integrated (widely spread and larger) the storage capacity, the better we can use renewables.
North-South (NS) connectivity in North America is also important. Canada and the northern tier American states need more power in the winter than in the summer, and as we gradually reduce natural gas use for home heating and cooking, this may even augment significantly. Furthermore, in much of the United States, the demand for electricity is higher in summer than in winter because of the intense need for air conditioning. Houston in the summer comes to mind. When I would visit Houston in August, I made sure to wear a tweed jacket to stay warm during workshops.
A well interconnected and stable grid also helps in many other ways.
The wind may not be blowing in Ontario on a given day, but if it is in the Maritimes and we have good EW connectivity, then renewable energy sloshes westward into the Ontario sector, reducing the need for CCGT (Combined Cycle Gas Turbine) activation. Another beneficial effect is that the available hydro power in Ontario stored in reservoirs behind dams may be better preserved for periods of intense demand. Spread this across an EW and NS interconnected grid, and many efficiencies ensue, leading to the possibility of elimination of all fossil fuel grid inputs.
Similar comments can be made about solar energy. Solar energy is weak in Canada in the winter, but “solar farms” in Nevada, Arizona and West Texas can feed into the grid, and help sustain the level of renewables use. The seasonality of solar power may dictate a policy of “over-building” of solar capabilities to accommodate this.
An integrated grid provides an insurance policy to homeowners, communities, and even large regional grids that are trying to factor in more local renewable energy (solar/wind) into their electricity use. In exceptional periods of high demand, even though these users at almost entirely “independent” or “off the grid”, connections to the grid reduce the risk of loss of service or degradation of service. However, as with any insurance policy, this must come at some price; otherwise, the economic basis of the interconnected grid is undermined.
But, behind all of these advantages, there will still be a large need for storage of energy, particularly at the scale of one or two hours to several days, to help save and redistribute energy on a daily basis, and taking into account renewable energy provision fluctuations over a weekly time scale. Storage in the EV fleet, storage as compressed air in sealed wellbores, storage using local pumped hydro projects, and smoothing of existing hydro access can all help, at different magnitudes, scales and locations.
Amicalement, Sincerely yours
Maurice B Dusseault, University of Waterloo
