Negative prices for power?? It happens! Even in Ontario, but this example is from Australia.
This solar farm in Australia has to shut down repeatedly when prices become negative; in other words, when the sun is shining strongly, and all the solar farms and the base load (coal power stations) are cranking out the MegaWatts hours, a surplus of power drives the markets down, even to the point of negative prices, to “force” suppliers to slow down or shut down their energy feed into the grid. Too much supply develops when the solar conditions are ideal and the energy demand is moderate.
We have a similar (yet different) problem in Ontario: mainly in June, July, August and September, Ontario repeatedly produces vast amounts of electrical power in excess of demand. The reasons for this are:
Base load provision is constant (nuclear power generation rate is constant)
Power demand is weak in the summer when the weather is in the 20-38 degree range in the day (little air conditioning, the days are long, power demands drop off, compared to winter)
But, by legislation, the Ontario Power Generator (OPG) is required to accept all of the renewable energy provided under contracts undertaken by previous governments to foster green, renewable energy uptake (generous feed-in tariffs, contractually guaranteed)
Thus, the wind farms and provisioners of solar energy have no incentive to turn off their feed-in power
…and even if they have less generous contracts, once a wind turbine is spinning, there is no reason to turn it off even if the price is low because the operating costs are close to zero
…so OPG provides the surplus energy in its grid at these times, at extremely low cost, often negative, to the USA (mainly Michigan), who are happy to accept it
…and there are other issues related to the provision of wind energy into the Ontario grid
Apparently, the “lost value” from the excess power approaches a billion dollars a year (lost value is not the same as income, and this value can be debated).
However, the solutions are there, but may not all be equally feasible or even possible for various reasons (geography, politics, etc.).
One solution is high integration with the Quebec power grid because hydroelectric power baseload is far more flexible than nuclear power base load. But, Quebec has generally been uncooperative in terms of East-West grid integration in Canada, as they have reliable American clients to the south who pay a good price.
Ontario could install many massive pumped hydro facilities to absorb the excess energy and provide it again when the need arises. Which valleys in Southwestern Ontario are you going to flood? In other words, grid-scale pumped hydro projects in Ontario are problematic.
Another solution, of course, is a massive increase in flexible energy storage, to the level of GWh (GigaWatt hours). Elon Musk believes his batteries are the answer. Massive battery arrays are being installed or considered in Australia, at a high cost per kWh. Others believe that the power-to-hydrogen-to-power approach is the answer, but it is plagued by several demons; although progress is being made, we are a long way from massive P to H to P systems for the grid. These approaches remain extremely costly for massive energy storage at the grid scale.
Southwestern Ontario is blessed with thousands of square kilometers underlain by salt (400 to 700 m deep) that could serve as storage sites for compressed air energy storage, a proven, economic and entirely viable technology for grid scale energy storage. Given the low cost of wind now, a combined wind farm and large-scale compressed air storage facility could provide dispatchable energy to balance demand and supply at a cost that is competitive, given the high value of flexible and dispatchable power (on demand, when you need it, high quality).
The compressed air storage concept can be down-scaled to MWh levels, and this is of substantial value to remote communities that cannot be cheaply serviced (100 km of power lines is expensive), to communities that wish to increase green energy provision, and to industrial entities that would benefit from green, dispatchable power input under their management.
Realistically, it is time to invest in green energy storage, and Ontario is extremely fortunate in having the right geology in the right place for grid-scale implementation. The barriers to implementation are complex, but inertia in our utilities seems to be a factor. We can do much better.
Amicalement / Sincerely yours
Maurice B Dusseault, PhD, PEng