https://theconversation.com/ontario-can-phase-out-nuclear-and-avoid-increased-carbon-emissions-128854
[links in online article]
Ontario can phase out nuclear and avoid increased carbon emissions
January 5, 2020
MV Ramana
Simons Chair in Disarmament, Global and Human Security at the Liu
Institute for Global Issues, University of British Columbia
Xiao Wei
MITACS Globalink Research Intern, University of British Columbia
As wind and solar energy have become cheaper, they’ve become a more
prominent and important way to generate clean electricity in most parts
of the world.
The Ontario government, on the other hand, is cancelling renewable
energy projects at a reported cost of at least $230 million while
reinforcing the province’s reliance on nuclear power via expensive
reactor refurbishment plans.
As researchers who have examined the economics of electricity generation
in Ontario and elsewhere, we argue that this decision is wasteful and
ill-advised, and the unnecessary cost differential will rise further in
the future.
One concern about renewables has been the intermittency of these energy
sources. But studies have shown it’s feasible to have an all-renewable
electric grid.
These feasibility studies, however, are always location specific. In
that spirit, we have carried out detailed modelling and found that it’s
possible to meet Ontario’s electricity demands throughout the year with
just a combination of renewables, including hydropower, and storing
electricity in batteries.
We also found that dealing with the intermittency of wind and solar
energy by adding batteries would be more economical than refurbishing
nuclear plants in the foreseeable future, well before the current
refurbishment projects are completed.
That’s because of the expected decline in the cost of batteries used to
store the electricity during the hours when the wind is blowing or the
sun is shining in order to supply electricity during the periods when
they aren’t. The cost of different kinds of battery technologies, such
as lithium-ion or flow batteries, have come down rapidly in recent years.
Modelling
To explore the relative economics of nuclear and renewable energy, we
constructed a very simple model that optimized the total cost of meeting
the electricity demand in Ontario for each hour of the year.
We used what’s known in physics as a toy model. It’s not intended to be
sufficiently accurate to reproduce reality in detail, but to capture the
basic and important elements of the system being studied. Our model is
not meant to actually calculate the cost of supplying electricity, but
only to compare the relative costs of different options, with the
condition that no fossil fuels be used.
Using a software program called pypsa, we started with an example that
modelled a fully renewable electricity system for European countries,
and then modified it significantly. Our target was Ontario’s hourly
electricity demand in 2017, taken from the province’s Independent
Electricity System Operator, known as the IESO.
We met this demand in two ways — batteries and refurbished nuclear
plants. Both cases incorporated solar energy, wind energy and hydro
power from existing dams. The base costs of solar and wind were taken
from a November 2018 report by the Wall Street advisory firm Lazard; the
prices have since declined.
For simplicity, we assumed that the variable costs of all these
technologies were zero. This actually favours the nuclear scenarios
because it ignores the cost of uranium fuel and radioactive waste disposal.
The availability factors for every hour of the year for the theoretical
solar and wind generators were also based on data from the IESO on
actual production of solar and wind energy in Ontario in 2017.
The maximum power available from large hydropower dams during any hour
of the year was assumed to be less than 85 per cent of the installed
capacity within Ontario of 9,065 megawatts; this is a conservative
assumption since the province could easily import more hydropower from
neighbouring Québec.
We ran a large number of scenarios with multiple cost and other
assumptions and derived fairly robust results.
Essential results
In all scenarios, the bulk of the demand was met by solar and wind
power, with a lower fraction met by hydropower. Even in the scenarios
with no batteries, less than 20 per cent of the electricity demand was
met by nuclear power.
Second, it would be cheaper to reduce this even further. Because of
safety and other operational reasons, it’s a bad idea to change the
outputs of nuclear plants quickly. Traditionally, reactor outputs have
been held steady.
But if, for argument’s sake, we allow the outputs of nuclear reactors to
go up and down as fast as needed by the grid, then our model predicts
that nuclear power plants would be used even less. If nuclear power
plants outputs are held steady, then they would supply more electricity,
but the cost to consumers would also be higher.
Finally, and perhaps most consequentially, if the costs of batteries
decline from current levels to those projected for 2025, then the cost
of supplying electricity using a combination of renewables and battery
storage would become cheaper than doing the same using nuclear power.
The cost of meeting the electricity needs for the province could be
further reduced if the availability of hydropower is increased.
Our choice of 2025 for the projection year, incidentally, is guided by
the fact that the current use of modern renewables in Ontario is low,
and there will be no need for batteries to store electricity until there
is a dramatic increase in the wind or solar power projects constructed.
The levels of renewables that will require storage are unlikely to be
reached before 2025.
In summary, our results show that for reasonable assumptions about
future battery costs and the current price tag for solar and wind power,
scenarios involving nuclear power are more than 20 per cent higher than
the cheapest scenario involving only batteries, solar, wind and the
current hydropower capacity.
If an extra 2,000 megawatts of hydropower capacity were to be available,
scenarios involving nuclear power would be over 30 per cent more expensive.
That means, simply put, that nuclear power isn’t needed to meet
Ontario’s electricity needs. And the absence of nuclear power won’t have
any impact on emissions in Ontario’s energy sector.
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