Monday, August 15, 2022

What will Saskatchewan's electricity supply look like through 2030?

I asked SaskPower via the "Contact Us" form if they could share a copy of the "10-Year Generation Supply Plan" that was mentioned on p106 of the 2021-22 Annual Report. The reply was "it's on the website" (I don't think it is) so I've been piecing the path to 2030 together out of a few different sources.

The post will explore Saskatchewan's electrical supply mix up to 2030, as well as hit these themes:

  • The difference between generating capacity (MW) and electricity supplied (GWh), because one looks good for ad campaigns and the other runs homes and industry,
  • Saskatchewan's go-forward dependence on natural gas as our primary energy source, and
  • A few thoughts about ownership and costs of renewables and who benefits.

It was fun to try and piece this together. There are definitely assumptions and missing pieces of information, and I've tried to flag those where they're obvious. Sources are linked in a spreadsheet at the bottom of this post. 

Scenario 1: 40% Renewables by Capacity (T&D Report) 

Here's what I've put together from SaskPower's annual reports, blog posts, found presentations, external reports, news articles, and more. Some key inputs to this model:

  • 2022 is from the System Map, 2027 is derived from the 5-year forecast in the 2021-22 Annual Report, and 2030 is based on a) a SaskPower Transmission & Distribution report found online dated October 2021 and b) a SaskPower blog post stating 7000 MW of generation capacity by 2030. 
  • Project-based capacity is added where known, like the Bekevar Wind Energy Facility in 2023 and the Great Plains Power Station in 2024. 
  • Most other values are linear interpolations between known/inferred data points (e.g. everything in 2028 and 2029 is an interpolation between 2027 and 2030). 

Insights from this model: 
  • Coal is not completely shutting down in 2030: Boundary Dam Unit #3 (equipped with Carbon Capture and Storage) will continue to add ~115 MW of generation capacity to the grid. 
  • Dispatchable power (available anytime: coal, gas, hydro) has a healthy buffer over the projected peak load. We need lights on calm, dark days! 
  • The sum of hydro, wind, and solar "renewable" energy total about 40%, which is about the minimum SaskPower has committed to by 2030 (they've given a range of 40-50%). 
  • Look at all that gas! Gas is the primary replacement energy source for coal.
  • One invisible data point (and source of model error/uncertainty) is that in the late 2020s a 650 MW interconnect will be completed to the US, allowing SK to import/export power. I assume this is factored into existing 2030 generation capacity models that have been published to date, but I'm not showing a 650 MW increase in capacity in any one year. 

With the chart above, megawatts (MW) of generation capacity do not tell the whole story. What matters is GWh of power delivered to end-users (more commonly kWh on your power bill). Recall: MW is instantaneous; GWh is accumulated. 100 W is how much energy your laptop is using right now, 500 kWh is what your home consumed last month. MW is like the instant flow from your faucet; GWh is like the water collected in the sink. 

Anyway, when you convert from megawatts (MW) of generation capacity to GWh (electricity supplied) a slightly different picture emerges. Gas gets bigger, solar gets infinitesimally small. This is because solar's capacity factor - the ratio of actual power provided to theoretical power provided under ideal circumstances - is about 15%*. Natural gas has historically run at a capacity factor of 58% the last few years, coal about 74%. 

* (in fact, in 2021-22 solar's capacity factor was just 2.5% according to SaskPower's annual report, but I've fudged it up to 15% to align with typical expectations. I'm guessing there was a rounding error not in solar's favour in the report)

Note: I'm only showing 2022, 2027 and 2030 as those were the years with the most data available on the power supply mix in those years. 

We'll do one final transformation on Scenario 1, flipping the above chart into percentages:

The takeaway is the "40% renewables" narrative refers to capacity which is only available under the best possible conditions. In reality we expect the electricity supplied from renewables (based on historical data) to be more like ~32%. 

Scenario 2: 50% Renewables by Capacity 

SaskPower noted in their 2020-21 Sustainability Report that by 2030, renewables could make "up to" 50% of Saskatchewan's supply mix. Let's explore how that would look:

Assumptions and insights:

  • I've assumed that most changes occur between 2027 and 2030. 
  • I've also assumed a) we're still expecting 7000 MW of generating capacity in 2030, b) there's not much room for hydro growth over Scenario 1, and c) that wind/solar displaces new gas. 
  • I've assumed, for lack of a published plan, that the ratio of wind-to-solar will be the same in 2030 as in 2027. 
  • At first glance it looks very similar to Scenario 1, but the wind and solar bars are bigger at the end of the decade. Dispatchable sources are still safely above peak load. 

Let's transform to GWh and, based on historical utilization rates, see how much work can actually be done: 

There is a problem with this chart that may be hard to spot at first: in 2030 in Scenario 2, we're making less power than in 2030 in Scenario 1. Within the constant 7000 MW of generating capacity we have to play with, the lower capacity factors of wind and solar have lowered the total output of the grid. 

I've shown natural gas utilization on the above trend, and below I'll show what would need to happen to meet the energy output of Scenario 1: we'll need to increase utilization (capacity factor) from a historical 58% to about 64%. Unlike intermittent energy sources, increasing utilization is easy with dispatchable sources.