Saturday, July 2, 2022

Feedback Opportunity: City of Saskatoon's Renewable Energy Strategy Survey

The Survey

The City of Saskatoon is consulting with citizens on its Renewable Energy Strategy which will be presented to City Council in 2022. I received an email to provide input via a survey. Let's do some homework, then come back to the survey. 

The Renewable Energy Strategy is anchored by Saskatoon's Low Emissions Community Plan (PDF), published in 2018. Let's highlight a few stated objectives and benefits from the Plan. 

Lots of jobs and reduced expenses for residents: 

(p6, Executive Summary. Click for big) 

And lower utility bills for residents and businesses: 

(p20, Benefits of a Low Emissions Community. Click for big)

Jobs and lower costs for residents? That's great! Right? 

When you click on the recent survey link (which is available until July 12, 2022 on the Renewable Energy Strategy Engage page) the first question is "what is your level of support for the following city-led initiatives?"

(from "Follow-up On What We Heard - Renewable Energy Strategy" survey, June 27 to July 12. Click for big)

Lots of these initiatives seem like net positives. Saskatoon's landfill gas capture power generation system has been marketed to citizens as a big green-energy win, with a 9-year payback (source, see FAQ section). Solar is good (right?). 

However, Question Three on the survey is essentially, "how do you want to pay for this?"

(from "Follow-up On What We Heard - Renewable Energy Strategy" survey, June 27 to July 12. Click for big)

In case the image doesn't work, the selectable options are: 

  • Increasing property taxes
  • Increasing utility rates
  • Borrowing through low-interest loans [BN: how are these paid back? My guess is property taxes and/or utility rates] 
  • None of the above

Conclusion: The City is telling us - or strongly hinting - that this group of renewable energy projects will fail to reduce rates, and likely cause us to be paying more.  

The question to explore: 

Why might (some of) these City-led renewable energy initiatives fail to meet (some of) the objectives of the Low Emissions Community Plan, resulting in increased property taxes and utility rates for citizens?

Let's hypothesize and/or investigate why these initiatives would increase costs, one initiative at a time. 

  • Landfill Gas Capture. Until this afternoon, I thought this project was a green-energy win with its 9-year payback. Then I found this memo suggesting the 9 years (from 2014) payback is now 30+ year payback due to lower-than-predicted gas volumes, maintenance costs and expensive contractors, unreliable equipment, and operational challenges (see also: this PDF slide deck showing maintenance challenges like condensate lines frozen shut in winter). 

  • Combined Heat & Power. Skip: I haven't read anything on this. 

  • Utility-scale solar pilot. What I like: "Utility scale" - this companion doc linked on the survey describes a 2.2 MW plant. What I don't like: Solar, specifically PV (photovoltaic) solar (contrast to: concentrating solar, which are just big mirrors). Why would this increase utility rate and taxes? 
    • It's low energy density. This PowerPoint PDF says 14 acres of land will be used. This page on Our World In Data helps illustrate how many meters-squared of land is used by different energy sources. If Saskatoon continues to build out utility-scale solar, we use up valuable land that could have been put other productive or social-good uses. We spend more time and materials maintaining a large footprint with a low impact. 

    • It's intermittent. Solar needs to be backed up by dispatchable energy (e.g. gas, coal, hydro).  The Background tab on the Engage page says Saskatoon is "ideal" for solar with 2,260 hours of bright sunlight per year. You can interpret that the effective utilization of a solar panel being ~26%. While the project documents talk about an 11-year payback and "cost neutral to ratepayers" (PowerPoint linked above), I hypothesize the City has not accounted for rising rates from SaskPower over the next decade(s) as they possible struggle to integrate renewables into their grid (book rec), rising costs of natural gas, and the rising cost of carbon (see my last post). If Saskatoon wants to pay for solar, they also have to want to pay for dispatchable energy to be on standby.

    • The life of the plant is 30 years. I have not seen (but have not looked for) a decommissioning and/or recycling plan for these panels which are full of heavy metals and circuitry fused into glass and silicon. Is it illogical to think that in the future we will impose thorough (and expensive) requirements for decommissioning and recycling solar PV panels? 

  • Rooftop solar on City buildings. All of the points about the utility-scale solar above, multiplied by project management, engineering, planning, permitting, and installation costs for dozens of city buildings instead of one large utility-scale site. Capital cost per MW of generation capacity skyrockets. Operating and maintenance costs per installed panel go up (think: electrician travel time and per-building delays).

  • Solar at the Wastewater Treatment Plant. Solar has been covered enough. 

  • Biogas use at the Wastewater Treatment Plant. This is the one item on the list I'm cautiously optimistic for. Biogas, like the Landfill gas project, should be a dispatchable (steady) source, unlike the intermittency of renewables. The plan (see companion doc) is to use biogas for heating at the WWTP, which would offset natural gas usage. It may also be used for electricity generation. 

  • Purchase renewable energy credits through SaskPower. It should be obvious why this would increase utility rates and/or property taxes. This is a straightforward payment of cash to the provincial utility with nothing tangible returned to the City.

  • Renewable energy storage. Pro: Adding a battery and limiting it to only storing renewably-generated energy would increase the effective utilization of renewable energy sources like solar and landfill gas. Con: Limiting the battery to charging on renewable energy may constrain useful functionality, e.g. charging the battery from grid/gas when it's dead may help mitigate local grid blips or brownouts. I suspect a high cost per MW/MWh at the scale the City might investigate. SaskPower is already investigating this at "grid scale" (see my last post) - maybe we should wait and see the results. 

Is this guy against renewables? Get him!

I am not opposed to renewable energy. I am a huge and growing fan of zero-carbon energy and decarbonization in general. Renewable energy has a role to play in our energy systems. 


I am generally opposed to (but open to exploring) small-scale renewable energy projects. As David C. MacKay writes in Sustainable Energy - Without The Hot Air, "every BIG helps!" Let's maximize the value of the time, energy, money, and raw materials by looking for big changes with big impacts. 

I am mildly opposed to, perhaps hesitant is a better word, the idea of municipalities executing their own strategies for sourcing and generating energy. The Grid by Gretchen Bakke had a powerful idea which I'll paraphrase/butcher: grids are best run on a socialism model. Owned by the people and delivering the widest public good. Since energy sources added to any part of our provincial grid impact every other part of it (and every ratepayer), the more centrally and systematically our grid is managed, the better. Like healthcare. (compare and contrast to dysfunctional grids and health care systems in the USA running on free-market models - also covered in Bakke's book). I think the people of Saskatchewan should be having this conversation at the provincial level. 

I am strongly opposed to deploying intermittent renewables like solar PV under the guise that they will lower utility rates and/or property taxes to ratepayers. I am not convinced this is doable (I've seen enough engineering projects with a positive benefit dragged 20 years into the future in Excel, missing risks, operations & maintenance costs, etc., to trust projections). Again: if we want to pay for solar (or wind, etc.) we have to also want to pay for dispatchable energy to be on standby. Paying to maintain and operate two parallel and redundant sets of infrastructure means costs go up. 

The point is: we have to have a conversation about if we care MORE about reducing emissions (undoubtedly good) than we care about the costs of building and operating intermittent renewables and/or small energy projects that don't benefit from scale effects. What is the best environment/energy value per time or dollar spent for citizens of Saskatoon? Is municipal the right place to build energy projects? What and where should our focus be, municipally and/or provincially? 

I don't want to say we shouldn't also make small changes. But we should be really, really sure they are changes in the right direction. If the LECP was trying to deliver lower costs and reduced energy poverty, this recent engagement survey signals we are not moving in the right direction. 

Last bit for now. Take a look at Page 12 of the Low Emissions Community Plan. The two most impactful initiatives Saskatoon can undertake, which are an order of magnitude higher impact from an emissions perspective than any other initiative, are procuring renewable energy and renewable gas from third-party producers. 

Call To Action

  1. Check out these resources:
  2. Review the Updates and Other Considerations (6 pages) document to prepare for the survey
  3. Complete the survey linked on the Engage Page before July 12, 2022

Fill out the survey however you want. 

If you're supportive of renewable energy projects in Question 1, I hope you signal your support for paying for them in Question 3. 

Closing Note

I've tried to cite sources, provide links, and use words like "hypothesize" to indicate uncertainty where I've done less homework and reading. I'm committed to learning more about decarbonization so leave me a comment (moderated/delayed due to platform spam) or a tweet with constructive feedback or corrections. 

Sunday, June 26, 2022

Things I learned and questions I'm asking from reading SaskPower's annual report (2020-21)

Over the last few years I have become more fascinated by energy and energy issues. I've read a bunch of books (here's my list and queue on the topic of energy), tuned into some great podcasts like Decouple, and even made a career change to be closer to the energy sector. 

I have not seen a terrific amount of dialogue about energy in Saskatchewan. That may due to channels I'm plugging into (or not). To learn more, I read SaskPower's 2020-21 Annual Report. These are some of the things I learned and some questions I think are worth asking. Any page numbers I mention refer to the 2020-21 report PDF.

0. Background and Terms 

Two related but critically different units in energy are the watt and the watt-hour. 

A watt represents power, which is the rate at which electricity is produced or consumed. A watt can be expressed in joules per second (energy per unit time). 

A watt-hour (more commonly: kilowatt-hour or kWh, or gigawatt-hour of GWh) represents energy which is a quantity of work done (in the physics sense). A watt-hour can be expressed in joules. 

Little example: if you have a 60 watt light bulb turned on for one hour, the light consumes at a constant rate of 60 watts, for a total energy consumption of 0.06 kWh. 

Big example: SaskPower's peak load was 3,722 MW (instantaneous production/consumption), their total generating capacity is 4,987 MW, and they supplied 24,634 GWh of energy in 2020-21. 

1. Saskatchewan is not a coal province (anymore). We're a natural gas province.

There's a trope in Saskatchewan when talking about electrification (of cars, appliances, heating, etc.) that when you electrify something, it's "coal-powered." Nice EV you've got there, did you know it runs on coal? 

I was surprised to learn that 43% of the province's generating capacity is natural gas, compared to 31% coal (page 6). By 2025, this is forecasted to be 40% gas, 21% coal, with wind making up much of the difference. 

2. SaskPower is going big on wind power, but isn't clear about utilization

On page 2, two new wind projects (Golden South Wind Energy Facility and Blue Hill Wind Energy Facility) are discussed, adding a combined 375 MW of generating capacity to the province's grid. This will more than double previous wind generation in the province. By 2025, they estimate 15% of the province's generating capacity will be wind. 

(Just for a sense of scale, the Queen Elizabeth (gas) Power Station in Saskatoon is listed at 623 MW)

The utility is not clear about the utilization or capacity factor of wind assets. On p117 there are tables that let us calculate a rough estimate. See this spreadsheet for my futzing around. 

In the first two columns I have copied data from p117. In columns F and G I've calculated the theoretical energy (GWh) that each source could generate if it were running at 100% utilization, 24/7/365. In columns H and I I've scaled those numbers by multiplying by peak load (3,722 MW) over total generating capacity (4,987 MW). 

This is more readable in chart form: 

Speculative conclusions from the above chart (this is 2020-21 data): 

  • Coal is the province's stable base load, running at the highest overall utilization (delivery divided by capacity, scaled to peak load. And don't confuse the highest utilization of goal with the highest generating capacity of gas) 
  • Wind is the least utilized source relative to its generating capacity (obviously due to its intermittency) 
  • Hydro is lower than I expected, but perhaps it, like gas, is more easily dialed up and down to handle variability in demand (customers) and supply (intermittent renewables)
  • This peak-adjusted scaling is not perfect but may be useful. The point is the utility should publish utilization, and even better, live supply and demand data like the province of Alberta.

Why utilization matters: one of SaskPower's corporate metrics (M17, see p30) is Renewable Generation Portfolio (%), or how much power generation capacity comes from wind (and solar, hydro, biomass, waste heat, flare gas, landfill gas). However, the numerator (actual electricity supplied) is more important than the denominator (theoretical capacity if the wind never stops blowing) for keeping our fridges running. 

Clarity around capacity factors and utilization for renewable sources are important. If 15% of our generation capacity by 2025 comes from wind, what does that translate to in electricity supplied?

3. Coal is being phased out by 2030 

Check out this paragraph from page 11: 

"Renewable power holds a central place on the roadmap to our province’s cleaner energy future. In the years ahead, wind and solar generation will play increasingly larger roles as generating options. As we phase out conventional coal-fired facilities in Saskatchewan by 2030, SaskPower will rely on natural gas generation to back up intermittent renewable generation until other emissions-free baseload power options are proven reliable, cost effective and available for our geographic region."

I didn't realize coal was being phased out. This is exciting from an environment standpoint. 

It is maybe slightly concerning from a energy security standpoint. Natural gas is dispatchable in the sense that power generation can be ramped up and down quickly to meet supply, but it's dependent on gas being in the pipe flowing to the plant. One of coal's only redeeming factors is that a great big pile of it can be stored on-site to buffer supply and demand. 

I did a bit more reading and learned that SK is Canada's third-largest natural gas supplier (source) and there are underground caverns all over SK and AB where gas is stored to buffer supply/demand (source). So maybe not a big deal. Once coal ramps down, we're dependent on the flow of gas for energy security, plus the 20% of generating capacity that comes from hydro.

There are some other cool ideas hinted at in this paragraph, longer-term nuclear and geothermal options for the province, where fuel is either stockpile-able indefinitely or functionally infinite. 

4. The utility is quite blunt about the need to back up wind (and solar) with gas

People are sometimes surprised to hear that increasing use of intermittent renewables (like wind and solar) must be combined with increasing use of more dispatchable energy sources like gas or coal. Note that hydro is dispatchable until the dam is empty. But it makes sense: when the sun stops shining and the wind stops blowing, we still want our phones charging. 

SaskPower states this in an unmissable spot on page 3: 

"As we continue to integrate increasing levels of renewable energy, natural-gas fired generation will play a foundational role in following intermittent supplies of wind and solar energy." 

It is discussed much more throughout. 

An interesting detail around backing up renewables is that SaskPower is building its first "grid-scale" battery soon. It will be 20 MW (about 0.4% of grid generating capacity) and be able to "power up to 20,000 homes for one hour." This is framed as a learning project for larger future options. I am skeptical but curious to see if battery storage technology can achieve "true" grid scale at a reasonable cost. It's good we're starting small. 

5. It's unclear what it costs to generate electricity in SK (operating costs and capital) 

I would love to see data or tables that make the following types of questions super easy to answer: 

  • What is the operating cost per kWh to supply energy, broken out by generation type and individual plant? 
  • What is the capital cost per MW of new capacity, also broken out by generation type and individual plant/project? 

I am not a finance whiz and I couldn't find this anywhere in this report. 

Without cost data it is difficult to ask questions and have discussions about the value of current and future projects. It is easy to compare wind to natural gas on an emissions basis, but what about capital cost, or operating cost?  Are the people in the province getting the most bang (literally, electricity) for their buck? Emissions is part of that conversation, but costs need to be understood too. 

6. SaskPower is not the sole electricity generator in the province (PPAs)

This is obvious to people who know about SaskPower's Net Metering program, where individual customers can sell their own power back to the grid (I did learn this applies to any power type like biomass or wind, too). 

I was surprised to learn (see page 4 of the report) is that 18% of SaskPower's generating capacity comes from Power Purchase Agreements (PPAs) with independent power producers (IPPs). Here, SaskPower is buying power from in-province private entities, or cross-border public entities like Manitoba Hydro. 

The majority of that 18% PPA-supplied capacity is natural gas, and there is over $10B committed to long-term (greater than 5 year) PPA contracts. 

I can think of lots of interesting questions to get into around PPAs:

  • Is SaskPower required to act as a monopsony, obligated to buy any power hitting the SK grid? Or can they say "no" to proposed projects and/or disable IPPs from feeding electricity into the grid, when needed?
  • When both public-owned (SaskPower) and private (IPP) electricity is available, which source gets priority in hitting the grid? How is that balanced? 
  • How are private- and publicly-owned sources balanced to ensure high standby costs are not passed on to ratepayers? The negative image that jumps into my mind is an IPP plant running at 100% with the SaskPower plant next door idling, with all the workers sitting around having coffee. 
  • Are PPAs an emerging or growing trend, or part of a stable and healthy energy infrastructure? I can imagine some people being quite shocked at nearly 20% non-publicly owned capacity, and others pushing for more private energy generation opportunities. 
  • If the bulk of IPPs are wind and solar (see p119 map), are purchase agreements structured to account for the fact that SaskPower is always the reactive party? (essentially, SaskPower needs to dial gas/coal/hydro up or down to react to renewables) Do SaskPower's costs increase as more private intermittent power is added to the grid, and is this accounted for in PPAs? How is the utility planning for more IPPs/PPAs in the future from more variable sources? Is grid management... easy right now, or hard?

7. The Risk Management section makes for interesting reading 

From p53 in the report, there's a detailed discussion of some of the top 10 risks facing the utility. Here are some of the more interesting ones and a few thoughts. 

#1: Environmental regulation. Changing regulations have forced the shutdown of coal by 2030. Saskatchewan will be for carbon in our gas use due to the ramp-up of the price of carbon from ~$40/tonne (today) to ~$170/tonne (2030). What's unspoken here, I think, is that if environmental regulations are a constantly-shifting target, that impacts the utility's ability to plan for the future. 

#2: Financial sustainability "is challenged by current economic conditions, growing capital requirements, increasing debt, and pressures to maintain competitive rates." Isn't it just a bit concerning when your provincial utility worries about their long-term financial health? What's the impact on the people in the province? 

#8: Industry disruption. Essentially, SaskPower's infrastructure is mostly in its twilight years, environmental regulations constrain how and when new supply is brought on, new types of loads like EVs are expected to change grid demand, and customer self-generation is growing. 

#10: Security and optimization of energy supply. p56: "Increasing the percentage of renewables in the supply mix - along with changing regulations resulting in the phase-out of conventional coal-fired generation - impacts system operability and has the potential to increase costs to integrate and maintain a secure system. The natural gas market continues to evolve [...] impacting supply and demand." 

8. Is nuclear renewable? Is anything? 

The nuclear part of this question was not answered in the 2020-21 report, and would make for an interesting debate. As I mentioned above, SaskPower has a corporate metric (#M17) for the percentage of generating capacity that comes from renewable sources. The metric explicitly includes wind, solar, and hydro, excludes fossil sources, and doesn't mention nuclear. 

The first flaw in this metric (again, discussed above) is that it's not clear how or if capacity factor and utilization play into that metric. An absurd exploit would be building 100 MW of solar panels... deep underground where they get no sunlight. Does the fact they're grid-connected mean they count towards capacity? 

The second flaw is that "renewable" is not well-defined, in this M17 metric or in society in general. When you look at the mass of raw materials required to generate 1 MWh of electricity, wind and solar don't look so hot - see p66 of this monster PDF report from the UN (note the page is numbered 56, but is 66 of the PDF). I am not against wind and solar energy but I think the renewables discussion should go deeper than visible emissions in one's own community. It takes concrete, glass, polymers, and a ton of mining and processing to build all of that "clean" energy infrastructure. 

The point is that if we care about decarbonization, a "renewable" metric that excludes nuclear may work against us in how we allocate capital and plan for major future energy sources. 


As I was reading, I was signing up to various SaskPower newsletters to get updates about changes in the future. I've not read everything there is to read on the topic and certainly have some errors above. My sense is the provincial energy mix is not a widely discussed or debated topic and I was hoping to start some of that - then again, maybe I'm plugged into the wrong channels and these questions are all asked and answered. 

What I've love to see in the future is more transparency from the provincial utility on current supply and demand (ideally, some live value that can be scraped or trended), broken down by energy type and source facility, like Alberta has. I would also like to see more discussion around costs by facility or aggregated by generation type.

I expect SaskPower to release their 2021-22 report shortly. I may make a follow-up post to see if anything has substantially changed. Thanks for reading. 

Sunday, February 20, 2022

AI/Machine Vision Water Meter Reader on a $12 CAD chip (plus Home Assistant integration)

In 2016 I bought and set up the emonPI Raspberry PI-based home energy monitor, which lets me trend and track energy consumption at home. 

Since then I've wanted to track water and gas usage, but until now I could not find any good solutions (within my abilities). We have an Elster C700 water meter but I was wary of tapping into the built-in digital encoder due to a tamper mechanism (this sentence also overstates my ability and ambition... I like solutions that someone else has pioneered first). 

This post is about deploying jomjol's AI-on-the-edge-device project to an ESP32-CAM module in order to get my analog water meter back into Home Assistant for monitoring, trending, and alarming. The audience is interested geeks and ESP32 beginners attempting to deploy this project for the first time. I'm going to expand on jomjol's instructions and talk about some of the mistakes I made along the way. I will also describe the kludgey, roundabout way I integrated data via MQTT back into Home Assistant. 

Results first: 

Home Assistant integration done!

Lots more details "after the jump".