Are solar + batteries feasible to heat every house in Minnesota with electricity when it's below -20F (-30C) for a week, we have <9 hours of daylight per day, and failing power literally means death? I genuinely don't know. Like I said, having a variety of solutions is the best outcome so we can choose the right one & have backups.
> just show your math.
I admit I can't. It's mostly gut-feeling from various science news sources I keep up with (e.g. Ars Technica; Skeptic's Guide to the Universe).
Only if you limit yourself to using solar generated with Minnesota's state borders.
Solar, Wind, HVDC transmission lines, short-term battery storage get us most of the way there, and is all on the process of being built out now. Medium term storage is still up in the air (flow batteries? compressed air?). Long term storage looks like hydrogen or natural gas with carbon capture. All these things seem more achievable than fusion in the next few decades.
> if you limit yourself to using solar generated with Minnesota's state borders
I live in a cold state. The idea of relying on out-of-state power, regulated and controlled by people with zero accountability to you, for life-and-death energy is a tough sell.
Bad news then. You most assuredly rely on natural gas from Texas traveling through a long underground pipeline to heat your homes and businesses. Relying on solar electricity from Texas or Arizona traveling through a long wire isn't going to change the status quo much.
> most assuredly rely on natural gas from Texas traveling through a long underground pipeline to heat your homes and businesses
Last I checked, we mine our own coal, pump our own oil and put up our own wind farms [1]. Minnesota, for what it’s worth, runs on renewables, coal and nukes [2]. The fifth of natural gas it does use comes from Canada, the Dakotas and Iowa.
These cold-state energy security concerns are a big part of the political puzzle that gets missed in the national discourse.
In northern states almost all residential energy use is heating. The amount of electricity used is minimal, therefore even modest amounts of electricity generation can meet need. Wyoming is the only northern state that has natural gas in notable amounts, all other states import a lot of their energy (especially heating) needs.
If most states stopped importing energy they would have to go back to wood and coal-fired stoves. That would be a huge quality of life reduction in terms of convenience and home air quality.
Heat pumps should be paired with rooftop solar and batteries whenever possible for resiliency. I admit the use of natural gas will decline in my lifetime, but probably won’t be fully deprecated.
The state you live in has one of the highest potentials for wind power in the country, easily backed by transmission, batteries, and as a last resort, natural gas.
High level, the energy transition isn't simply a fossil->renewables story, but also a centralization->highly decentralized story.
Totally agree, though I don’t know how wind performs in extended and deep subzero / heavy snow conditions. Hydropower is the traditional baseload for the Midwest, but it’s tough to square the destruction to natural beauty that entails in comparison with a remote nuclear set-up.
I grew up in Minnesota, but left before there was much wind farming in the SW part of the state. (I've been told, SW Minnesota is one of the best places for wind farming.) Wind farming does work well in SW Minnesota.
However, I also remember a news story about some used wind turbines relocated from California that had trouble due to inadequate heaters to keep the lubricant from getting too viscous.
What does the geothermal story look like? I expect it's expensive to first set up, but after that, maybe it's cost-effective and reliable? Asking because I genuinely don't know, but haven't seen it mentioned in this subthread.
Note that there are two common uses of "geothermal". One is for geothermal power generation, and but there's also an unfortunate use of the term in describing ground-loop heat pumps and similar technologies. Ground loop heat exchanges are a godsend for heat pump efficiency in the deep of the Minnesota winter, but it's very different from a source of heat that's practically exploitable for electricity generation.
From the context, I think your link is relevant to the GP's question.
However, if you search for "geothermal Minnesota", you'll get hits primarily related to ground-loop heat pumps.
Note that in the Minneapolis area, the ground will freeze down about 3 feet in winter, so you need to bury your ground loop deeper than that. The frost line is even deeper up in the Duluth area. (Also, you need to use an air compressor to purge the vast majority of water out of any in-ground sprinkler systems before the ground freezes.)
To keep warm, I'm estimating 2,628 kwh for a month for a home for a family of 3. In our magical Minnesota where everyone lives in houses with 3 people and only electric heat pumps, we'd have 1,900,000. This means, we'd need 4,993,200,000 kwh in the coldest month (4.993 Twh).
500,000 kilowatt of panels would produce ~33 gwh in the worst month (January). So, we'd need 151 times that many to have a good chance of doing this with purely solar. That'd mean 75,500,000 kw of solar panels. Assuming that we could install these for $1.50/w, that'd cost 113,250,000,000 and there's still a chance that we'd freeze people to death.
To mitigate that risk, we'd want to add ~500 gwh of batteries (just guessing as to needed capacity here). At a price of ~150/kwh, we'd be looking at ~75,000,000,000 in energy storage prices.
Feel free to check my math, as I did that pretty quickly. The figures are absurdly high due to scaling for the worst case type scenarios. Summer months would correlate with lower demand and more than double the supply.
Sensibly speaking, noone would try to do this. Its like building an offgrid home. You can get 90% of the way there and add a generator, or you can spend 10x more be truly offgrid. Almost everyone chooses the former. Maybe even 80%. Solar is great and very cost effective, but the returns diminish the deeper one goes.
Nice. I just looked up last February's bill for my ~1700sqft detached SFH in Saint Paul. It was apparently 6.8 therms/day (12 deg F average temp for the month). That maths out to about 5916 kWh for the coldest month (6.8 therms * 29 kwh/therm * 30 days), or a little more than double your estimate. March was 5.9 therms/day and Jan was 5.4 therms/day. So I think your costs are on the conservative side of things... or possibly my home is very inefficient :)
E: Ah, it occurs to me that you're using electric heat pumps, which are probably much more efficient than my NG boiler.
Yes, I pulled the estimate for really efficient heat pumps. To convert to all electric heat like that estimate, we'd have to replace a lot of gas heat with electric. Might as well go for the most efficient thing.
Compared to the nearly $200B in infra investment that I was estimating, that looks easy, lol.
I realize this isn't relevant for a discussion about future investment, but the current "value" of the whole energy infrastructure for a state is probably in the hundreds of billions of dollars, right? It's been built out over decades, of course, so the actual costs per year are much lower.
That's definitely possible. Going based upon the output of something like Catawba, that looks like ~3 nuclear plants. I bet that could be done for less than 100B, though I'd just be guessing. I also don't know anything about operations costs for that.
Also, I estimated solar at $1.5/watt. That's probably at least 50% too high.
I think because it's the learned defensive reaction. What ends up happening is that you have someone who really hates fossil fuels who is more than willing to back policies that require a quality of life drop or a massive cost shift onto individuals to achieve 100% renewables. So whenever it comes up anything positive you say about renewables has to be come with the explicit caveat that it's not yet a 1-1 replacement.
It's one of those issues the overwhelming majority of people are on the same page about what we should do but at the ends you have "my livelihood depends on coal" on one end and "my life is insulated against the downsides of full-renewables so I'm privileged enough to have out of touch opinions" on the other and that's who shows up in comment sections.
We don't need to do that. But the media focuses on things like that and turns everything into some sort of weird argument that renewables are literally going to freeze gramma to death. Its overwhelmingly about emotion.
Its the same as what we see with EVs, tbh. Oh noes, what if you get caught in a snowstorm!? Imagine if 80% of the cars were EVs and they got stuck and there were... no chargers! Picture yourself freezing to death because of "those people".
Real world performance and goals are not correlated well with media hyperbole.
Eventually we have to get to zero net carbon emissions. But the worst case is just to create carbon based fuels from CO2 extracted from the atmosphere and use it in places/for uses which cannot be covered by renewable electricity directly (the far north, airplaines, ...)
We can look at how solar/wind/storage compete with putative fusion. Fusion is a baseload source, so let's see how they would do to provide "synthetic baseload".
Selecting the state of Minnesota, 2011 weather data, and 2030 cost assumptions, this would be about 70 Euro/MWh. The cost optimized solution would involve 222 hours of hydrogen storage, 5 hours of battery storage, 4.2x peak power of solar and 2.4x peak power of wind.
In central California with ideal conditions, one day’s worth of storage roughly doubles the price of a solar system that is correctly sized for net zero production in November (assuming a wood stove is supplementing a heat pump).
I don’t think storage will be feasible in places like Minnesota. The following makes far more economic sense:
- Double solar / wind production by buying 2x more panels vs. “normal” states.
- Go all electric (heat pump / induction) for appliances and vehicles.
- Buy 8-24h worth of house batteries.
- Use a fossil fuel generator to top off batteries during outages (this more than doubles the generator’s end to end efficiency)
- Sell excess electricity to the grid, where it is used for subsidized carbon capture.
This should be completely resilient against storms and power outages, and extremely carbon negative. It would cost about 2x as much as best case renewables.
Thanks, this was informative. It wasn't clear to me, but I think the study does not account for switching heating from burning NG in the dwelling to electricity. I don't have numbers, but I'm pretty sure that's going to introduce an enormous load on the system, and is my main source of skepticism for wind/solar/storage as a solution for all electricity generation in places like Minnesota.
I honestly wonder if large scale population of the northern areas is feasible without carbon fuels. Historically chopped wood was used to heat northern homes and camps, later coal and oil and I guess now to some extent electricity, but as you say, renewable energy doesn't apply there. If places like Minnesota are a net negative for green/renewable energy, their costs may be much higher to offset generation in more favorable climates.
Not are carbon fuels are carbon negative - biofuel pulls down carbon from the atmosphere when it's created, so is considered carbon neutral.
I think it's highly likely we'll be burning a lot of algae fuel in the coming decades in situations where the energy density of carbon fuels is necessary.
There are plenty of other renewables usable than solar. Wind power would be the obvious one, as wind is often a great complement to solar anyway. Then there are long-distance transmission lines, water power, energy from biomass. Finally, if everything else fails, create hydrocarbons from CO2 in sunny places, ship those "eFuels" to Minnesota.
I wonder if we should seriously consider moving people away from such cold climates and towards warmer ones. Air conditioning is cheaper and coincidentally happens at about the same time as maximum solar power.
> just show your math.
I admit I can't. It's mostly gut-feeling from various science news sources I keep up with (e.g. Ars Technica; Skeptic's Guide to the Universe).