The Home Improvement Thread. Successes and Failures

[BassAle]

With net metering you pay X for each kWh in and get paid that same X for each out. Seems fair to you. But, you're using the power distribution company's infrastructure to deliver your energy.

I actually agree with you here -- it does hurt the power companies bottom line. Here in Maine, that most likey means a for-profit utility owned by a foreign energy conglomerate (there are a few small electric utility co-ops, but most of the state is covered by one of two large foreign-owned utilities). They're making a profit, which means a transfer of wealth from Maine residents to off-shore shareholders. I'm not feeling bad right now -- they have to take a hit to their profits to make up for the relatively small number of customers selling them solar power at full retail cost.

It obviously doesn't work if every customer installs solar because no one pays for the infrastructure, but right now it's basically forcing a huge foreign company to subsidize solar to lower Maine's carbon footprint.

There has been talk of ending net metering for a while in Maine (and it actually did end net metering for new installs for a little while when Republicans controlled the state legislature for a short period of time).

I expect they will let net metering go on for a while longer to encourage homeowners to install solar, and will eventually phase it out for new installs, which will make it pretty much impossible to offset "100%" of your utility bill. In Maine, you can only earn credit on your bill that you cash in when your production dips below your usage -- you can't actually generate revenue. You'd have to sell back more power than you use over the course of a year to break even, since you'd only get paid wholesale prices for your excess.

[BassAle]

I literally do not believe the two acres calculation. North Dakota and Maine are about the same latitude.

My system has a footprint of around 625 square feet. Roof-top mounted, on a south facing roof with a 40 degree slope.

I'm also not off-grid. I'd need a much larger system to fill my needs in the winter time if I were off grid. This only works out because it's grid tied and I can bank credits in the summer that pay for my electricity I pull from the utility during the winter.

[unofan]

I literally do not believe the two acres calculation. North Dakota and Maine are about the same latitude.

He's calculating it as though his house was an independent utility off the grid where the only power available was from his solar panels. So even though rooftops could supply adequate power the majority of the time, he's calculating based on the "what if we get 5 cloudy days in a row" scenario and therefore his output from the day before that streak of bad weather had to be sufficient to power the house for 6 consecutive days.

Which again, isn't a realistic measurement because 99.99% of people don't disconnect from the grid.

[The Sicatoka]

He's calculating it as though his house was an independent utility off the grid where the only power available was from his solar panels. So even though rooftops could supply adequate power the majority of the time, he's calculating based on the "what if we get 5 cloudy days in a row" scenario and therefore his output from the day before that streak of bad weather had to be sufficient to power the house for 6 consecutive days.

Which again, isn't a realistic measurement because 99.99% of people don't disconnect from the grid.

Yes, I said "worst case" scenario -- one sunny day followed by five cloudy. I see that pattern frequently in the nearest commercial solar farm near me.

And if you don't disconnect from the grid the power company has to have the same infrastructure, solar or not. They need to cover their material (depreciation) and operations costs. And with solar you're only buying a fraction of what you normally would. That's why a higher cost of service connection monthly fee (and lower per kWh price) seems appropriate.

[LynahFan]

He's calculating it as though his house was an independent utility off the grid where the only power available was from his solar panels. So even though rooftops could supply adequate power the majority of the time, he's calculating based on the "what if we get 5 cloudy days in a row" scenario and therefore his output from the day before that streak of bad weather had to be sufficient to power the house for 6 consecutive days.

Which again, isn't a realistic measurement because 99.99% of people don't disconnect from the grid.

This is all correct, and it's true that almost nobody with a choice disconnects from the grid. This is exactly why solar isn't the answer for electricity production writ large - if a given utility only uses solar as a source, that would be equivalent (from an acreage and storage perspective) to all of their customers choosing to disconnect from the grid. Sure, you might get a 2nd order economy of scale by doing it at the utility level, but it's just never going to be a viable alternative at meaningful capacities.

[The Sicatoka]

During the recent Texas / ERCOT fiasco, the northern plains had excess energy (fossil and wind) but no way to get it to the ERCOT grid.

So, I hereby amend my prior statement to: We need large scale energy storage and better transmission infrastructure (to get supply to demand) before solar and wind are fully viable.


Three hardest building projects in America today? I'd argue (a) nuclear power plant, (b) fossil fuel pipeline, and (c) interstate high-voltage transmission line.

[unofan]

During the recent Texas / ERCOT fiasco, the northern plains had excess energy (fossil and wind) but no way to get it to the ERCOT grid.

So, I hereby amend my prior statement to: We need large scale energy storage and better transmission infrastructure (to get supply to demand) before solar and wind are fully viable.


Three hardest building projects in America today? I'd argue (a) nuclear power plant, (b) fossil fuel pipeline, and (c) interstate high-voltage transmission line.

I agree with A, not so much B (having lived through the Dakota Access Pipeline ****storm), and C I would carve out further to "inter-seam high-voltage transmission lines." The RTOs do a good job of getting transmission lines pushed through within their respective grids. It's the East-West-ERCOT seams that have the huge bottlenecks.

[BassAle]

During the recent Texas / ERCOT fiasco, the northern plains had excess energy (fossil and wind) but no way to get it to the ERCOT grid.

So, I hereby amend my prior statement to: We need large scale energy storage and better transmission infrastructure (to get supply to demand) before solar and wind are fully viable.


Three hardest building projects in America today? I'd argue (a) nuclear power plant, (b) fossil fuel pipeline, and (c) interstate high-voltage transmission line.

There is a huge fight in Maine over a transmission line to connect HydroQuebec to Massachusetts.

[BassAle]

Yes, I said "worst case" scenario -- one sunny day followed by five cloudy. I see that pattern frequently in the nearest commercial solar farm near me.

People I know that are truly off-grid use a propane whole-house generator for the "worse case scenario". If it's been a cloudy day, it might have to fire up for a bit to top off the batteries.

[dxmnkd316]

This is all correct, and it's true that almost nobody with a choice disconnects from the grid. This is exactly why solar isn't the answer for electricity production writ large - if a given utility only uses solar as a source, that would be equivalent (from an acreage and storage perspective) to all of their customers choosing to disconnect from the grid. Sure, you might get a 2nd order economy of scale by doing it at the utility level, but it's just never going to be a viable alternative at meaningful capacities.

This reminds me. I did a few projects at a coal fired power plant. Someone told me how long it takes for the turbine to stop spinning on shut down. I remember it was measured closer to days than hours. It was mind boggling.

[LynahFan]

This reminds me. I did a few projects at a coal fired power plant. Someone told me how long it takes for the turbine to stop spinning on shut down. I remember it was measured closer to days than hours. It was mind boggling.

True for natural gas turbines as well. If you commit to gradual spool-ups and spool-downs, then you can really tighten up the tolerances, because you don't have to worry about the metal parts heating up or cooling down at different rates. Tight tolerance = less leakage around the turbine blade tips = more efficient. Every percent counts when you're talking about a 100MW turbine.

[The Sicatoka]

True for natural gas turbines as well. If you commit to gradual spool-ups and spool-downs, then you can really tighten up the tolerances, because you don't have to worry about the metal parts heating up or cooling down at different rates. Tight tolerance = less leakage around the turbine blade tips = more efficient. Every percent counts when you're talking about a 100MW turbine.

If you can tick the efficiency up 0.1% you are legendary.

And that's why nat-gas peaking plants (fast up, fast down) to cover demand peaks sound great, but they aren't as efficient as they could be because of their very rapid response design.

[The Sicatoka]

It's the East-West-ERCOT seams that have the huge bottlenecks.

Yeah, the ISOs* get all crabby-itchy about building the transmission bridges between systems (that are badly needed).


*MISO, SPP, CAISO, ERCOT, take your pick.

[Kepler]

Dumb (maybe) question: why aren't the 48 one grid? Is that for safety (one goes, we all go) or is it legacy compounded by greed?

A power grid seems to naive me like a free trade area: bigger is better as diversity gives more leeway to serve both supply and demand.

[unofan]

Dumb (maybe) question: why aren't the 48 one grid? Is that for safety (one goes, we all go) or is it legacy compounded by greed?

A power grid seems to naive me like a free trade area: bigger is better as diversity gives more leeway to serve both supply and demand.

East-West is legacy; Texas being its own grid is because it's Texas and doesn't want any of that federal regulation stuff up in its business.

Being separate grids has some benefits; a failure of one won't impact the others, it's harder to compromise a patchwork than a unified grid, and so on. Whether those benefits outweigh the drawback, I'm not sure anyone really knows.