Understanding Solar Energy

Hot water tank heated by electricity and powering on at noon is flattening curve. You can say hot water tanks are cheapest, simplest and fastest deployed energy storage device.

Solar + hot water tank can provide any house in US with 100% solar hot water (from PV!) for 80% of time, remaining 20 % of time you can have 10-99% solar heated water.

So we should focus on saying to people that if they buy solar and add electric heating element to hot water tank, then PV system will pay itself much sooner and their batteries will last longer. Becasue it is known and predictable load, you need hot water every day. And hot water is order of magnitude more energy then TV, lighting...

By lowering household usage like this we can make energy transition faster, cheaper.

Also proper construction - house heated only 10 days in a year - https://www.youtube.com/watch?v=5KHScgjTJtE

And similarly the battery prices are very outdated. I don't blame the author for using those estimates, I frequently do too just because getting access to current data usually requires paying money.

But making decisions on that data without understanding that current prices and near-term prices will be about half of that price will lead to bad decisions. And when thinking 5-10 years out, not taking the full exponential drop in battery and solar prices is beyond foolish.

They also use the duck curve to represent energy demand, when it only reflects grid demand minus utility solar and wind.

There's nothing particularly confusing about the duck curve but it must be the most misunderstood (and/or misrepresented) graph in all energy.

> I work for (as a data engineer) does utility scale solar + battery installation and site management.

Did you build your own excel/python nightmare or is everyone using 3rd party management software for this?

> as long as we collect data on the batteries they will be able to be warrantied

Can you share some of the data? Beyond power in/out, do you monitor humidity, vibrations, temperature ?

how do you like it? I have a 20 year career in large scale consumer app/web/b2c tech, but i've always wanted to work in renewables. Is it easy enough to break into? Is there many non-hardware roles (i have no hardware skills)? any advice / vibes?

V2L is one of the reasons I bought the car I did - instead of getting battery backup for the random outages that PG&E gifts us (literally power drops likely to happen whenever we gust over 25mph), I installed a 12 circuit transfer switch and my 75kWh battery in the car can provide reasonable backup without running cables throughout the house (reasonable = 1.9kW max so no hair dryers or running toaster oven + microwave at the same time).

Newer vehicles (like 2025 Ioniq5) can do 12kW throughput (and many trucks can do 9+ kW already).

Once V2H standards are confirmed and deployed I would be able to integrate the Car batteries with home batteries and solar.

There might not even be any need for V2G or V2H.

Just charging your car when the demand is low is probably enough to drastically reduce the overall cost of the system. And this has basically no impact on the battery lifespan.

Arbitrary vehicle to home/home battery/grid connection is indeed coming in very short order.

https://enphase.com/ev-chargers/bidirectional

There are other products already available to do it (DCBel), and it can be hacked of course, but at the current moment everything comes with substantial corner case blind spots, mostly related to grid-forming/following switching and to the resilience of the power electronics.

> a log burner for heat

for areas that experience winter, this is a decisive issue.

If you live in a passivhause-style home, air source heat pumps ("minisplits" for our US readers) may work, and you might be able (at least in the southwest of the USA, with high insolation during winter) to get away with local battery storage to cover your heating needs with PV.

But if you don't, PV-driven heating during the winter, even with the very high COP's of air source heat pumps, is not realistic without much larger battery systems than you could reasonably have on site.

Covering non-heating domestic electricity costs with PV these days is relatively easy, and we should do it as much as possible. Covering the heating part for places with winter climates (especially in areas with low insolation) is much, much harder and really requires effective grid infrastructure.

In Czech republic - europe - they made law that says anyone can built up to 100 kWp solar array, without any building permits, township meetings, HOA nonsense etc. You want it, you can build it.

Best way to be independent of your neighbors polluting your air with their wood burning furnace is show them PV works, and is cheap.

If you had to commute daily, wouldn't you buy a smaller commuter EV? Something from Hyunda or Nissan? The depreciation on that Lighting will be rough if you had to drive it 80 miles/day.

The article posted by wolfram74 is part one of two, covering solar PV history up through the early 1980s.

Here's part two of the series with more recent history: https://www.construction-physics.com/p/how-did-solar-power-g...

Even this fairly long two-part discussion misses some of the more important technical developments of the past 20 years.

Converting trichlorosilane to pure silicon via CVD growth in Siemens-type reactors is now much more energy efficient due to changes in rod geometry and heat trapping via reactor design. A significant minority of purified silicon is now manufactured via even more efficient fluidized bed reactors.

The solar industry is dominated by Czochralski process monocrystalline silicon, but it's now continuous Czochralski: multiple crystals grown from a single crucible, recharging the molten silicon over time; the traditional process used a crucible once and then discarded it.

The dominant silicon material has switched from boron doped p-type silicon to gallium doped p-type silicon (mentioned by pfdietz) to phosphorus doped n-type silicon (used by the currently dominant TOPCon cell technology as well as heterojunction (HJT) cells and most back contact cells).

Changes in wafering that you mentioned (like the reduced kerf diamond wire saw) have reduced silicon consumption per wafer and therefore per watt, even holding cell technology constant.

The dominant cell technology has moved from Al-BSF to PERC to mono-PERC to TOPCon. Heterojunction and back-contact cells are not yet dominant, but they are manufactured on a multi-gigawatt scale and will probably overtake TOPCon eventually. Each one of these changes has eked out more light conversion efficiency from the same area of silicon.

Cells mostly still use screen-printed contacts made from conductive silver pastes, much like 20 years ago, but there has been continuous evolution of the geometry and composition of applied pastes so that silver consumption per watt is now much lower than it used to be. This is important because silver has the highest cost per kilogram of any material in a typical solar panel, and it's the bottleneck material for plans to expand manufacturing past the terawatt scale.

Wafer, cell, and module manufacturing have become much more automated. That reduced labor costs, increased throughput, and increased uniformity.

My understanding is that China recognized the potential of solar power around 20 years ago and decided they wanted to be the world's manufacturing hub for solar panels. The government invested in R&D early, and today we are reaping the fruits of that investment.

The same thing is happening now with storage, but western governments are weary of losing that battle as well. To address this massive tariffs were put in place by the previous US administration, and are likely to be increased by the current administration. Hopefully this doesn't slow down the production of batteries, but instead just moves the production out of China and into other countries, but that remains to be seen.

You're in luck! The author's earlier piece on the subject attempts to address that exact question. Learning curve effects and piggy backing off the computer chip industry are major factors if I recall, but I haven't reread the piece in a while.

https://www.construction-physics.com/p/how-did-solar-power-g...

CdTe is still out there, from First Solar, but it's not much of the market (and has scalability problems due to the need for tellurium, even if the active layer is much thinner than in silicon cells.)

One little advance that swept the industry a couple of years ago was replacement of boron as a dopant by gallium. Boron doped silicon has light induced degradation, which was determined to cause a small loss in efficiency due to formation of boron trapping centers under prolonged light exposure. Gallium-doped silicon doesn't have this problem.

Assuming you would stay in Chicago for other reasons, the solution for a high heating bill is 1) air seal and upgrade insulation in your house, and then 2) replace your furnace with a low temperature heat pump.

Chicago has electricity prices 25% lower than the national average. If you want to see an example in your area, watch Technology Connections heat pump videos on YouTube.

I second the other reply. I live in Chicago and installed an air source heat pump. (Mitsubishi hyper heat). Its served me well for two winters so far. My next step is probably to replace all my windows and doors to get better efficiency.

How do the costs of long distance, high voltage lines compare to batteries for addressing solar intermittency??

With net metering going away now people want batteries for self consumption, then the grid becomes a backup.

In my area we still have net metering but the grid tends to go down a lot with even a mild storm, so many have backup propane generators, however some like me are doing whole house solar with batteries for backup instead, it cost 3x as much but pays you back over time with little maintenance compared to a generator.

I will admit there is a prepper aspect, with well and septic and solar the only thing I need is food which I can try and grow. The Sol-Ark inverter in my install even offers EMP hardening which I almost went for :).

Getting grid hookup in rural property can be expensive or impossible depending on where you are at, solar with satellite internet means no problem wherever you want to build if done right.