In sunny states like California, solar power from Solar City is at an unsubsidized 18 cents per kwh. However, is subsidized which brings it down to 12-15 cents per kwh for many locations. This is cheaper than the lowest tier of PG and E electricity at 15.5 cents. There are 4 pricing tiers and they increase and usage increases and go up to 25 cents per kwh. Solar Cities scaling and technology plans could bring the unsubsidized price of home solar electricity down to 9 cents per kwh. This would be lower than the average price of US electricity at 12 cents per kwh. Elon Musk also plans to provide batteries for power storage so that the solar power does not burn off as heat at the feeder stations on the one way power grid.

2015-06-22: Solar Power for Everyone

Technological change will fundamentally transform the power industry. The question is whether that transformation can happen fast enough to matter, either for the survival of the utilities or, more important, for the preservation of the climate. In the past, energy transformations—wood to coal, coal to oil—have taken 50 years or more to unfold as infrastructure was slowly replaced. New York has a home-energy-audit program, whereby a team will come to your home, determine how much insulation it needs, and identify other ways of boosting your energy efficiency, much the way that Green Mountain Power assessed the Borkowskis’ house. “But at current rates of penetration it will take us centuries to do the whole state”. This time, though, technological change may be coming so rapidly that a quick adaptation is possible. The week that I was in Canarsie with Kauffman, Mary Powell flew to California to attend Elon Musk’s announcement of his new home battery, the Powerwall. Green Mountain Power was the only utility in the country that was ready to sell the new battery on the first day that it became available. And Powell was excited by its low price: $3000, far below what analysts had predicted, and low enough that her company could immediately begin installing it for customers, especially those who wanted backup electricity in case a snowstorm disabled the grid. 1 week after the battery launch, Musk described demand for the batteries as “just nutty” and “off the hook.” His company had already sold all the batteries it could make through the middle of next year and was discussing expanding its giant new factory, in Nevada, even before construction was completed. The day after Tesla’s launch, Solar City announced that, beginning in 2016, it will routinely package Musk’s new batteries with its panels in some markets. If utilities won’t relent and embrace innovation, homes and businesses will soon be able to circumvent them altogether. The threat is real enough that it might actually soften the attitude of even recalcitrant utility executives.

2016-09-22: Towards 2 cents / kwh. This is extremely good news.

This new 2.42 cents / kwh bid in Abu Dhabi is less than 50% the price of electricity from a new natural gas plant. It’s less than the cost of the fuel burned in a natural gas plant to make electricity – without even considering the cost of building the plant in the first place. The solar bid in Abu Dhabi is not just the cheapest solar power contract ever signed – it’s the cheapest contract for electricity ever signed, anywhere on planet earth, using any technology.

2018-09-15: Here’s some underreported good news. By 2020, it will be cheaper to build new solar than to keep coal plants running. billions of $ of coal plant builds are being canceled every year in China / India (and elsewhere).

2019-04-02: Cheaper than installed energy

Now, after decades of subsidizing solar and wind, we’re on the verge of a new, radically different point in history – the point at which building new solar or wind power (or new energy storage systems, in some cases), is cheaper than the cost of continuing to operate existing coal- or gas-fueled power plants.

2021-10-20: Here’s a bit more on the factors that make new technologies so much cheaper.

Factories physically embed the technology in the factory instead of in workers’ heads. Factory products often require few skills for installation or use. We want our energy technology to have knowledge embedded in factories instead of humans and be easy to use. Solar panels, batteries, and nuclear microreactors are underrated technologies for this reason. There is a vast opportunity for simplification in small-scale generation hookups, whether solar or another source. In 10 years, it should be normal to go to Home Depot, buy $1500 worth of solar panels and batteries, install them as a Saturday project, and be off-grid capable by the end of the day. An older house might require 1 hour from an electrician to make the final hookup. The same simplicity will be available for utility-scale installations of any manufactured energy technology.

2020-05-14: Forecasts are far too conservative

Solar prices have dropped faster and lower than almost anyone has expected, and are decades ahead of forecasts

This article explains the learning rate for solar & wind, and observes that coal doesn’t have a learning rate because the cost of the fuel puts a hard lower limit on how cheap things can get. the price of nuclear isn’t dropping because of increased regulatory burden and a lack of scale.

2021-03-04: Solar oversupply

I’m pretty convinced that even with business as usual CO2 emissions will drop like an anvil in most developed countries over the next 10 years.

Solar panels are getting so cheap, new plants will add many more panels than what their grid connection can handle. The industry refers to this as a high DC:AC ratio. You might have 300 MW of panels (DC) for 100 MW of inverters (AC). This means even when it is cloudy you are sending power to the grid at 100% of AC capacity. And you can produce at high output later into the evening. This makes solar firm power. In many ways this firm solar is more reliable than an analog fossil power plant. Most new projects also include batteries. They charge on DC so they can use some of the excess power during the day and then use the same inverter and grid connection to sell into the evening peaks. I’m not sure many people have fully internalized this change yet. Off grid folks have started doing it at a small scale, because it is cheaper to add more solar than buy more batteries to get through cloudy periods. You only need enough batteries to get you through the night.

2022-11-11: The grid will have to be massively upgraded

Decarbonization models suggest that the transmission system will need to 2x in capacity or more. Rooftop and community solar, and home and EV batteries, can only go so far, especially any place other than the southwest, and those investments must be made everywhere. Electricity transmission allows a single investment to aggregate and provide power to multiple regions. Transforming the way the grid works, and the way we work with the grid, requires both hardware and software changes.
Advanced conductors: New kinds of transmission lines that can carry more current. The exponential power losses from increased current dissipate as heat and cause lines to sag due to the aluminum expanding. Advanced conductors use stronger cores to limit sag and allow more power on the line. The next frontier is superconductors.
Power flow management: Electricity takes the path of least resistance, so power flow can be managed by changing the resistance. These semiconductor-based devices can change the characteristics of a line temporarily to influence where the power goes. This leads to better use of existing infrastructure for more reliable and cheaper power.
Line sensing: Current carrying capability is determined by the weather conditions. Sensing and communicating the microclimates of transmission lines allow for far more effective use of the existing system.
Modular transformers and converters: Electricity transformers are the building blocks of the grid; they are the components that turn low voltage into high voltage and vice versa. Converters are the components that turn AC to DC. Both of these essential components need a modular solution. Our grid is surprisingly bespoke — modular transformers and converters would enable a faster and cheaper expansion of capacity.

2023-04-10: Grid-forming inverters are crucial

The vast majority of today’s inverters are “grid-following” ones, spitting out current with characteristics that match those that the inverters see on the grid. This means that unlike turbines they provide no way of pushing the grid in a preferred direction. Indeed they can worsen conditions by amplifying existing imbalances. Grid-forming inverters offer a step change away from the world of instantiated electromagnetism and into a realm of code and electronics. With the right electronics, adding renewables and the storage which comes along with them to the grid can make it more stable, not less. Grid-forming inverters allow microgrids and macrogrids to be joined together far more easily. They also help consumers attached to grids to build out their own generating and storage systems in a way that the grid can draw on.

insulated gate bipolar transistor (IGBT) can connect DC to AC without the need to be synchronous

Technology which uses IGBTs does not have that problem. It also offers much more flexible switching, making the conversion process much easier, and takes up less space. That has proved quite the advantage. 99% of the HVDC systems now sold are based on IGBTs. And its attractions are also making the overall market larger. HVDC is not just a way to link far-off generators to existing grids, as in China and a number of developing countries with big, remote dams. It can also provide bridges from one part of a grid to another, thus easing congestion. And it can link together grids that could never be united into a single ac system.

2023-09-04: Solar is at 0.5% of GDP, and total investments for the energy transition need to reach 10% of GDP.

Solar deployment is now happening at $500b annualized rate.

Which technology deployments were larger than this? The US’s aircraft production during WWII seems to have peaked at $400b (inflation-adjusted). Global datacenter construction appears to be $200b/year. Solar deployment is ~0.5% of global GDP and growing 43% Y/Y.

2023-09-08: We need more sophisticated interconnection models to lower the need for more transmission capacity. That said, we still need a lot more new lines.

NERC would like to see the grid’s gatekeepers add a new kind of model to their interconnection studies. These “electromechanical transient,” or EMT, models can simulate the behavior of inverter control systems in exquisite detail, showing how they react to disturbances.

Grid operators such as SPP and the Midcontinent Independent System Operator are now carrying out such studies, but they are running into complications. The models require a lot of computing power, and people who know how to run them are in short supply. Perhaps more important, the models only deliver accurate results if they are using accurate information about the equipment that will be installed, and its control settings. That information is often unavailable, because when interconnection studies begin, solar or wind developers don’t know what equipment they’ll install years down the road.