All right. Welcome back. We're going to review everything we've just gone through, put it all together, and show how the pieces all fit together. This is a review. You'll be hearing things you've already heard, but it's worthwhile hearing them again because it sometimes takes some time for new concepts, new ideas, and new perspectives to sink in, so it's worth the time. Starting from the beginning, we talked about what electricity system used to look like. It was pretty straightforward. It was mostly fossil dependent. For example, coal played a major role in electricity production in the US. There was a utility, an entity that generated, transmitted, distributed electricity. The extent the consumers were involved to any of this, it was a pretty minimal involvement. There perhaps, there's some old fashioned mercury-based thermostat in the wall, and that was pretty much it. But that's all changing rather quickly. Shown here, for example, is wind power rapid growth, more than a tripling over this 10 year time period to a whopping 651 gigawatts at the end of 2019, larger now. Not only is wind big as a total, but as a percent of generation in some countries it's very large. Leader is Denmark, but a number of other countries get more than 20 percent of their electricity from wind, and 13 countries get more than 10 percent. A similar story we've told throughout the course for solar photovoltaics, which is rapidly growing. At the end of 2019, 627 gigawatts. It's about to or it's probably about now, early 2020 it's roughly caught up with wind in terms of its global capacity. Here again, the penetration as a percent of the total is climbing. Though PV is not quite where wind is, it's a little lagging but catching up. As you can see, a number of countries, column five or six get more than eight percent of their electricity from solar PV. If you break that down and look at a narrower geographic area, the numbers get larger. The US State of California, at the end of 2019, was at roughly 20 percent solar PV and it's gone up since then. Another way to think about where the renewables fit in, if we take a global perspective, in 2019, about 75 percent of all new power plants built used renewables. That number, as you can see, has increased dramatically. Renewable, most all wind and solar PV, though there are roles for other ones such as hydro, biomass, and geothermal, are dominating new construction of power plants worldwide. In the US, for example, here's what the electricity net generation looks like by fuel based on a kilowatt hour, generation basis. You can see in the US, coal was the majority fuel and climbed steadily up from 1950 till about 2005, 2007, and has dropped dramatically since then, with natural gas, renewables making up the gap. Similar graph in the UK. Now, this story varies quite a bit by location. In Asia, coal is still of interest and coal plants are still being built. But in other countries, for example, US and the UK, coal plants are being shut down. This story varies by country. What will [inaudible] electricity systems look like going forward? Well, we don't know because the future is unclear, but things are in very rapid change shown by some of the graphics here. We're building large solar PV and wind worldwide. The employment impacts are significant where, well, over 10 million jobs worldwide are in renewables. There are new markets developing new policy tools such as auctions, new markets such as ancillary service markets. This is where there are challenges with this new power system shown, for example, hereby the duck curve. With the US State of California, which has one of the largest, if not the largest solar PV penetrations worldwide, is figuring out day-by-day how to make electricity systems work. As we've talked about, California is solving this problem by, for example, in the example of California, getting stronger links to neighboring power grids, in the case of California, neighboring states. There are solutions, but there are challenges. What are the renewable electricity generating technologies? There are many. Shown here is a list of the ones that we hear about or that seem appropriate and relevant now. From wind to solar PV to concentrating solar, hydro-power, geothermal, biomass, and then some ones that are more on the R&D level, tidal wave and other related technologies such as OTEC. But if you step back and look at what is going on in the market, look what the resource availability is, look what the technologies, look at the cost perhaps most importantly. It pretty clear what's going on. That wind and solar PV are moving to dominate new renewables construction. There are opportunities in the other technologies, but from an aggregate global level, wind and solar PV are dominating. On the concept of the renewable electricity technologies, wind and solar PV are growing very rapidly worldwide. Wind and solar PV have a significant difference from most other renewables and from fossil-fired to nuclear power plants as well. They are what are called variable. Sometimes the terminology is intermittent or non-dispatchable. Basically, what that means, we could talk about it again, this is all review, is that wind and solar PV cannot be turned up and down quite the same way in other power plants. Now, you can turn wind and solar PV down. But you can't turn them up to meet demand, at least in the same way you can, say, a natural gas power plant or even a coal plant. They're not dispatchable. You cannot say, hey, we need you now, come online because wind and solar PV are subject to the wind and the sun, and we don't control those. We'll take a quick break here, come back in the next video and talk about reviewing again the markets and the industry structure.
