Return to our summary. We then looked at detail at five specific renewable energy technologies, wind, solar PV, concentrating solar power, also called CSP, ocean energy and biofuels. To summarize what has happened on the wind and solar PV, these are data from the US, but it does capture a global pattern. The slide is slightly complex, so let me remind you what it's showing. The black lines here are the cost of generating electricity from natural gas. These black lines are only for the natural gas itself plus the O&M of the plant. In other words, it's a marginal cost. It doesn't account for the cost of building or buying the gas turbine itself. These cost vary year-by-year, mostly due to natural gas price changes. There's also some projections because a lot of these plants work on essentially hedging basis. You can see a slight downward trend because in general, natural gas has gotten less expensive. That's what a cost and a marginal sense to generate electricity from natural gas. The blue circles are contracts for wind power, actual contracts, and they are shown by the year they were signed. The bigger the circle, the larger the contract. Again, these are US only data, but it does show a similar pattern globally. Notice how the cost of wind, the cost as reflected in actual contracts, has come down significantly over time. Since about 2012, though it varies by year, it's been cheaper to generate electricity from wind than from natural gas. Because the dashed blue line, which is the average of the wind contract signed by year, cross below the black dots. The solar contract prices are shown in the yellowish orange circle. Notice they start quite a bit higher, but the solar PV has shown a dramatic price decrease over the last 10 years and the crossover was about 2017. In other words, since about 2017, it has been less expensive in the US to generate electricity from solar PV than from natural gas and that price comparison accounts for the cost of building and buying the solar PV, but assumes the natural gas is already in place so throwing the marginal operating costs the natural gas. The overall point that wind and solar PV are cheaper than natural gas in many cases though certainly not all. This analysis is a bit limited in the fact, it's looking the price per megawatt hour that doesn't account for dispatchability for carbon emissions, for all sorts of other factors, but it's a good starting point. In summary, wind and solar PV have gotten less expensive, where they are in many cases, less expensive than generating electricity from fossil fuels, specifically natural gas. If we look at forecasts of prices for wind and solar PV, we expect to see continued major declines. Here's some data for, we'll look at wind offshore and onshore. Offshore is more expensive. The size, this is the 2018 blue chart here for offshore here, and greenish for onshore captures the range and the background gray is fossil fuel cost range. Now you can see wind offshore is typically but not always in the same range as fossil. Onshore is in the same range and is expected by 2030 that both of these drop dramatically where offshore will be at the bottom of the range, and onshore will be below the fossil fuel costs range by 2030. Similar for solar PV, it's now in the range. These are global data, not US, but by 2030 it's expected to be usually, but not always below the range of fossil. In summary, wind and solar PV can be cost-effective now depending on the specifics but because of wind and solar PV electricity are expected to drop dramatically from 25 percent for onshore wind to 58 percent for solar PV by 2030 and it'll become increasingly, or at some point, always more cost-effective than generating from fossil fuel. We talked about some specific wind technologies to watch that are promising, exciting and are worth paying attention to. We talked about repowering, where existing wind turbines that are operating working just fine. In some cases, it makes sense to take those down and put up the new technology because the wind turbine technology is advancing so quickly, it can make financial sense to replace it like a three-year-old computer, which works fine when new computers may be that much better, it's worthwhile replacing. We talked about floating platforms for offshore wind. Where offshore wind is limited a bit because if you go too far offshore, the water is too deep and once you go beyond roughly 25-30 meters, it's just too expensive to sink pilings and building platform up that high. That puts a lot of offshore areas essentially unavailable for wind. But floating platforms that are tethered to the bottom by a chain or something similar but actually float open up large, newer areas of deeper water for wind and they are handful, less than five large floating platform wind power plants operating now as of early 2021, but that number could grow quickly. We talked about turbine size, where turbines are getting larger and larger and the newest turbines are over 10 megawatts. Is there a limit to that? Not exactly clear. They're getting harder and harder to move because they are so enormous. But there appears to be no inherent physical limit to this. It's worth watching where turbine size goes. Finally, we talked about the wind technology to watch of hybrid plants, which could be wind combined with storage or wind combined with PV. The advantage is you can essentially smooth the output or provide more of a dispatchable electricity if you have multiple sources. If your only fuel is wind, the wind dies down, the power plant output goes down. But if you have storage, then you can continue providing electricity for example. We'll take a quick break here and come back and talk about solar PV technologies to watch.
