Hydro has hints of a negative slope, though one would want to look at >15 years of data to address that.
Between removing the worst dams from a fish kill point of view and silting up of reservoirs behind the dams, you will have negative slope unless you find new dam sites. or you can increase generation from existing dams. I think the low hanging fruit is already picked for both of those.
I was wondering what the dropping levels of Lake Mead would have on production at Hoover Dam going forward.
"The plummeting water levels have reduced the Hoover Dam’s power generation by 23 percent." - Hoover Dam: No Power Without Water | Hydroelectric Power
One would think the obvious best applications of solar and wind power generation would be in some of the areas hardest hit. Arizona and the Southwest. Areas where you have vast expanses of nothingness, lots of sun. It kills me where they put some wind turbines here in Vermont. Where there was once a tremendous view of hills, mountains and the lake, there are those hideous white towers. Their only tangible benefit is to those that received the tax credits. Each area of the country has their own best solution(s). We do have opportunities in Vermont for geothermal, some limited additions from solar, but primarily replacing oil with natural gas.
Do remember that 'nothingness' is mostly in the eye of the beholder. Personally, I haven't found any such areas. Plenty of spaces that were once commonly described as empty, useless, nothingness, have since been found to be valuable and essential habitats and watersheds and other resources. Just because certain lands can't support thick tall green agricultural crops doesn't mean it is empty or useless or 'nothing'.
Ouch, I didn;t mean that to sound negative I meant vast open areas of desert, non-populated areas. Many areas out west fit that description.
I'd greatly prefer that the solar be installed over developed areas, making use of the sunlight that otherwise falls uselessly on existing human-made impervious surfaces such as buildings, concrete, asphalt, and gravel. Building should have either solar roofing material, or solar above the roof. Solar road paving is not yet ready for prime time (if it will ever be ready), but solar panels make great shading in parking lots: I believe the vast open un-populated deserts are best left as-is for now, as a resource for the future when we better understand their habitats and many other valuable functions that we don't yet understand. We have already wrecked far too much other space before learning enough about what it really did.
Of course The more practical reason is the infrastructure is already in place, and there is minimal distance for the electricity to travel. I keep wondering if a straight DC connect is in the future. Seems awfully wasteful to convert the DC panel output to AC, only to convert to DC a few feet later.
That was in Italy last year, where I saw far a far high rate of solar PV installations than here. I'd feed it all into the local electric grid, so you can purchase it at home. The AC-DC conversion loss is down to a few percent, so may be worthwhile when it automatically routes all the excess power not used locally back into the universal AC grid. Isolated parking lot chargers will end up dumping considerable excess energy when cars are not plugged in. When traveling in Italy, I saw a far higher rate of solar PV installations than exists here. Most was installed atop homes, barns, and commercial and industrial buildings, using existing structures to capture sunlight that was otherwise wasted on non-biological, non-natural surfaces. Even some freeway sound isolation barriers were covered with PV. The parking shade installation above was among the few not on an existing structure. A few more were in open fields. Some covered the otherwise inaccessible field inside freeway cloverleafs.
Perhaps I don't understand correctly where the 15+ % energy losses from wall to battery are from in car charging.
The inverters under my PV panels are 96.0% efficient, the newer version is rated 96.5%. Of course, this conversion must happen both ways. And only a portion of that wall to battery loss occurs in the AC-DC conversion stage. More happens in the DC to battery path. Even with all DC, voltages must still be boosted and bucked from panel (variable) to power bus (hopefully nearly constant) to battery (variable), so conversion losses will very likely remain similar. And if the DC power bus is lower voltage to be similar to an individual PV panel output, then wiring losses (and/or wiring costs) will rise sharply, at x-squared rates.
The wall to car loss also includes any energy used by the battery's thermal management system, if equipped, and likely any maintenance charging on a full battery.
