Solar power had a banner year in 2020. The U.S. PV industry established an annual high-water mark with 15 GW (gigawatts – one billion watts) of capacity additions, which raises cumulative PV capacity to 74 GW. This breaks down to a 46 GW cumulative capacity for utility scale PV installations and a 28 GW cumulative capacity for small PV installations. The PV electricity share of total U.S. utility electricity generation is 3.2% in 2020.

PV capacity additions topped wind for the first time in 2020. Wind capacity additions in 2020 are 14 GW, which is well below the forecast. Note that wind capacity is reported at the rated summer capacity. In 2020, all wind capacity additions are onshore wind farms that are located primarily in the high wind Midwest region. At the end of 2020, cumulative U.S. wind capacity is 118 GW. In terms of electricity supply, wind electricity contributed 8.4% of total U.S. utility electricity generation in 2020.

The U.S. PV and wind capacities in 2020 are close to the capacity projections presented in ‘A Grand Plan for Solar Energy’ that ASAP published in the January 2008 issue of Scientific American. PV is proving to be the solar technology of choice with few concentrating solar power plants being built. The goal of bringing PV to optimum-scale manufacturing and installation levels by 2020 has been realized. Most importantly, the installed cost of PV plants in 2020 is much lower than the Solar Grand Plan’s projection of $1.30 per watt for non-tracking PV systems.

PV manufacturing is at the optimized multi-GW scale and combined with gains in PV panel electricity generating efficiency to over 20% has brought down the installed cost of utility-scale PV plants to the $1.00/watt neighborhood. In should be noted that approximately 70% of the large, ground-mounted PV plants incorporate sun tracking systems. The added cost of tracking systems is offset by increased electricity generation, which nets positive economic returns in most areas of the country.

ASAP projects robust growth in annual PV and wind capacity additions. The extension of the solar investment tax credit provides a tailwind for PV growth. The solar investment tax credit will remain at 26% through 2022 for all residential, commercial, and utility PV projects that begin construction in 2021 and 2022. The tax credit drops to 22% for PV projects starting construction in 2023. Beginning in 2024, the tax credit for the residential PV market drops to 0% while the commercial and utility PV markets have a permanent 10% solar tax credit. In addition, the wind industry received a limited extension of the production tax credit for wind projects beginning construction by December 31, 2021.

With the knowledge and experience gained, the U.S. is poised for the Terawatt Challenge, 2021-2050.

Summary (see the details):
The U.S. had 77 GW of solar capacity as of the end of 2020. To replace the usage of fossil fuels with solar energy while meeting future growth, on the order of 3 TW of solar capacity will be required by 2050, an increase of 40 times current capacity! This is the "Terawatt Challenge". Based on the analysis in the original SGP from 2008, and the in-process "SGP Stage Two", this is entirely feasible if a variety of difficult but doable challenges can be met:

• Challenge:  Energy storage
• Challenge:  Distribution, both electricity and hydrogen
• Challenge:  Infrastructure siting

The United States has an abundance of solar and wind energy potential – enough to supply its entire energy needs. This can be done using existing technology and at an affordable price. To get there requires a coordinated national-level effort. The steps are:

• Build solar PV plants in the sun-rich desert Southwest
  • U.S. located PV manufacturing plants
• Build wind farms in the wind-rich Midwest
• Build electricity storage to designed to smooth variable PV and wind electricity supply
  • Battery
  • Compressed air energy storage (CAES)
  • Molten Salt
• Construction of a HVDC transmission system to transport PV and wind electricity nationwide
• All electric transportation
  • Battery electric vehicles
  • Hydrogen fuel cell electric vehicles
• Conversion to electric home and commercial space heating
  • Advanced heat pump technology

Electrification of the total U.S. energy system is the only effective way to combat global warming. The largest uses for fossil fuels are electricity generation, transportation, home/commercial space heating, and industrial processes. Electricity demand will increase significantly to accommodate transportation and space heating. Public adoption of electric cars is important if we want to end transportation carbon emissions, which is important since transportation accounts for 70% of U.S. oil consumption.

An all PV and wind electricity system will allow us to expand domestic jobs and economic well-being while providing us with a sustainable and emissions free energy path for the future.

The use of carbon-free solar and wind electricity allows us to reduce CO2 emissions in 2100 by 92% below current levels. It is important for the rest of the world to follow suit if global warming is to be tamed.