First, it has been long acknowledged that natural gas would be the interim solution to slow the rate, and we are seeing that happen. Natural gas, essentially methane gas or CH4, produces 50 to 60% less carbon dioxide than coal. Since about 2007 energy from coal in the U.S.has declined while natural gas energy has increased. A lot of this may be due to declining gas price, but we can hope that decisions by policy makers played a major role. Coal is primarily used in electricity generation, and will fade out as coal fired plants age and are closed down.
The next good news is the growth of renewable energy, particularly wind and solar.
From the graph above, is is clear solar and wind make up most of the recent increase of renewable energy. The annual increase in new capacity is only growing about 8% a year, but more like 16% in the last few years, far less than our historical examples.
Wind energy has steadily been expanding both worldwide and in the U.S. We add about 6 gigawatts of wind power each year. Wind now supplies 6% of the U.S. electrical needs, and is projected to supply 20% by 2030 and 35% by 2050.
Solar is really starting to pick up steam. In 2018 the U.S. installed 10.6 gigawatts of PV power, a rate of 20% increase per year. The installation rate is expected to reach 15 gigawatts each year and the total installed base doubling in 5 years.
The driver behind solar's exponential growth has been declining solar PV panel prices. From 2010 to 2018 utility scale scale electrical generation has reduced in cost by 84%. The U.S. Dept. of Energy's 2020 goal of 6 cents per kWhr for utility scale electricity was met in 2017. (The SunShot Initiative is a federal government aimed at making solar energy affordable.)
The final piece of good news is the declining cost of batteries as evidenced by the sudden emergence of electric cars.
While batteries have yet to make a dent in the electrical grid, the role of electrical energy storage of some sort is part of the SunShot goal, starting around 2030:
Storage becomes important once the amount of solar energy becomes cheap and abundant enough to be needed during nighttime hours, allowing a time lag between generation and consumption.
These developments hint at how the U.S. can achieve an 80% reduction in greenhouse gas emissions by 2050.
Emissions from coal is declining at bout the amount natural gas is increasing. Since natural gas gives more energy per pound of CO2 emitted, there is a net increase in energy. Natural gas, the rise of renewable energy, and increases efficiency, are supplying the growing demand for energy.
The Path:
By combining all these facts, a path forward toward a planet free of fossil-fuels starts to become clear.
2020-2030
- Production of electricity from energy sources other than fossil fuels is ramped up at an exponential rate, increasing about 30% each year.
- Solar and wind energy will continue to be the biggest gainers.
- Hybrid and electric vehicles will grow at a steady rate.
2030-2040
- Renewable energy growth will continue at a steady, linear rate.
- Electric vehicles will increase in number, powered by these new sources of energy.
- Batteries will become affordable, making electric vehicles cheaper than internal combustion cars.
2040-2050
- Few gas powered cars made after 2040.
- Slower progress will be made where dense or lightweight fuel is required. Cement production and methane emissions are also concerns, time-wise.
- By 2050 solar will comprise about 50% of the energy needs, wind 35%, with nuclear, hydro, and other renewable energy sources making up the rest. We don't know that mix for sure, but the trends at this time suggest it.
Bottom line: Encouraging recent developments point to wind and solar as the probably course of action in replacing carbon based fossil fuels with renewable energy over the next three decades.
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