Mind-boggling potential
During one year, the Earth absorbs about twice as much energy from the sun as will ever be obtained from all of the Earth's non-renewable resources. That’s the combined energy from all coal, oil, natural gas, and uranium that ever existed in six months of sunlight.
A humongous potential
The energy potential of the sun is not breaking news. Already in 1931 the ingenious Thomas Edison saw the potential - as well as the big caveat:
“I’d put my money on the sun and solar energy. What a source of power! I hope we don’t have to wait until oil and coal run out before we tackle that”
- Thomas Edison, 1931.
The question of how long we have to wait is indeed the tricky part.
Will we run out of oil and coal before living on green energy from the sun?
In a word, no. The world will have shifted to alternative energy sources before we literally run out of oil and coal. If for no other reasons, because at some point extracting more coal and oil from Earth will become too expensive.
The real question!
The more important question is: Will it happen before it’s too late? Before greenhouse gas emissions have trickered critical tipping points and left the Earth climate out of control?
LCOE/LEC baby!
Whether we will start using energy from the sun and stop burning coal and oil all depends on the levelized cost of electricity (LCOE) aka the Levelized Energy Cost (LEC). It is given by this equation (sorry to get technical on you but it's important):
Sum of costs over a lifetime / sum of energy produced over a lifetime.
The cost of solar energy
The first solar cell was invented in 1954 by Bell Laboratories and was available to the public in 1956. But the price was very high: $300 for a one-watt solar cell.
In 2019, the average solar panel cost in the US was $3.05/watt.
$300 in 1956 is equivalent to $2,160 in 2019 meaning that the price per solar generated watt has decreased over 700 times.
Simple math
If the levelized cost of solar energy (and other renewable energy sources) is lower than for fossil fuels, then the market forces will do their job.
Unless the world is stupid enough to keep subsidizing fossil fuels thereby counteracting great green innovations. That would be crazy, right..?
Subsidies for coal
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Full costs of fossil fuels not included
The problem is also that the definition of costs in energy production is often too narrow not including the full cost of externalities such as air pollution and climate change. Including the full costs of burning fossil fuels would tip the LCOE towards solar and other green energy sources much more quickly.
20 times less greenhouse gas emissions
Energy produced by solar power reduces greenhouse gas emissions by 95 percent compared to coal. Wind power even more: a 98.5 percent reduction.
| Energy source | Greenhouse gas emissions Life cycle CO2 equivalent in gigatons (gCO2eq/kWh) |
| Coal | 820 |
| Gas | 490 |
| Biomass | 230 |
| Solar Power | 41 |
| Geothermal | 38 |
| Hydropower | 24 |
| Wind | 12 |
Source: Wikipedia - Greenhouse gas emissions
Good news!
The good news is that the cost of solar energy is going down. And going down quickly. In just one year (2018) onshore wind and solar saw an 18 percent improvement in competitiveness.
A major challenge with solar and wind power is the storage of energy. But also here, there is good news with a 79 percent decrease in lithium-ion battery storage costs since 2010.
“The conclusions are chilling for the fossil fuel sector. Some existing coal and gas power stations, with sunk capital costs, will continue to have a role for many years, doing a combination of bulk generation and balancing, as wind and solar penetration increase. But the economic case for building new coal and gas capacity is crumbling, as batteries start to encroach on the flexibility and peaking revenues enjoyed by fossil fuel plants.”
- Bloomberg News, 28 March 2018
2018 projections for 2022 electricity prices
Estimated levelized cost of electricity for new generation resources entering service in 2022 (2017 $/MWh) (capacity-weighted average)
| Energy (plant type) | LCOE ($2017 / MWh) |
| Wind, offshore | $124.60 |
| Biomass | $102.20 |
| Coal* | $95.10 |
| Advanced nuclear | $90.10 |
| Advanced combustion turbine | $79.50 |
| Hydroelectric (water) | $73.90 |
| Solar | $59.10 |
| Advanced combined cycle natural gas | $48.10 |
| Wind, onshore | $48.00 |
| Geothermal | $43.10 |
Source: The U.S. Energy Information Administration (EIA) *2015 price as no new capacity build in 2017
Still a long way to go
In 2017, 442.6 TWh of energy was generated from solar power. That’s 1.73 percent of the total world electricity use. So there still a long way to go.
But moving in the right direction
In five years from 2012 to 2017 solar energy capacity almost quadrupled. Solar energy generation continues to grow by 35 percent a year. So things are moving in the right direction. In 2014, the International Energy Agency predicted that solar energy could reach 27 percent of global electricity by 2050.
