Energy pay-back time (EPBT) results for fixed-tilt ground mounted installations range from 0.5 years for CdTe PV at high-irradiation (2300 kWh/(m^2·yr)) to 2.8 years for sc-Si PV at low-irradiation (1000 kWh/(m^2·yr)), with corresponding quality-adjusted energy return on investment (EROIPE-eq) values ranging from over 60 to ~10.
If you want to see other publications on the same topic, try hitting Google Scholar with search terms "photovoltaic" "life cycle" "energy payback". For the most accurate results, restrict your search to recent years. Manufacturing processes are revised rapidly and studies from the turn of the millennium are now badly obsolete. (Though even in 1990 PV systems were net energy positive on average; the worry that PV system manufacturing consumes more energy than the lifetime output appears to be a holdover from the very early (1970s) days of terrestrial PV systems.)
Except you don't, you just see limited installations here and there.
If solar power has such a quick payback period why aren't more investment groups funding it?
Are the panels not available in sufficient quantity?
Global installations for 2016 are also on track to set a new record, surpassing 2015 installations by 48%: https://cleantechnica.com/2016/11/30/global-solar-installati...
And despite these records, the manufacturing side of the industry is currently demand-constrained rather than supply-constrained.
When you say you there's just "limited installations here and there," are you estimating from whatever you personally see in your local area?
Also, global solar is going up like crazy. Global sustained growth rate of around 40% is crazy fast. If that keeps on for a bit more than ten years, 100% of current global electricity demand is covered by solar. Just for comparison, there exists no two subsequent full years of iPhone production where Apple would have managed to achieve 100% growth.
I think his numbers didn't take into consideration the expensive backup power plant that you have to have ready even if you have adequate solar capacity.
1 L of diesel has about 39 MJ of energy. That's about 10 kWH (a Tesla Powerwall) in the size of a Nalgene bottle.
I think that as intermittent renewable energy sources get cheaper and cheaper, in addition to time-shifting of arbitrage from batteries, energy storage in chemical bonds may make sense. Methods to create synthetic fuels from electricity are in their very early days, and all of them are terribly inefficient; most go through hydrogen and that step alone results in a huge loss of energy.
So for applications where energy density is needed, e.g. jets, the fuel costs will just be that X% higher than being able to use straight electricity + battery.
I can definitely imagine a world where creating synthetic fuels from excess grid energy is cheaper than fossil fuel extraction, but it involves tons of research and development in those synthetic fuel methods, and many decades of improving renewable technologies at their current rate.
EROI Fuel
---- ----
35.0 Oil imports 1990
18.0 Oil imports 2005
12.0 Oil imports 2007
6.8 Photovoltaic (wikipedia)
14.4 Photovoltaic [2] (from recent analysis of post-2008 data)
And once you start looking at the slow and steady pace of improvement in storage technologies, it looks highly possible that around 2025-2030, only specialized energy applications ever make new investments in fossil fuel based technologies. And that's without accounting for the negative externalities that fossil fuel users (all of us) make everybody else subsidize. Existing infrastructure will continue as long as its economical, of course, but there's most definitely a huge turning point around the corner in energy technology.
[1] https://en.wikipedia.org/wiki/Energy_returned_on_energy_inve...
[2] https://www.researchgate.net/publication/311170056_Solar-PV_...
PV output is electricity already, to get electricity from coal you'd need to throw away 2/3rds of the energy as heat, about half for gas, reducing their EROI by that factor in a correct comparison. So if it's electricity you want then PV is already winning over fossil fuels I think.
Similarly, for powering cars with gasoline they're not as efficient in converting that energy "well-to-wheel" as EVs, as the losses in battery storage and electric motors are much smaller, giving you a "miles driven return on energy input" measure about 3x higher for a PV charged car vs ICE.
You can avoid the generation loss on natural gas by piping to the home and burning it directly for heat in areas that need heat, getting close to 100% efficiency with modern central heating systems, but then in those same situations you can use an electric heat pump and get 3-500% efficiency, since you're only moving the heat around, not generating it.
"Independent research has verified the ability of air source heat pumps to maintain energy efficiency well above other electric heating systems, with coefficients of performance (COP) of between 2 to 3, in temperatures as low as -15⁰ F. Multiple manufacturers have developed ASHPs designed for cold climate operation, incorporating features such as two-stage compressors and advanced defrost capabilities.
Where data is available to evaluate the energy savings impacts of [Western Minnesota] customers moving from less efficient electric heating systems, the energy savings associated with the heating demand served by the hybrid ASHP systems is found to be in the range from 10% to more than 40%, with median savings of around 22%."
It looks like the Western Minnesota region where they ran this trial has colder winters than Denver, so Denver-area results would be even better. The best air source heat pumps should be able to save energy over resistance heating for the vast majority of American households. They will also save energy over direct combustion of natural gas in a household furnace if the natural gas is instead burned in a combined cycle electrical plant. They will not reduce energy consumption or emissions vs. a home natural gas furnace if your winter-time grid electricity mix has a substantial coal component.
http://www.economist.com/news/science-and-technology/2171130...