[Easier said than done.]
- Biomass. If we devote all the arable land on earth to energy production rather than food crops and presumably just don't eat, we could generate 7 to 10 terawatts.
- Wind. If we build wind farms on 100 percent of the sufficiently windy land, we could produce 2.1 terawatts.
- Hydroelectric. If we dam all the remaining rivers, we could come up with 0.7 to 2 additional terawatts.
- Finally, nuclear. We could produce 8 terawatts by constructing 8,000 nuclear power plants, which would mean one new plant every two days for the next 40 years.
[See below for information on Solar Power and it's constraints.]
Finally, to the extent that we continue to rely on fossil fuels, we must capture the resulting CO2 emissions at power plants before they escape into the atmosphere. The captured CO2 would then be injected underground or under the ocean floor for safe long-term storage.
[The key thing to note is "on a very small scale". Unless the CCS is easy, automatic and natural, it is not going to be easy to scale up the process to any significant and meaningful degree.]
[Yes. Politics are getting in the way of alternative energy, but alternative energy is not the panacea for all our problems. The "solutions" are not as simple as the author here is suggesting.]
[That is optimistic at best. Energy saving technologies usually requires rare earth elements to manufacture. And these are in short supply (the name "rare earth elements" might have been a clue):
A 2007 law requiring the phase-out of incandescent light bulbs may increase demand for terbium, europium and yttrium, used in compact fluorescent bulbs that comply with higher efficiency standards, according to the report.]
[He also led the Millennium Village Projects, which while well-intentioned, created new and arguably larger problems. The road to hell... good intentions... etc.]
[This article is optimistic at best. It is unrealistically upbeat, glosses over (or is unaware of) limitations, trade-offs, and true costs.]
- First, biomass. If we devote all the arable land on earth to energy production rather than food crops and presumably just don't eat, we could generate 7 to 10 terawatts.
- Next, wind. If we build wind farms on 100 percent of the sufficiently windy land, we could produce 2.1 terawatts.
- Third, hydroelectric. If we dam all the remaining rivers, we could come up with 0.7 to 2 additional terawatts.
- Finally, nuclear. I know you don't like nukes, Randvek, but the professor's evident aim was to tote up all power sources that aren't net emitters of greenhouse gases. He thinks we could produce 8 terawatts by constructing 8,000 nuclear power plants, which would mean one new plant every two days for the next 40 years.
From another website: Brother, Can You Spare 22 Terawatts?
...in 2002 the United States used 3.3 terawatts (TW), China 1.5 TW, India 0.46 TW, Africa 0.45 TW and so forth. Totaling it all up, Nocera finds, "the global population burned energy at a rate of 13.5 TW." A terawatt equals one trillion watts.So, is solar power the way to go?
Nocera calculates that if 9 billion people in 2050 used energy at the rate that Americans do today that the world would have to generate 102.2 TW of power—more than seven times current production. If people adopted the energy lifestyle of Western Europe, power production would need to rise to 45.5 terawatts. On the other hand if the world's 9 billion in 2050 adopted India's current living standards, the world would need to produce only 4 TW of power. Nocera suggests, assuming heroic conservation measures that would enable affluent American lifestyles, that "conservative estimates of energy use place our global energy need at 28-35 TW in 2050." This means that the world will need an additional 15-22 TW of energy over the current base of 13.5 TW.
"...converting sunlight into energy useful to people is a huge unsolved technological problem. In 2000, author Richard Rhodes and nuclear engineer Denis Beller calculated that using current solar power technologies to construct a global solar-energy system would consume at least 20 percent of the world's known iron resources, take a century to build and cover a half-million square miles. Clearly a lot of technological innovation needs to take place before solar becomes an option for fueling the world."
Can Solar Power provide 50% of our energy needs?
If you believe the link, and the figure above yes.
This is a link to an article on the newest (opened in Feb 2014) and largest solar thermal plant. The Ivanpah Facility has an array of mirrors occupying 3500 acres, producing enough energy to power 140,000 homes. However, it is probably already obsolete as cheaper photo-voltaic (PV) cells/panels would be more feasible.
But even for PV solar power, there are deployment or implementation and other issues.
First, geographical proximity. Where the sun shines steadiest and where people live don't always coincide.
Second, alignment of output and demand. Sunlight is strongest at noon, but most residential demand is in the evening.
To put it simply, the sun don't always shine.
The Rare Earth Elements needed for alternative energy means...
Solar Energy: Not So Clean After All.
Solar energy turns sunlight into electrical power. What’s not to like? Well, there is that whole process of manufacturing solar panels, which requires a great deal of energy. All that energy requires generation via means other than solar power — usually coal.
“In the case of silicon-based solar panels, which are the most common type, the silicon material requires melting silica rock in roughly 3,000-degree F ovens,” notes The Data Center Journal. “That energy, however, typically comes from coal plants, meaning that although solar panels may produce no emissions when in operation, they indirectly produce a fair amount during manufacturing.”
And what to do with the solar panels when their productive life is over in about 25 years or so? And what about all the waste chemicals generated by the solar panel manufacturing process? The Union of Concerned Scientists write that the photovoltaic (PV) cell manufacturing process “includes a number of hazardous materials,” similar to “those used in the general semiconductor industry,” such as “hydrochloric acid, sulfuric acid, nitric acid, hydrogen fluoride, 1,1,1-trichloroethane, and acetone.” If we’re talking about thin-film PV cells, it’s worse, as UCS explains, since those have “more toxic materials than those used in traditional silicon photovoltaic cells, including gallium arsenide, copper-indium-gallium-diselenide, and cadmium-telluride.”
Is Low Energy Nuclear Reaction (LENR) a possible solution for our energy needs in the future?
The consensus at present seems to be that LENR is undeniable. The problem is the output. Generally, if you put in 1 unit of energy, you want to get more than 1 unit of energy out. For now the output for LENR seems to be in the low positives. That in 1 unit in gets you 1+ (but maybe less than 2) unit out. But that is still a positive.
The question is not simply if there is a positive output (i.e. > 1), but the ratio of output, and the concentration of energy. Coal and Oil are excellent sources of energy because of their "energy density". A litre of petrol can take you a long way. In contrast, you need 3500 acres in the desert to collect solar power for 140,000 homes. A similar coal power plant need less land.
LENR is currently not very promising because the energy density is rather low. It remains to be seen how it develops.