Alternative energy is any energy source that is an alternative to fossil fuel. These alternatives are intended to address concerns about fossil fuels, such as its high carbon dioxide emissions, an important factor in global warming. Marine energy, hydroelectric, wind, geothermal and solar power are all alternative sources of energy.
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- We self-flagellate sometimes about our carbon footprint, but we don't even realize what that means.
- Steve Blood as qtd in James Hamblin, “The Electricity-Generating Bicycle Desk That Would Power the World”, The Atlantic, (Jan 7, 2014).
- When electricity is needed, say, after the sun has set, the hot liquid silicon -- so hot that it's glowing white -- is pumped through an array of tubes that emit that light. Specialized solar cells, known as multijunction photovoltaics, then turn that light into electricity, which can be supplied to the town's grid. The now-cooled silicon can be pumped back into the cold tank until the next round of storage -- acting effectively as a large rechargeable battery.
"One of the affectionate names people have started calling our concept, is 'sun in a box,' which was coined by my colleague Shannon Yee at Georgia Tech," Henry says. "It's basically an extremely intense light source that's all contained in a box that traps the heat."
- Jennifer Chu, "Sun in a box' would store renewable energy for the grid”, Massachusetts Institute of Technology, (5 December 2018).
- There's enough alcohol in one year's yield of an acre of potatoes to drive the machinery necessary to cultivate the fields for one hundred years.
- Henry Ford as quoted in Biopolymers, Polyamides and Complex Proteinaceous Materials I (2003) by Stephen R. Fahnestock, Alexander Steinbüchel, p. 395.
- Right now alternative energy is still treated as a supplement rather than a substitute for fossil fuels within the energy industry as presently constituted. The rapid growth of alternative energy should not therefore be seen as a radical break with the domination of fossil fuels. That still needs to occur.
- John Bellamy Foster, as quoted in A Resistance Movement for the Planet - Full Interview, Left Voice, (July 02, 2017).
- As long as the starting material is grown on farmland, Searchinger says, biofuels will be bad for the planet.
But Alex Farrell at Berkeley sees a way out of this. He says the focus of the biofuels industry needs a rapid change of direction, away from using cropland — which is where most U.S. biofuels come from today — and toward other sources of starting material.
"We could replace all of the ethanol that we consume in California just using waste that goes to the landfill today, and turning that into ethanol," Farrell says.
Environmentally friendly biofuels could also be made from agricultural waste or grasses grown on land that's not suitable for crops. The biofuels industry is heading in that direction, but the technology to make use of fuels other than corn and soy is still in its infancy.
- Biofuels have grabbed the attention of engine researchers ever since the oil-crisis and escalating costs of petro-chemicals cropped up in the ׳70s. Ethanol and methanol were the most widely researched alcohols in IC engines. However, the last decade has witnessed significant amount of research in higher alcohols due to the development of modern fermentation processes using engineered micro-organisms that improved yield. Higher alcohols are attractive second/third generation biofuels that can be produced from sugary, starchy and ligno-cellulosic biomass feedstocks using sustainable pathways. The present work reviews the current literature concerning the effects of using higher alcohols ranging from 3-carbon propanol to 20-carbon phytol on combustion, performance and emission characteristics of a wide range of diesel engines under various test conditions. The literature is abound with evidence that higher alcohols reduce carcinogenic particulate emissions that are prevalent in diesel engines.
- B.Rajesh Kumar, S.Saravanan “Use of higher alcohol biofuels in diesel engines: A review”, Renewable and Sustainable Energy Reviews, Volume 60, (July 2016), pp. 84-115.
- The assumption that high jet steam wind speeds in the upper atmosphere correspond to high wind power has now been challenged by researchers of the Max Planck Institute for Biogeochemistry in Jena, Germany. Taking into account that the high wind speeds result from the near absence of friction and not from a strong power source, Axel Kleidon and colleagues found that the maximum extractable energy from jet streams is approximately 200 times less than reported previously. Moreover, climate model simulations show that energy extraction by wind turbines from jet streams alters their flow, and this would profoundly impact the entire climate system of the planet.
- Max Planck Institute for Biogeochemistry, “Gone with the wind: Why the fast jet stream winds cannot contribute much renewable energy after all”, (November 30, 2011).
- Even if we wanted to run the grid on renewables right now we couldn’t, because you’d need fossil-fueled turbines to make up for the fact that the renewable supply cannot be dispatched on demand.
- Robert N. Noyce in "Sun in a box' would store renewable energy for the grid", by Jennifer Chu, Massachusetts Institute of Technology, (5 December 2018).
- It is difficult to believe, but it is, nevertheless, a fact, that since time immemorial man has had at his disposal a fairly good machine which has enabled him to utilize the energy of the ambient medium. This machine is the windmill. Contrary to popular belief, the power obtainable from wind is very considerable. Many a deluded inventor has spent years of his life in endeavoring to "harness the tides," and some have even proposed to compress air by tide- or wave-power for supplying energy, never understanding the signs of the old windmill on the hill, as it sorrowfully waved its arms about and bade them stop. The fact is that a wave- or tide-motor would have, as a rule, but a small chance of competing commercially with the windmill, which is by far the better machine, allowing a much greater amount of energy to be obtained in a simpler way. Wind-power has been, in old times, of inestimable value to man, if for nothing else but for enabling him, to cross the seas, and it is even now a very important factor in travel and transportation. But there are great limitations in this ideally simple method of utilizing the sun's energy. The machines are large for a given output, and the power is intermittent, thus necessitating the storage of energy and increasing the cost of the plant.
A far better way, however, to obtain power would be to avail ourselves of the sun's rays, which beat the earth incessantly and supply energy at a maximum rate of over four million horsepower per square mile. Although the average energy received per square mile in any locality during the year is only a small fraction of that amount, yet an inexhaustible source of power would be opened up by the discovery of some efficient method of utilizing the energy of the rays. The only rational way known to me at the time when I began the study of this subject was to employ some kind of heat- or thermodynamic-engine, driven by a volatile fluid evaporate in a boiler by the heat of the rays. But closer investigation of this method, and calculation, showed that, notwithstanding the apparently vast amount of energy received from the sun's rays, only a small fraction of that energy could be actually utilized in this manner. Furthermore, the energy supplied through the sun's radiations is periodical, and the same limitations as in the use of the windmill I found to exist here also. After a long study of this mode of obtaining motive power from the sun, taking into account the necessarily large bulk of the boiler, the low efficiency of the heat-engine, the additional cost of storing the energy and other drawbacks, I came to the conclusion that the "solar engine," a few instances excepted, could not be industrially exploited with success.
Another way of getting motive power from the medium without consuming any material would be to utilize the heat contained in the earth, the water, or the air for driving an engine. It is a well-known fact that the interior portions of the globe are very hot, the temperature rising, as observations show, with the approach to the center at the rate of approximately 1 degree C. for every hundred feet of depth. The difficulties of sinking shafts and placing boilers at depths of, say, twelve thousand feet, corresponding to an increase in temperature of about 120 degrees C., are not insuperable, and we could certainly avail ourselves in this way of the internal heat of the globe. In fact, it would not be necessary to go to any depth at all in order to derive energy from the stored terrestrial heat. The superficial layers of the earth and the air strata close to the same are at a temperature sufficiently high to evaporate some extremely volatile substances, which we might use in our boilers instead of water. There is no doubt that a vessel might be propelled on the ocean by an engine driven by such a volatile fluid, no other energy being used but the heat abstracted from the water. But the amount of power which could be obtained in this manner would be, without further provision, very small.
Electricity produced by natural causes is another source of energy which might be rendered available. Lightning discharges involve great amounts of electrical energy, which we could utilize by transforming and storing it. Some years ago I made known a method of electrical transformation which renders the first part of this task easy, but the storing of the energy of lightning discharges will be difficult to accomplish. It is well known, furthermore, that electric currents circulate constantly through the earth, and that there exists between the earth and any air stratum a difference of electrical pressure, which varies in proportion to the height.
- Nikola Tesla, "The Problem With Increasing Human Energy: With Special References To the Harnessing Of The Sun's Energy", Century Illustrated Magazine, (June 1900).
- With an efficiency of 97 percent, bicycle technology is nearly perfect. So why do we use it only for transportation?
- Andy Wekin and Steve Blood as qtd in James Hamblin, “The Electricity-Generating Bicycle Desk That Would Power the World”, The Atlantic, (Jan 7, 2014).