The underlying problem with EROEI calculations is that EROEI is based on a very simple model. The model works passably well in simple situations, but it was not designed to handle the complexities of intermittent renewables, such as wind and solar PV. Indirect costs, and costs that are hard to measure, tend to get left out. The result is a serious bias that tends to make the EROEIs of solar PV (as well as other intermittent energy sources, such as wind) appear far more favorable than they would be, if a level playing field were used. In fact, published EROEIs for solar PV (and wind) might be called misleading. This issue also exists for other similar calculations, such as Life Cycle Analyses and Energy Payback Periods.Proposed types of energy alternatives are often analyzed using Energy Returned on Energy Invested (EROEI) calculations. For each type of energy product that is produced, a ratio of the energy output to energy input is calculated. A high ratio gives an indication that the particular approach is very efficient, and thus is likely to produce an inexpensive energy product. Coal is a typical of example of a fuel with high EROEI. Wood cut using a hand saw would also have a very high EROEI. On the other hand, a low ratio of energy output to energy input, such as occurs in the production of biofuels, is expected to be high cost, and thus is not suitable for expanding.A derivative concept is "net energy." This is defined as the amount of energy added, when "Energy Input" is subtracted from "Energy Output," or variations on this amount.1 There are many other related concepts, including "Energy Payback Period" and "Life Cycle Analysis." The latter can consider materials of all sorts, not just energy materials, and can consider pollution issues as well as energy issues. My discussion here indirectly also relates to these derivative concepts, as well as to the direct calculation of EROEI.The actual calculation of EROEI amounts varies a moderate amount from researcher to researcher. On the input side, the researcher must make decisions regarding exactly what energy inputs should be included (manufacturing the solar panel, transporting the solar panel to the construction site, building the factory that makes the solar panel, disposing of toxic waste, etc.). These energy inputs are then all converted to a common base, such as British Thermal Units (Btus). On the output side, amounts are fairly clear when the production of fossil fuels is involved, and the calculation is "at the wellhead." When output from a device such as a solar panel is involved, there are many issues to be considered, including how long the solar panel is expected to last and how many hours of solar output will actually become available given the solar panel's siting (which may not be known to the researcher). In theory, the energy costs of ongoing maintenance should come into the calculation as well, but will not be available early in the life of the panel when the calculations are made.
Gail Tverberg makes the excellent point in many of her articles that fossil fuels, while being subsidized in part, overall are able to return an energy surplus, which is realized as profits for the oil company AND taxes remitted to the government. Solar and wind aren't viable without subsidies and do not produce a net energy gain sufficient to allow for taxes to be skimmed off the top at any point in the process. That they cannot produce a surplus sufficient to pay taxes is strong evidence the EROEI is near zero, or negative, which means solar and wind may be a net energy sink.
Many people believe wind and solar energy capturing devices can replace a substantial percentage if not all of our fossil fuel usage. Below you will find pictures and charts detailing the necessity of the fossil fuel supply system and the massive industrial infrastructure in this "renewable" dream.Mark Z. Jacobson Department of Civil and Environmental Engineering, Stanford University was coauthor of another article. It can be found in Scientific America - "A Path to Sustainable Energy by 2030".http://www.scientificamerican.com/article/a-path-to-sustainable-energy-by-2030/They proposed that starting in 2012, 50% of the worlds needs could be supplied by 3,800,000 five megawatt wind capturing devices to be installed by 2030. Here are the numbers:3,800,000 5 megawatts each supply50% of the world's energy needs in 18 yearsTHIS MEANS211,111.11 Machines a year578.39 Machines a day for 18 years24.10 Machines each hour each day for 18 yearsEACH ONE INSTALLED EACH DAYI am choosing wind energy capturing devices because they have a higher Energy Return on Energy Invested than solar energy capturing devices. I continually use the phrase "capturing devices" for what are usually called solar panels and wind machines because these are devices that capture the sun or wind energy. Let me cut right to the results of this study. The base of this 2.5 megawatt turbine in the pictures that follow (half the megawatts in the Jacobson/Delucchi study) used 45 tons of rebar and 630 yards of cement. This computes in barrels of oil and in tons of CO2 for each base:For the Concrete478.8 Barrels of oil in 630 yards of concrete.409.5 Tons of CO2 released for 630 yards of concrete.For the RebarTaking a conservative 3 barrels of oil per ton the rebar would require 135 barrels of oil for the base of the 2.5 MW Turbine.89 tons of C02 released for 45 tons of steel for the base.All TogetherThe concrete and steel together for one base use613 barrels of oil for each base alone.Each base release 498 tons of CO2Before looking at two of the energy requirements to install these 3800000 machines here are some interesting pictures of installing a wind energy capturing device from http://www.cashton.com/North_Wind_Turbine_Const-DM-CS-SB-2-reduced-in-size.pdf . The machine we are looking at is only 2.5 MW turbine not the larger 5 MW proposed by Jacobson and Delucch.
The pictures clearly illustrate that the fossil fuel supply system and a vast industrial infrastructure support the manufacture and installation of these wind energy capturing devices. The tons of rebar and the yards of concrete offer a chance to look at the energy requirements for both. It is also important to point out that all the equipment used to install the turbines also have the fossil fuel supply system and the massive industrial infrastructure supporting them.In researching this, the information for concrete was more definite than the range of energy required to make rebar.REBAR"Under the most ideal circumstances, the energy required to produce solid iron from iron oxide can never be less than 7 million Btu per ton (MMBtu/ton). Since the energy required to melt iron under the most ideal circumstances is about 1 MMBtu/ton, the inherent thermodynamic advantage of making liquid steel from scrap rather than from iron ore is about 6 MMBtu/ton. When process heat losses are included, the advantage falls in the range of 9 to 14 MMBtu/ton. . . . current total energy requirements for the pro- Petroleum provides only a small amount of enduction of finished steel products in different pIants and countries from iron ore range from 25 to 35 MMBtu/net ton."https://www.princeton.edu/~ota/disk3/1983/8312/831210.PD(http://www.eurosfaire.prd.fr/7pc/documents/1355390994_jrc_green_steel.pdf)The range above supports the 25 to 35 MMBtu/net ton. With various iron making processes, iron has a range of Btus per ton. Converted to barrels of oil the range is 2.17 to 4.83 barrels of oil per ton of rebar.Taking a conservative 3 barrels of oil per ton the rebar would require 135 barrels of oil for the base of the 2.5 MW Turbine.On average, 1.8 tonnes of CO2 are emitted for every tonne of steel produced.http://www.worldsteel.org/publications/position-papers/Steel-s-contribution-to-a-low-carbon-future.htmlThis means 1.98 tons of C02 emitted for every ton of steel produced.CEMENT ENERGYMultiply 1.10231 to convert tonnes to tonsOne yard of concrete equals two tonshttp://www.cemexusa.com/ProductsServices/ReadyMixConcreteFaq.aspxTwo tons equals 1.81437 tonnes4426832.62 Btus in a yard of concrete5800000 Btus per barrel of oil0.76 barrels of oil in a yard of concrete32.06 gallons of oil in a yard of concrete0.65 tons of CO2 per yard of concrete478.8 Barrels of oil in 630 yards of concrete20195.52 Gallons of oil in 630 yards of concrete409.5 Tons of CO2 per 630 yards of concretehttp://www1.eere.energy.gov/manufacturing/industries_technologies/imf/pdfs/eeroci_dec03a.pdfTHE CONCRETE PROCESShttp://www1.eere.energy.gov/manufacturing/industries_technologies/imf/pdfs/eeroci_dec03a.pdfhttp://www1.eere.energy.gov/manufacturing/industries_technologies/imf/pdfs/eeroci_dec03a.pdfOn-site energy values are based on actual process measurements taken within a facility. These measurements are valuable because the on-site values are the benchmarks that industry uses to compare performance between processes, facilities, and companies. On-site measurements, however, do not account for the complete energy and environmental impact of manufacturing a product. A full accounting of the impact of manufacturing must include the energy used to produce the electricity, the fuels, and the raw materials used on-site. These "secondary" or "tacit" additions are very important from a regional, national, and global energy and environment perspective.Normal weight concrete weighs about 4000 lb. per cubic yard. Lightweight concrete weighs about 3000 lb. per cubic yard. If a truck is carrying 10 cubic yards, then the weight of the concrete is approximately 40,000 lb.The tonne (British and SI; SI symbol: t) or metric ton (American) is a non-SI metric unit of mass equal to 1000 kilograms; it is thus equivalent to one megagram (Mg). 1000 kilograms is equivalent to approximately 2 204.6 pounds.http://www1.eere.energy.gov/manufacturing/industries_technologies/imf/pdfs/eeroci_dec03a.pdfIt is important to realize we have only looked at the energy for the concrete and rebar for the base of a 2.5 MMwatt turbine. Behind this device and most sun and wind capturing devices are a global system of providing energy and materials. And this support is further supported. Here is one mining truck among a worldwide fleet of trucks that also must be manufactured. It is like a thread on a knitted sweater that when you pull it thinking you will get a small piece, you end up with a whole ball of yarn.
Solar and wind energy capture devices cannot be manufactured, shipped, installed, maintained and replaced without the existing fossil fuel-powered industrial infrastructure. The same externalities are involved with them, as well.
The US solar industry is a bigger employer than oil and gas extraction, but it fears disruption under a Trump presidency
The US solar workforce expanded by 20% last year, reaching nearly 209,000 jobs, despite a modest decline in the PV manufacturing sector, according to a new report.One out of every 83 jobs created in the US in 2015 was in the solar industry, the report says.With a total current workforce of 208,859, the US solar industry now employs three times as many workers as the country's coal-mining industry. And the solar industry is now a bigger employer than many sub-sectors within the oil and gas industry - including the extraction sector, which employs 187,200 people after shedding jobs last year, and the pipeline construction sector, which employs 129,500.
That graphic with the cubic mile of oil illustrates the necessary shift to distributed power production.
Aluminum smelting ... is an electrolytic process, so an aluminum smelter uses prodigious amounts of electricity; they tend to be located very close to large power stations, often hydro-electric ones, and near ports since almost all of them use imported alumina. A large amount of carbon is also used in this process, resulting in significant amounts of greenhouse gas emissions.