It would be elegant if wind and solar energy capturing devices could actually maintain a modicum of the wonderfully rich lifestyles many of us live. I believe this is a false dream and that BAU (business as usual) is not sustainable or “green” nor really desirable for the future of the earth or even our species.
Prove This Wrong
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.
Wind, Water, and Solar Power for the World
Nix nuclear. Chuck coal. Rebuff biofuel. All we need is the wind, the water, and the sun
By Mark Delucchi/ SEPTEMBER 2011
“We don’t need nuclear power, coal, or biofuels. We can get 100 percent of our energy from wind, water, and solar (WWS) power. And we can do it today— efficiently, reliably, safely,
sustainably, and economically.
We can get to this WWS world by simply building a lot of new systems for the production,
transmission, and use of energy. One scenario that Stanford engineering professor Mark
Jacobson and I developed, projecting to 2030, includes: 3.8 million wind turbines, 5 megawatts each, supplying 50 percent of the projected total global power demand.”
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”.
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 supply
50% of the world’s energy needs in 18 years
211,111.11 Machines a year
578.39 Machines a day for 18 years
24.10 Machines each hour each day for 18 years
EACH ONE INSTALLED EACH DAY
I 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. It is misleading to not realize they require energy and natural resources.
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 Concrete
478.8 Barrels of oil in 630 yards of concrete.
409.5 Tons of CO2 released for 630 yards of concrete.
For the 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.
89 tons of C02 released for 45 tons of steel for the base.
The concrete and steel together for one base use
613 barrels of oil for each base alone.
Each base release 498 tons of CO2
(A barrel of oil is 42 gallons)
Before 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 turbines, each standing 485 feet tall and weighing 2,000 tons
The project utilizes 2.5 MW turbines on 100 meter towers.
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.
“Common rebar is made of unfinished tempered steel, making it susceptible to rusting. Normally the concrete cover is able to provide a pH value higher than 12 avoiding the corrosion reaction. Too little concrete cover can compromise this guard through carbonation from the surface, and salt penetration. Too much concrete cover can cause bigger crack widths which also compromises the local guard. As rust takes up greater volume than the steel from which it was formed, it causes severe internal pressure on the surrounding concrete, leading to cracking, spalling, and ultimately, structural failure. This phenomenon is known as oxide jacking. This is a particular problem where the concrete is exposed to salt water, as in bridges where salt is applied to roadways in winter, or in marine applications. Uncoated, corrosion-resistant low carbon/chromium (microcomposite), epoxy-coated, galvanized or stainless steel rebars may be employed in these situations at greater initial expense, but significantly lower expense over the service life of the project. Extra care is taken during the transport, fabrication, handling, installation, and concrete placement process when working with epoxy-coated rebar, because damage will reduce the long-term corrosion resistance of these bars.” http://en.wikipedia.org/wiki/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.”
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.
On average, 1.8 tonnes of CO2 are emitted for every tonne of steel produced.
IRON ORE PROCESS
THE CONCRETE PROCESS
On-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,
It 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.
YOU DO THE MATH