This is part 2 of what I hope to write as a series on technologies we already have, but have either failed to deploy, or underused, that could help get us to a carbon emission free economy.
To be clear, I am not saying we may not have delayed too long already, or that these technologies are silver bullets that will reverse everything tomorrow. I am only stating that there is no need for technological breakthroughs; we already have everything we need. Had we chosen a different path we would not be where we are. There is no better time than the present to act.
Parts 1 and 1B were on energy efficient building shells. www.dailykos.com/...If you have not read them, you should start there.www.dailykos.com/... I would like to quote one of the comments here written by OneWayFish. “DanielEMichelsen is spot on with nearly everything he wrote here. I am a professional engineer who designs building shells. This is in my wheelhouse.”
A brief note on the picture. When I uploaded it, I was confronted with the Kos warning about being sure you have permission to use the picture you are uploading. It is a picture of the very first solar water heater I ever installed, taken with my camera at the time it was completed. Its name in my computer includes “first day of operation.” The unit turned 12 this year and although it has been monitored for problems, it has never been serviced or needed any repairs. Past its installation, it simply turns out free hot water every sunny day. I suspect I have photo rights.
So, we start by assuming that your building shell needs little to no heat if constructed properly. (Old house retrofits might need some, but not much.) But you still need some energy to power your home. Hot climates will still need some minimal cooling. (But we also need to think about not living in the desert.) The challenge is to produce that energy sustainably without emitting carbon dioxide. There are many ways to accomplish this.
Renewable energy can be broadly subdivided into 2 categories depending on the ownership of the equipment. There is “distributed generation” which is understood to mean that the electric power or heat is produced on site, and the equipment is generally owned by the user. Then there are “utility scale” installations which are large industrial sized renewable energy plants that sell electricity into the marketplace.
They can also be divided into categories other ways. Solar, wind and Hydro power all come to mind fairly readily. Let’s start with Wind Power.
Wind itself has two distinct ways to harvest power. There are the old water pumping windmills, and then there are the modern wind turbines that produce electric power. The water pumpers need high torque at low speeds to work well and this is not wind power’s forte. It is an interesting technology that with rare exceptions can be safely relegated to the past. Water pumpers played a huge part in settling the plains states, but today, the best way to pump water with wind is an electric pump connected to an efficient turbine.
The formula for calculating the output of a turbine is Power = ½ the density of the air X the swept area of the turbine X the velocity of the wind cubed, or P = 1/2dA * V3. (My small d is for density, which is usually represented by the Greek letter rho, but I can’t seem to find rho on my keyboard.) Notice that the velocity of the wind is cubed. This is critical to understand.
Since the drag of friction with the earth slows wind down, the higher you go the faster the wind. Tall towers have huge paybacks because power is a function of the velocity of the wind cubed. Did I mention that when calculating this, the speed input is cubed? If you put a turbine up 100 feet you get significantly more power than at 50 feet, and significantly less than at 200 feet. The big joke in the small scale wind industry about the 3 main complaints of owners of wind turbines are:
1: My tower is too short!
2: I wish I had a taller tower!!
3: Darn that salesman, (s)he should have talked me into a taller tower!!!
Another reason for tall towers is that turbulence decreases with altitude along with the increase in speed because the friction with the earth that creates much of the turbulence is farther away. (For you meteorologists, amateur and otherwise, convection is capable of creating greater turbulence, but usually it is only a problem in thunder cells not a daily occurrence.) This is important because turbulence is capable of tearing turbines apart. The peak of a house roof is the last place you want a turbine because the roof creates a huge amount of turbulence. It is not uncommon to see home turbines mounted this way sitting idle without their blades, because the blades are gone with the wind. Even if the blades survive, the bearings usually die a painful early death.
One more factor is the length of the blades define the swept area of the turbine which is basically a square function. This means that larger turbines get more power from a given amount of material inputs. The larger the turbine, the more cost effective and efficient it is.
Combined, these factors are why home wind power is relatively rare. Wind power is best harvested in the country, away from tall buildings with large turbines sitting atop very tall towers. Your back yard or roof do not meet these criteria.
One complaint about turbines is that they kill birds. Properly located this is not a huge problem. What is a huge problem is FAA regulations that require blinking red lights on towers. This disrupts navigation systems in migrating birds and can cause them to circle the tower until they die of exhaustion. The solution is not to castigate or ban towers, it is to change the regulations. A bright red light could suffice, and if it does not blink, most if not all of the problem goes away.
For years the myth has been out there that due to the variability of wind, we can never get more than 20% of our power from wind turbines. But critics never delve into WHY? It turns out that the why is that the grid is inadequate to redistribute wind power effectively enough to meet demand. If we start with the assumption that the grid is adequate, then there is no theoretical upper limit on how large a percentage of our power wind can supply. If the local wind is stalled, it is harder somewhere else. The atmosphere is constantly moving so it can’t stall everywhere at once.
Large wind turbines are arguably the least expensive electricity we can produce. Anti wind turbine campaigns are almost always Astroturf. That is a fake grassroots movement promoted by monied interests.
Around 2006 I took a homebrew turbine construction class in Door County Wisconsin. While I was driving around I wanted to hear the large turbines in the neighborhood. I drove right up to one and had to roll my windows down to hear it. So much for noise. Properly sighted, noise is simply not an issue.
So going back to our two broad categories of energy production, wind power is, hands down, best suited to Utility scale installations.
Part 2B will start to deal with solar energy, which is a switch hitter. Some forms can be most effectively deployed as distributed generation. Some are best suited to utility scale, and others can be used for either.