Wind Power

Introduction

I recently published a paper where I covered the numerous types of Alternative Energy Sources and their positives and negatives. I will not go into my personal opinion regarding the subject of Alternative Energy Sources and global warming as I covered that in full in the previous piece so in this article I will simply focus on just one type of Alternative Energy Source and that is the more common and cleaner type - Wind Power. Wind Power has been around a long long time and what I like about it is that unlike other green and supposed clean energy sources such as solar power where the solar panels are made, in part, by poisonous metals, wind power is very clean as there are no byproducts now nor when time comes for disposal of the old wind towers and turbines. The only downside to wind power, as I will discuss in more scientific detail later on, is that there are only so many optimal places with enough and proper wind and the average time which a wind turbine is actually being hit by a stream of air with enough force to create energy is, at best, 40% of the time which makes wind farms fairly inefficient. But these are small problems to have compared to other alternative energy sources such as nuclear power plants as we recently witnessed what happened in Japan or the costly and hazardous disposal of massive tons of solar panels.

That said, here is my continuation on Alternative Energy Sources. One thing of note - I had several diagrams and graphs in the last part of the paper, in the Appendix, showing various data which is discussed in detail in the paper but unfortunately I am unable to upload anything so I'll do my best to be clear given the diagrams and graphs won't be there to assist as a visual aid. But I did search and add links in the Citation section on which you can click and find very similar data tables and graphs to help better understand the points I'm trying to make regarding Wind Power.

Wind Power: The Cleaner Alternative

Mankind has been using various forms of wind power for over 5,000 years, such as propelling sailboats, or for natural ventilation in buildings. Using wind power for mechanical energy came a bit later. In the 17th century BC the Babylonians used wind power for irrigation while the Sinhalese, in 300 BC, used the monsoon winds to power their furnaces. More recently, in the U.S., windmills were first used to pump water from wells. These multi bladed wind turbines sat on top of a wood or steel lattice and were a common fixture of the North American landscape, and were one major factor in allowing for farming and ranching over vast areas where water was not readily accessible. The first modern wind turbines were built some 30 years ago and due to technological advancements they have become more and more efficient. There are many good reasons why we should be using wind turbines for energy. Reasons such as zero pollution, provide extra income for rural farmers by renting land for turbines (about $2000–$4000 per year per turbine), creates more jobs per GW of electricity generated than coal power stations, wind power is a renewable source of electricity, and it is also a sustainable source of electricity.

So how do wind turbines make electricity? Simply stated, a wind turbine works the opposite of a fan. Instead of using electricity to make wind, like a fan, wind turbines use wind to make electricity. The wind turns the blades, which spin a shaft, which connects to a generator and makes electricity. Utility-scale turbines range in size from 50 to 750 kilowatts. Single small turbines, below 50 kilowatts, are used for homes, telecommunications dishes, or water pumping. Wind turbines can be classified by the location in which they are to be used. Onshore, offshore, or even aerial wind turbines have unique design characteristics. The most common types of wind turbines are horizontal-axis wind turbines. Horizontal-axis wind turbines (HAWT) have the main rotor shaft and electrical generator at the top of a tower, and must be pointed into the wind. Small turbines are pointed by a simple wind vane, while large turbines generally use a wind sensor coupled with a servo motor. Most have a gearbox, which turns the slow rotation of the blades into a quicker rotation that is more suitable for generating electricity. Since a tower produces turbulence behind it, the turbine is usually pointed upwind of the tower. Turbine blades are made stiff to prevent the blades from being pushed into the tower by high winds. Additionally, the blades are placed a considerable distance in front of the tower and are sometimes tilted up a small amount. The most common modern wind turbines are usually three-bladed, sometimes two-bladed or even one-bladed (and counterbalanced), and pointed into the wind by computer-controlled motors. The rugged three-bladed turbine type has been championed by Danish turbine manufacturers. These have high tip speeds of up to 6x wind speed, high efficiency, and low torque ripple which contribute to good reliability. This is the type of turbine that is used commercially to produce electricity. The blades are usually colored light gray to blend in with the clouds and range in length from 20 to 40 meters (60 to 120 feet) or more.

Now that we know a bit of wind power history and how a wind turbine works, just how much wind is out there for us to harness? The answer is quite surprising - the total amount of economically extractable power available from the wind is considerably more than present human power use from all sources. An estimated 72 TW of wind power on the Earth potentially can be commercially viable, compared to roughly 15 TW average global power consumption, from all sources in 2005. However, not all the energy of the wind flowing past a given point can be recovered due to inefficiencies in wind turbines and inherent diseconomies of scale. For instance, the wind turbines at the back end of a wind farm will get less wind compared to the turbines in the front. Also, wind speed and direction are not constant, and even with computerized turbines it is impossible to always point the turbine directly into the wind for maximum efficiency. These are all factors constantly being looked at and improved on so one would expect wind turbine efficiencies to be much higher in the coming years.

So if the technology has been available for so many years, in some form or other, and the potential has been there since the earth was formed, why haven’t we taken advantage of this great power and become energy efficient a long time ago? Part of the answer I’m sure involves geo-political issues which cannot be easily identified or measured so we’ll focus on the more tangible facts, cost and practicality. One factor is that the cost of install capacity for wind farms is extremely high as are operation and maintenance costs. As a side note, politicians often tout the high operation and maintenance costs as a positive, calling it job creation, especially in the current economic downturn where unemployment is on the rise, claiming that one benefit of building new commercial wind farms is the creation of new jobs. This is true in the short run but in the long run these jobs are taking away employees from other fields which can be an issue in a tight job market, and it also means that wind farms will be expensive to operate, even after the expensive initial build. Because of the inherent inefficiencies mentioned earlier the typical capacity factors, for wind farms, are 20–40%, with values at the upper end of the range in particularly favorable sites. For example, a 1MW turbine with a capacity factor of 35% will not produce 8,760 MWh in a year (1 × 24 × 365), but only 1 × 0.35 × 24 × 365 = 3,066 MWh, averaging to 0.35 MW. Therefore, unlike fueled generating plants, such as coal fired or natural gas, which are largely dependent on high constant fuel costs, the capacity factor for wind farms is limited by the inherent properties of wind.

According to EWEA, the world’s largest renewable energy association, with over 200 members from over 40 countries, the power production costs of wind-generated electricity have fallen steadily as the technology has developed. The average cost for a coastal turbine has decreased from approximately 8.8 €cents/kWh (for a 95 kW turbine installed in the mid-1980s) to 4.1 €cents/kWh for a recent 1,000 kW machine A cost reduction of over 50% in the last 15 years has occurred for electricity from wind power. As a rule of thumb, manufacturers expect the production cost of wind power to decline 3-5% for each new generation of wind turbines they add to their product portfolio. Future cost reductions are a function of how the market grows. Looking forward, using analysis based on the “experience curve” method, it is anticipated that power production costs will continue to decrease. With a doubling of total installed capacity, the cost of production per kWh from new wind turbines will fall by between 9% and 17%. This is great progress, given that most countries have just recently started investing heavily in wind power.

So is this reduction in wind power costs good enough to allow it to compete with traditional fossil fuel energy sources? It all depends on whether or not you take into account the negative externalities created by the pollutants of fossil fuels. Many argue that since these externalities eventually end up costing citizens real money, then they should be taken into account. A Commission-funded project - ExternE – estimates that the cost of producing electricity from coal or oil would double and the cost of electricity production from gas would increase by 30 %, if external costs, in the form of damage to the environment and health, were taken into account. The study continues to estimate that these costs amount to approximately 1% to 2% of EU’s GDP, or between €85 billion and €170 billion, not including the cost of global warming and climate change. If those environmental costs were levied on electricity generation according to their impact, many renewables, including wind power, would not need any support. If, at the same time, direct and indirect subsidies to fossil fuels and nuclear power were removed, the need to support renewable electricity generation would seriously diminish or cease to exist. The total avoided external costs through the use of wind power amounted to nearly $2.8 billion in 2000. By 2020, taking EWEA projections for wind energy to be generating 425 TWh/a, the level of avoided external costs would have risen to an annual $32 billion. So obviously, if negative externalities were to be taken into account then wind power would be sustainable without government subsidies. Or if one were to take into account the billions of dollars of direct and indirect government subsidies to traditional fossil fuel industries, such as big oil companies, wind power again would be able to compete without any additional government subsidies.

A British Wind Energy Association report gives an average generation cost of onshore wind power of around 3.2 pence (between US 5 and 6 cents) per kWh (2005). Cost per unit of energy produced was estimated in 2006 to be comparable to the cost of new generating capacity in the US for coal and natural gas: wind cost was estimated at $55.80 per MWh, coal at $53.10/MWh and natural gas at $52.50. Other sources in various studies have estimated wind to be more expensive than other sources but one thing is clear, through research and development costs for wind power have been coming down considerably. In 2004, wind energy cost a fifth of what it did in the 1980s, and one would expect that downward trend to continue as larger multi-megawatt turbines are mass-produced. Installed cost averaged $1,700 a kW in 2007. Given that many facilities can’t produce large modern turbines and their towers and foundations, it will take a few years to further reduce the high installed cost.

If installed cost can be taken down further it will not be long before wind power can compete with fossil fuels on any level and in any market. The fact that wind power is perceived so positively by citizens it definitely has a fighting chance as politicians will look to please voters by budgeting billions of dollars to the development of wind farms. That is the key it seems, efficiencies of wind turbines will only increase while costs decrease if enough money is put into research and development. If cost has been driven down by 50% in 15 years, during which time most countries did not contribute substantial amounts of money toward the development of wind power, imagine what can happen in the next 15 years with most, if not all the developed nations, are throwing billions on top of billions of dollars to get this technology into mass production. It is very exciting to watch and even though in the short run the government will have to substantially subsidize wind power in order to make it feasible, it will be well worth it in the near future when we have cheap and clean energy and depend less on volatile countries to provide for our energy needs.

This brings up another issue however. The geo-political arena, especially in the Middle East, can become even more unstable if those countries were to lose or have their main source of income diminished. I’m speaking of oil of course and no one can predict what would happen in the Middle East if oil were to become too cheap due to a much lower demand. So the question is, would major governments around the world allow oil prices to come down in function of demand or would they prop them up to prevent destabilizing the Middle East even further? Nobody really knows but my guess is that the government would interfere somehow. All of these attempts to make us independent of Middle East oil could prove to be in vain should congress or the president step in and slow down the progress we are making toward an energy independent state. One thing is for sure however, it doesn’t hurt to at least have the infrastructure in place should we have the need to break away from our dependence of Middle Eastern oil. It will at least give us more negotiating power when it comes to negotiating peace or for better oil prices. It will be a good 10 or 20 years before the world develops mature enough alternative energy sources, and hopefully during that time we will have a much safer and friendlier middle east. I for one will be watching closely how alternative energy sources develop and grow around the world. I really hope the U.S. remains competitive and strives to be the leader in the fight to become energy independent.

- Maximilian Wilhelm

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