About wind power
An Engineer's opinion.
This discussion addresses the economic and engineering aspects of wind power only. Other considerations require a separate discussion. I have tried to make this as clear as I can without resorting to jargon. Electric power is a complex field and there are actually few colleges teaching power engineering these days.
The idea of wind power has enormous appeal. In theory, the fuel is free, it is a renewable resource and it’s use offsets an amount of fossil fuel. All of these things are, at least on the surface, true. However, the wind power proponents either ignore or gloss over the drawbacks to using wind power. There are many factors that make wind power – in practice – a very unattractive option from an engineering standpoint. I’ll address some of these, but first some basics.
Power 101
First, power must be generated. This can be accomplished by various means. Hydropower, natural gas fired turbine or combined cycle plants, coal fired plants and nuclear facilities. There are a few other ways, but they are usually very small (biomass, geothermal) or seldom used due to high fuel costs (oil) and will be left out of the discussion. Further, generating assets can be classified as base load, load-following or peaking.
Hydro requires a flow of water to turn a turbine. For this to work there must be sufficient head to turn the turbine. Simply put, there has to be a difference in height between the intake and discharge of the water used. Every readily usable source of hydro is currently in use in the US. To build additional plants would require the building of dams and flooding of large amounts of territory. Canada built some enormous hydro projects that flooded vast areas a few years back. This is not an attractive option in the US. Hydro plants are always considered base load units in that they are either full on or off-line. Base load constitutes the lower limit of demand on the power grid. Base loaded plants run at their maximum output and therefore at their maximum efficiency.
Gas turbines are simply jet engines coupled to a generator set. A typical use for this type of generator is as a “peaking” unit. That means that they fire when demand picks up to a point where on-line base load and load-following assets cannot cover demand. A combined cycle plant uses the waste heat from the jet engine exhaust to generate additional power via a heat exchanger. Steam produced by the heat exchanger drives a steam turbine and generates additional power. Combined cycle units can be used as either base load (rarely, due to high fuel costs) or load followers. Load following plants increase or decrease output as demand fluctuates above the base load. Load followers run at somewhat lower efficiency when running below full power.
Coal and nuclear plants use the same general principle. Fuel is used to heat water into steam. The steam is then used to turn a turbine which in turn spins the generator. Coal units burn the fuel in a boiler. Most of these plants use pulverized coal – essentially they grind the coal into a fine powder and blow it into the firebox. Nuclear plants use a chain reaction in the core to produce the necessary heat. Nuclear plants are always used as base load units nowadays (some plants were used as load followers initially, but none are used that way now as far as I am aware). Coal plants can be used either way, but usually bigger plants are used as base load units as much as possible due to efficiency concerns. Load following units can best be thought of as a supercharger on the system. They run at relatively low levels of power output until demand increases. When needed, they increase output to meet increased demand for power up to their maximum output. But the key point is that they have to remain on the grid, running at less than peak efficiency at all times to be available to respond to load changes. The peaker units would be brought in when the load following units near their peak output.
That is a very, very brief overview of generation.
Transmission and distribution
Once the electricity is produced, it has to be sent to where it is needed. This is accomplished through transmission and distribution. Transmission uses extremely high voltages in order to reduce “line losses”. Basically, as voltage increases, the current decreases; the lower the current, the less line heating and line loss. To accomplish transmission, voltages from the generating plant are “stepped up”- increased - to the transmission voltage by use of a transformer. The voltages have to be “stepped down” – reduced - at the other end of the line, requiring another transformer. Transmission voltages vary widely, but are always in the higher kilovolt ranges. Line losses are a big factor in deciding where plants need to be located. The farther away the plant is from the end user, the more the line loss is experienced. At some point, all of the electricity generated at a given plant will have been used up in line losses. (Transmission transformers are enormously large and expensive, by the way).
Distribution is accomplished by further stepping down the voltages, often several times, each step requiring another transformer. If you trace your power line back, you’ll see a transformer either on a pole or on the ground not far from where you live. Distribution system voltages vary widely until they reach the consumer. In the US, household use is always 120/240 volts. Industrial use is somewhat different and will be ignored for purposes of this discussion. The transmission/distribution network together with the connected generating assets is known as the grid. The grid is controlled by means of sophisticated load dispatch systems which increase or decrease generator outputs in response to demand.
That wraps up Power 101. Frankly, this is over-simplified, but if I really went into the more esoteric aspects, I would lose everyone but the engineers very quickly. These days, I’d likely lose a lot of them as well, since colleges have been teaching less and less about 3-phase power. Electric power is a rather complicated field.
Boiling everything down, then:
Power is generated, sent through wires and arrives at the point of use. The power supply must be able to respond to a change in demand, either increased or decreased demand, instantaneously. Electric power cannot be stored; it must simply be available when needed. Generating assets must be able to respond when demand changes. Base load units run at or very near full load at all times, load followers cycle up and down as needed and peakers kick in to meet high demand.
Wind power
Use of wind power can certainly offset a given amount of fossil fuel. This should be easy to understand. If you are getting electricity from a wind generator, you don’t need to burn a certain amount of coal or gas. This is a true statement. There are, however, certain problems with this logic.
First, the construction of wind generators requires enormous up-front capital costs. Typically, I have seen estimates that wind generators cost at lease 50% more than equivalent coal/gas installations. It’s actually higher than that due to some other factors regarding infrastructure (discussed below).
Construction of wind farms requires very, very large areas. Farms are being built that cover thousands of acres. The advocates of wind power are all for building these huge farms – as long as they are far away from where the advocates have to actually look at them. Why? Because these tower arrays are ugly. Well, I guess that’s dependant on who is looking at them, but I think they are unsightly. The residents of Martha’s Vineyard went ballistic when an offshore farm was proposed near them. The NIMBY effect rules in the planning of these farms. Hence, the farms tend to be sited far from the population centers where the power is most needed. This leads to increased line losses as discussed above.
In addition to the towers themselves, a vast infrastructure has to be built to connect all of those towers to the rest of the grid. This encompasses cable, towers or poles to carry the cable, transformers, switchgear and protective relaying. This amounts to a large expense and increases as more and more generating towers are placed. There is a definite impact to the environment and raw resources from all the manufacturing involved here. That impact is routinely ignored or downplayed by advocates of wind power.
Another problem with wind power is that the units tend to be full on when they are producing at all. This causes a problem in load dispatching. These wind power units cannot load follow, but are not reliable enough to use as base load units. Remember, base load is the lower limit which the grid must sustain. They also cannot be used as peakers. Most load dispatch systems I am familiar with somewhat reduce their load following plants output when wind power is available. But the load followers remain on line and producing ready to increase output when the wind power drops offline. So it is somewhat disingenuous to claim that wind power is replacing fossil generation. The fossil plants remain online albeit at a somewhat lower output. This lower output is accomplished at a somewhat lower overall efficiency. If you understand the modified Rankine Cycle that governs how power plants operate, you understand how this works.
Then there is the insurmountable engineering problem. The wind cannot be relied on to blow all the time within the operating parameters of the wind turbine. If the wind is not sufficient to turn the turbine blades no power is produced. If the wind is blowing too hard, the unit shuts down to protect itself and no power is produced. Therefore, the utilities are required to have 100% backup available for the wind generation because the power has got to be there when demand increases. Why? Because if the voltage is pulled down enough on the grid due to an increase in demand, the entire grid will collapse. Best case projections allow for wind systems to be available 35% of the time. Those projections are actually not accurate because they do not take into account time of day loading. In other words, the wind systems may be capable of producing power at night when demand is lowest, not during the day when it is most needed.
Basically, although some amount of fossil fuel is not used when the wind farms are actually on line, these projects can never be cost justified from an engineering standpoint due to the 100% backup capacity required. This is going to apply regardless of how high fuel prices go. There may be other justifications for construction of such a system, but the fact is that if one system is so unreliable that it requires a 100% (reliable) alternate backup, it makes no engineering sense to install the first system. Economically, you are spending more than double what you actually need to, to achieve the desired result.
This is an area I know rather a lot about, having spent my career in the utility business.
The installation of every, single utility-owned project has been a purely political decision. I limit it to utility-owned because that is my field. But it is no different for any other project.
Bottom line - wind power cannot ever be economically or engineering justified. Any system that is so inherently unreliable as to require an installed 100% backup system cannot be justified. If you were required to buy a car that would only run a percentage of the time and could start or stop at completely unpredictable random times, would you be happy? And then after buying that car, you were required to buy another fully functional one to cover the times the first was unavailable? On top of that, the second car has to be kept idling at all times to pick up when the first car drops out on you. Would that make any sense to you?
From a purely engineering standpoint, installing a reliable system to cover for an unreliable system is never justified. It is a waste of time and money. In engineering, you build the reliable system and scrap an unreliable one.
However, State and Federal laws, rules and political pressures have made many utilities invest in what they know to be a losing technology for no other reason than to gain points with regulators. I know - I have been there when the projects were approved. Every person in the room understood it was a complete and utter waste of money - but the regulators encouraged (or outright required it) it AND ALLOWED THE UTILITIES TO PASS THE COSTS THROUGH to the consumers. Hence, the company gets "good boy" points AND doesn't actually have to pay for anything at all. The environmentalists successfully taxed every one of you (and me) with a technology that just makes them feel warm and fuzzy all over.
These projects could never be built without subsidies. Wind power proponents lobby and pressure the Government into providing substantial subsidies for the construction of these facilities. So the taxpayers foot the bill to build the wind farms. The utilities are required to buy the power produced by privately owned wind farms – when they are actually on line – often at a higher price than they can produce power from their own facilities. And the utility has to build full, stand-by generating assets to be there when the wind power isn't. So it's a triple whammy and waste of resources. We pay to build the wind power sites, pay again to build 100% redundant fossil systems and pay higher rates for the power as well.
There may be other reasons for installing wind power, but those reasons are political and/or moral (depending on viewpoint). Any argument that these projects make economic or engineering sense is not realistic. That’s my opinion, based on many years of experience in the power field, as contrary as that is to environmentalist dogma on this issue.
This discussion addresses the economic and engineering aspects of wind power only. Other considerations require a separate discussion. I have tried to make this as clear as I can without resorting to jargon. Electric power is a complex field and there are actually few colleges teaching power engineering these days.
The idea of wind power has enormous appeal. In theory, the fuel is free, it is a renewable resource and it’s use offsets an amount of fossil fuel. All of these things are, at least on the surface, true. However, the wind power proponents either ignore or gloss over the drawbacks to using wind power. There are many factors that make wind power – in practice – a very unattractive option from an engineering standpoint. I’ll address some of these, but first some basics.
Power 101
First, power must be generated. This can be accomplished by various means. Hydropower, natural gas fired turbine or combined cycle plants, coal fired plants and nuclear facilities. There are a few other ways, but they are usually very small (biomass, geothermal) or seldom used due to high fuel costs (oil) and will be left out of the discussion. Further, generating assets can be classified as base load, load-following or peaking.
Hydro requires a flow of water to turn a turbine. For this to work there must be sufficient head to turn the turbine. Simply put, there has to be a difference in height between the intake and discharge of the water used. Every readily usable source of hydro is currently in use in the US. To build additional plants would require the building of dams and flooding of large amounts of territory. Canada built some enormous hydro projects that flooded vast areas a few years back. This is not an attractive option in the US. Hydro plants are always considered base load units in that they are either full on or off-line. Base load constitutes the lower limit of demand on the power grid. Base loaded plants run at their maximum output and therefore at their maximum efficiency.
Gas turbines are simply jet engines coupled to a generator set. A typical use for this type of generator is as a “peaking” unit. That means that they fire when demand picks up to a point where on-line base load and load-following assets cannot cover demand. A combined cycle plant uses the waste heat from the jet engine exhaust to generate additional power via a heat exchanger. Steam produced by the heat exchanger drives a steam turbine and generates additional power. Combined cycle units can be used as either base load (rarely, due to high fuel costs) or load followers. Load following plants increase or decrease output as demand fluctuates above the base load. Load followers run at somewhat lower efficiency when running below full power.
Coal and nuclear plants use the same general principle. Fuel is used to heat water into steam. The steam is then used to turn a turbine which in turn spins the generator. Coal units burn the fuel in a boiler. Most of these plants use pulverized coal – essentially they grind the coal into a fine powder and blow it into the firebox. Nuclear plants use a chain reaction in the core to produce the necessary heat. Nuclear plants are always used as base load units nowadays (some plants were used as load followers initially, but none are used that way now as far as I am aware). Coal plants can be used either way, but usually bigger plants are used as base load units as much as possible due to efficiency concerns. Load following units can best be thought of as a supercharger on the system. They run at relatively low levels of power output until demand increases. When needed, they increase output to meet increased demand for power up to their maximum output. But the key point is that they have to remain on the grid, running at less than peak efficiency at all times to be available to respond to load changes. The peaker units would be brought in when the load following units near their peak output.
That is a very, very brief overview of generation.
Transmission and distribution
Once the electricity is produced, it has to be sent to where it is needed. This is accomplished through transmission and distribution. Transmission uses extremely high voltages in order to reduce “line losses”. Basically, as voltage increases, the current decreases; the lower the current, the less line heating and line loss. To accomplish transmission, voltages from the generating plant are “stepped up”- increased - to the transmission voltage by use of a transformer. The voltages have to be “stepped down” – reduced - at the other end of the line, requiring another transformer. Transmission voltages vary widely, but are always in the higher kilovolt ranges. Line losses are a big factor in deciding where plants need to be located. The farther away the plant is from the end user, the more the line loss is experienced. At some point, all of the electricity generated at a given plant will have been used up in line losses. (Transmission transformers are enormously large and expensive, by the way).
Distribution is accomplished by further stepping down the voltages, often several times, each step requiring another transformer. If you trace your power line back, you’ll see a transformer either on a pole or on the ground not far from where you live. Distribution system voltages vary widely until they reach the consumer. In the US, household use is always 120/240 volts. Industrial use is somewhat different and will be ignored for purposes of this discussion. The transmission/distribution network together with the connected generating assets is known as the grid. The grid is controlled by means of sophisticated load dispatch systems which increase or decrease generator outputs in response to demand.
That wraps up Power 101. Frankly, this is over-simplified, but if I really went into the more esoteric aspects, I would lose everyone but the engineers very quickly. These days, I’d likely lose a lot of them as well, since colleges have been teaching less and less about 3-phase power. Electric power is a rather complicated field.
Boiling everything down, then:
Power is generated, sent through wires and arrives at the point of use. The power supply must be able to respond to a change in demand, either increased or decreased demand, instantaneously. Electric power cannot be stored; it must simply be available when needed. Generating assets must be able to respond when demand changes. Base load units run at or very near full load at all times, load followers cycle up and down as needed and peakers kick in to meet high demand.
Wind power
Use of wind power can certainly offset a given amount of fossil fuel. This should be easy to understand. If you are getting electricity from a wind generator, you don’t need to burn a certain amount of coal or gas. This is a true statement. There are, however, certain problems with this logic.
First, the construction of wind generators requires enormous up-front capital costs. Typically, I have seen estimates that wind generators cost at lease 50% more than equivalent coal/gas installations. It’s actually higher than that due to some other factors regarding infrastructure (discussed below).
Construction of wind farms requires very, very large areas. Farms are being built that cover thousands of acres. The advocates of wind power are all for building these huge farms – as long as they are far away from where the advocates have to actually look at them. Why? Because these tower arrays are ugly. Well, I guess that’s dependant on who is looking at them, but I think they are unsightly. The residents of Martha’s Vineyard went ballistic when an offshore farm was proposed near them. The NIMBY effect rules in the planning of these farms. Hence, the farms tend to be sited far from the population centers where the power is most needed. This leads to increased line losses as discussed above.
In addition to the towers themselves, a vast infrastructure has to be built to connect all of those towers to the rest of the grid. This encompasses cable, towers or poles to carry the cable, transformers, switchgear and protective relaying. This amounts to a large expense and increases as more and more generating towers are placed. There is a definite impact to the environment and raw resources from all the manufacturing involved here. That impact is routinely ignored or downplayed by advocates of wind power.
Another problem with wind power is that the units tend to be full on when they are producing at all. This causes a problem in load dispatching. These wind power units cannot load follow, but are not reliable enough to use as base load units. Remember, base load is the lower limit which the grid must sustain. They also cannot be used as peakers. Most load dispatch systems I am familiar with somewhat reduce their load following plants output when wind power is available. But the load followers remain on line and producing ready to increase output when the wind power drops offline. So it is somewhat disingenuous to claim that wind power is replacing fossil generation. The fossil plants remain online albeit at a somewhat lower output. This lower output is accomplished at a somewhat lower overall efficiency. If you understand the modified Rankine Cycle that governs how power plants operate, you understand how this works.
Then there is the insurmountable engineering problem. The wind cannot be relied on to blow all the time within the operating parameters of the wind turbine. If the wind is not sufficient to turn the turbine blades no power is produced. If the wind is blowing too hard, the unit shuts down to protect itself and no power is produced. Therefore, the utilities are required to have 100% backup available for the wind generation because the power has got to be there when demand increases. Why? Because if the voltage is pulled down enough on the grid due to an increase in demand, the entire grid will collapse. Best case projections allow for wind systems to be available 35% of the time. Those projections are actually not accurate because they do not take into account time of day loading. In other words, the wind systems may be capable of producing power at night when demand is lowest, not during the day when it is most needed.
Basically, although some amount of fossil fuel is not used when the wind farms are actually on line, these projects can never be cost justified from an engineering standpoint due to the 100% backup capacity required. This is going to apply regardless of how high fuel prices go. There may be other justifications for construction of such a system, but the fact is that if one system is so unreliable that it requires a 100% (reliable) alternate backup, it makes no engineering sense to install the first system. Economically, you are spending more than double what you actually need to, to achieve the desired result.
This is an area I know rather a lot about, having spent my career in the utility business.
The installation of every, single utility-owned project has been a purely political decision. I limit it to utility-owned because that is my field. But it is no different for any other project.
Bottom line - wind power cannot ever be economically or engineering justified. Any system that is so inherently unreliable as to require an installed 100% backup system cannot be justified. If you were required to buy a car that would only run a percentage of the time and could start or stop at completely unpredictable random times, would you be happy? And then after buying that car, you were required to buy another fully functional one to cover the times the first was unavailable? On top of that, the second car has to be kept idling at all times to pick up when the first car drops out on you. Would that make any sense to you?
From a purely engineering standpoint, installing a reliable system to cover for an unreliable system is never justified. It is a waste of time and money. In engineering, you build the reliable system and scrap an unreliable one.
However, State and Federal laws, rules and political pressures have made many utilities invest in what they know to be a losing technology for no other reason than to gain points with regulators. I know - I have been there when the projects were approved. Every person in the room understood it was a complete and utter waste of money - but the regulators encouraged (or outright required it) it AND ALLOWED THE UTILITIES TO PASS THE COSTS THROUGH to the consumers. Hence, the company gets "good boy" points AND doesn't actually have to pay for anything at all. The environmentalists successfully taxed every one of you (and me) with a technology that just makes them feel warm and fuzzy all over.
These projects could never be built without subsidies. Wind power proponents lobby and pressure the Government into providing substantial subsidies for the construction of these facilities. So the taxpayers foot the bill to build the wind farms. The utilities are required to buy the power produced by privately owned wind farms – when they are actually on line – often at a higher price than they can produce power from their own facilities. And the utility has to build full, stand-by generating assets to be there when the wind power isn't. So it's a triple whammy and waste of resources. We pay to build the wind power sites, pay again to build 100% redundant fossil systems and pay higher rates for the power as well.
There may be other reasons for installing wind power, but those reasons are political and/or moral (depending on viewpoint). Any argument that these projects make economic or engineering sense is not realistic. That’s my opinion, based on many years of experience in the power field, as contrary as that is to environmentalist dogma on this issue.
posted by Gaius Arbo | 3:18 PM
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