The Promise of More Efficient Solar Power

Technology Review of December 18, 2009 had an article entitled, Hot Electrons Could Double Solar Power. It's worth a little review of how solar photovoltaic cells work. A PV is essentially two layers of semiconductor material, one of which has an excess of electrons and the other a shortage of electrons. When a photon from the sun hits an electron, it dislodges it, sends it through a curuit, to the other side, creating electricity.

The article discusses how certain of these electrons respond to different wavelengths of sunlight. Some PV cells are adapted to one wavelength or another. In the blue light wavelength of the sun, the electrons have high energy, but it dissipates as heat before it can escape the cell and produce electricity. Researchers are finding ways to make the PV cell sufficiently thin and configured in such a way, as to take advantage of these "hot electrons" and produce much more electricity from a given surface area than the current state of the art of photovoltaics.

In my book, How to Tell a Btu from a BLT, I discuss in my chapter on solar energy the heat transfer mechanism by which the sun's heat is transmitted through the vacuum of space and the fact that PV cells have efficiencies ranging from 8% to 35%. The Technology Review article reports the promise of PVs with an efficiency of 67%. This is an enormous breakthrough in solar technology. It has an enormously positive impact on land use for central station generation using photovoltaics. Moreover, it brings distributed generation using photovoltaics one step further toward reality. One can imagine a the day when a significant portion of household power requirements come from a PV array on one's roof during the day (especially in the Southwest) and we rely on the grid at night. This would relieve a huge burden of building new generation and transmission infrastructure by the nation's electric utilities. But most amazingly, 67% efficiency is a twice the efficiency of the average coal or nuclear steam generating plant that exists today. Now that's progress!

Sunday New York Times - Solar Power That Blends In

Sunday's (9/27/09) New York Times (Sunday Business) - Solar Power, Without All those Panels is a very interesting advance in the use of photovoltaic cells and one I would like to see more use of. It seems to me that the use of solar power as a distributed generation alternative, rather than a central station alternative, is best use and best practices.

Home builders are including "building integrated photovoltaics" in roof tiles that will generate power directly into the home. The article provides an example of one product, installed in a California home, that will generate 2,400 kilowatt-hours per year for about 300 square feet of roofing tiles that contain photovoltaic cells. If you use about 1000 kilowatt-hours per month, this will reduce your consumption of central station power by 20%. That is a huge reduction in consumption and, if universally applied, would reduce the need for new power plants and transmission lines in the U.S. very significantly. It might also shift some of our electricity consumption from central station power plants from periods of peak consumption into off-peak periods because the solar roofs would be generating power when we need it most: at the peak time of day when the sun is shining, hottest temperatures and peak air conditioning consumption.

This fits very well with the concept I propose in my book (How to Tell a BTU from a BLT): Conservation Without Deprivation!

The Modular, Scalable Nuclear Reactor

Anyone who has been involved in the engineering design and construction of a new nuclear power plant will admit the process is long, risky (financially) and with too much government red tape and delays. They will also tell you that as a result, you only get one shot at building a nuke--so build it big. The latest crop of nuclear power plant designs are 1,100 MWe (Westinghouse/Toshiba) and an astounding 1,700 MWe (Mitshubishi Heavy Industries).

Along comes Babcock & Wilcox (a company well experienced in electric power and with a big nuclear design of its own when the first 104 U.S. Nukes were developed) with mPower, a modular, scalable nuclear plant that comes in sizes ranging from 125 MWe to 750MWe. These designs are safer than the existing fleet and the newer designs because the configuration is such that it eliminates the worst design basis accident that is postulated: the LOSS OF COOLANT ACCIDENT or LOCA. The existing fleet and the newer nuclear offerings have to be designed to withstand a break in the main piping that cools the reactor core--LOCA. Much of the regulatory angst and engineering challenges surround this hypothetical accident.

B&W's design is different. It is totally self contained and, therefore, does not include the system (Reactor Coolant Loop) that requires engineers to worry about its breaking. The other advantages are reduced regulatory requirements, only a three year construction cycle and a five year refueling cycle, meaning the utility only has to replace the nuclear fuel every five years, instead of every 18 months prevalent today.

The other obvious advantages are that smaller utilities can take advantage of nuclear power because it can be built in smaller, more affordable increments in much less time than the big units. In addition, it can be built in smaller pieces providing system flexibility. A small utility cannot afford to lose 1000 MWe of power when a plant has a forced outage if it only has a 4000 MWe system. So it can't build plants that are so big. However, if it can build 125 MWe or 25o MWe, the system can maintain its flexibility and reliabilty if a unit is forced out of service.

This is the type of nuclear plant innovation that will allow the U.S. to achieve the long process of weaning itself off of polluting fossil fuels.

Cafe Etiquette

Yesterday's WSJ Article ("No More Perks: Coffee Shops Pull the Plug on Laptop Users" ) discusses shop owners' frustration with loitering laptop users who take advantage of free electricity and WiFi while buying nothing and displacing paying customers.

It points up how oblivious we all are to our use of energy both direct and indirect. When we use the internet we either have a desktop plugged in, a laptop we have had to charge up or some other portable device that also had to be charged. But we speak with forked tongue: We speak conservation and renewables out of one side of our mouths and banter about this great, energy consuming technology out of the other side.

Remember, the internet isn't in the airwaves because angels deliver it on splendid wings. There are servers, mountains of servers, all over the world that provide us with the internet. And they require power. Lots of it. Moreover, those servers have to be cool. And I don't mean wearing a pair of Ray-Bans, a spiffy hat with a cigarette dangling. Those servers need air conditioning all of the time.

Here's the point: the small things we do mindlessly, consume energy constantly. And no matter how conservation minded we would like to be, are we really willing to give up the pleasure and utility of modern technology. Laptop users consume a shopowner's electricity and WiFi because it's "free" but it should be as carefully conserved as if it were your own. The proprietor meets his overhead by selling food and drink; the freebies are an inducement to buy.

So, I'll quote the wisdom of my literary agent, Amanda Mecke: "There is no free lunch --- or electricity anywhere."

CONGRESS RESTORES FUNDING FOR HYDROGEN FUEL CELLS

Finally, some sanity from the Congress. Steven Chu, Secretary of Energy, killed fuel cell research a while back. Now it has been restored (MIT Technology Review: Hydrogen Fuel Cell Funding Restored) by the legislature, you know, that bicameral body that sits in session on our behalf in the District.

Secretary Chu prefers biofuels and better batteries, but that is not mainstream thinking. Thinking long into the future, hydrogen-based fuel cells make a lot of sense. In the interim, fossil fuel-based fuel cells--methanol for automotive propulsion and diesel and natural gas (among others) for stationary fuel cells--should be aggressively developed by Dr. Chu and the DOE.

There will come a day when planet earth can yield up no more hydrocarbons. Our planet is finite. At that time, the hydrogen-based fuel cell (hydrogen cracked from water), fully developed and ready to go, will displace the interim technology. We need to be fully prepared for the hydrogen future--a world in which all electricity is generated by nuclear power plants and all hydrogen comes from the oceans. A time when there is no measurable air pollution, greenhouse gases and the insidious effects of mercury and arsenic from burning coal.

And thank you to Amanda Mecke, my literary agent, for kindly passing on this article to me.

China Outpaces U.S. in Cleaner Coal-Fired Plants

My literary agent, Amanda Mecke, sent me an article with the same title as this blog post. The essence of it is the following quotations:

"While the United States is still debating whether to build a more efficient kind of coal-fired power plant that uses extremely hot steam, China has begun building such plants at a rate of one a month."

"With greater efficiency, a power plant burns less coal and emits less carbon dioxide for each unit of electricity it generates. Experts say the least efficient plants in China today convert 27 to 36 percent of the energy in coal into electricity. The most efficient plants achieve an efficiency as high as 44 percent, meaning they can cut global warming emissions by more than a third compared with the weakest plants."

What they are talking about is supercritical (extremely hot steam) coal fired plants and the quotations are true. I am currently, personally involved in financing two of these plants in the United States. The problem is twofold: (1) The Congress has put a moratorium on the financing of Coal Fired Plants by the Department of Agriculture's Rural Utility Service. This prevents Rural Ekectric Cooperatives in this country from accessing government loans to build these coal fired plants. That's why I am involved, providing private funds to finance what the government (led by Harry Waxman) will not. (2) Most of those in the government making these decisions do not know the difference between a conventional coal fired plant and a supercritical one.

The average coal unit in the U.S. has about a 33% efficiency. Increasing efficiencies to 44%, as the article states, would eliminate one third of all of the carbon dioxide emitted by the existing coal plant fleet.

That means we can have it all: Coal fired power plants with less pollutants across the board. All we need in our government is knowledge, reason, cooperation and less dogma from radical environmentalists. This can transition the U.S. over a reasonable period of time to non-polluting (or much less polluting) technologies.

NY Times: U.S. Drops Fuel Cell Research

"Developing those cells and coming up with a way to transport the hydrogen is a big challenge, Energy Secretary Steven Chu said in releasing energy-related details of the administration’s budget for the year beginning Oct. 1. Dr. Chu said the government preferred to focus on projects that would bear fruit more quickly."

The above quotation from the Times of May 7th demonstrates how misguided and disconnected bureaucrats and elected officials are from the real world of energy. Transporting hydrogen has never been a good idea. Why are they even thinking about it?

On March 9, 2009, only two months ago, the following news was released by the Department of Energy:

"Solid Oxide Fuel Cell Successfully Powers Truck Cab and Sleeper in DOE-Sponsored Test
DOE, Delphi, Peterbilt Join to Test Auxiliary Power Unit for Commercial Trucks"

The fuel cell was constructed by Delphi Corporation and ran on straight-from-the-pump diesel fuel. The release went on to say, "The unit is compact and can be configured to use natural gas, bio-diesel, propane, gasoline, coal-derived fuel, or military logistics fuel."

If Dr. Chu and our government would like to focus on projects that will bear fruit more quickly, they need to start paying attention to their own research apparatus at the DOE and the money tax payers are spending on this really outstanding research.

The current liquid fuels transportation infrastructure can support fuel cells run on methanol and diesel. This is the future of automotive propulsion.

How Many Windmills Does It Take?

In the last post, we estimated that the U.S. would need to double (more or less) the electric generating capacity, 1,000,000MW, in order to power a fleet of 135,000,000 electric cars. Remember, we left out trucks and buses.

Currently, at the end of 2007 there was about 15,600MW of wind generating capacity. Let's estimate, for argument's sake, that at the end of 2008 there was 20,000MW of wind capacity in the U.S. So how many windmills would it take to charge 135,000,000 automobiles?

Let's orient ourselves with some criteria. There are a number of wind turbine sizes available from manufacturers but for our purposes let's assume that we use the largest size--2.5MW. We also assume that each of these wind turbines is running full tilt (no pun intended) during the six hours we're charging the fleet. The fleet is charged at the same time of day, let's say overnight, and that there is sufficient wind to run the turbines at maximum output. None of this is realistic but we're trying to estimate an order of magnitude.

So, how many? Simplistically: 1,000,000MW divided by 2.5MW per turbine results in 400,000 new wind turbines. If we assume our existing fleet were composed of 2.5MW turbines (which it is not), we would have approximately 8000 wind turbines (20,000 divided by 2.5). There are more wind turbine units in the country because the original sizes were smaller, so it could be 2 or 3 times that number. A truly national study of the number of units required might be significantly larger to account for all of the changing variables.

The point is this: there is no time soon or possibly ever that the U.S. will increase the number of wind turbine units by one or two orders of magnitude. Not feasible.

Of course, one could argue that wind turbines are only one source of renewable energy that could be used, and I concede that. But we could make similar calculations for all of the renewable energy sources combined--and as much as we all would like it to--it's just not going to get us there. Moreover, as I argued in a previous post, electric cars are too inefficient and the infrastructure to support them too capital intensive to pursue this ill advised course. It's not sustainable.

The realistic solution in a future post.

Electric Cars: The Electric Infrastructure Required

My literary agent passes on articles to me (She's really helpful.) from time to time and I like to comment on them here. I do this to illustrate and quantify people's qualitative assessments. Back in February I wrote a post about electric cars and suggested that the electric generating infrastructure required should be examined very carefully. So let's do a little quantitative examination of the infrastructure required.

First, let's establish some facts. There are 17,342 electric generators in the U.S. and they have a nameplate capacity of approximately 1,000,000 Megawatts. A Megawatt equals 1,000,000 Watts or 1000 kilowatts. There are 244 Million motor vehicles in the U.S., 135 Million cars and the rest are trucks and buses.

Let's set some design criteria to size our infrastructure. First, I want my infrastructure to be built in phases. So I'm only going to design and build enough power plants, transmission lines and distribution lines to charge and power 135 Million automobiles. We'll deal with the trucks and buses later. In addition, let's size the electric car's motor and let's be realistic. A Honda Civic has a 140 horsepower engine which amounts to a 104kW electric motor. That's realistic. Phoenix Motorcars of Ontario, California provides its SUT/SUV vehicle specifications that I think are realistic. The top speed is 95 miles per hour; it can travel 100+ miles per charge; in can go 0-60 in less than 10 seconds and it requires 6.6 kilowatts for a five to six hour charge. The motor is 147 horsepower or 110 kW. Torque is 369 ft-lbs.

So how much additional power would the U.S. require to instantaneously power all of these vehicles. The utilities that provide electricity to each of us must design and build enough power stations to supply the peak load plus a reserve or capacity margin. The margin is an amount of oversupply in case power plants have an unanticipated outage and avoids blackouts. It's why power in the country is available virtually continuously.

Let's calculate the instantaneous additional power required:

135,000,000 x 6.6 kilowatts = 891,000,000 kilowatts or 891,000 Megawatts.

When one adds a 15% capacity margin, the figure increases to 1,024,650 Megawatts, doubling existing electric generating capacity in the U.S. I have personal, hands-on experience as an engineer and a banker in the construction of power plants. It is a vastly massive undertaking. The people who do it routinely in this country are unknown and unsung . . . except by me, of course, and I have high respect for them and high regard for their skill.

Of course this is an instantaneous figure. It assumes we're all plugged in at the same time. It does not account for time zones, different driving characteristics, different characteristics of the many utility service territories in the country, different size vehicles, different battery technology, and the current overall utilization rate of existing power plants, etc., but it is in the ballpark. One can argue one way or another that it's three quarters of that figure or 50% greater. But it is huge. It is extremely costly. And I haven't begun a discussion of the transmission lines, and the opposition to building them, that would be required as well.

In the next post, we'll take a look at how many power plants would be required and how much electricity renewable energy would need to generate to power the theoretical electric vehicle fleet of the future.

Fuel Cell Catalysts: The Inexpensive Alternative

My literary agent was kind enough to send me an article on the potential replacement of platinum as a reactive catalyst in fuel cells, replacing it with an iron and carbon-based alternative. Commercialized, this would be an extreme breakthrough in the state of the art of the fuel cell. Since I am currently writing the chapter on fuels cells for my book (Energy: The Primer How to Distinguish a BTU From a BLT), it was apropos.

A fuel cell creates electric energy without combustion. Rather, a chemical reaction breaks apart the fuel, likely hydrogen, although other fuels can be used, and sends the electrons through an electric circuit. This can drive a car motor or any electrical device. The electron then recombines with its hydrogen nucleus and air, forming water out the tail pipe.



Source: http://www.p2sustainabilitylibrary.mil/issues/emergeoct2005/index.html

There are two important points about fuel cells: (1) They create little or no pollution and (2) They are much more efficient than the internal combustion engine. A Proton Exchange Membrane (PEM) fuel cell, like the one pictured above, can achieve efficiencies of up to 45%, nearly twice that of the internal combustion engine. PEM fuel cells operate at low temperatures, 150 to 200 degrees Fahrenheit. Other types of fuel cells operate at temperatures up to 1800 degrees, making them candidates for combination with a steam cycle (rankine cycle, similar to today's combustion/steam turbine combined cycle power plants) and achieving efficiencies of 60% to 80%.

The fuel cell is not new but it is our future. It is the reason people can travel through and live in space because it provides electricity and water. It's applications are endless from locomotion to distributed generation to stationary power plant applications. It will reduce pollution dramatically and fuel consumption in all applications by 50%. Imagine, a fuel cell propelled car routinely getting 40 to 50 miles per gallon and power plants with twice the efficiencies they average today.

This is where U.S. energy policy should lead us. If I were president . . . .

Smart Grid

A smart grid is more than smart. It can be entertaining too. Utilities look at their wires in the most utilitarian way. You see, Broadband Over Powerlines is a real technology that can give utilities much more information about and control over the grid.

Think of the simplest things. What if the utility stopped burning gasoline, tires and shoe leather to read your meter each month. Wouldn't it be simpler to install a chip in your electric meter that is the same one on your cell phone? All it has to do is call the billing office once per month, report the kilowatt-hours you've used and send you a bill. That's smart. Or . . . just send the data back over the power lines to the billing office.

During blackouts it is sometimes difficult for utilities to pinpoint every home without power. What if the cell phone in the meter had a battery backup and called the utility office to report it was not getting power. Simple.

But there is more that a smart grid can do. It can provide continuous feedback to the utility about power usage throughout the day and night. Possibly avoiding widespread blackouts during peak times by doing rotating load shedding. It can provide you with time of day pricing. You want to run the dishwasher or washing machine after 10:00 p.m.? You can have a discount.

But there's more. Broadband over power lines can provide entertainment. Cable, telephone and internet services can be brought in over power lines. Imagine, every electric plug in your home can be a broadband data port and provide you with many services competitively.

It would be nice to have a little competition for your entertainment dollar, rather than the monopolies that control them now. Wouldn't it?

SUSTAINABILITY

We hear this word from time to time, so I thought we would examine it further. Apples, they're sustainable. Oranges too. Crops in general, barring some catastrophic event, are sustainable. It means we can perpetuate something, virtually forever.

However, with respect to energy,we are not currently in sustainable mode. The United States and the rest of the world have vast supplies of fossil fuels. They will last hundreds of years, maybe more. But they're not sustainable. We cannot perpetuate them beyond their finite limits, notwithstanding their abundance.

So, what is sustainable? Certainly, hydroelectric power is sustainable, assuming it continues to rain in some catchment basin forever. Wind power is sustainable, presuming the wind will blow forever. This too is a good assumption. Will the wind blow when you most need it is still up in the air. Solar power is certainly sustainable, at least for the five billion years of sunlight we have left. It presumes we have sufficient materials to continue to build solar collectors and photovoltaic cells. This is also a good assumption for the foreseeable future. But the sun shines on its own terms.

That's supply side sustainability. And at the moment with current technology the sustainability of these wonderful resources will not provide sufficient energy to displace fossil fuels long into the future . . . and maybe never. I'm not any happier than anyone else about that, but realism when it comes to sustainability is no vice. Paraphrased and stolen from, possibly, Cicero.

Unfortunately, we don't have enough demand side sustainability. Maybe I should say that the other way around. We have too much demand side sustainability. As a society, we constantly, almost mindlessly, sustain our demand for energy. Think of it in terms of two statistics: population growth and consumptive growth. Nothing is static.

There are seven billion people on planet earth. In one hundred years, who knows, that could increase by fifty percent. I didn't look up the estimates. Doesn't matter. All of those people will use energy. They're not going to sacrifice. In terms of growth in consumption, just look at yourself and others around you. Be honest. Desktop? Laptop? Blackberry? Cell phone? More than one? Digital camera? LCD or Plasma TV? Shall I go on?

Let's take something simple, like the digital camera. Are you willing to go back to using 35 millimeter film in a single lens reflex camera ? I date myself. The SLR didn't require a charge and only needed a battery for the flash. And a little flat battery for the light meter that lasted for years. Is such a thing even available any more, except on Ebay?

People are not willing to go backwards, no matter how many of us vocalize for sustainability. But there is an energy source that is sustainable and possibly forever, as best one can determine that period of time. I refer to the nuclear fast breeder reactor. This reactor actually creates more fuel than it uses. It can perpetuate the current known stock of uranium by 100 fold. And if we use the vast amounts of uranium that are in the sea, it is as close to sustainability as one can get with the population and consumption growth we experience.

Is this easy? No. Does it require resolve? Indeed. Is it a more plausible goal with the cooperation of the world's governments? Of course. Is there risk of proliferation? There is. But there are risks in everything we do. And when it comes to energy, it's all dirty in one form or another. No matter what technology we use, it creates something to clean up after. The question is do we run after tens of billions of annual tons of pollutants in the atmosphere? Or do we deal with a football field's worth of nuclear spent fuel and reprocessing risk over a long period of time? Let me know?

The Invincible Ignorance of Government Officials

Ian Bowles, the secretary of energy and environmental affairs for the State of Massachusetts contributed an Op-Ed piece to the New York Times yesterday, March 6, 2009. After reading it, I had that sinking feeling in my stomach when I hear yet another government official get it wrong. Let’s tackle some major points one by one.

It’s admirable that President Obama would like to double renewable energy in three years. But it’s not likely. In three years, we’ll see. But let’s be realistic. There is just not enough renewable energy to double renewables (including hydroelectric power) from the current 7% of total energy consumed to 14% in that time period. Currently, coal contributes 22% of all energy consumed, mostly for electric power generation, and that represents 49% of all of the electricity generated in the United States. Are we really going to produce enough renewable energy in three years to essentially displace one third of the billion-plus tons of coal we burn each year? Natural gas represents 23%, petroleum 40% and nuclear power is 8% of all energy consumed. Biomass and hydroelectric power represent 89% of the 7% of renewables that we consume now. Government officials have to start reading their own government’s statistics produced by the Department of Energy (DOE) and the Energy Information Administration (EIA) before they spout this blather. In 2030 the EIA estimates that non-hydroelectric renewable energy will account for about 8% of all the energy consumed in the U.S.

There is a lot of hot air coming out of Washington and state capitals about renewables but let’s be factual. Ian Bowles wants offshore wind but it has been no easy task for developers to build a wind project off the coast of Massachusetts in Nantucket Sound. Opposition from Senator Kennedy and others have delayed this project. And the Long Island wind project was buried because Long Islanders just didn’t want to look at wind mills that were 400 feet tall and had a 400 foot wing span. Moreover, Mr. Bowles and others like him promote hydroelectric plants, but try getting one built in this country. There is no more big hydro coming because of objections ranging from fish spawning, recreational use of rivers, water usage fights, silting and huge water impoundments that submerge vast amounts of real estate along with the towns and people displaced by the deluge. There were protests in the states over the Three Gorges project in China. Everyone wants renewable energy until you start using vast amounts of their land near to where they live.

Mr. Bowles doesn’t like large transmission lines. He says that transmission losses “gobbles up an estimated 2 percent to 3 percent of electricity nationally.” First, let’s get this straight: Transmission and Distribution losses gobble up as much as 9% of the electricity generated at the power plant. That’s just a fact and it has not prevented us from building transmission in the past and it will not do so in the future. I commend to Mr. Bowles the EIA’s Annual Energy Review 2007, page 221, footnote “f”. It’s right there in the fine print. We need big transmission for important reasons. People do not want to live near power plants, so they are more often than not in more remote areas. We have to transmit that power to the load center. Moreover, more transmission lines will de-bottleneck the very inadequate electric transmission system in the country and reduce the need for additional generation. That means less fuel burned, less pollutants in the air and less carbon dioxide. I also commend to Mr. Bowles the "National Electric Transmission Congestion Study" produced by the DOE in August 2006.

The final point I’ll address is cap and trade. This is tantamount to a tax on all of us because the extent to which we burn fossil fuels, all of which contain carbon to one extent or another, will not be reduced for decades. And they will only be reduced in any significant way if we have a comprehensive (non-political) energy policy with real teeth. EIA’s statistics for all energy use that I quoted above show us that 85% (coal: 22%, natural gas: 23%, petroleum: 40%) of all energy used comes from carbon-producing fossil fuel. The cap and trade tax is a pretext. It will not reduce carbon any time soon but it will burden all of us, especially the least capable among us of paying it, with more taxes that our central government can waste. It's just taxes gussied up to look like something else.

With respect to an energy policy with teeth, if I were president . . . .

Electric Car Charging in San Francisco

There is an article (http://www.physorg.com/news154288469.html) encouraging the use of electric charging stations in San Francisco as a way of cleaning up inner city air. My first thought is that I spend time in San Francisco occasionally and I find the city to be very clean, without any intrusion on my senses. Moreover, I work in New York City each day and I have spent my entire life in that city, having been born, raised and employed there and no where else. NYC is light years better in terms of air quality than it was when I was a boy.

But let's look at electric cars realistically. From the standpoint of efficiency, they're not better than the traditional internal combustion engine. Each car must be charged with electricity generated at a central station power plant. The average steam electric generating station in the U.S. is about 33% efficient. So two thirds of the energy used to generate a Kilowatt-hour is gone before it leaves the plant. In addition, losses on the transmission and distribution system (the wires that carry power) amount to up to 10% and the drive train of the vehicle, motors, electric power quality, etc. will likely reduce efficiency by a similar amount. Those additional reduction in efficiency, another 20%, reduces the electric car efficiency to around 26%. This is not much better than the internal combustion engine.

One can argue that we are reducing pollution. But are we? Or are we really displacing pollution. Every fossil-fuel burning power plant emits pollution of various kinds and amounts depending on the fuel used. What we do not endure from a tail pipe we still endure from a power plant stack. One can also argue that it's easier to control pollution from thousands of power plants rather than millions of cars and with that I agree. But is displacing the emissions from your vehicles to another community for the sake of your own air really fair?

Before the U.S. embarks on an all out electric car phase, the amount of infrastructure both in terms of power plants and millions, tens of millions, of charging stations should be examined very, very carefully. There has to be a benefit associated with the huge cost, not just the illusion of pollution reduction. Plus, if there's a black out, especially an extended one like the 2003 blackout of a large swath of the U.S., how will cars be charged? Is this potentially a national security issue?

There is a better way at this. One that is more efficient and ultimately pollution free. But that's for a future blog post.

Sun + Fossil Fuel = Efficiency

I read an article (http://www.technologyreview.com/energy/22080/page1/) about how about using the heat of the sun can boost the efficiency of existing fossil fuel power plants. I thought this was an interesting concept to explore.

One type of power plants that is prevalent is called a combined cycle plant. It uses two different types of engines (cycles) to create electricity. One cycle is a combustion engine called a gas turbine or combustion turbine (Brayton Cycle) and the other is a steam engine or steam (Rankine) cycle. It is represented by the graphic (Source: Texas Utilities).

Let’s explain what’s going on here and how adding solar energy can improve the engine’s efficiency. Think of the Gas Turbine Cycle above as if it were an aircraft engine, which are also gas turbines. As you can see this engine drives an electric generator to create electricity. The exhaust gases from this engine are very hot, and if allowed to escape to the atmosphere, will dissipate and be of no use.

However, power plant designers have devised a way to capture and reuse this waste heat by running it through a boiler and powering a steam turbine cycle, represented at the bottom portion of the graphic above. Combined Cycle Power Plants are currently the most efficient way to create electricity.

So, how do we introduce the sun into this mix? In some combined cycle power plants, the boiler in the steam cycle is capable of being fired with additional fossil fuel, usually natural gas. This boosts the output of the plant during the peak times of the day when electricity use is at its highest. However, because it is firing additional fuel to obtain the increased output, it will usually be less efficient to do so. So why do it? The price of power is higher at the height of electric use or peak time of the day, so it is worthwhile to have reduced efficiency for additional plant output. Using heat provide by a solar collecting array eliminates the need for the additional fossil fuel.

Although sunlight may be free, the technology that turns sunlight it into steam is not. The power plant will have to build and pay for the solar array, but, as a result, over time the plant will produce more energy when it is most needed at a more predictable cost rather than the volatile and unknown expense of the displaced fossil fuel long into the future.