Showing posts with label hydrogen. Show all posts
Showing posts with label hydrogen. Show all posts

Saturday, January 5, 2008

Scientists split CO2 into CO and hydrogen

Researchers at Sandia National Laboratories in New Mexico have designed a a solar reactor to recycle carbon dioxide and produce fuels like methanol or gasoline.

The solar reactor contains 14 cobalt ferrite rings, each about one foot in diameter and turning at one revolution per minute. As an 88-square meter solar furnace blast sunlight into the unit, the rings heat up to about 2,600 degrees Fahrenheit. At that temperature, cobalt ferrite releases oxygen. The rings subsequently cool to about 2,000 degrees and are exposed to CO2. The cobalt ferrite, which is now missing oxygen, will take oxygen from the CO2. So, the reactor divides carbon dioxide into carbon monoxide and oxygen, leaving behind just carbon monoxide. With the cobalt ferrite restored to its original state, the reactor is ready for another cycle.

That carbon monoxide can then be used to make methanol or gasoline, which are essentially just combinations of hydrogen and carbon.

Scientists Use Sunlight to Make Fuel From CO2
http://www.wired.com/science/discoveries/news/2008/01/S2P

Cheers!
Sam Carana

Thursday, October 25, 2007

Combat Global Warming with Evaporative Cooling

Combat Global Warming with Evaporative Cooling - by Sam Carana

To combat global warming, wind turbines along the coastline could be used for the dual purposes of generating electricity at times when there is wind and evaporating water at times when there is no wind. Just a small breeze over the water can give the top water molecules enough kinetic energy to overcome their mutual attraction, resulting in evaporation of water and associated cooling of both water and air.

Such dual use of wind turbines can be implemented at many places where turbines overlook water; evaporation will work most effectively in hot and dry areas, such as where deserts or dry areas meet the sea or lakes. Evaporative cooling will add humidity to the air, which can also cause some extra rain and thus increase fertility of such dry areas as a beneficial side effect.

The energy needed to run the turbines can be obtained and stored in a number of clean, safe and renewable ways. ]

At times when there is plenty of wind, surplus energy from the turbines could be used to convert Water into hydrogen by means of electrolysis. Alternatively, bio-waste could be burned by means of pyrolysis to create both hydrogen and agrichar, which could be used to enrich soils. The hydrogen could be kept stored either in either compressed or liquid form, ready to power fuel cells that can drive the turbines at any time, day or night.

Another alternative is to run the turbines on electricity from concentrated solar thermal power plants in the desert. A desert area of 254 km² would theoretically suffice to meet the entire 2004 global demand for electricity. Ausra offers a solar thermal technology that uses the sun's heat to generate steam, which can then be stored for up to 20 hours, thus providing electricity on demand, day and night. Ausra points out that just 92 square miles of solar thermal power facilities could provide enough electricity to satisfy all current US demand.

Finally, there are some environmental concerns about wind turbines. There are concerns about carbon dioxide being released into the atmosphere in the process of making the concrete for the turbines. To overcome this, turbines could be made using alternative manufacturing processes, which can be carbon-negative. Furthermore, a recently completed Danish study using infrared monitoring found that seabirds steer clear of offshore wind turbines and are remarkably adept at avoiding the rotors.

In conclusion, wind turbines have a tremendous potential. They can potentially generate 72 TW, or over fifteen times the world's current energy use and 40 times the world's current electricity use. Offshore and near-shore turbines can make seawater evaporate and thus cool the planet, at times when they are not used to generate electricity.


References:


Ausra
http://ausra.com/

Wind power - Wikipedia 

Monday, October 15, 2007

Agrichar

Bio-char pellets, EpridaMost households only use one or at most two different rubbish bins, one for recyclables (paper & packaging) and one for general waste. It makes a lot of sense to add a third type of rubbish bin, for biowaste, i.e. kitchen waste, soil and garden waste.

Many people already compost such biowaste in the garden, but all too often such biowaste disappears along with the general waste in the rubbish bin. As displayed on the picture below, analysis in Waikato, New Zealand, shows that about half of household waste can consist of kitchen waste, soil and garden waste. Such waste ends up on rubbish tips, where the decomposing process leads to greenhouse gases, such as methane. And all too often, farmers burn crop residues on the land, resulting in huge emissions of greenhouse gases.

What we throw away, Waikato, New ZealandAll such biowaste could deliver affordable energy by using the slow burning process of pyrolysis to produce agrichar or bio-char, a form of charcoal that is totally black. Organic material, when burnt with air, will normally turn into white ash, while the carbon contained in the biowaste goes up into the air as carbon dioxide (CO2). In case of pyrolysis, by contrast, biowaste is heated up while starved of oxygen, resulting in this black form of charcoal.

This agrichar was at first glance regarded as a useless byproduct when producing hydrogen from biowaste, but it is increasingly recognized for its qualities as a soil supplement. Agrichar makes the soil better retain water and nutrients for plants, thus reducing losses of nutrients and reducing the CO2 that goes out of the soil, while enhancing soil productivity and making it store more carbon.

When biowaste is normally added to soil, the carbon contained in crop residue, mulch and compost is likely to stay there for only two or three years. By contrast, the more stable carbon in agrichar can stay in the soil for hundreds of years. Adding agrichar just once could be equivalent to composting the same weight every year for decades.

Agrichar appears to be the best way to bury carbon in topsoil, resulting in soil restoration and improved agriculture. Agrichar has the potential to remove substantial amounts of CO2 from the atmosphere, as it both buries carbon in the soil and gets more CO2 out of the atmosphere through better growth of vegetation. Agrichar restores soils and increases fertility. It results in plants taking more CO2 out of the atmosphere, which ends up in the soil and in the vegetation. Agrichar feeds new life in the soil and increases respiration, leading to improvements in soil structure, specifically its capacity to retain water and nutrients. Agrichar makes the soil structure more porous, with lots of surface area for water and nutrients to hold onto, so that both water and nutrients are better retained in the soil.

In conclusion, recycling biowaste in the above way is an excellent method to produce hydrogen (e.g. for cars) and to bury carbon in the soil and improve production of food. Agrichar is now produced for soil enrichment at a growing number of places. The top photo shows agrichar in pellet form from Eprida. Australian-based BEST Energies has built a demonstration pyrolysis plant with a capacity to process 300 kilograms of biowaste per hour. It accepts biowaste such as dry green waste, wood waste, rice hulls, cow and poultry manure or paper mill waste. The plant cooks the biomass without oxygen, producing syngas, a flammable mixture of carbon monoxide and hydrogen. The agrichar thus produced retains about half the carbon of the original biowaste (the other half was burned in the process of producing the syngas).

Also important is to compare different farming practices. Carbon is important for holding the soil together. Farmers now typically plough the soil to plant the seeds and add fertilizers. This ploughing causes oxygen to mix with the carbon in the soil, resulting in oxidation, which releases CO2 into the atmosphere. Ploughing leads to a looser soil structure, prone to erosion under the destructive impact of heavy rains, flooding, thunderstorms, wind and animal traffic. Given the more extreme weather that can be expected due to global warming, we should reconsider practices such as ploughing.

Furthermore, the huge monocultures of modern farming have become dependent on fertilizers and pesticides. The separation of farming and urban areas has in part become necessary due to the practice of spraying chemicals and pesticides. Instead, we should consider growing more food on smaller-scale farms, in gardens and greenhouses within areas currently designated for urban usage. Vegan-organic farming can increase bio-diversity; by carefully selecting complementary vegetation to grow close together, diseases and pests can be minimized while the nutritional value, taste and other qualities of the food can be increased.

An issue of growing concern is nitrous oxide (N2O), which is 310 times more potent than CO2 as a greenhouse gas when released in the atmosphere. Much release of N2O is related to the practices of ploughing and adding fertilizers to the soil. Microbes subsequently convert the nitrogen in these fertilisers into N2O. A recent study led by Nobel prize-winning chemist Paul Crutzen indicates that the current ways of growing and burning biofuel actually raise rather than lower greenhouse gas emissions. The study concludes that growing some of the most commonly used biofuel crops (rapeseed biodiesel and corn bioethanol) releases twice the amount of N2O, compared to what the International Panel on Climate Change (IPCC) estimates for farming. The findings follow a recent OECD report that concluded that growing biofuel crops threatens to cause food shortages and damage biodiversity, with only limted benefits in terms of global warming.

All this is no trivial matter. Soils contain more carbon than all vegetation and the atmosphere combined. Therefore, soil is the obvious place to look at when trying to solve problems associated with global warming. By changing agricultural practices, we can add carbon to the soil and can minimize release of greenhouse gases.

References:

- Soils offer new hope as carbon sink
http://www.dpi.nsw.gov.au/research/updates/issues/may-2007/soils-offer-new-hope/

- Surprise: less oxygen could be just the trick
http://tinyurl.com/ywalt4

- What we throw away
http://www.waikato.govt.nz/enviroinfo/waste/whatwethrowaway.htm

- The Carbon Farmers
http://www.abc.net.au/science/features/soilcarbon/

- Living Soil
http://www.championtrees.org/topsoil/

- BEST Pyrolysis, Inc.
http://www.bestenergies.com/companies/bestpyrolysis.html

- Eprida, Inc.
http://eprida.com/hydro/

- Biofuels could boost global warming, finds studyhttp://www.rsc.org/chemistryworld/News/2007/September/21090701.asp

- Biofuels: is the cure worse than the disease?
http://tinyurl.com/yq9t8o

Companies producing agrichar:
- terra preta at bioenergylists.org
http://terrapreta.bioenergylists.org/company

The Hydrogen Economy

Hydrogen fuel cells constitute an efficient way to store energy and as such they form an important component in our struggle to contain global warming. Hydrogen fuel cells are a convenient and clean way to power cars and supply electricity on demand virtually everywhere. 

The importance of hydrogen as a technology is huge, as it constitutes the clean and renewable storage compliment to clean and renewable ways to capture energy, such as solar, wind, geothermal, wave and hydro-power.

The Hydrogen Economy is much more than that; it promises to change the fabric of our society. Hydrogen, holds the promise to break up the current cartel of energy suppliers that works hand-in-glove with a military-industrial complex that holds the entire world in a suffocating stranglehold. Hydrogen can clean things up and set the economy free. Hydrogen is the elixir that can remedy our polluting habits to create a better society, without the monopolies, the pollution, the taxes, regulations and the military controls that come with the current ways of supplying energy. Currently, energy is largely obtained from sources that centralize the economy around a single supplier, such as a huge nuclear plant or coal-powered plant. Similarly, oil is pumped up under monopoly conditions and transported in huge tankers, which has created these almighty oil companies that extend their grip over society through services stations and political lobbying to keep cars polluting the world.

We should look forward to a world in which anyone can capture energy for free in their backyards, from renewable power sources such as solar, wind, geothermal and hydro-power. This energy can be directly stored in fuel cells that are built into heating and cooling systems of buildings, lights, TV-sets, stereo equipment, computers, cars, mowers, scooters, power tools, etc. Wherever you now see rechargeable Lithium batteries used, such as in mobile phones, think hydrogen and you'll get a preview of the bright future that awaits us. Hydrogen fuel cells will enable us to cut the wires through which the puppetmaster controls us now. Hydrogen fuel cells hold the promise to set us free. Let's take a serious effort to give this technology a chance!

References:


Solar power and electric cars, a winning combination!

Who killed the electric car? It's an excellent documentary video, a must see! It was released on DVD to the home video market on November 14, 2006. 
http://earthissues.multiply.com/video/item/16 http://wikipedia.org/wiki/Who_Killed_the_Electric_Car%3F

There's more great footage at the Earth Issues website, such as a race between an electric car called the X1 against a Ferrari and a Porsche, and underwater recharging of an GM EV1 battery.

The electric car dates back to the 1830s, when Robert Anderson of Scotland invented the first crude electric carriage. Around 1900, electric cars outsold all other types of cars in America. Why? Because they did not have the vibration, smell and noise of gasoline cars and required neither gear changes to drive nor much manual effort to start (as with the hand crank on gasoline cars). The only good roads then were downtown and most car travel was local, perfect for slow electric vehicles with a limited range.

Now it's time to reinvent the electric car, for its convenience and for the positive contribution it can make in terms of the environment and global warming. Solar power and electric cars is a winning combination. Let me explain. Wind and solar power is not continuous, and this is where car batteries can help out, by storing electricity at times of high supply, to feed electricity back into the grid when supply is low. I can well imagine car batteries both drawing and feeding power to/from the grid at night. Intelligent net metering will assist with this.

How much solar power is needed for all this electricity? How much surface does it take to supply solar energy? The red squares on the image below show how much surface needs to be covered in theory by solar power facilities to generate enough electricity to meet the entire demand of respectively the World, Europe (EU-25) and Germany.

http://en.wikipedia.org/wiki/Image:Fullneed.jpg
Using concentrated thermal solar power, a mere area of 254km x 254km of desert land would theoretically suffice to meet the entire global demand for electricity for 2004.

The electricity can be transported nationwide over high voltage direct current (HVDC) lines, with line losses of about 3% per 1000 km (620 miles), adding $0.01 - $0.02/kwh to the local price of electricity.

Of course, it's hard for solar power to cater for peak demand during cold winter evenings, so it makes sense to complement solar energy with stored energy, wind energy, hydro energy, geothermal energy, etc, depending on local conditions. Anyway, as Ausra calculates, if solar facilities would store energy in molten salt, they could cater for almost all US day-and-night electricity needs, and would theoretically fit inside a square with 153 km sides. To additionally accommodate an entirely electrified vehicle fleet, the land area would grow to a square with sides of not more than 211 km.

From this perspective, the "how much surface" in the above question was better rephrased into "how little surface". Solar power alone could well provide enough energy for both our current electricity needs and can supply the additional energy needs to run our cars as well. Indeed, cars need not be bad from an environmental perspective. In fact, the combination of cars and solar power can be a winner for both. Again, let me explain.

Electricity can be stored in car batteries during the day, when cars are parked under roofs that are covered with solar panels that recharge the batteries. That could easily recharge the car battery enough for the owners to drive home and still leave sufficient power in the battery for other use. Note that 70% of Americans drive less than 33 miles per day. Late afternoon, when most people return home, they can plug their cars in at home for their own power use in the evening. Many will even have sufficient energy left to feed power back into the grid, selling electricity at top rates due to peak demand for power in the evening. Even if the battery became fully discharged in the evening, this still makes economic sense, as one can recharge later from the grid (during the night or early in the morning) when rates should be cheaper. Imagine there's a lot of wind during one part of the night. The meter will indicate that this is a good time for empty batteries to recharge. Conversely, when there is no wind in the evening, one will be able to get top dollars for feeding electricity back into the grid, pre-setting the battery to keep enough charge to get to work in the morning. As discussed, the car can then fully recharge from the solar panels on the roof of the parking place at work.

Sounds far-fetched? I'm very impressed with the Tesla Roadster, which has specs that many don't expect from electric cars, specifically an acceleration from 0 to 60 in about 4 seconds and a top speed of over 130 mph. It also looks great! You can recharge the battery at night in your garage and it will cost you as little a $2.50 in electricity for a full recharge.

With the Tesla, you'll be able to drive up to 250 miles on one single charge. This radius is achieved partly with regenerative braking that stores energy produced when braking. Recharging an empty battery with an EVSE system (operating at 70 amps) takes as little as 3.5 hours, but it also comes with a mobile-charging kit that lets you charge from any standard electrical outlet, e.g. in case you get stranded with an empty battery. Anyway, this short recharge time allows one to feed power back into the grid in the evening (when demand is high and supply from solar power sources is low) and still recharge later at night or early in the morning. Indeed, later at night rates are low, so it makes sense to recharge then. If sufficient wind is blowing, supply from wind turbines may be abundant in your area.

Electric cars requires less maintenance, since there are very few moving parts; you don't need to change engine oil, filters, gaskets, hoses, plugs, belts, there's no catalytic converter or exhaust pipe to replace. The Tesla uses Lithium-ion (Li-ion) batteries, for a number of reasons. They charge rapidly, have higher voltage, weigh less and last longer than Nickel Cadmium (Ni-Cd) batteries. Li-ion batteries do not contain polluting substances such as cadmium, lead or mercury. Li-ion batteries do not have the memory effect that makes that other batteries decrease in capacity when they are recharged before they are empty. Li-ion batteries do not have to be fully discharged, before they can be recharged, so one can top them up several times a day, e.g. at home or at the office. Nevertheless, Li-ion batteries will deteriorate over time, Tesla estimates that the battery pack needs to be replaced after about 100,000 miles. Also, cost is an issue; the Tesla Roadster 2008 model has a price-tag of $92,000 and the battery pack warranty is limited (I think it's only warranted for 100,000 miles, while it does cost thousands of dollars to replace). But battery cost is expected to come down in future, while at the same time battery capacity and performance is expected to increase over time.

Also have a look at Google's initiative on plug-in cars:

Google still uses plug-in hybrids, but it sets a trend away from using fossil fuel. There are also ethanol-electric hybrid cars; more than a year ago, Saab (General Motors Swedish car unit) already showcased such a car, combining an electric motor with an E85 Ethanol engine.

Google.org has issued a request for proposals to the tune of $10 million in order to advance sustainable transportation solutions.

Let me also pass on some links to the Rocky Mountain Institute in Colorado, at:

They envisage a "Hypercar," made of ultralight, super-strong, carbon composite material, which is 12x as strong as steel on impact. Manufacturing cars and trucks using these materials would dramatically increast the range of electrical cars.

Hydrogen is another way to store energy and is also promising in expanding the range of electric cars.

In conclusion: Just like we shouldn't rely on any single source of power (wind, hydro, solar power, geothermal, wave, tide and more), we shouldn't rely on a single way of storing power either. Apart from using car batteries for storage, we can think of capacitors, hydrogen, fly-wheels, compressed air, steam, sodium, molten salt, pumped-up water, etc. Clocks in the old days used weights to store energy. Similarly, bricks could be used as weights in larger contraptions. At even larger scale, we could use the Great Lakes as a reservoir not only of water, but also of energy. At times of peak supply of wind and solar power, surplus power could be used to pump water back from a lower to a higher lake, in order to use hydro-power at times when supply of other types of power is low. Free markets are good in sorting out which technology works best where and when. I have no doubts that the nuclear alternative will be prohibitively expensive once risk factors are better taken into account (accidents, waste management, terrorism, etc).