Renewable and alternative energies
The world's population consumes about 15 terawatts of power, a business worth some $6 trillion a year (1/10 of the world's economic output). Renewable and alternative energies (hydro, wind, solar, geothermal, waves, biomass and waste, biofuels) represent already some 17% of this production.
This web site aims at providing information about the current state of renewable and alternative energies and future prospects.
Hydro
By far the largest source of renewable energy, hydro-electric power produces about 15% of the world's electricity, compared with 3% for other renewables, with still lots of room for growth. New Energy Finance, a research firm, reckons that less than one-third of the world's potential capacity has been developed.
Thousands of data centers, filled with thousands of powerful computers, consume lots and lots of energy, rivaling aluminum smelters in the energy they consume. Often just as much power is needed for cooling them as for computing. Building them close to a dam solves both issues in an optimal way.
Advantages
- Energy can be produced reliably and constantly.
- Can also store energy (by pumping water back up) to meet peaks in demand.
Drawbacks
- Dams are expensive to build
- Dams can impact dramatically human settlements, historical sites and fishes
- Dams deteriorate, and if they break it can have a devastating impact downstream.
Biomass
Advantages
- Energy can be produced reliably.
- Easy to store energy to meet peaks in demand.
- Some of it can be liquefied and used in vehicles, planes, boats...
Drawbacks
- Some biomass could be eaten by people instead of used
for energy (eg 200 kg of corn can either fill one car tank or feed one
person for one year).
Biomass research/innovations
- Solazyme
- Uses algal biotechnology to renewably produce clean fuels,
chemicals, foods and health science products from agriculture and
industrial biomass (glycerol, starches, sugars, cellulosics, switch
grasses, wood waste).
Wind
World capacity of wind power is growing at 30% a year and will exceed 100 gigawatts in 2008 (about 1% of world-wide electricity use).
Modern wind turbines extract about 50% of the wind power, close to the theoretical (Betz) limit of 16/27 (59%).
Advantages
- Modern turbines produce electricity at only 8 cents per kWh and falling.
- Wind turbines offer more revenues from electricity production to farmers per square meter than either biofuels or solar panels.
- Unlike most power stations, wind farms can be built one piece at a time, providing revenues since the first turbine was completed.
Drawbacks
- The intermitency of wind means that if used to meet a large fraction of the demand, it should be coupled with other technologies. Extra capacity can be used to pump water uphill in existing or purpose-built hydroelectric plants, ready for use when demand spikes. Wind power can also be well complemented with sun power, as most windy days are not sunny just like most sunny days are not windy.
- People often avoid living in windy locations, so electricity grids have to be extended to bring wind-based electricity to them.
Wind research/innovations
- WhalePower
- Increases blade efficiency with bumps on the leading edge (biomimicry inspired by humpback whales).
- Ti'éole
- Helps you to build a wind turbine yourself, for your own garden, with cheap material.
- wind engine using boat sails
- The sails moved around a fixed vertical axis. Free technology. In French.
- boat sails prototype
- Video in French of a prototype using boat sails that still works with very little wind.
- Enercon
- They have developed a "direct-drive" system with a generator that can operate at low rotational speeds and does not require a gearbox (gearboxes are exposed to lots of vibrations and movements inside the turbines). However, such generators are very heavy and tend to be more expensive.
Offshore wind turbines
- Clipper Windpower
- They are building a 7.5 MW offshore prototype (as of December 2008).
Solar
Strong research in solar cells is producing many interesting projects to increase power output.
Advantages
- Energy can be produced near where it will be consumed (solar panels can be put on the roofs of houses).
- Good complement to wind power, as most windy days are not sunny just like most sunny days are not windy.
Drawbacks
- Solar panels require silicon, currently in short supply. As silicon output increases (it takes 3 years to build a new plant to produce silicon), other bottlenecks may be the silicon ingot- and wafer-makers, or the ones producing the specialist chemicals that coat cells.
- Solar energy has been subsidized by governments in Germany, Spain and the US. Now cuts in these subsidies bring uncertainty to demand.
- Solar cells get dirty, reducing their power generation.
Solar research/innovations
- Innovative financing schemes
- Article about 2 utilities that pay all of the cost of installing solar panels on your rooftop. In addition you get a share of the revenues generated (electricity is sold to the grid by the utilities, with reduced line loss and less paper work for them than the construction of a new plant).
- Kender solar
- An attempt to harness the solar heat stored in the air as much as direct solar light. Sponsors this site.
- Hydrosol-2
- New method for solar-heated two-step water-splitting thermochemical processes operating at temperatures below 1500 K, sponsored by DLR (the German Space Agency)
- Nicole Kuepper
- Inventor of cheap low-temperature solar cell manufacturing without costly equipment.
- GreenField Solar
- Builds high intensity solar cells and concentrators of solar light and heat.
- New solar cell material
- Comprised of a hybrid of plastics, molybdenum and titanium, it fluoresces and phosphoresces, using the visible spectrum of light energy.
- 3-Dimensional Nanotube Solar Cell for Visible and UV Light
- William Yuan has designed a 3D solar cell that works for visible and UV light, which makes it highly more efficient and powerful.
Thin Film
Thin films of solar cells are roughly half as efficient (meaning that a panel must be twice as big to generate the same amount of power) as standard crystalline solar panels, but a third cheaper (watt for watt) and way more versatile - they can be mounted on a variety of materials including flexible plastics and fabrics.
- First Solar
- The biggest force in the thin film industry. It makes its cells from a chemical called cadmium telluride.
- Nanosolar
- They believe that a combination of copper, indium, gallium and selenium known as CIGS will prove cheaper to produce on a mass scale than cadmium telluride-based thin films.
Space Solar Power (SSP)
Around the clock, 1.3 gW of solar energy pour through every square kilometer of space around the Earth. Space Solar Power is an attempt to catch this energy and beam it to isolated places or vehicles.
- Space Island Group
- Plans to build large SSP systems piggy-backed onto empty fuel tanks converted into living quarters.
- Solarbird
- Mitsubishi Electric bets on squadrons of small satellites orbiting in formation.
Solar Associations
- Swissolar
- Swiss association of solar energy professionals.
Experimental
Experimentations at the edge of science. Might work. Might not.
- BlackLight Power
- An attempt to release latent energy from the hydrogen atom.
- Cavitation heaters
- Mechanical energy applied to weirdly shaped rotors with holes that
would create over-unity heating (more energy produced than was put
in the system).
- Orbo
- Based upon time variant magnetic interactions (magnetic
interactions whose efficiency varies as a function of transaction
timeframes). They attempt to generate energy from this variation.
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References:
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