Author Archives for Philip Proefrock

Gravel Batteries Offer a Solution for Renewable Energy Storage


One of the most frequent objections to renewable energy systems is that their production is too variable. But technologies continue to be developed that will allow storage of power generated from wind, solar, and other intermittent renewable sources. The latest development comes from researchers at Isentropic in Cambridge, England who propose giant batteries filled with gravel and argon gas. These batteries would provide a number advantages over pumped hydro, which is presently used for almost all electricity storage today, as well as over underground compressed air storage.

The gravel battery system would use excess capacity generated by a renewable source to heat and pressurize the argon gas and then pump it through a gravel filled silo to store energy. Then, when demand calls for electricity, the system is simply operated in reverse to generate electricity. According to the company, the system’s “round trip efficiency is over 72% – 80%.” This is comparable to the efficiency of pumped storage hydro, which has an efficiency of 70 – 85%. But gravel batteries are much more compact, and can be more readily installed in relatively flat areas characteristic of many areas with good windpower potential, such as the American Great Plains. A gravel battery can use far less land (1/300th) than that required for a pumped hydro lake, as well.

Underground compressed air storage is another technology that has been suggested, but that requires the presence of underground caverns, which are not always present where you might want to put a power storage facility. In addition to being able to be located anywhere, gravel batteries could be relatively inexpensive because they do not need costly materials. Costs could be as low as $55/kWh, and $10/kWh at scale for large installations.

via: Worldchanging

Oyster Offshore Wave Generator Is 2.5x Better Than Predecessor


Power generation from waves continues to develop as Aquamarine Power has unveiled its new, second-generation Oyster 2 wave power generator. According to the company, “The new 800kW device will measure 26 metres by 16 metres and will deliver 250 per cent more power than the original Oyster 1 which was successfully deployed at the European Marine Energy Centre (EMEC) in Orkney last summer.” A test installation is planned for 2011 and will use three wave devices connected to a single power generation station to produce 2.4 megawatts of electricity.

Like the Pelamis wave generator (now, sadly, sitting on the shore for lack of maintenace funds), the Oyster rides on the surface to harness wave power. This means that Oyster cannot coexist with surface vessels, unlike other underwater systems. But, instead of housing the generator at sea, where conditions are harsh and maintenance and repair are costly, the Oyster system harnesses wave power to drive hydraulic systems and on-shore turbines to produce electricity.

The new Oyster incorporates many improvements over the original design, including simplified construction requiring less steel to produce and design to enable easier mass production.  Aquamarine Power expects to deploy Oyster in farms of 100MW generating capacity or more. An animated Oyster video shows more about how the system operates.

via: Inhabitat

Using Underwater Kites to Generate Power


Minesto, a spin-off from Swedish automaker Saab, is developing what it calls it’s “Deep Green” technology, underwater kites tethered to the ocean floor that could produce continuous energy from tidal flows. A single Deep Green turbine could produce up to 500 kilowatts of electricity. And tides are much more regular than winds, so that the energy produced would be less erratic and variable.

The kites have a 12m (almost 40 ft) wingspan. The kites would remain at least 20m (66 feet) below the surface, to prevent conflicts with ocean navigation and minimize visual impact. Tidal flow as low as 1.6 meters/second can be used to create the lift necessary to move the kite.

Since the underwater kite is anchored to the ocean floor, it is able to move at much faster speeds, which makes the turbine more effective, as it traverses back and forth in order to generate electricity. Although wind-based deepwater offshore power systems are difficult to install and operate, Deep Green tidal kites would be well suited for instalation in deeper waters. Furthermore, the underwater kites are much lighter and easier to install than the equipment needed for other deepwater generation systems. Deepwater generating systems have the additional expense and technical hurdles of transmitting the power over a greater distance. But the higher efficiency and more consistent generation offered by Deep Green could offset those drawbacks.

The company indicates the Deep Green system offers an operating cost of 0.06-0.14 Euros/kWh, as compared to 0.15-0.30 Euros/kWh for other tidal systems, and 0.10-0.12 Euros/kWh for offshore wind systems.

A scale model of Deep Green will be tested in Northern Ireland next year as the next stage of development for this system.

via: Slashdot

Weather Notes from Both Poles


Indicators continue to show disturbing trends and unexpected events, indicating that changes are taking place in the Earth’s environment. The South Pole has had its warmest year ever (since recordkeeping began in the 1950s), and the North Pole experienced unexpected rain in late April.

“My business is weird, wild and wacky weather, and this is up there among fish falling from the sky or Niagara Falls running dry,” according to David Phillips, a senior climatologist with Environment Canada. “I mean, it really is strange. You just don’t expect it to rain in the High Arctic in April; maybe in July and August.”

Phillips also indicated that over 50 years of historical weather data show “no signs of rainfall ever occurring in April in the High Arctic.” The unusual rain could be an indicator of further shifts beginning to take place in Arctic weather patterns due to the continuing warming of the region.

The Amundsen-Scott South Pole Station recorded the highest average annual temperature in 2009. It was also the second warmest year on record for overall surface temperatures on the Earth, according to NASA.

Links: CBC News and Yahoo News

Printed Paper Solar Cells


Solar panel materials are getting thinner and thinner. Now, MIT researchers have announced a method for printing solar cell material on paper.

The efficiency of this method is far lower than other kinds of solar cells. The paper solar cells have an efficiency of around 1.5-2%, while commercial silicon wafer solar panels are generally around the 15-20% efficiency range. However, the scientists point out that this is still a reserach technology and is years from commercialization.

Even if the efficiency does not improve dramatically, it may be possible that cheap and abundant solar collecting materials provide a better and more cost-effective way of getting power, especially for portable electronic devices.

The relative effect of the chemicals and processes used in system may also be an issue. If there are less harmful materials used in a printed solar cell technology, the benefits that offers may also outweigh the relative efficiency gap as compared with the more toxic option.

via: Inhabitat and CNET

Solar Aero’s Bladeless Wind Turbine


A research company in New Hampshire recently announced the patent of their bladeless wind turbine, which is based on a patent issued to Nikola Tesla in 1913. The Fuller Wind Turbine developed by Solar Aero has only one rotating part, the turbine-driveshaft. The entire assembly is contained inside a housing, so that this turbine offers several advantages versus blade-style (primarily horizontal-axis type) turbines. With a screened inlet and outlet, this turbine does not present a danger to wildlife such as bats and birds. To an outside observer, the only movement visible is the entire turbine housing as it adjusts to track the wind. This also makes it a good candidate for use near military surveillance and radar installations, where moving blades would otherwise cause difficulties.

According to the company, the turbine is expected to deliver power at a cost comparable to coal-fired power plants. Total operating costs over the lifetime of the unit are expected to be about $0.12/kWh. The turbine also should have fewer maintenance requirements, leading to lower lifetime operating costs. The turbine itself can also be supported on magnetic bearings, and all of the generating equipment kept at ground level, which will also make maintenance easier. The company estimates “final costs will be about $1.50/watt rated output, or roughly 2/3 the cost of comparable bladed units.”

The Tesla turbine operates using the viscous flow of a fluid to move the turbine and thereby produce energy. The Tesla turbine “consists of a set of smooth disks, with nozzles applying a moving gas to the edge of the disk. The gases drag on the disk by means of viscosity and the adhesion of the surface layer of the gas. As the gas slows and adds energy to the disks, it spirals in to the center exhaust. Since the rotor has no projections, it is very sturdy.” Disks in the turbine need to be closely spaced in order to capture the viscous flow,. In order to be effective, the Tesla turbine also needs to have extremely thin disks to minimize turbulence at the edges. Tesla was not able to find metals of sufficient quality to make this work effectively, but apparently, nearly a century later, those limitations have been overcome.

Solar Aero’s current example is an unassuming trailer-mounted unit, but a unit the size of the one pictured (see website) “should be capable of 10kW output with no problem,” according to the inventor. The number of disks determines the amount of power that can be produced. It will be interesting to see if this technology takes off, and if the technology is something that can be scaled up to provide utility level power production, or if it is only a niche system. In any case, it is interesting to see alternatives to bladed wind turbines.

Link: Solar Aero

Germany Wants 1 Million Electric Vehicles by 2020


While Volkswagen hasn’t been a name we’ve discussed much when talking about electric vehicles, the company today unveiled its Golf Blue-e-motion concept vehicle in conjunction with an announcement from the German government focusing on electric vehicles.

German Chancellor Angela Merkel has launched a “national platform for electric mobility” that plans to have one million electric vehicles on the road in Germany by 2020. With several domestic manufacturers all working in this direction, such a goal does not seem too far fetched. BMW, Mercedes and Audi have all been moving forward with their own electric vehicle plans.

The electric Golf should have a range of 150km (about 90 miles). It is expected to be to market as a production vehicle in 2013. Volkswagen also has forthcoming hybrid versions of its Jetta and Passat, as well as a hybrid version of the Golf which will be launched in the same timeframe.

via: CBC News and

Drawing Power from Dutch Coastal Dikes


Plans are being considered to turn the famous Dutch dikes into tidal power generators. Although originally built to protect the people and land of the Netherlands, now a committee of various government representatives has issued a recent report including some suggestions to revise the operation of the dikes to create a more pleasant and more natural land behind the dikes, and to provide a source of power. Openings in the series of dikes would provide ideal locations for tidal power plants.

The Netherlands have had protective ocean dikes to guard the coastline since the disaster in 1953 when more than 1800 people were killed and over half a million acres of land was flooded by the North Sea. After this tragedy, the extensive Delta Works were constructed over the next four decades, and the last parts of the project were finally completed in 1997.

Energy, however, is not the primary motivator for this. Instead, it is an interest in restoring the natural condition to estuaries and tidal flats whose character has significantly degraded over the years since the dikes were installed. “Opening water locks would allow the tide to return to now stagnant waters, the report stated. This would be a boon to nature, because certain plants and animals, which have all but disappeared since the estuaries were closed off, can return. Deeper into the delta lies a fresh water basin where smelly algae bloom in the summer. Allowing salt water to reach these outer stretches again could improve conditions for residents and holiday-makers.

In the aftermath of a catastrophe, it is all to easy to focus solely on preventing that tragedy, no matter the cost. ‘With all the focus on safety after 1953, [committee director Joost] Schrijnen said, “other aspects were neglected.” He now wants to change that. “But without sacrificing safety,” he added.‘ Turning the dikes into a power generating solution, as well as improving environmental quality seems like a solution that will provide multiple benefits, in addition to protecting the land from the sea.

link: nrc handelsblad

via: Slashdot

Chevy Adds Another Member of the Volt Family


Some interesting Earth Day news comes from Chevy. It’s a new Volt, which is being unveiled in China today: “Chevrolet is leveraging Auto China 2010, which starts today in Beijing, to introduce the Volt MPV5 electric concept. The five-passenger multi-purpose crossover concept demonstrates the potential of the Voltec propulsion system by utilizing the same foundation as the Volt, for gas- and tailpipe emissions-free electric driving.

The MPV5 uses the same Voltec propulsion system found in the Volt. “The same T-shaped 16 kwh lithium ion battery and 1.4 L 4 cylinder generator is used, but in this configuration only has an EV range of 32 miles, with an additional 300 miles of gas range on a full tank.”

The Volt MPV concept is slightly bigger in all dimensions, as well as being in a crossover configuration. The Volt MPV5 has a slightly longer wheelbase, and is about 7 inches (181 mm) longer, 3 inches (73 mm) wider, and 7 inches (182 mm) taller than the Volt. The Volt MPV5 also offers 62.3 cubic feet (1764 liters) of cargo space with the seats folded and 30.5 cubic feet (863.7 liters) of space with the seats up.

GM obviously believes in the REEV platform they have developed with the Volt. Although there are no production plans for this concept vehicle yet, it is good to see potential alternatives that could leverage GM’s work and reach other consumer segments with different versions of the electric car concept.


Vertical Farming That Does Work


Although we’ve been sceptical about the financial viability of vertical farming schemes, that doesn’t mean we are opposed to bringing more greenery into urban areas in any way, and systems that merge vegetation with buildings can be both beneficial and beautiful. We are definitely fans of green roofs.

Parabienta is a wall garden panel system that provides a growth medium to support plants and allow them to grow along vertical surfaces. Vegetated vertical panels help to reduce solar gain on walls, much the same as green roofs help reduce the heat island effect and lower temperatures on roofs. As an added benefit, Parabienta panels have also been shown to help buffer noise, particularly desirable in an urban environment.  It might not grow tomatoes, but it will add some welcome green to an urban context.

Parabienta was originally developed by the Shimizu Corporation in Japan. But, while they appear to have used it on projects themselves, the company’s website has only a single brief mention of the material. Although it has been around for a few years now, it doesn’t appear to be readily available as a product for project use, though it was reported that the company was hoping to grow sales of the system (at a cost of about $80 per square foot, including installation and irrigation) to a few million dollars per year.

via: Transmaterial