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Category: energy – Page 284

Stanford engineers invent a sonar device that works outside the water

Radar and LiDAR have been incredibly quick and effective tools for mapping and surveying the Earth’s surface from aircraft and satellites, but while they can deliver accurate readings through cloud and even forest canopy cover, they can’t tell you what’s below the surface of the sea. Seawater absorbs far too much of the signal.

Sonar remains the most effective way to map out the sea floor – but the vast majority of the oceans that form 70 percent of the Earth’s surface remain unmapped, because sonic waves have hitherto only been able to be sent out from underwater. Sound waves sent from air into water lose more than 99.9 percent of their energy in the translation; it’s why the outside world goes so wonderfully silent when you dive down to the bottom of the pool. The meagre remaining 0.1 percent of the energy does create a sonar signal, but that loses a further 99.9 percent of its energy upon coming back up from the water into the air.

Sonar is commonly used for submarine detection, among other things, by military forces the world over, chiefly using devices on the undersides of ships. But the closest things thus far to an airborne sonar system are “dippers” like Thales’ FLASH system; low-frequency, wide-band sonar systems that dangle from cables out the bottom of helicopters and dip into the sea below like noisy teabags. These methods are slow, expensive, and no good at covering large areas.

A strategy to transform the structure of metal-organic framework electrocatalysts

The oxygen evolution reaction (OER) is a chemical process that leads to the generation of molecular oxygen. This reaction is of key importance for the development of clean energy technologies, including water electrolyzers, regenerative fuel cells and rechargeable metal-air batteries.

The extent to which this reaction occurs has so far been limited in many materials, which has restricted the conversion efficiency of some types of technologies. Materials scientists have thus been trying to identify alternative materials, including metals, and hydroxides, that could be used as electrocatalysts to fuel this reaction. The materials identified so far, however, are far from ideal for large-scale implementation, as they are either not particularly resistant or too expensive.

A class of materials widely investigated as possible electrocatalysts for the OER are (MOFs), hybrid and crystalline compounds that consist of a regular array of positively charged metal ions surrounded by organic molecules. While these materials have promising , scientists have yet to identify optimal strategies to enhance their performance.

Tasmania declares itself 100 per cent powered by renewable electricity

The Tasmania government has declared that it has become the first Australian state, and one of just a handful of jurisdictions worldwide, to be powered entirely by renewable electricity.

In a statement released on Friday, Tasmanian energy minister Guy Barnett said that state had effectively become entirely self-sufficient for supplies of renewable electricity, supplied by the state’s wind and hydroelectricity projects.

“We have reached 100 per cent thanks to our commitment to realising Tasmania’s renewable energy potential through our nation-leading energy policies and making Tasmania attractive for industry investment, which in turn is creating jobs across the State, particularly in our regions,” Barnett said.

Hydrogen-powered VTOL drone flies for 3.5 hours

VTOL (vertical take-off and landing) drones are quite versatile, as they combine the vertical flight of a helicopter with the fast and efficient forward flight of a fixed-wing airplane. This one features an extended range, thanks to a fuel cell power system.

The experimental aircraft was developed by a team at the Netherlands’ Delft University of Technology (TU Delft), working with colleagues from the Royal Netherlands Navy and the Netherlands Coastguard. It has a 3-meter wingspan (9.8 ft), weighs 13 kg (29 lb), and features 12 motor/propeller units distributed on its two wings. Even if several of the motors fail, it can reportedly still fly and land successfully.

The drone is also a “tail-sitter”-type VTOL. This means that when taking off and landing, its body is angled upwards, allowing the propellers to work more like a helicopter’s rotor blades. For going into forward flight, the thrust is electronically redistributed between the 12 motors, causing the aircraft to level out into a horizontal orientation.

H3X claims it’s tripled the power density of electric aircraft motors

If there’s one major thing that’s holding back an electric revolution in the aviation world, it’s energy storage. But there are a ton of very clever people banging away at the problem of how to increase the energy density of batteries, and another growing faction working to make long-range, fast-fueling hydrogen-fuel-cell powertrains the standard for future flight.

Either way, it’s going to happen in the coming decades, and one new company out of Minneapolis is turning its attention to the other critical element of the propulsion system. H3X Technologies is bursting out of the gate with an integrated electric motor design it says can deliver the same sustained power as some of the best motors on the market at a third or less of the total weight.

Weight, of course, is a big deal in aviation – and that goes double for electric aircraft. Every pound carried skyward represents a pound less payload you can carry, a reduction in the range you’ll get from your battery or hydrogen tank, and ultimately a loss of money for the owner.

An $11 trillion global hydrogen energy boom is coming. Here’s what could trigger it

“California curtailed between 150,000–300,000 MWh of excess renewable energy per month through the spring of 2020, yet saw its first rolling blackouts in August because the grid was short on energy,” says Paul Browning, CEO of Mitsubishi Power Americas (formerly known as MHPS). “Long-duration energy storage projects like ours that are designed to shift excess energy from periods of oversupply, like California in the spring, to periods of undersupply, like California in late summer, are critical to ensure similar events are avoided as we continue to make significant strides towards deep decarbonization.”

Storing fuel in salt caverns isn’t new, but hydrogen’s growing role in decarbonization has revitalized interest in the concept. The U.S. Strategic Petroleum Reserve has long stored emergency crude oil in underground salt caverns on the Gulf Coast, and notes they cost 10 times less than aboveground tanks and 20 times less than hard rock mines. The Reserve has 60 enormous caverns, typically 200 feet in diameter and 2,500 feet tall, and one “large enough for Chicago’s Willis Tower to fit inside with room to spare.”

Caverns can be created in salt domes by drilling into the salt dome and injecting the rock with water, which dissolves the salt. The resulting brine is extracted, leaving a large cavity. The next step is storing hydrogen in the cavern. Hydrogen electrolyzers can convert water into hydrogen by using renewable energy from solar and other sources. The hydrogen can then be stored, and reconverted to electricity when needed.

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