As world leaders endorse climate goals like reaching net-zero greenhouse-gas emissions within the next 30 years, companies are pushing to move their projects from research and development to commercial phases. The net-zero objective—balancing emissions produced and emissions removed from the atmosphere—has spurred growth in the business of sustainable energy, which generates fewer emissions than fossil fuels. Some of these possibilities, like satellites that can wirelessly beam down solar energy from orbit, remain experimental, while others, like underwater turbines that harness tidal movements, have progressed from prototypes to commercial demonstrations. What are the newest developments in generating power from the sun, water, air and Earth?
Using the sun as an energy source is nothing new in the subject of ecology. Unfortunately, from the very beginning, we faced the problem that sunlight on earth is often limited due to the weather, seasons or simply the daytime cycle.
Scientists and engineers say within the next decade solar energy could come consistently from much closer to the source—wirelessly beamed down as microwaves or laser beams from orbiting satellites to receiving stations on Earth connected to the electrical grid.
The basics are to put a large, very large platform in space, harvest sunlight, where the sun shines, essentially 99.95% of the time, and send it to markets on the ground, where, on average, the sun is shining only about 15% of the time, as indicated by the president of Mankins Space Technology, a company working on developing a 1-mile-wide solar power satellite prototype that will use microwave beaming.
Transfer of energy to the ground would take place via microwave transmission. This technology has already been tested: The U.S. Naval Research Laboratory sent 1.6 kilowatts over a distance of 0.6 mile last year. Engineers at the Japan Aerospace Agency have sent about the same amount of energy the length of a football field. Other groups working on the experimental technology, like The California Institute of Technology, plans on testing prototypes, which can transfer solar power in space via a steerable microwave beam, by the end of 2022.
Norwegian company Wind Catching Systems is developing a floating offshore wind farm, called Windcatcher, that will stand nearly 300 meters high – about the same as the Eiffel Tower. The system would be made up of more than one hundred turbines stacked in a framework. It could produce enough power for 80,000 homes.
Most offshore wind turbines are designed to be placed on fixed foundations in shallow water. However, while floating turbines can harness greater energy from the high winds that occur farther out to sea, their huge blades tend to max out at wind speeds of around 11 meters a second.
The Windcatcher gets around this by using a larger number of smaller blades. These are not only capable of harnessing faster winds, but can also make more rotations per minute than larger blades, generating more energy.
Placing the turbines next to each other in the framework also allows the Windcatcher to use the “multirotor effect,” where the turbulence created by each turbine can be harnessed by the surrounding turbines. This also helps to maximize the amount of energy each structure can generate.
The company says the unit will be able to turn 360 degrees to capture wind from any direction and generate electricity sent via underwater transmission lines back to shore.
The unit can produce up to five times more energy using one-fifth the space of typical offshore wind farms.
SkySails Group, a Germany-based power company, is developing kites that fly a quarter-mile off the ground to produce energy. As the kite rises, it unwinds a tether connected to a winch and generator, which convert the force on the tether into electricity.
High-altitude wind is the largest untapped energy resource on Earth, as noted by SkySails. Its largest kites are nearly 1,940 square feet in size—generating about 200 kilowatts of power, and meant to replace diesel generators in remote, off-grid islands and villages.
An airborne system can reach up to 800m high (half a mile), far above the 200 to 300m (660 to 980ft) tip of the tallest wind turbines. The theoretical global limit of wind power at high altitude has been estimated to be about 4.5 times greater than what could be harvested at ground level.
The company has installed several pilot kites at sites including the Indian Ocean island nation of Mauritius, with plans to connect them to the grid. Starting next year, the company plans to start shifting toward commercial rollout, and eventually hopes to increase its kite size and flying altitude.
A French company, Airseas, has developed an 10,800-square-foot kite called Seawing that attaches to a ship’s bow with a cable and pulls the vessel along using wind power. The company’s aim is to help decarbonize the shipping industry.
In addition to sun and wind, water is also gaining popularity. The Scottish company Orbital Marine decided to use tidal energy to create the most powerful tidal turbine in the world.
The tidal turbine produces so much energy that it can power around 2,000 U.K. homes and offset more than 2,400 tons of carbon annually. The device off the coast of Orkney supplies electricity to the mains via a special submarine cable.
Attractive conditions for extracting energy from the tides are often located in hard-to-reach places (headlands or rocky areas around remote islands). Orbital Marine emphasizes, however, that their installation is relatively cheap and adapting it to other places will not be too much of a problem. The company is currently looking to commercialize O2 so that it becomes: A catalyst to harness the resources of tidal streams around the world to play a key role in tackling climate change while creating a new, low-carbon industrial sector.
Eco Wave Power developed an innovative technology for production of clean electricity from ocean and sea waves.
They aim to generate clean & affordable electricity, using a simple but smart design, allowing floaters to be attached to piers, jetties and existing marine structures. These floaters use the rising and falling movement of waves to generate electricity. The technology requires less than two feet of water to produce energy.
The company opened a 100-kilowatt facility connected to the grid in Gibraltar in 2016 that will be refurbished and moved to Los Angeles within the next three months. It expects to connect another power station in Jaffa, Israel, to the local grid by midyear this year. Future projects include possible facilities in New Jersey, California and Portugal.
To produce power from geothermal energy, wells are dug a mile deep into underground reservoirs to access the steam and hot water there, which can then be used to drive turbines connected to electricity generators.
Some geothermal power plants pipe that steam or water—between 300 and 700 degrees Fahrenheit—to the surface for use as direct heat. Other plants can also convert that heat into electricity. The hydrothermal resources are injected back into the ground after cooling.
More than 60 geothermal plants operate in the U.S. today, providing nearly 4 gigawatts of electricity, which can power more than one million homes. It turns out, however, that most of geothermal power plants are located in places adapted to it by nature, such as Nevada or California with geothermal hot spots like geysers or volcanoes, or where tectonic plates grind past each other and Earth’s heat can move more easily through the crust.