New Urgency Spurs Development of Renewable Energy Technologies
As droughts, fires, extreme weather events, and rising seas become harder to ignore, researchers are accelerating the development of more powerful technologies to harvest energy from renewable energy sources. Interconnects will play a key role.
There are still a few skeptics who deny global climate change, but over the past year the discussion has largely shifted to what if anything can be done to mitigate its effects. Rising global temperatures, ocean levels, and the extreme weather events scientists predicted would accompany unchecked carbon emissions are now being reported daily around the world. A new sense of urgency has begun to spur research and development of renewable energy alternatives to fossil fuels.
The future of energy appears to be focused on electrification of nearly every aspect of our daily lives, from communication to transportation. However, generating electrical energy to support this evolution by using coal, oil, and natural gas will increase of carbon emissions and exacerbate rising temperatures. Hydroelectric power remains an important source of renewable electrical energy, especially in the Western U.S., China, and Brazil, but protracted droughts are threatening adequate reservoir levels needed for efficient operation. Additional sources of renewable energy, including biomass, geothermal, and hydrogen, contribute relatively little to our total energy production.
The current mix of electricity generation in the U.S. remains highly tilted toward fossil fuels.
The race to develop grid-scale alternatives began years ago, but the pace of exploration and innovation to develop entirely new solutions has quickened. Harsh environment connectors are key to these technologies.
Wind and solar power have become the most well-developed renewable power sources. Wind farms consisting of from five to 120 turbines have sprung up on the plains of every continent and in offshore locations. These huge machines continue to grow, with the largest standing 853 feet high with blades 351 feet long. The Haliade-X 13 wind turbine, for example, produces a maximum of 14 megawatts (MW) with competitive machines rated to 16 MW. It is estimated that about 120–175 wind turbines are required to replace a single coal-fired generating station.
Solar energy production has scaled from rooftop solar panels that provide the electrical demands of a single home to large commercial solar arrays that serve the needs of a community. The efficiency of perovskite photovoltaic cells have improved from approximately 3% in 2009 to 25% in 2020, while the cost per cell has made it competitive with conventional sources. Flexible solar cells can conform to curved surfaces while others are integrated into rooftop tiles, improving the appearance of a residential solar installation.
The well-documented problem with wind and solar generation is that turbines need consistent wind and solar panels require bright sunlight to be productive. During periods of calm winds, cloud cover, and nighttime, both sources produce no energy and require a backup. The economics of wind and solar fall apart when a local utility must maintain conventional generating resources to assure reliable 24/7 service. To solve this imbalance between supply and demand, engineers are developing new high-capacity energy generation and storage systems to assure constant supply. Some of these approaches are designed to support peak intermittent demands while others can become a new primary source of energy.
Storage of grid-level energy has been the focus of intense research for years. Conventional lead-acid batteries have been retired in favor of more advanced chemistries, including lithium-ion batteries. Tesla is building a 300-megawatt battery in Geelong, Australia, to stabilize the output of local wind farms and solar arrays. It will utilize modular Tesla Megapack rechargeable lithium-ion technology to provide 450 megawatt-hours of energy storage. The US$22 billion Australia-Asia PowerLink project will deliver 17-20 GW of solar electricity to Singapore using the world’s largest battery storage facility and 2,600 miles of undersea cables starting in 2027.
Flow batteries which convert electrical energy to stored chemical energy have been employed in several locations for load leveling and intermittent disruptions. Intense research is being applied to addressing issues of high-cost materials as well as extending the recharge life cycle.
Cost plays a key role in utilization of these storage alternatives. One solution in development may be a grid scale battery based on air and iron which utilizes a reversable rust process to store energy at an estimated cost of 1/10th of lithium-ion batteries. Another approach to low-cost energy storage is the compression of carbon dioxide which generates stored heat during the charge cycle. To discharge, the liquified CO2 is evaporated and expands to drive electric turbines. A 4.0 MWh pilot plant is expected to begin production in 2022. Construction is underway in the U.K. for the 250 MWh CRYOBattery which uses cryogenic cooling technology to convert ambient air into liquid. This liquid can be stored and released when needed to drive a turbine. It uses surplus electricity from wind farms to compress the air.
The world’s largest tidal turbine was launched in April 2021. It is moored to the seabed and generates 1MW by capturing tidal flow. Stored kinetic energy in the form of heavy weights suspended in a vertical mine shaft can be lifted with excess energy in periods of low demand and lowered to spin generators in peak demand periods. Another proposal uses the principals of phase change to capture and release heat to store energy. A 200 KW “blowhole” generator has been installed in Tasmania which harnesses wave energy by channeling water in and out of a concrete chamber. Several compressed air storage systems have been built using underground tanks or caverns to store high-pressure air which can be released to turn a turbine. Using the principal of buoyancy, a grid of buoyant tubes is pulled down to the sea floor and allowed to rise turning a turbine. Excess electricity from nearby offshore wind turbines could be used to submerge the tubes.
Nuclear energy production is one of the most efficient low-pollution sources of electricity we have today. However, the industry has earned a poor reputation for safety and cost overruns and, coupled with a handful of nuclear power station incidents in the U.S., Russia, and Japan, the nuclear option has been in the doldrums for the past 30 years. New technology, coupled with the rise of “mini” nuclear generation plants, are regaining interest in nuclear power. The U.S. Department of Energy is currently funding 10 nuclear reactor projects based on next generation designs.
Small Modular Reactors (SMRs) feature control systems that inherently shut down if a failure occurs, eliminating the potential for disasters that have plagued the industry. They are designed to serve a relatively small number of consumers in a limited geographic area, which reduces the cost and power loss of long transmission lines. SMRs may be manufactured in a factory and trucked to the installation site, eliminating years of design, siting, construction, and certification time.
NuScale is an example of this new generation of compact modular nuclear reactors. This light water reactor module is only 65 feet tall and 9 feet in diameter and can generate 77 MW of electricity. A group of modules can be switched on and off the grid to support variations in demand.
Military posts in remote locations have been identified as ideal candidates for deployment of SMRs to replace fuel hungry diesel generators. A one-megawatt micro nuclear generator that fits in a shipping container could be quickly deployed to power about 1,000 homes in disaster areas. One proposal locates micro nuclear generation modules on self-contained barges which could be quickly deployed anywhere in the world.
Another major player is Natrium, which is a sodium-cooled fast reactor designed to run 24/7 with 345 MW capacity. Bill Gates has been an active supporter of the Natrium reactor design. The company is expected to build a demonstration plant at the site of a retired coal-fired generation plant in Kemmerer, Wyoming, by the mid to late 2020s. Decommissioned coal-fired power stations make ideal sites for installation of these next-generation reactors, as they can take advantage of the existing generators and transmission infrastructure as well as continuing employment of experienced utility workers. Maintaining the existing tax structure also benefits the local community.
Three additional fourth generation nuclear power reactor designs include the Very High Temperature Reactor, the Molten Salt Reactor, and the Pebble-Bed Reactor, each of which have demonstration units in various stages of construction. China is reported to be nearing completion of the world’s first thorium molten salt nuclear reactor.
The concern about the hazards of nuclear power generation cannot be ignored, nor the issue of safe transportation and storage of spent nuclear fuel. This new generation of nuclear reactors can mitigate the objections by the much-reduced levels of waste radioactive materials, as well as opening of long-term safe storage facilities that already exist. Clear unbiased analysis of the risks associated with transport and storage of waste material compared with the environmental impact of extraction, transportation, processing, and burning of fossil fuels could change a lot of attitudes toward the nuclear option.
The ultimate solution would be the successful harnessing of nuclear fusion, a goal that has frustrated scientists for years. Requiring temperatures similar to that of our sun, fusion would offer nearly unlimited clean and renewable energy. The Korean Superconducting Tokamak Advanced Research Reactor recently maintained 180 million °F plasma for 30 seconds, a world record. Helion Energy raised US$500 million in funding to complete the startup’s 7th generation prototype machine, which it expects will demonstrate a net increase in energy output by 2024.
The key to the successful transformation to clean and renewable energy production ultimately depends on an adequate transition period that allows new technologies to be fully developed and deployed at grid scale. A rush to adopt and become dependent on immature solutions could threaten grid reliability and result in unacceptable utility rates.
All these innovations will make extensive use of utility-grade transmission as well as system management interconnects. In the U.S., the recently passed Build America, Buy America Act will provide $65 billion to upgrade the country’s splintered and antiquated electrical distribution system, providing excellent opportunities for connectors to influence new energy technologies for years to come.
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