The US Energy Information Administration projects renewable energy sources will provide nearly half of the world’s electricity within the next three decades. Most of this, the EIA predicts, will come from solar, wind, and hydropower.
But not all sectors are growing at the same rate. Meanwhile, opportunities for clean energy production exist beyond the big three. Here’s a breakdown of alternatives to fossil fuels from the Union of Concerned Scientists, and some of the recent technological developments in those sectors.
Wind Power is Moving to Deep Water
Some communities don’t want large wind towers as part of their landscape, opposing wind energy primarily on their looks. Others are concerned with the impact on bird and bat populations. Ecologists also cite the possible impact wind turbines have on animals living around the turbine bases.
But new technologies allow recent deep ocean wind projects in formerly unusable locations, far away from bird migratory routes. This technology utilizes floating piers connected with cables to the seabed. This also minimizes the impact on sea life around the turbines.
Wind power is now one of the fastest-growing renewable energy sectors in the world, thanks to lowered capital costs and international investment from some of the world’s largest utilities as they work to reach carbon neutrality goals.
Solar Power When the Sun Doesn’t Shine
Solar energy generation is the fastest growing sector of clean energy technology in the world. It’s also one of the oldest. Chinese home builders were using passive solar techniques as early as 4000 BC. Solar collectors, photovoltaic panels, or thin-film sheeting to turn sunlight into electricity are the core of solar power production. But additional technologies are extending and improving solar’s reach.
Breakthroughs in battery technology have led to an uptick in battery backup for solar electric production. This is true both for individual home systems and for solar farms. Individual storage systems typically use Lithium-ion or Lithium Ferro Phosphate (LiFePO4) batteries. In some areas, peer-to-peer options allow users to share their solar production with neighbors via microgrids.
Solar farms may use lithium-ion, redox flow, lead-acid, or molten-salt batteries. When added to solar farms, battery backups enhance the flexibility options of power system grids and may increase the use of clean solar energy during periods of high demand.
While the term “solar power” may bring to mind traditional panels fitted to the slope of a rooftop or a desert solar farm, in the future solar energy will be produced anywhere using integrated technology indistinguishable from regular building materials. Floating solar farms already exist in China, Japan, the UK, and California. In many new buildings, photovoltaics are now being integrated into roof tiles, skylights, windows, and building facades, making the energy producing components part of the structure. The US Department of Energy is even looking at how to integrate solar power generation into 3,000 miles of interstate noise abatement systems.
Water Drives Nature and Energy
Leonardo da Vinci described water as “the driving force of all nature.” It also provides nearly 20 percent of the world’s electricity. Hydroelectric is one of the top three clean energy sectors. But this sector is growing slower than others as local communities and environmental groups push back against environmental disruption caused by big dam projects to local wildlife and river ecosystems.
Drought has also caused a significant impact on power capacity at some hydroelectric sites. The Hoover Dam has experienced an output drop of nearly 25 percent after two decades of an ongoing drought. While five wide-head turbines designed to operate with lower water elevations have recently been installed as a way to deal with these issues, most of the dam’s turbines rely on higher water pressure in order to generate electricity.
But technology and ingenuity are still finding ways to expand the sector’s reach. Some are looking at necessary existing dams around the world used for flood control or irrigation. These could be retrofitted with turbines for power generation. Others are conducting research on the viability of building pumping stations on existing dams. This older technology uses surplus energy in times of high power production to pump water back into a higher reservoir, allowing it to flow back down to generate energy when it’s needed.
Still others are looking to the tidal or kinetic river flow for power generation. This technology uses natural water velocity or river flow to turn smart in-stream turbines. The turbines are designed to anchor directly to the river bed with little or no environmental impact, minimal space, and very little infrastructure. They can be connected to the grid or used as off-grid solutions for remote areas.
Meanwhile, the National Hydropower Association is working with a number of environmental groups like the Union of Concerned Scientists and the World Wildlife Fund to identify and tear down unnecessary dams in order to improve the health of American rivers.
Is Biomass Green or Dirty?
Unitl 2018 biomass energy was the third-most widely used renewable energy source in the world, at which time it was surpassed by solar. Biomass uses animal manure and agricultural waste to create energy. It is heavily used in underdeveloped areas of the world for both cooking and heating purposes because of its low cost and availability.
While some low-tech biomass uses can have a negative impact on the environment, newer uses can be cleaner. Through the application of technology, resulting gases created from burning biomass can be captured and used for electrical power generation or can be converted into other power byproducts like methanol, hydrogen for fuel cells, and synthetic natural gas.
Geothermal: Warming from the Center
Since geothermal relies on heated water or steam sourced from the earth for electricity production, geothermal plants have been limited to locations where this energy is easily accessed. However, in areas of heavy geothermal activity like California and The Phillippines, geothermal offers electricity production with a carbon footprint 20 times smaller than that of conventional coal-fired plants.
But a 2019 report by the US Department of Energy suggests there could be increased access to geothermal resources using existing technologies borrowed from the oil and gas industry. While the report goes on to say geothermal energy could produce as much as 120 gigawatts of energy by 2050, this requires drilling to depths that might concern some environmentalists. If it were successful, however, such a technological leap would lead to a nationwide, secure, “always-on” resource for clean energy production.
No matter the sector, green energy is paving the way for a better future and a cleaner world.