Other renewables
The U.S. has a considerable amount of untapped geothermal energy, and it isn’t intermittent. We have tapped much of our hydroelectic potential with big dams, but small dams can be retrofitted for more capacity, as well as water pipes for conduit hydro. Building new dams may be inadvisable because concrete has a large carbon footprint and methane from decomposing plants leaks from flooded areas. Nevertheless, hydroelectric power meshes nicely with solar and wind power, since it runs nearly continuously and can be ramped up quickly to offset fluctuations.
Under development
Wave and tidal energy is currently under development. Ocean water is 800 times denser than air and much more powerful. It is therefore the largest untapped source of renewable energy on the earth. Waves and tides are also more constant than the sun or winds, so extracting power from them could provide useful baseline energy. However, working underwater is much more difficult and salt water is highly corrosive. So wave and tidal energy would be the most expensive of renewables.
Algae-based biofuels for aircraft are also under development. Seaweed farming could draw CO₂ out of the atmosphere. Enhancing the weathering of minerals could also remove CO₂, but may be too energy-intensive or costly.
Scientists are creating isomers which work as solar thermal fuels. Isomers are like rechargeable batteries, but instead of storing electricity, they store sunlight and release heat. Researchers are also developing better batteries and materials for solar and wind applications.
Cement accounts for about 7% of global man-made greenhouse gas emissions. Numerous companies are working on new cement production methods which greatly reduce, eliminate, or sequester such emissions, for instance by capturing CO₂ in the concrete itself. Using more wood in construction could help by sequestering carbon rather than emitting it by building with cement and steel.
Nuclear fission reactors could be improved with sodium rather than water as a coolant, but those are years away from widespread implementation. Modular reactors could reduce costs. Fast breeder reactors could be powered by what is presently considered spent fuel for hundreds of years, and they would reduce stockpiles of radioactive waste materials, if in fact we can make that technology work in the future. Fast reactors could also make it economical to extract uranium from seawater. Nuclear fusion, which remains unproven, could solve our energy problems all by itself, but it’s unlikely ever to become economical compared with lower tech solutions.
The U.S. has a considerable amount of untapped geothermal energy, and it isn’t intermittent. We have tapped much of our hydroelectic potential with big dams, but small dams can be retrofitted for more capacity, as well as water pipes for conduit hydro. Building new dams may be inadvisable because concrete has a large carbon footprint and methane from decomposing plants leaks from flooded areas. Nevertheless, hydroelectric power meshes nicely with solar and wind power, since it runs nearly continuously and can be ramped up quickly to offset fluctuations.
Under development
Wave and tidal energy is currently under development. Ocean water is 800 times denser than air and much more powerful. It is therefore the largest untapped source of renewable energy on the earth. Waves and tides are also more constant than the sun or winds, so extracting power from them could provide useful baseline energy. However, working underwater is much more difficult and salt water is highly corrosive. So wave and tidal energy would be the most expensive of renewables.
Algae-based biofuels for aircraft are also under development. Seaweed farming could draw CO₂ out of the atmosphere. Enhancing the weathering of minerals could also remove CO₂, but may be too energy-intensive or costly.
Scientists are creating isomers which work as solar thermal fuels. Isomers are like rechargeable batteries, but instead of storing electricity, they store sunlight and release heat. Researchers are also developing better batteries and materials for solar and wind applications.
Cement accounts for about 7% of global man-made greenhouse gas emissions. Numerous companies are working on new cement production methods which greatly reduce, eliminate, or sequester such emissions, for instance by capturing CO₂ in the concrete itself. Using more wood in construction could help by sequestering carbon rather than emitting it by building with cement and steel.
Nuclear fission reactors could be improved with sodium rather than water as a coolant, but those are years away from widespread implementation. Modular reactors could reduce costs. Fast breeder reactors could be powered by what is presently considered spent fuel for hundreds of years, and they would reduce stockpiles of radioactive waste materials, if in fact we can make that technology work in the future. Fast reactors could also make it economical to extract uranium from seawater. Nuclear fusion, which remains unproven, could solve our energy problems all by itself, but it’s unlikely ever to become economical compared with lower tech solutions.
