The United States exiting the Paris Climate Accord generated big news, but the fact remains that renewable technology is advancing quickly with big investments being made in wind-, solar- and hydropower. The question is not when renewable energy will take the place of fossil fuels, but which technology will be most efficient at harnessing the power of nature.
Hydropower is kinetic energy generated using tidal patterns to activate turbines. The Office of Energy Efficiency & Renewable Energy says that “all coastal areas experience two high tides and two low tides over a period of slightly more than 24 hours.” The consistent and reliable nature of the tides has propelled hydropower to a valuable renewable energy resource. The largest tidal power station in the world is in South Korea and can generate 254 MW per day; enough to provide electricity to a city of 500,000 people, such as Sacramento, CA.
Advantages of Hydropower:
- Many heavily populated cities are situated on the coasts, allowing the collection and distribution of hydropower to occur efficiently without the need for massive storage
- The activation source, the tides, fluctuates less than solar and is more predictable than the wind.
- At 80%, its efficiency is far greater than solar, coal, or wind.
- Costs of construction for a tidal power plant are high, making the payback period long and the cost per kilowatt-hour uncompetitive with fossil fuels.
- Adversely affects aquatic life and migration patterns.
- There are only about 40 sites on Earth with the required high and low tide differences of more than 16 feet to harness waves for electricity.
Currently, the United States does not have any tidal power plants operational, and there are only a few sites along America’s coasts where it would be economical to implement, namely the Pacific Northwest and the Atlantic Northeast. However, there is a project in the East River of New York that is implementing tidal turbines, which is a more durable and expensive version of wind turbines.
Riding the Wind
Wind currents have been used for thousands of years to power windmills and propel ships. Today the technology is focused on generating electricity in an environmentally friendly way. Wind currents are created by the heating of the atmosphere by the sun, the rotation of the Earth, and the Earth’s surface irregularities. The U.S. Department of Energy reports that in 2016, total wind capacity in the U.S. had the ability to power over 20 million homes or about 16% of the population. The U.S. generates more wind energy than any other country.
- Does not take up a lot of space and can be installed both onshore and offshore.
- Farmers can diversify their income by leasing land for wind power plants. In 2015, $222 million in annual land lease payments were made.
- In 2015, levelized prices of wind energy were as low as 2 cents per kWh, which makes it cost competitive with other sources of electricity.
- The wind is unpredictable, so production is sporadic and difficult to forecast.
- Wind turbines are noisy while operating and therefore are not ideal near residential areas.
- Costly transmission lines must be built to deliver electricity from remote, windy areas to where consumers are located.
Solar is the newest of these three renewable energy sources. The sun’s energy is absorbed through panels containing photovoltaic cells to generate power. When the particles are absorbed, it creates an electrical imbalance in the cell, and the particles move faster, creating electricity. The U.S. is the third-largest solar market in the world and has the production capability of powering more than 5.4 million homes. The Department of Energy says that prices continue to fall, but on average, local permitting and inspection processes add upwards of $2,500 to the initial costs, which hinder growth.
- Solar is the most abundant energy source on Earth; 173,000 terawatts of
solar energy strike the Earth continuously. The Department of Energy says this is 10,000 times the world’s total energy use.
- Solar is the easiest of the three types to integrate into residential areas, as panels can be placed most anywhere.
- Produces energy silently, with very little need for maintenance.
- Exposure to the sun is limited in some places, requiring more cells to produce the needed energy and batteries to hold reserves.
- Absorption is more effective at certain angles, and many solar panels do not rotate themselves to the optimal exposure angle, which decreases the amount of energy generated.
- The inefficiency of solar panel technology requires large, ugly panels to be installed, which discourages many from pursuing the renewable energy source. However, technology advancements are changing the way people power their home with solar.
While each of these technologies has different startup and maintenance costs, experts seem to agree that the location of those in need of power matters most in determining which form of technology to employ. While all three of these renewable energies can be employed on a large scale, solar has already emerged as the most commonly used form of renewable energy by residential consumers. As technologies improve, the costs to install decrease, which makes it more and more likely that hydro, solar and wind renewable energies will be embraced over fossil fuels before long.