What Is Similar To Hydropower?

Hydropower is a renewable source of energy that utilizes the natural water cycle to generate electricity. It is considered a clean and sustainable energy source as it does not produce greenhouse gas emissions. Hydropower stations capture the energy from flowing water to turn turbines and generate electricity. According to recent statistics, hydropower accounts for over 16% of global electricity generation and makes up 71% of renewable energy production worldwide.

While hydropower has many advantages, it also has some limitations. Building large dams and reservoirs can be environmentally disruptive and expensive. In this article, we will discuss some of the main alternative renewable energy sources that are similar to hydropower in certain ways, but may offer their own benefits and advantages. The goal is to provide an overview of the various technologies that can also harness natural resources to produce clean and renewable electricity.

Solar Power

Solar power generates electricity from the sun’s rays using photovoltaic cells typically arranged in solar panels. When sunlight hits the cells, it excites the electrons and causes them to flow, creating an electrical current that can be captured and fed into the electrical grid or used directly at the source. Solar panels can be installed on rooftops or ground-mounted over large areas to generate electricity.

Solar power works as an alternative to hydropower because it harnesses renewable energy from the sun. It does not require damming rivers or rivers at all. Solar power can be deployed almost anywhere that receives sufficient sunlight. According to Our World in Data, global solar power capacity has grown massively since 2000 to over 1,000 gigawatts as of 2021. Solar power represented over 15% of renewable electricity generation in 2022, up from 13.5% the previous year, and continued growth is projected (EcoWatch).

Solar energy can supplement or replace hydropower as a carbon-free renewable energy source. It offers advantages such as no moving parts, minimal operation and maintenance costs, and modularity from small to utility-scale installations. With sufficient sunlight and area for panels, solar power provides a viable alternative to generate electricity without needing dams or diversions.

Wind Power

Wind power is the use of wind turbines to mechanically generate electricity. Wind turbines convert the kinetic energy in wind into electrical energy that can be distributed. According to Global wind power capacity statistics, by the end of 2020, global wind power capacity reached 743 GW. The global capacity has increased exponentially, more than doubling in the last 5 years from around 350 GW in 2015.

Wind turbines have large blades that harness the wind’s kinetic energy as it propels the blades. The rotational motion created spins a shaft connected to a generator to produce electricity. Utility-scale turbines are increasingly being built onshore and offshore with typical capacities of 2-3 MW. The size of wind turbine blades has increased dramatically in recent years, with leading models now over 100 meters long. This allows them to capture more wind energy.

While the wind turbine components have become larger, technology innovations have also made turbines more efficient by optimizing control systems, materials, blade design, and other aspects. The average turbine generates over 15 million kWh annually, providing power to around 1,500 homes. With the growth in wind power capacity around the world, turbines are making a substantial contribution to electricity grids.

Geothermal

Geothermal energy comes from the natural heat inside the earth. The temperature increases as you go deeper underground – in some places exceeding 500°F at around 10,000 feet deep¹. This heat can be harnessed in a few different ways to generate electricity.

Geothermal power plants are built over geothermal reservoirs in the earth’s crust. Wells are drilled into the reservoirs to pump hot water or steam to the surface. The steam rotates turbines which activate generators and produce electricity. After being used, the cooled water is returned back into the earth.

The geothermal capacity worldwide has gradually increased over the last decade, reaching around 15 gigawatts in 2022². Countries like Iceland, New Zealand, and Indonesia where geothermal resources are more readily accessible have integrated it into a substantial portion of their energy mix.

Compared to other renewables, geothermal provides reliable base load power capable of operating 24/7. However, its potential is geographically limited based on the location of reservoirs. Enhanced geothermal systems are being researched to produce geothermal power outside of ideal locations.

Tidal Power

Tidal power is one of the alternative energy sources similar to hydropower that harnesses the energy of tides to generate electricity. Tidal power uses the rise and fall of ocean tides and converts the energy of tidal currents into electricity (EIA). The key component of tidal power is a barrage or dam built across an estuary or coastal inlet. Tidal barrages function like traditional hydropower dams by temporarily holding back the tide and releasing the stored water through turbines to generate electricity. There are also tidal stream generators that function like underwater wind turbines to capture the kinetic energy from tidal currents.

Although not as widely used as hydropower, tidal power offers some key advantages. Tidal currents are highly predictable, allowing tidal power to provide continuous base load power generation similar to coal or nuclear plants. Tidal power is also renewable and does not emit greenhouse gases. However, tidal power can affect marine life and navigation similar to hydropower dams. Currently, global tidal power capacity is estimated at over 500 MW, with the largest plant being the 254 MW Sihwa Lake Tidal Power Station in South Korea (EIA). Though still small, many countries are evaluating tidal power as part of their renewable energy expansion plans.

Wave Power

Wave power or wave energy refers to technologies that harness the energy in ocean surface waves and convert it into electricity. Waves are caused by wind blowing over the ocean, and contain huge amounts of energy that can be captured and used as an energy source. According to the U.S. Energy Information Administration, the theoretical annual energy potential from waves off U.S. coasts is estimated at 2,640 trillion kilowatt-hours.

There are a few different ways to harness energy from waves, but most rely on wave energy converters that utilize the rising and falling motion of waves to capture energy. Some common wave energy converter designs include:

• Point absorbers – Buoy-like structures that bob up and down with wave motion. This motion drives an electrical generator.
• Oscillating water columns – Partially submerged structures that use wave action to compress air within a chamber. This air flow spins a turbine.
• Overtopping devices – Structures that focus waves over their tops into a reservoir. The water is then released to spin turbines.

Wave power holds great potential as a clean, renewable energy source. However, it faces challenges around technology durability in harsh ocean conditions and transmitting the electricity back to shore. According to NREL, globally over 20 different companies are currently working on wave energy converter technologies.

Biomass and Biofuels

Biomass refers to organic matter that comes from plants and animals, and can be used as an energy source. Common types of biomass used for energy production include wood, crops, waste from animals, and organic municipal and industrial waste. Biomass contains stored energy from the sun. When biomass is burned, the chemical energy is released as heat and can be used to generate electricity with a steam turbine. Biomass and biofuels are considered renewable energy sources because if properly managed, biomass can be replenished.

Biofuels are fuels made directly or indirectly from biomass. The two most common types of biofuels are ethanol and biodiesel. Ethanol is made by fermenting the sugars in crops like corn, sugar cane or sweet sorghum, and is primarily used as a blending agent with gasoline. Biodiesel is produced from oils or fats using transesterification and can be used in diesel engines. Biofuels are attractive energy sources because they are renewable and have lower lifecycle greenhouse gas emissions compared to fossil fuels. However, large scale production of biofuels may compete with food production for land use.

According to the U.S. Energy Information Administration, biomass energy consumption in the United States was around 4,930 trillion Btu in 2022 [1]. Global electricity generation from biomass totaled 685 TWh in 2021, up from 318 TWh in 2000 [2].

Hydrokinetic

Hydrokinetic power is a type of hydropower that generates electricity from the natural movement of water, such as ocean currents, tides, and inland streams, without the need for dams or other barriers [1]. Hydrokinetic turbines are placed directly in flowing water to harness the kinetic energy from the natural flow to turn a generator and produce electricity.

In-stream hydrokinetic power uses the flow of rivers and streams to generate electricity. Turbines are placed directly in the stream flow like small underwater windmills. The flowing water moves the turbine blades, which spin a shaft connected to a generator to produce electricity. In-stream hydrokinetic does not require dams or diversion of the water flow, so it has a minimal environmental impact on rivers.

Advantages of in-stream hydrokinetic power include its low environmental impact, ability to generate consistent baseload power from rivers and streams, and potential to provide distributed generation to local communities and industries. Challenges include the variability in stream flow, turbine maintenance and longevity in water, and uncertain regulatory framework. Overall, in-stream hydrokinetic represents a promising renewable energy source that leverages existing stream assets.

Pumped Storage

Pumped storage hydropower uses cheap electricity, often during off-peak hours when electricity demand is low, to pump water from a lower reservoir to an upper reservoir. During periods of high electrical demand, the stored water is released back to the lower reservoir through a turbine to generate electricity (1). This allows pumped storage plants to act like a battery, storing energy and generating electricity when it is needed most.

According to the International Hydropower Association, total installed pumped storage hydropower capacity was estimated at 158 GW globally in 2019 (2). In the United States, pumped storage hydropower capacity reached 18,776 megawatts in 2021, providing about 93% of utility-scale electrical energy storage in the country (3). While most pumped storage capacity is in Europe, China, and Japan, many countries are investing in new pumped storage projects to support the integration of variable renewable energy sources like solar and wind power.

Pumped storage hydropower plays an important role in stabilizing the electrical grid by providing grid reliability services. It allows excess renewable energy to be stored rather than curtailed. The fast ramping capabilities of pumped hydro also complement solar and wind power, enabling increased renewable energy penetration. With energy storage needs expected to grow dramatically, pumped storage hydropower will continue to be an attractive large-scale energy storage solution.

Sources:
(1) https://www.hydropower.org/factsheets/pumped-storage
(2) https://www.iea.org/data-and-statistics/charts/pumped-storage-hydropower-storage-capability-by-countries-2020-2026
(3) https://www.statista.com/statistics/1031121/pumped-storage-hydropower-capacity-us/

Conclusion

In summary, there are several renewable energy sources that can serve as alternatives to traditional hydropower, each with their own advantages and disadvantages. Solar power harnesses the sun’s energy using photovoltaic panels, and has become increasingly affordable and efficient in recent years. Wind power utilizes large turbines to capture kinetic energy from the wind, and like solar, has expanded greatly in capacity and fallen in cost. Geothermal taps into underground heat reservoirs to generate steam and spin turbines. While geothermal capacity is site-limited, it provides consistent baseload power. Tidal harnesses the immense power from the tides, but facilities are expensive and site-limited. Wave energy devices capture the energy of ocean surface waves, but the technology is still under development. Biomass converts biological material into energy sources like methane gas, liquid fuels, or electricity. However, it requires large amounts of feedstock and land. Hydrokinetic devices generate power from free-flowing water, with less environmental impact than dams. Pumped storage facilities act like large batteries by pumping water uphill and then releasing it to spin turbines when power is needed. In conclusion, each of these technologies offers renewable alternatives to traditional hydropower dams, with their own distinct advantages and practical limitations.