Why Is Solar Energy Better Than Water?
Solar and hydroelectric power are two major renewable energy sources that offer clean alternatives to fossil fuels like coal, oil, and natural gas. Unlike fossil fuels, renewable sources like solar and hydroelectric do not directly emit greenhouse gases that contribute to climate change. There are several key differences between solar and hydroelectric power when it comes to cost, scalability, environmental impact, and other factors. This article provides an overview of the advantages and limitations of both solar and hydroelectric energy.
Solar power harnesses energy from the sun and converts it into electricity using photovoltaic panels. Hydroelectric power generates electricity by using turbines that are spun by moving water. Both are considered renewable sources because they are continuously replenished – the sun shines every day and the water cycle is never ending. When comparing the two, there are pros and cons to each in terms of upfront costs, total capacity, ecological effects, accessibility, and more. This article will analyze the strengths and weaknesses of both solar and hydroelectric power.
Solar Capacity Factors
The capacity factor refers to the actual output of a power plant compared to its maximum possible output. It is expressed as a percentage, with higher percentages indicating more efficient utilization of a plant’s capacity. Solar PV systems tend to have higher capacity factors than other renewables like wind or hydro. According to the National Renewable Energy Laboratory, the average capacity factor for solar PV systems in the U.S. is around 25%.[1] The capacity factors of PV systems depend on many factors like location, panel tilt, tracking systems, and local weather patterns. Desert regions like Arizona can achieve capacity factors over 30% whereas cloudier regions may be closer to 20%.
Overall, solar PV systems tend to achieve high capacity factors because they generate power whenever the sun is shining. Unlike intermittent wind resources, solar irradiation levels are more consistent throughout sunny days. With improved panel technologies and sun tracking systems, capacity factors for solar PV systems continue to increase.
Cost and Scalability
Overall, solar power is more cost effective and scalable than hydropower. According to Ecoflow, the average cost to build a new hydropower plant is around $2,000 per kW, while utility-scale solar costs between $1,000-1,500 per kW. Solar panel prices have also dropped over 90% in the last 10 years, making solar very cost competitive. In terms of scalability, solar has a major advantage as panels can be installed almost anywhere and scaled up easily by adding more panels. Hydropower requires specific geography and is limited by suitable damsites. Chariot Energy notes that globally there are few remaining quality sites for new large dams. Solar’s modular nature allows it to scale rapidly to meet energy demand. The Quora post compares costs and notes that while hydro was cheaper historically, costs are increasing as the best sites are taken, while solar costs continue to decline.
Environmental Impact
When comparing the environmental impact of solar power and hydropower, there are pros and cons to consider for each.
On the pro side, solar power has very little environmental impact once the solar panels are installed. Solar panels generate electricity without emissions, noise, or pollution. The main environmental concerns are associated with the manufacturing process and materials used to make solar panels, which have become cleaner and more sustainable over time. Solar power can be installed on homes and buildings without drastically changing the local environment or ecosystem.
However, hydropower has some environmental benefits as well. Hydropower is a renewable energy source and does not directly emit greenhouse gases. The reservoirs created by hydropower dams can also be used for recreation and activities like boating and fishing.
On the con side, large hydropower projects can have major environmental impacts by changing river flows, altering local wildlife habitats both upstream and downstream, and impacting water quality and sediment transport. The dams required for hydropower flood large areas of land and can displace human populations as well. There are concerns about methane emissions from the decomposing plant matter in hydropower reservoirs. Smaller “run-of-river” hydropower projects have less impact but still alter the natural water flows.
Overall, from a purely environmental perspective, solar power has advantages over large-scale hydropower projects because it generates renewable electricity with minimal disruption to local ecosystems. Solar has a clear edge when it comes to environmental sustainability (https://blog.ecoflow.com/us/hydro-power-vs-solar-energy/). However, hydropower’s environmental pros and cons depend heavily on the size and design of each specific project.
Energy Storage
Solar energy can be more easily stored than hydroelectricity, giving it an advantage when it comes to flexibility of energy supply. Solar energy can be stored directly in batteries or indirectly as other forms of energy produced through solar electricity, like hydrogen fuel or heat. This allows solar power to supply energy on demand, even when the sun isn’t shining. Large-scale batteries like the Tesla Megapack allow solar farms to store excess daytime energy for use at night. Homeowners with rooftop solar can store solar energy in batteries like the Tesla Powerwall for use when the panels aren’t generating electricity. Hydroelectricity requires use of pumped storage plants to store potential energy by pumping water uphill into a reservoir so it can later flow downhill to generate electricity. However, suitable sites are geographically limited. Only about 5% of hydro capacity globally uses pumped storage due to topographical constraints and high costs of around $2,500 per kW of storage capacity (Source). This makes large-scale energy storage more difficult with hydroelectricity compared to solar power.
Accessibility
Solar energy has a major advantage over hydropower when it comes to accessibility and democratization. Solar panels can be installed in most locations that receive sufficient sunlight, whereas hydropower requires the right topographical conditions like fast-flowing rivers or waterfalls to generate electricity (Source: https://blog.ecoflow.com/us/hydro-power-vs-solar-energy/). This makes solar energy much more accessible and able to be distributed across communities. Solar has a decentralized nature that allows individuals and businesses to install solar panels on roofs and produce their own electricity. In contrast, large hydropower dams tend to be centralized mega-projects that require substantial infrastructure and investment. Solar energy has opened up energy production and control to regular people, not just large utilities and corporations. The modular and scalable nature of solar lends itself to democratization and accessibility in a way that massive hydropower projects do not.
Reliability
When it comes to reliability, hydropower has historically had an advantage over solar power. Hydroelectric dams can generate electricity 24/7 as long as there is sufficient water flow. Solar power relies on sunny days and is intermittent, generating only when the sun is shining (see https://solarpower.guide/solar-power-vs-hydropower).
However, extended droughts can severely impact the reliability of hydropower by reducing water levels. During California’s 2011-2017 drought, hydroelectric generation dropped significantly, forcing increased reliance on natural gas (see https://chariotenergy.com/chariot-university/solar-energy-vs-hydropower/). Solar power is not affected by droughts in the same way and can provide more consistent energy in drought-prone regions.
Additionally, improvements in energy storage technology are making solar power more reliable and grid-friendly. Battery storage systems can store solar energy for use when the sun isn’t shining. With sufficient storage capacity, solar power can provide consistent baseload power around the clock (see https://blog.ecoflow.com/us/hydro-power-vs-solar-energy/).
Safety
Hydroelectric dams and the water around them can be extremely dangerous. According to Pacificorp, surfaces around dams can be very slippery which can cause people to fall into the water. Damsafety.org notes that “low-head dams are especially dangerous because the water around them often appears to be tranquil and inviting.” There have been many accidental drownings because people underestimate the power of the water or currents near dams.
Activities like swimming, wading, boating, or fishing near spillways is very risky, warns Hydro Quebec. The currents can trap and pull people under. There can also be unpredictable releases of water from dams which significantly alter water levels quickly. Many organizations strongly advise staying away from dams and restricted areas near hydro facilities. Proper fences, warning signs, and buoys should be installed and obeyed.
While dam failures are rare, they can be catastrophic. Poor construction, inadequate maintenance, earthquakes, and flooding events can all contribute to dam failures. Robust safety regulations and practices are critical to avoid accidents and loss of life.
Global Potential
When analyzing the global potential of solar power versus hydropower, the evidence clearly shows that solar has a much greater capacity for growth and expansion worldwide. While hydropower relies on specific geographical conditions like large rivers or elevation changes, solar power can be implemented nearly anywhere. According to https://blog.ecoflow.com/us/hydro-power-vs-solar-energy/, solar energy’s theoretical potential is over 600 terawatt hours (TWh) per year globally, compared to just 16 TWh for hydropower. With solar panel efficiencies and storage solutions improving, solar power has an opportunity to transform the global energy landscape in a way hydropower simply cannot due to inherent geographical limitations.
Conclusion
In summary, there are several key reasons why solar energy is better than hydroelectric power in most cases:
Solar energy has a higher capacity factor than hydroelectric dams, meaning solar can produce a more consistent supply of electricity. While droughts and seasonal changes impact hydroelectric output, solar panels can reliably generate energy year-round in most locations.
Solar energy is highly scalable and modular, with the ability to install small rooftop systems or massive utility-scale solar farms. In contrast, large hydroelectric dams require massive upfront investments and major environmental interventions like dams and reservoirs.
From an environmental perspective, solar has a clear edge over large hydro projects that radically transform river ecosystems and disrupt natural water flows. Solar panels can be installed in existing areas like rooftops to minimize land use impacts.
While limited pumped hydro storage offers an advantage for hydropower, the rapid declines in battery storage costs improve solar’s ability to provide power when the sun isn’t shining. And distributed solar with storage provides better energy resilience and security.
Overall, solar photovoltaics provide a flexible, low impact, and sustainable energy solution that can scale to meet the world’s electricity demands. The modularity and declining costs of solar give it significant advantages over hydroelectricity in the long term.
