Common Questions About Renewable Energy

Renewable energy sources like solar, wind, and hydropower are gaining momentum across the globe. But how exactly does renewable energy work, and can it realistically replace conventional energy sources? This article explores the most common questions about renewable energy and its role in building a carbon-neutral society.

What is Renewable Energy?

Renewable energy comes from natural sources or processes that are constantly replenished. Major types of renewable energy include:

Solar power: Captures energy from the sun using panels with photovoltaic cells.
Wind power: Harnesses the wind with large turbines to generate electricity.
Hydropower: Uses flowing water to spin turbines connected to generators.
Bioenergy: Converts biomass from plants and waste into fuel and electricity.
Geothermal: Taps into underground reservoirs of steam and hot water to produce energy.

These resources are considered renewable because they are naturally replenished over relatively short timescales. The five major renewable sources accounted for 12.2% of total U.S. energy consumption and 17.5% of electricity generation in 2019, according to the U.S. Energy Information Administration (EIA).

In contrast, non-renewable energy relies on finite resources like fossil fuels (coal, oil, and natural gas) and nuclear fuel. While abundant, these supplies will eventually dwindle. Coal, petroleum, and natural gas accounted for 80% of total U.S. energy consumption in 2019, highlighting the nation’s continued dependence on non-renewable sources.

Benefits of Renewable Energy

Transitioning to renewable energy offers considerable benefits:

Environmental advantages: Renewable sources produce little to no greenhouse gas emissions, limiting their contribution to climate change. In 2019, renewables avoided an estimated 455 million metric tons of CO2 emissions in the U.S., equal to 9% of total energy-related emissions. Growing the renewable share can significantly curb emissions from the power sector.

Renewables also have minimal adverse effects on the environment compared to other energy supplies. For example, wind turbines and solar arrays don’t pollute the air and water like power plants. And unlike coal mining, the extraction of fuel does not scar natural landscapes.

Economic opportunities: The renewable energy sector is a major U.S. employer. Wind turbine service technicians and solar photovoltaic installers are among the two fastest growing occupations, with each expecting to add over 5,000 new jobs by 2029, per EIA projections. Expanding renewable capacity can create domestic jobs in manufacturing, construction, and other industries.

Renewables can also save consumers money. Costs for renewables are decreasing substantially, making them more competitive with conventional energy. And home solar panels or geothermal heat pumps can lower utility bills. Tax credits and incentives at the federal and state levels help offset the upfront costs as well.

Energy independence: Unlike finite resources that requires imports from other countries, renewable energy sources are abundantly available domestically. Expanding U.S. renewable capacity decreases our reliance on imported fossil fuels and increases energy independence.

Grid resiliency: Distributed renewable energy systems with battery storage offer reliability in the case of extreme weather events. During hurricanes or wildfires, on-site solar panels can provide backup power to homes and businesses when grid power is disrupted.

Sustainability: Renewable resources replenish naturally, so they will never run out. By investing in renewables now, we can safeguard energy supplies for current and future generations. The inexhaustible nature of renewables provides long-term energy security.

Impact on the Environment

There is overwhelming scientific consensus that renewable energy has a much lower environmental impact than conventional energy supplies. Life cycle assessments consistently show that renewables generate fewer polluting emissions and wastes.

The National Renewable Energy Laboratory (NREL) analyzed the cradle-to-grave sustainability of various energy technologies. Solar panels, wind turbines, and hydropower plants were found to have minimal impacts across metrics like climate change, air pollution, water use, and ecological damage. Fossil fuel technologies had substantially higher environmental impacts.

Specifically, wind power produces just 2% of the life cycle air pollution emissions of coal power per unit of electricity generated, according to NREL data. The carbon footprint of hydropower is around 75 times lower than natural gas. And solar’s global warming emissions are up to 6 times lower than those of fossil fuel plants.

Renewables are not completely free of environmental effects, but these are modest compared to other energy sources. For example, large solar farms can impact desert ecosystems if not properly sited and managed. And wind turbines pose a minor hazard to birds and bats. However, research shows careful siting and mitigation measures can reduce wildlife impacts significantly.

On the whole, peer-reviewed studies overwhelmingly demonstrate that renewables are far more eco-friendly than oil, coal, and natural gas. Expanding renewable energy is crucial for mitigating climate change and protecting the environment.

Economic Viability

One common concern with renewable energy is upfront costs. Installing solar panels or a wind turbine requires high initial investments. And historically, fossil fuel plants could generate cheaper electricity than renewables. However, costs have changed dramatically in the last decade.

According to NREL, utility-scale solar electricity costs dropped 89% between 2009 and 2020, thanks to improving technologies and economies of scale. Home solar panel systems saw a 70% decrease in costs over the same period. The story is similar for wind power, with turbine prices declining by around 40% over the last 10 years.

As a result, renewables have reached historic cost competitiveness. In 2020, the U.S. Energy Information Administration reported that:

Onshore wind is the cheapest electricity source, with an average cost of $28 per megawatt-hour.
Solar photovoltaics follow at $36 per MWh.
By comparison, advanced natural gas plants average $44 per MWh.

And costs are projected to continue falling, making renewables ever more economically appealing.

Various incentives also help offset the initial price tag. The federal investment tax credit (ITC) offers a 26% tax credit for residential solar installations. Many states provide additional rebates, performance incentives, and net metering programs. These can discount modern residential solar systems by 50% or more.

For homeowners, rooftop solar panels offer long-term savings on electric bills too. Once the system is paid off, additional electricity is essentially free. The economics will continue improving with energy storage that harnesses solar energy at night.

When all factors are considered, renewable energy is increasingly cost competitive with conventional fuels. And supportive policies can accelerate adoption by reducing costs for consumers, manufacturers, and energy developers.

Frequently Asked Questions

How does renewable energy work to generate electricity?

Renewable energy technologies harness natural resources and turn them into usable power through various processes. Here is a simplified explanation for the most common sources:

Solar: Solar cells inside the photovoltaic panels convert sunlight directly into direct current (DC) electricity using semiconducting materials. Inverters then convert the DC to usable alternating current (AC).
Wind: As wind pushes the blades of the turbine, a rotor spins to turn an internal shaft connected to a generator. This creates an electromagnetic field that results in AC electricity.
Hydropower: Flowing or falling water strikes turbine blades or buckets, spinning a shaft. The motion spins electromagnets inside a generator, producing AC electricity.
Bioenergy: Plant matter like crops, wood, and waste are burned to heat water, producing steam that spins turbines. This mechanical energy is converted into electricity by generators.
Geothermal: Naturally heated subsurface water travels through wells to the power plant. There, the hot steam from the reservoirs spins turbines coupled with generators to produce electricity.

So in summary, most renewables use mechanical processes to spin magnets within an electrical generator. The spinning magnets generate AC power that can be fed into the grid for practical use.

Can renewable energy realistically replace fossil fuels?

Many experts believe renewable energy can indeed replace the majority of fossil fuel use, especially for electricity generation. According to the Department of Energy, the U.S. has the potential to get over 80% of its power from renewables by 2050.

Achieving this will require substantial political commitment and public/private investment. But renewables have several advantages working in their favor:

Abundant domestic resources – The U.S. has vast solar, onshore wind, geothermal and hydropower potential. Offshore wind is also an untapped resource.
Drastically falling costs – As outlined earlier, costs have dropped dramatically, making renewables the most affordable energy option in many cases.
Ever-improving technologies – Technologies will continue advancing, driving efficiency up and costs down further. Energy storage is a game-changer for overcoming renewable intermittency too.
Supportive policies – Government incentives and emission reduction targets encourage the energy transition. Many states have renewable portfolio standards that require utilities to get a percentage of their electricity from renewables.
Corporate demand – Major companies like Google, Amazon, and Walmart are demanding clean energy and investing in large renewable projects. This appetite helps drive the market.
Public opinion – A Pew Research Center survey found that 90% of Americans favor expanding solar panel farms and wind turbine farms. Just 9% oppose expansion.

Overcoming challenges around upfront costs, transmission, and inertia of the current system will take time and continued effort. But the tide is turning in favor of renewables becoming a primary energy pillar. The potential is demonstrated by countries like Denmark, which generated over 40% of its 2019 electricity from wind power.

Are renewable energy sources reliable?

Critics argue renewable sources are too intermittent to meet constant energy demands. The sun does not always shine, and wind speeds fluctuate. This leads to concerns about reliability compared to the relative consistency of fossil fuels.

There are several factors that make renewables dependable energy providers:

Capacity factors – While weather-dependent, modern wind turbines and solar arrays seldom operate below 20-30% of their maximum capacity thanks to diverse geographic placement. Capacity factors are improving as technology progresses too.
Forecasting – Sophisticated forecasting models predict wind and sunlight conditions over different timescales, enabling better electricity delivery planning.
Geographic distribution – Distributed renewable sources spread over large areas mitigate local weather effects and balance out variability.
Grid integration – Utilities already adjust electricity supply and demand to avoid shortfalls. Adding renewables is manageable, especially when forecasts are accurate.
Energy storage – Battery storage systems help address intermittency by saving surpluses and dispatching power during lulls. Other storage solutions like pumped hydropower and thermal energy provide suppleness.
Complementary sources – Using a diverse mix of renewables improves reliability. For example, solar and wind can balance each other out as weather patterns change.

In a seminal 2012 study, a team of researchers at Stanford University modeled a reliable grid comprised of 90-99% renewable electricity across the continental U.S. The diverse combination of geographically-distributed wind, solar, geothermal and storage was able to match energy demands at 5-minute intervals for a full year. This demonstrates full reliability based solely on renewables is feasible.

As technology improves and grid management evolves, renewable sources can absolutely provide stable and dependable energy generation.

What are the most prevalent types of renewable energy?

The renewable resources making the largest contributions to U.S. energy supply today are:

Hydropower

Provides over 7% of total U.S. electricity.
Accounts for 36% of renewable electricity generation.
Cumulative capacity is over 100 gigawatts.
Traditional dam-based hydropower provides reliable base load power. Run-of-river and tidal systems are newer technologies.

Wind power

Supplies over 7% of total U.S. electricity.
Accounts for 42% of renewable electricity generation.
Cumulative capacity is over 122 gigawatts.
Utility-scale onshore turbines make up most capacity, but U.S. offshore wind is expanding.

Solar power

Accounts for just under 2% of total U.S. electricity but is the fasting growing renewable.
Supplies almost 20% of renewable electricity.
Cumulative capacity is over 75 gigawatts.
Includes utility-scale solar farms as well as commercial and residential rooftop systems.

Bioenergy

Makes up almost 5% of total U.S. energy and 12% of renewables share.
Uses solid biomass, liquid biofuels, biogas and municipal waste.
Biomass from forest products is the largest bioenergy source.

Geothermal

Provides 0.4% of total U.S. electricity and 2% of renewables mix.
Capacity is around 3.8 gigawatts.
Harnesses high-temperature hydrothermal resources located along tectonic plate boundaries.

Solar, wind, and hydropower offer the greatest potential moving forward thanks to falling costs, scalability, public support, and policy momentum. But bioenergy and geothermal will play important roles as well.

What are challenges facing greater renewable energy adoption?

While the prospects for renewables are strong, expanding their role faces some stubborn challenges:

Upfront costs – Developing utility-scale renewable plants requires major capital investment. These costs are falling but remain barriers, especially for smaller providers.
Inconsistent policies – Renewable energy tax credits and incentives fluctuate or have expirations. Policy uncertainty slows industry growth and investment.
Grid limitations – Additional transmission infrastructure is needed in some areas to add more renewables. Outdated grids strain with variable sources.
Energy storage – Affordable and scalable storage is needed to fully mitigate renewable variability. Battery costs are declining but remain high.
Entrenched interests – Influential lobbying groups for incumbent industries obstruct policies supporting renewables. The transition threatens conventional energy business models.
Low public awareness – Knowledge gaps persist among consumers around renewable technologies and options for switching. Misconceptions about reliability and costs exist.

Targeted policies like extended tax credits, upgraded transmission, and public education campaigns can help address these roadblocks. Continuing to drive down costs will also make integration more feasible.

How can individuals and businesses transition to renewable energy?

Citizens and companies can take a number of steps to switch from conventional to renewable energy:

Homes

Install solar panels or wind turbines to generate onsite renewable electricity
Purchase shares in community solar projects to receive credits
Check if your utility offers an affordable 100% renewable energy option
Under some electricity markets, sign up for renewable energy certificates (RECs)

Businesses

Install solar arrays or wind turbines onsite at your facilities
Enter a long-term power purchase agreement (PPA) with an offsite renewable energy project
Look into options offered by energy retailers and utilities serving commercial customers
For large corporations, directly invest in developing new renewable plants to power operations

Green power programs offered by over 850 U.S. utilities provide perhaps the simplest option. These programs allow customers to opt for renewables through their existing utility provider without onsite generation. Utility green pricing programs have over 700,000 subscribers across the country.

The Database of State Incentives for Renewables & Efficiency (DSIRE) provides a comprehensive list of state, local, utility, and federal incentives and policies for renewable energy. Using DSIRE, individuals and businesses can find opportunities and financial support specific to their location.

The Promise of a Renewable Future

Renewable energy holds remarkable potential to sustainably power modern civilization while avoiding the harmful consequences of fossil fuels. As costs decline and technologies improve, renewables are poised to transform societies around the globe. While obstacles remain, we now have economically viable and proven tools to transition toward a 100% renewable energy future. Harnessing nature’s own forces can provide us energy in perpetuity, while allowing the environment to prosper.