When people talk about alternative energy, green energy, and renewable energy, it may sound like they’re talking about the same thing — and then someone throws in sustainable energy.
Climate change, greenhouse gases, and emissions are high on the political agenda, which will shape the future of our energy usage.
Let’s clarify some of the jargon around the world’s much-heralded green recovery with this guide to the world’s alternative energy sources.
What Are Alternative Energy Sources?
Energy — be it alternative, green, renewable, or even sustainable — is all around us. Energy is described as the ability to do work.
The Merriam-Webster Dictionary defines alternative energy as “usable power (such as heat or electricity) that comes from a renewable or green resource.”
The Cambridge Dictionary standard definition lists alternative energy as: “energy from moving water, wind, the sun, and gas from animal waste.” However, its business definition goes a little further, stating: “Alternative energy refers to energy sources other than fossil fuels (such as coal, petroleum, and diesel) and includes all renewable and nuclear energy sources.”
Both agree that alternative energy includes renewable resources. However, “green” is pretty vague, and while “gas from animal waste” is quite clearly understood, it’s hardly the first image that comes to mind when thinking about alternative energy sources.
So, the consensus is that fossil fuels are not alternative energy sources, leaving nuclear energy, renewables, natural gas, and more under the alternative energy umbrella.
Fossil fuels are finite resources that release harmful carbon dioxide when burned. The most commonly used fossil fuels are oil, coal, and petroleum.
So, alternative energy is an energy source that’s not a fossil fuel. Let’s look in more detail at all alternative energy sources.
What Is the Difference Between Alternative and Renewable Energy?
Renewable energy is replenishable energy that never runs out and that’s use won’t affect its future availability. Humans use the following renewable energy resources, albeit there is debate about how renewable some of these energy technologies are:
- Solar energy: We will be harnessing the Sun’s power for many billions of years.
- Wind energy: The Earth’s rotation and heat differences ensure breezes turn wind turbines and windmills to create electricity.
- Hydropower: Moving water in rivers, lakes, and dams can rotate turbines to create electricity.
- Geothermal energy: We heat homes and drive electricity generation turbines from ever-replenishing geothermal heat trapped below the Earth’s surface.
- Marine or tidal energy: Wave or tidal energy can drive turbines to create electricity.
- Bioenergy: Energy derived from organic materials and their byproducts come in three primary forms — solid biofuels, biogas, and liquid biofuels like ethanol made from corn and plant materials. Also known as biomass, these are renewable because they can be replaced within a human lifetime.
- Nuclear: New and developing technologies may keep power plants running for longer.
Some people think nuclear power isn’t a renewable energy source because there is a finite amount of uranium available with estimates that only 90 years of supplies remain, based on conventional reactor demands. However, others argue that new technology will lower current high uranium extraction costs, transforming nuclear energy from a sustainable energy source into a renewable energy source.
Similarly, some consider hydroelectric power to be sustainable rather than renewable because of the heavy raw material demands associated with building hydroelectric dams. The same sustainable moniker is sometimes applied to geothermal power, too, because not all the heat drawn is replaced.
What Are Examples of Alternative Energy Sources?
Alternative energy sources include the renewables listed — they are an alternative to fossil fuels — and several more. Alternative energy is a broad church that covers all non-fossil-fuel-based energy sources and processes.
Possibly the most important alternative energy source we use at the moment is natural gas. It is a fossil fuel but relatively clean burning. Its extraction can cause environmental issues, and its status as an alternative energy is often hotly debated. We use natural gas to heat our homes and produce electricity. In 2019, natural gas accounted for 24.2% of the world’s energy needs.
Heat pumps are a fast-growing alternative energy source. There are three main types: ground source, air source, and water source. They all work slightly differently but essentially draw energy from either ground, air, or water to provide heating and hot water to people’s homes.
Wood burning is both an alternative energy fuel source and also not. Confusing. Chopping trees to burn in wood stoves can lead to deforestation, which, in turn, contributes to global warming. On the other hand, new trees can be grown, making them a source of biomass renewable energy. If a new tree is grown for every tree cut down, wood burning is sustainable.
Hydrogen gas is a byproduct of burning fossil fuels and natural gas, and of nuclear power and biomass processes. Hydrogen fuel cells can create electricity, NASA used hydrogen fuel to send rockets to space, and adapted cars use it as a pollutant-free fuel.
Hydrogen can be derived from organic, biodegradable waste. Technology also exists to split water via electrolysis, leaving behind hydrogen and creating almost no pollutants. In addition, the energy efficiency of electrolysis is very high if the machines run on renewable energy sources.
What Types of Alternative Energy Sources Do We Use Today?
Most countries use a wide range of energy systems for power generation. As a result, energy production depends on the type of energy source nearby and the amount of energy required.
In 2016, some 65% of Iceland’s primary energy came from geothermal power, with 20% from hydro electricity and just 15% from fossil fuels. About 85% of all houses in Iceland are heated with geothermal energy.
Different countries all have diverse energy ecosystems shaped by the sources of energy available to them. For example, Scotland doesn’t sit on huge geothermal energy sources but has enormous onshore and offshore wind resources. In 2019, wind farms and other renewable energy sources supplied 90.1% of Scotland’s electricity.
China is the global leader in solar power with its large-scale solar farms offering more than 250 gigawatts (GW) of installed electricity capacity. The United States is second with 75 GW of installed capacity of photovoltaic solar cells.
Methane gas is a significant alternative energy. Methane is a byproduct of oil and gas production processes. Methane lasts for around 12 years in the atmosphere compared to many centuries for carbon dioxide, but methane is very destructive in the atmosphere during its short lifetime.
Some 40% of methane originates naturally while the remaining 60% comes from human activities, including waste sites and agriculture. Methane can be captured and processed then used in natural gas pipelines to heat homes, making it an alternative energy source.
What Alternative Energy Sources Are Inexhaustible?
Inexhaustible alternative energy sources are the renewable energies that we won’t run out of. These include:
- Solar energy
- Wind energy
- Geothermal energy
- Marine or tidal energy
- Bioenergy, including methane
What Alternative Energy Sources Are Exhaustible?
An exhaustible alternative energy source is nuclear energy. Some people argue nuclear power is a renewable energy source, despite there being long-term uranium sourcing issues. New technologies and extraction techniques in so-called breeder reactors could make nuclear material last indefinitely. Fossil fuels — oil, gas, and coal — are not alternative energy sources, and they are also exhaustible.
What Is the Best Alternative Energy Source?
The best alternative energy source is hard to determine. For example, solar is great in sunny places but no good when the sun doesn’t shine. Wind power is fabulous on breezy days but not on still days. Hydropower is dependable and efficient but requires large-scale construction work.
What Is the Most Efficient Alternative Energy Source?
Hydropower is the most efficient alternative energy source if you’re only looking at how well it converts energy.
- Wind: achieves 35-50% efficiency usually, with a 59% maximum efficiency level (100% efficiency means no wind would flow past the turbine).
- Solar panels: currently convert around 17-19% of the solar thermal energy they receive, albeit much work is being done to make photovoltaic cells more efficient.
- Geothermal: performs quite poorly compared to the others, its worldwide average is 12% energy efficiency, with some plants reaching up to 21% energy efficiency.
- Hydropower: The most efficient alternative source, hydro converts around 90% of energy into electricity.
- Nuclear: These power plants will often achieve 33-45% efficiency.
- Bioenergy: covers a wide range of fuels from methane to corn-based ethanol. Typically, the biomass-to-fuel efficiency is between 32-65%.
- Marine or tidal: is very much in its infancy, and more development is needed. Water is heavier than air and a marine turbine has to be heavier and sturdier, but it can capture more energy than a wind turbine.
Why We Use Alternative Energy Sources to Battle Climate Change
Renewable energy and alternative energy sources are vital tools in the battle to reduce greenhouse gas emissions and the amount of carbon dioxide in the atmosphere. Fossil fuels have been reliable and cost-efficient ways to produce power for decades, but that is changing as governments look to greener energy sources.
Indeed, a new report claims that by 2025, almost 80% of United States coal plants will be retired or more costly to run than solar or wind.
A study by the University of California, Berkeley, concluded that, by 2035, some 90% of the U.S. electric grid could be powered without greenhouse gas emissions while also offering cheaper electricity rates to consumers.
The falling price of alternative energy sources and their increased efficiency will help the world on its target to net-zero emissions by 2050, as agreed in The Paris Agreement.
Replacing Fossil Fuels
The 18th-century industrial revolution brought about mass use of coal to power factories, heat homes, fuel steam-driven trains, and more. Natural gas has been used by humans since 900 B.C. and gained popularity in the United States in the early 19th century.
Oil and petroleum use originated in ancient times, too, with recorded use as far back as 480 B.C. — they were also used in the industrial revolution. The 20th century and the internal combustion engine propelled oil to paramount importance in fulfilling the world’s energy needs.
These processes have released billions of tonnes of greenhouse gases into the atmosphere, contributing to global warming.
Can Alternative Energy Sources Effectively Replace Fossil Fuels?
Alternative energy sources may eventually replace fossil fuels, but there is a lot of investment and work to do before that is achievable.
Many alternative energy sources provide us with electricity but not constantly. The Sun doesn’t always shine, and the wind doesn’t always blow. Coal, natural gas, and nuclear power plants are dependable energy sources that help keep the lights on.
Just over half of a U.S. home’s energy use is on space heating and air conditioning. We need reliable energy sources to keep us warm in the winter months, which is why many people use gas-based heating systems. However, policymakers are now looking at localized solutions. Instead of piping gas all over a country for heating, local air source or ground source heat pumps could keep homes warm.
Capturing excess renewable energy is vital, too. Large-scale battery farms are set to increase, storing electricity created on sunny or windy days in batteries that release the energy during peak demand or when no renewable energy is being produced.
Investment continues to flow into alternative energy sources. According to U.S. Energy Information Administration forecasts, renewables could overtake natural gas as the United States’ largest electricity provider around the year 2030.
Fossil fuels may be set to decline, but they will be an essential part of the energy mix for many decades to come.
Environmental Cost of Green Energy and Clean Energy Sources
Green energy and clean energy sources seem to offer a win-win for our energy-hungry society. But, green energy is not a panacea for climate change.
There are many downsides to alternative energy sources, and not just the carbon footprint of building and installing them in the first place.
Hydropower construction uses enormous quantities of cement, and dams can affect local wildlife, displace populations, and even create new microclimates.
Wind turbines kill birds, bats, and insects. People living near them sometimes complain of noise pollution.
Solar panels require a lot of space, taking up valuable room in an already crowded world and destroying habitats. Solar cells require many precious minerals and resources, too, and great care will need to be taken to recycle them when they come to the end of their working lives.
Geothermal power plants emit noise and unpleasant sulphuric smells while tidal and wave energy disrupt marine life.
Nuclear power plants have inherent issues with radiation and how to release water used in their processes safely.
The Future of Alternative Energy Sources
Alternative energy sources are at the start of what could be a takeover of the world’s energy supply. The movement to cleaner, sustainable energy sources is underway and hard-baked into political rhetoric.
Fossil fuels, nuclear power, and natural gas will provide a lot of global energy for a long while yet, but their days of dominance appear shorter with every decade that passes.
Brought to you by amigoenergy
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