Renewable Energy Overview

RE is Growing

Shares of renewable energy throughout the world


Solar farms, wind farms, hydroelectricity (and other hydrokinetic projects), biomass plants, and geothermal energy projects have the potential to deliver much of the world's energy needs - depending on how much investment these RE sources receive. Renewable energy sources currently account for over ¼ of the electricity generated in the global energy mix, as an overall rough average between all RE sources combined (although that figure could more than double by mid-century - see the chart from BNEF below).

In its World Energy Outlook, the International Energy Agency identifies pathways for clean energy technological solutions needed to reach global carbon neutrality (i.e. net zero greenhouse gas emissions) by 2050. It also details interim goals that will ensure the world is on the path to carbon neutrality. In order to achieve the 2050 goal, by 2030 low carbon sources (the majority of which will ultimately be RE sources) need to generate 75% of the world's energy (up from ~40% today, including nuclear as a low carbon energy source).

Many European countries; especially Northern European nations; led by Norway, Sweden, Iceland, Germany, Denmark, and the United Kingdom - have a large share of renewable energy production in their energy mix. Most countries throughout Europe invest in significant development of renewable energy technologies and substantial generation from RE sources.  Dropping prices for renewable energy, and favorable public policies for renewables, have seen the share of RE generation take the lead in energy production in many countries throughout Europe.

The whole of the United States generates about 20% of its electricity from renewable energy sources; despite many states having renewable portfolio standards that require those states to generate a certain amount of their energy from renewables. The U.S., the U.K., Denmark, France, Sweden, and New Zealand, among other countries, have mandated their countries reach carbon-neutrality by mid-century (Sweden aims for net zero emissions by 2045), in large part by the use of renewable energy.

Many Latin American countries produce a significant amount of renewable energy, about ¼ as an overall rough average of the majority of Latin American countries' overall energy mix; though some countries in Latin America produce much higher shares of renewable energy. China produces around ¼ of its electricity from RE sources for its electricity generation (despite having a much higher share of RE generating capacity in its energy mix). Meanwhile, India has a renewable energy capacity of over ⅓ of its total installed energy capacity.

However, it must be noted that the amount of renewable energy generation varies widely from country to country, and from region to region within countries. States and provinces within countries have wide variations of renewable energy generation as a share of a country's energy mix, and have varying mandates for future renewable energy production. For example, in the United States, California produces over 40% of its energy from renewable sources, and is under a statewide mandate to get 100% of its electricity (100RE) from clean energy sources by 2045.

Falling Cost of Solar and Wind


Sources of renewable energy (RE) include hydroelectric energy (and hydrokinetic energy), wind (onshore and offshore), solar (PV and solar thermal technologies), biomass (and biofuels), and geothermal. Each of these forms of RE are discussed below in the "Sources of Renewable Energy" section.

Wind and solar have achieved cost-competitiveness with fossil fuels and have also reached high levels of efficiency recently. For reference, below is Lazard‘s levelized cost of energy (LCOE) chart - showing that RE (especially onshore wind farms and utility-scale solar) is becoming more affordable.

On the LCOE chart, it’s onshore wind farms and utility-scale solar photovoltaics (PV) with the best (or tied for the best) overall prices of all energy sources.

Onshore wind and utility-scale PV are now priced lower than coal. Both onshore wind and utility-scale PV are now at cost parity, or even cheaper, than gas combined cycle (when the full LCOE is taken into account, and in certain circumstances)>>> 

Lazard‘s levelized cost of energy (LCOE)

Future Expansion of RE


Bloomberg New Energy Finance (BNEF) sums up the projected rise of solar and wind in the below chart (this is a chart of global installed RE RE generation should closely mirror the trend seen in capacity markets). While solar and wind are projected to expand significantly, hydroelectric capacity is projected to remain constant. As hydro remains constant, wind and solar are quickly growing, and will soon dominate the global RE market (hydro is currently the dominant form of global RE). In fact, in the United States, wind (at just over 8% of total electricity generation) has already overtaken hydro (at just over 7%) as the dominant form of RE.  In much of Europe, wind has long surpassed hydro in the RE generation market.

Below is a chart of RE's rise to mid-century (BNEF's green scenario), and a few of BNEF's top-line takeaways from their energy outlook to 2050>>>

Achieving Net-Zero by 2050, BloombergNEF's Green Scenario: New Energy Outlook 2021 | BloombergNEF

"1. Wind and solar make up almost 50% of world electricity in 2050 – “50 by 50” – and help put the power sector on track for 2 degrees to at least 2030.

2. A 12TW expansion of generating capacity requires about $13.3 trillion of new investment between now and 2050 – 77% of which goes to renewables.

3. Europe decarbonizes furthest, fastest. Coal-heavy China and gas-heavy U.S. play catch-up.

4. Wind and solar are now cheapest across more than two-thirds of the world. By 2030 they undercut commissioned coal and gas almost everywhere."


Sources of Renewable Energy




Grand Coulee Dam, Washington state

The largest single source of renewable energy worldwide is hydroelectricity, mostly from hydroelectric dams. Hydropower represents a significant portion of total overall world RE production - about 60% of the world's renewable electricity generation is from hydroelectricity (and in the U.S., about 35% of all renewable electricity generation is from hydroelectricity). As far as electricity consumption originating from hydroelectricity, over 16% of the world's electricity needs are met by hydroelectricity (around 7% in the U.S.).

In the United States, renewable energy represents about 20% of total energy generation as an overall average of all 50 states, although Washington state gets over 90% of its energy from hydroelectricity alone. Hydroelectricity represents just over 7% of total U.S.electricity generation (as a total average when all the states are factored in).

Dams can easily be installed in almost any waterway, including rivers in remote rural areas. A reservoir (water from a river, lake, or another waterway) is let through a hydroelectric dam by the dam's operators when it's time to generate electricity. The kinetic energy of the water flowing through the dam turns turbines, which generate electricity. Although hydroelectric dams have proven to be a reliable energy source, dams do present myriad issues.

Dams, both large and smaller scale, produce some ecological problems and require constant maintenance. Dams do tend to result in large reservoirs of stagnant water, erosion of wetlands, and erosion of areas surrounding the dam, along with other problems for the local ecosystems downstream from where dams are developed. These ecological problems caused by hydroelectric dams can be mitigated with ecological remedies implemented by the dams' developers and operators.

Freshwater tidal energy; as well as ocean waves, currents, and tides, also represent dynamic, abundant sources of renewable energy. Hydrokinetic systems are in use in freshwater lakes and rivers throughout the world today. These RE sources are environmentally friendly; as long as care for the affected ecosystems is implemented and maintained by the RE developers.

The most common types of these freshwater hydrokinetic systems include tidal barrages and tidal stream generators. Ocean sources of hydropower remain in the research and development phase and have reached the demonstration phase for a few projects worldwide...

Please see:

Hydrokinetic and Marine Power


London Array Offshore Wind Farm 

Wind power is generated with the conversion of energy by wind turbines into electricity (the kinetic energy of wind turns electricity-generating turbines). Wind farms are installed on uninhabited land, unused desert land, agricultural land, or offshore (most offshore wind farms are currently in Northern European countries).

Wind farms have some of the lowest environmental impacts of all large-scale renewable energy sources.

Wind is the source of over 6% of the world's electricity needs (over 20% of global electricity generation), and that number is rapidly climbing. In the United States, over 8% of electricity needs are met by wind, and in countries in Europe, the average for wind is about 14%. Some European countries generate a much higher share of wind energy for their electricity needs. For example, Denmark generates over half of its electricity from wind power.

Large-scale wind farms are much more common than units for individual homes. Smaller wind turbine units are increasing in production, however, and are capable of powering anything from large appliances or generators, to RVs, to entire buildings; depending on the size of the turbine.

Please click & read:

Breakthroughs in wind energy technology

London Array – paving the way for efficient offshore wind energy farms

Anholt Offshore Wind Farm — Denmark’s most powerful source of renewable energy

The Block Island Wind Farm – America’s ONLY operational offshore wind farm

It must be noted that employment opportunities in clean and renewable energy, especially wind and solar are consistently growing; while the cost of RE is decreasing, and the efficiency of clean energy continues to increase.



Photovoltaic (PV) solar power entails harnessing the sun's energy to directly produce electricity by converting sunlight into electricity through solar PV cells (the "photovoltaic effect"). New solar technologies are developing at a rapid pace, bringing the cost of community solar and some rooftop solar to reach cost parity with coal and some gas energy generation. Some solar PV is now priced below the cost of fossil fuels (in the cases of utility-scale thin-film PV and utility-scale crystalline PV).

Solar cells are becoming more efficient, thinner, smaller, transportable, flexible, and even spray-on. This allows for easy installation, use, and efficient energy production. Solar PV cells, solar panels, solar micro-grids, and solar farms, have been used to power a wide range of applications.

Solar technologies are used in everything from the calculator powered by a single solar cell, to off-grid homes powered by an entire photovoltaic array; to solar farms powering thousands of homes and buildings in a city. Large-scale, or mega, solar farms are growing in deployment worldwide. Concentrated Solar Power (CSP), solar towers, dishes and troughs, are all growing sources of renewable energy (solar thermal energy sources).

As opposed to PV, which directly generates electricity, solar thermal uses solar energy indirectly, to heat a working fluid. Solar thermal, including CSP and solar water heaters (among a few other forms of solar thermal), uses technology (generally special mirrors for solar energy creation - heliostats) to harness the sun's energy; but then that energy heats a working fluid, which is ultimately used to generate electricity (traditionally the energy production takes the form of steam that turns turbines, as in many other forms of energy generation). One benefit of solar thermal is that a few forms of energy storage are readily available when this form of renewable energy is employed.

Please click & read:

Recent breakthroughs in solar photovoltaic and solar thermal technologies

Community solar and net metering – pushing renewable energy forward

Ivanpah Solar Electric Generating System

The 550 megawatt Topaz Solar Plant



Biomass includes food crops that easily convert to energy like corn, sugarcane, wheat, soybean, palm, and sorghum. Biomass sources also include agricultural by-products, forestry remnants, as well as other organic matter (this category of biomass includes crop residues, agricultural waste, other waste streams, wood chips, peat, and bark). Sources of biomass also include non-food energy crops such as switchgrass and various types of algae.

Biomass includes organic matter and biodegradable wastes that can be used as biofuel (ethanol and biodiesel). Biomass can produce energy for a municipality in a biomass power plant, be converted into biofuel, or even power a farm (see the link to anaerobic digestion below).

Biomass/ biofuel can be derived from numerous types of organic cellulosic plants (energy crops such as switchgrass), in addition to waste (municipal waste, agricultural residues, forestry remnants, etc...). Using cellulosic feedstocks is a way to avoid using crops needed for food, and also represent readily available or easy to produce feedstocks. Cellulosic biomass feedstocks are abundant, inexpensive, non-food sources for biomass/ biofuel energy production.

Many varieties of plant species can be used for biomass/ biofuel production, however, algae is an especially promising biomass source. Algae are among the fastest-growing plants in the world, and as much as 60% of their weight is plant-based oil - making algae a potent source for energy generation.

Please see:

Algae- the future of biofuel

Anaerobic digestion - a proven solution to our waste problem

Cellulosic biofuel - fuel solutions



Geothermal power also has small and large-scale designs. Geothermal heat pumps, on the small end of the spectrum, are less common than industrial plants. Geothermal plants are located near natural energy sources; tectonic plate boundaries, volcanoes, hot springs, and geysers. Geothermal energy is primarily power generated from natural steam and hot rocks, magma, or lava which heat water underground in the earth's crust.

The majority of geothermal power is produced by conveying heated water or steam back to the surface so that its heat can be extracted through a heat exchanger, or its pressure can be used to drive turbines. An example of an area of the world rich in geothermal energy potential, production, and use is Iceland.

Please see:

Geothermal district heating in Iceland

Of course, there are a few other potential RE sources, including forms of kinetic renewable energy and futuristic RE ideas not mentioned above. Other types of RE in widespread use today include, most notably, hydrogen and hydrogen fuel cells, although the main type used today is 'grey' hydrogen for industrial applications. Grey hydrogen is sourced from fossil fuels for use in fossil fuel-intensive industries. 'Green' and 'blue' hydrogen (green is made with RE and blue is made using carbon capture) can potentially, eventually, be used to help meet the world's energy needs.

More R&D is needed for the rest of Europe, the USA, and Australia (among other countries in Asia and elsewhere that have shown an active interest in hydrogen fuel cells), to use hydrogen/ hydrogen fuel cells efficiently and effectively as a major energy source. However, there are already significant hydrogen fuel cell bus projects in some European countries.