May 26th, 2020

What is renewable energy?


By Submitted Article on March 23, 2020.

Submitted by the southern alberta group for the environment

The challenge is to reduce the enormous amount of fossil energy we use and replace it with cleaner energy. Pollution has an enormous impact on human health and the integrity of natural systems, so less of it is better for everyone. Renewable energy technologies convert energy from inexhaustible sources into electricity. The energy source in the case of solar panels (photovoltaics) is the sun, whereas the energy source for wind turbines is the velocity and mass of the wind.

Renewable energy technologies require fossil energy to manufacture (as 90 per cent of world energy consumption is currently derived from fossil fuels), and these processes result in various forms of pollution. This is no different than conventional energy technologies: coal production, oil and natural gas refining, and electricity generation plants also produce pollution. As such, using less energy is always the best choice to reduce pollution.

The main reason for installing commercial-scale renewable energy technologies is to reduce pollution compared to conventional fossil-fuel technologies. To do this, the renewable technology must generate more energy when compared to the energy consumed in their manufacture (and to install and maintain). Every one unit of fossil energy invested up front in the renewable energy technology permits more units of energy to be delivered from the sun or the wind.

Here are some examples: In the case of solar, the energy it takes to manufacture a square metre of panel is 1,150 kWh. A kWh, or “kilowatt-hour,” is the same unit of energy in which you purchase your electricity. In Lethbridge, a square metre of solar panel will produce about 225 kWh of electricity each year. If the solar panel lasts its expected lifespan of 25 years, it will produce five times more energy than it took to manufacture it.

Similarly, the energy it takes to manufacture a common two-megawatt wind turbine is 2.8 million kWh. The wind turbine will produce about 3.5 million kWh each year for an expected lifespan of 20 years. A wind turbine will produce roughly 25 times more energy than it took to manufacture it.

What is renewable energy? Today, it is a process of making fossil fuels more productive: Take one unit of energy from a fossil fuel, use it to make a renewable energy technology, and generate five to 25 times more energy over time. Because you are increasing the efficiency of the original unit of fossil fuel, you are creating smaller amounts of pollution per kWh of electricity produced.

The caveat: renewable energy technologies have to be installed in locations that maximize sun or wind exposure, and all of the electricity generated must be used. This requires a well-designed and operated electricity system that will receive electricity when it is generated and provide electricity when it is needed.

In summary, when one wonders what renewable energy is today, think of it as improving efficiency (making more energy from each unit of fossil-fuel energy invested), and think of it as a means of reducing pollution. We live in a full world: renewable energy technologies are an existing way to do better and begin to reduce our environmental impact.

For more information, please visit sage-environment.org.

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2 Responses to “What is renewable energy?”

  1. Michelle Stirling says:

    Wind and solar cannot support even basic society because of the low return on energy invested. Prof. Michael J. Kelly explains this. https://www.cambridge.org/core/journals/mrs-energy-and-sustainability/article/lessons-from-technology-development-for-energy-and-sustainability/2D40F35844FEFEC37FDC62499DDBD4DC/core-reader Alberta is too far north for viable solar – anything north of the 35 N latitude, solar is an ‘energy sink’ (uses more energy to make the panel that it will produce). This report ‘IN THE DARK ON RENEWABLES” explains the Alberta context of renewables. https://blog.friendsofscience.org/wp-content/uploads/2018/11/In-the-Dark-on-Renewables-FINAL-Nov-18-2018.pdf Video: https://youtu.be/l7ZUiz-vQgA Likewise, please see Robert Lyman’s report “Transition to Reality” https://www.thegwpf.org/energy-policy-needs-to-transition-to-reality/ Another excellent resource is Prof. Emeritus Vaclav Smil; he has about 40 books on the topic. See this free video: https://youtu.be/5guXaWwQpe4 (Note: I am the Communications Manager for Friends of Science Society and posting this information in the public interest. Thank you.).

    • SAGE Chair says:

      Thank you, Michelle Stirling for your contribution to this discussion.

      There are two main points in our article in The Lethbridge Herald. The first is that renewable energy technologies improve the efficiency of fossil energy sources, and that this efficiency lowers the pollution generated per unit of energy delivered. This should be no more controversial than an automobile with better mileage and lower emissions, or one assisted with battery technology to offset fuel consumption.

      The assertion that the EROEI of photovoltaics above 35N latitude is lower than one (and therefore a net loser of energy or ‘energy sink’) is not correct. The value we used is on the conservative end of the range provided in current life-cycle analyses using international standards (ISO 14040:2006). The energy output of PV solar panels is based on RETScreen modelling developed in Canada, and validated by the actual output of the many solar installations in Alberta.

      SAGE is very familiar with the work of Vaclav Smil. We agree with his 2014 article in Scientific American that states: “There are many environmental reasons to reduce dependence on fossil fuels, even beyond the quest for reduced greenhouse gas emissions. Burning fossil fuels emits sulfur and nitrogen oxides that lead to acid rain and photochemical smog, black carbon that adds to global warming, and heavy metals that harm human health. Reliance on fossil fuels also causes water pollution and ruins land. A switch to nonfossil energy is environmentally desirable, although some of the alternatives also have significant environmental impacts.”

      As to our second main point, you will note the heavy emphasis on reduction of energy consumption. Smil also says: “The most important way to speed up the gradual transition to renewables is to lower overall energy use. The faster demand rises, the harder it is to supply a large fraction of it. Recent studies have shown that there are no insurmountable technical problems to reducing energy use by a third, both in the affluent world and in rapidly modernizing countries, notably through efficiency gains.”

      The challenges of energy transition that your links refer to is also of concern to SAGE. The rapid transition rates required in the next ten years (as is the consensus statement of the world’s climate scientists as expressed by the IPCC) is indeed daunting, particularly as we have squandered a thirty-year opportunity to do so since Dr. James Hansen testified to a Congressional committee that anthropogenic global warming had been detected and validated by scientific observation. Based on the current climate science, delaying the transition to ‘later’ is officially over.

      But even if the Friends of Science does not respect valid science, it shouldn’t be too contentious to accept renewable energy technologies based on the prosaic grounds that they work and they lower pollution per unit of energy delivered for human use.