TIL about wind and solar power


What will it take to generate the electricity our society needs, without generating carbon emissions? In this episode of TILclimate (Today I Learned Climate), Dr. Magdalena Klemun at the MIT Institute for Data, Systems and Society joins host Laur Hesse Fisher to begin exploring this question, starting with wind and solar power. What exactly are wind and solar power? What challenges do we currently face when trying to use wind and solar to generate most of our electricity? What’s the role of energy storage, and what could our future zero-carbon energy mix look like?

Dr. Magdalena Klemun, a postdoctoral associate at the Trancik Lab at the MIT Institute for Data, Systems and Society, works on understanding how the economic and environmental performance of technologies evolve in response to different innovation efforts, with an emphasis on the cost evolution of photovoltaic systems and nuclear power plants, and on the environmental performance evolution of natural gas technologies. She has degrees from MIT, Columbia University, and Vienna University of Technology.

TILclimate is produced by the MIT Environmental Solutions Initiative.

Season two of TILclimate focuses on our global energy system, its relationship to climate change, and what our options are for keeping the lights on while creating a clean energy future. We're partnering with the MIT Energy Initiative, which will air longer interviews with each guest to take a deeper dive into these topics.

For more episodes of TILclimate by the MIT Environmental Solutions Initiative, visit tilclimate.mit.edu

For related podcasts from the MIT Energy Initiative, visit:




Laur Hesse Fisher: [00:00:00] Hello and welcome to Today I Learned: Climate, the show where you learn about climate change from scientists and experts. I’m Laur Hesse Fisher from the MIT Environmental Solutions Initiative, recording from my home due to the coronavirus pandemic. If you’re listening to this while self-isolating, be well to yourself and others during this tough time.

You’re joining our energy and climate series, which we’re running in collaboration with the MIT Energy Initiative. We’re now going to start digging into, what will it take to generate the electricity our society needs, without generating carbon emissions?

For the rest of the season, we’re going to be exploring our clean energy options -- wind, solar, storage, nuclear and others -- and the benefits and drawbacks that come with each of these technologies.

It might not be a surprise that we’re kicking it off with a conversation about wind and solar power. And to do this, we spoke with Dr. Magdalena Klemun.

Magdalena Klemun: [00:01:09] My name is Magdalena Klemun, and I'm a postdoc at the Institute for Data Systems and Society here at MIT. I'm interested in the fundamental mechanisms of innovation and how they affect different clean energy technologies and lead to improvement over time.

Laur Hesse Fisher: [00:01:26] And wind and solar power have improved a lot in the last few decades -- but we’ll get to that in a minute . Wind power and solar power are very different kinds of energy sources than coal, oil, natural gas, and even nuclear power. First, they are renewable.

Magdalena Klemun: [00:01:44] Instead of burning a fuel that contains carbon renewable technologies convert either the kinetic energy in air or in water -- in the case of wind and hydro -- into electricity, or they convert light into electricity. That would be photovoltaics.

Laur Hesse Fisher: [00:01:59] Photovoltaics are probably what you think of when you hear about “solar energy.” These are the blueish panels that you might have seen on roofs of buildings or in big rows on land. Sunlight is absorbed by the solar panel, which causes a process that dislodges electrons and creates an electric charge.

As we’ve covered in a previous episode, fossil fuels like coal, oil, and natural gas are burned to create steam and turn a turbine. Wind and hydro power also involve turning a turbine, but they do so using the force -- or kinetic energy as Dr. Klemun called it -- of the wind or flowing water. So that means you don’t need to burn anything to turn the turbine and generate the electricity.

Magdalena Klemun: [00:02:40] And since we live in a world where what we're really trying to get rid of is carbon. That's a pretty convincing proposition.

Laur Hesse Fisher: [00:02:47] Wind and solar power are appealing ways to generate electricity for a lot of other reasons, too.

Magdalena Klemun: [00:02:53] The economics are different across locations, but also every single country on this planet has direct access to solar and wind energy. And so that's pretty unique for an energy source. If you consider, for example, that 70% of global resources of natural gas are concentrated in five countries.

 And then another reason is that renewable energy technologies have proven easy to scale. So all we need to do to build a megawatt scale solar photovoltaic plant instead of a small rooftop system is to put more solar panels in a row and more rows next to each other.

So in other words, we scale by repetition, and that's relatively easy.

Laur Hesse Fisher: [00:03:33] This is relative to coal, natural gas, and nuclear power plants, which require a lot of infrastructure to build.

Magdalena Klemun: [00:03:40] And in addition to that, renewables are abundant in the sense that there's enough wind and sunlight and kinetic energy to supply all of our electricity needs.

Laur Hesse Fisher: [00:03:48] Right, our planet has no lack of wind or sunlight and there’s no fear that we're going to run out any time soon.

In 2019, renewable energy generated about 18% of our electricity in the United States. ... In just this past year, wind power actually overtook hydropower as the United States’ top renewable electricity source. In fact, in some states, like Kansas, Iowa and Oklahoma, over a third of the electricity that the state produces comes from wind power alone.

Magdalena Klemun: [00:04:25] Looking back in time, both solar photovoltaics and wind have grown rapidly, actually faster than expected by many international organizations and also by academic researchers. Wind and solar capacity have doubled approximately every three years over the past 30 years. So that's a significant growth trajectory.

And that growth has been driven by a couple of interrelated factors. In the 1960s and 1970s,

a lot of investment and policy support in renewables was driven by concerns about energy security. Particularly in the area of fossil fuels, the US relied heavily on imports from other countries. And then over time these policies supported significant investments in research and development to, for instance, increase the efficiency of solar panels. And that made the technology better. It also made it more reliable and cheaper.

At a high level, most renewable energy sources are competitive or cheaper than fossil generation across different locations. And solar photovoltaics is also increasingly cost competitive.

A solar panel now will cost about 1% of what it cost in 1980 and that's a really significant change.

Laur Hesse Fisher: [00:05:44] All of this is sounding like really good news for wind and solar power… But, there’s a catch.

Magdalena Klemun: [00:05:51] Wind and solar electricity are available when the wind blows and when the sun shines. But that's sometimes, but not always when consumers demand energy.

Laur Hesse Fisher: [00:06:01] This is a huge difference from fossil fuels and also from nuclear energy. As long as we have the oil, natural gas, uranium, we can use it pretty much whenever we want to generate electricity. But we can’t always produce electricity from wind turbines and solar panels.

Remember how in episode 1, Harvey Michaels spoke about how the electric grid needs to always be in balance? Here he is from that episode:

Harvey Michaels: [00:06:29] The complexity of the grid is that there needs to be exactly the right amount of power put into the wires to serve all the instantaneous needs of all the people on the system. It doesn't really have the ability to store electricity in the wires themselves.

Laur Hesse Fisher: [00:06:47] That means that if you want lights at night, having solar power during the day doesn't help you. Same with when the wind’s not blowing.

There are ways to help with this problem.

Magdalena Klemun: [00:06:59] The term energy storage refers to a class of technologies that capture energy available at one point in time to make it available at another point in time.

Laur Hesse Fisher: [00:07:08] To give a few examples, there are large-scale batteries, like the lithium ion batteries that are in electric cars. Another is something called pumped hydropower, which creates a flow of water when we need it.

Magdalena Klemun: [00:07:23] Pumped hydro essentially means that when we have excess electricity in the grid, we use this electricity to pump water up on a mountain. And then we release it through a turbine and the generator to generate electricity when prices are high, and we want to make money.

Laur Hesse Fisher: [00:07:41] The thing is, all this energy storage costs money, and when you factor in the cost of these storage technologies, that adds to the cost of wind and solar power.

Magdalena Klemun: [00:07:52] For each unit of electricity generated by a wind turbine or by a solar panel, you also need to factor in the cost of the amount of storage that you need to make sure the electricity is available on demand. And when we do that, renewables are cost competitive only in some locations and for some storage technologies.

Laur Hesse Fisher: [00:08:14] So a big question is, will energy storage become cheap enough for wind and solar to provide most of our electricity? And if so, when?

Well, it turns out that this could be possible more quickly if we bring in some other technologies as well.

Magdalena Klemun: [00:08:33] In the absence of significant breakthroughs that can reduce the cost of energy storage -- and these breakthroughs might very well happen, but we don't know -- in the absence of these breakthroughs, a good pathway is one where both wind and solar grows significantly, and storage does as well. But then we also expand transmission infrastructure, and we invest in demand side management so we don’t expect energy storage to do 100% of the job.LHF: Demand side management means we change when we use electricity, and how much of it we use.

Laur Hesse Fisher: [00:09:08] So in this scenario, Dr. Klemun is saying that if our electric grid could more easily move electricity across locations or shift it over time, that could partially replace the need for energy storage, because these things also help smooth out the variability of wind and solar.

Magdalena Klemun: [00:09:27] Renewable electricity costs with storage would be half as expensive if we use [these?] other technologies to meet demand during the hours where wind and solar are not available.

Laur Hesse Fisher: [00:09:39] There’s another way to provide clean electricity on demand.

Magdalena Klemun: [00:09:44] If you look at the scenarios that allow us to stabilize CO2 concentrations in the atmosphere, most of these scenarios actually assume that there is a mix of wind and solar, as well as other clean technologies, such as nuclear and fossil generation with carbon capture and sequestration. If we can commercialize it.

Laur Hesse Fisher: [00:10:06] Real quickly, carbon capture is when you burn fossil fuels but capture and permanently store the CO2 before it enters the atmosphere. As Dr. Klemun just said, carbon capture isn’t commercially viable yet. There’s still a lot of research and market development that’s needed for carbon capture to be adopted at a large scale.

Magdalena Klemun: [00:10:28] Technologies like nuclear and fossil generation with carbon capture and sequestration can supply energy on demand. By keeping these technologies in the mix, we at least keep the option alive to use these technologies rather than artificially constraining our options. It’s like you’re putting a lot of very important eggs in very few baskets.

Laur Hesse Fisher: [00:10:49] This is why we’re going to spend the next several episodes looking at these technologies. We’ll cover energy efficiency, and how it can help us in the clean energy transition; and we’ll dig into nuclear power, carbon capture and storage, and even fusion energy.

But if you’re interested in learning more about renewable energy, then you’re in luck: the MIT Energy Initiative has a bunch of episodes that explore batteries and storage, solar power, and how the cost of energy technologies change over time. Google MIT Energy podcast or check out the links in our show notes. We’ll also include links to Dr. Klemun’s own research at the group she works with, the Trancik Lab at MIT."

Feel free to send us your questions over email: tilclimate@mit.edu or on Twitter, @tilclimate

Thank you to Dr. Magdalena Klemun for speaking with us, and as always, thank you for listening.



Additional Resources

The world’s current energy breakdown

The full break-down of where the US gets its energy


Check out this selection of Dr. Klemun’s research:

Mitigating Methane Emissions of Natural Gas

Intersection between Emissions Reductions and Technological Innovation in Wind and Solar

Also see:



An educator guide for this episode can be found below.


Critical Thinking 

  • In the episode, Dr. Klemun mentions that “the economics are different across different locations” for different types of renewable energy, especially wind and solar energy. Can you think of why this might be the case? If so, what are some locations that wind or solar might be cheaper?
  • How is it that the cost of solar technology is now 1% of what it was in 1980? What are some of the mechanisms discussed in the episode that led to this decrease? Can you think of some ways in which we can continue to use these methods, or find new ones, to further reduce the costs of things like storage? 


  • Dr. Magdalena Klemun talks about how solar and wind are more optimal in different locations. What countries have the highest energy usage from solar? What about wind energy? Look up where these countries are on the map and try to understand why they use either wind or solar.
  • Pumped Hydro is brought up in the discussion on energy storage. The definition given for energy storage by Dr. Klemun says that energy storage“ refers to a class of technologies that capture energy available at one point in time to make it available at another point in time.” Can you find other energy storage methods that are used commonly?  


  • There are several scenarios for our future energy mix discussed in this episode. The two most prominent were an energy mix that is completely composed of renewable energy, like wind and solar. The second involved keeping some fossil fuel plants online with still developing technologies like Carbon Capture and Storage, which is briefly touched on in the episode. Based on this episode and your own research, which do you think would be the optimal energy mix for the US or whichever country you wish to research? Why?



  • Have students play with the Climate Interactive simulator, to toggle around with increasing solar and wind energy, as well as increasing natural gas, to really see the effects of what some of the energy mixes discussed in the episode and how they will affect the climate. 


Need additional open source educational resources related to the topic of electric grids? You may find these free teaching materials from MIT OpenCourseWare (OCW) useful:

Fundamentals of Advanced Energy Conversion 

Level: Undergraduate

This course covers fundamentals of thermodynamics, chemistry, flow and transport processes as applied to energy systems. Topics include analysis of energy conversion in thermomechanical, thermochemical, electrochemical, and photoelectric processes in existing and future power and transportation systems, with emphasis on efficiency, environmental impact and performance. Systems utilizing fossil fuels, hydrogen, nuclear and renewable resources, over a range of sizes and scales are discussed. 


The Physics of Energy 

Level: Undergraduate 

The course is designed for people who want to understand the fundamental laws and physical processes that govern the sources, extraction, transmission, storage, degradation, and end uses of energy. Learn about how different types of energy technologies function, with an emphasis on combustion technology. 


Introduction to Sustainable Energy 

Level: Undergraduate

This class assesses current and potential future energy systems, covering resources, extraction, conversion, and end-use technologies, with emphasis on meeting regional and global energy needs in the 21st century in a sustainable manner. Instructors and guest lecturers will examine various renewable and conventional energy production technologies, energy end-use practices and alternatives, and consumption practices in different countries. Students will learn a quantitative framework to aid in evaluation and analysis of energy technology system proposals in the context of engineering, political, social, economic, and environmental goals. 


Fundamentals of Photovoltaics

Level: Undergraduate

Fundamentals of photoelectric conversion: charge excitation, conduction, separation, and collection. Lectures cover commercial and emerging photovoltaic technologies and cross-cutting themes, including conversion efficiencies, loss mechanisms, characterization, manufacturing, systems, reliability, life-cycle analysis, risk analysis, and technology evolution in the context of markets, policies, society, and environment.