Will Renewables Replace Fossil Fuels?


Wind+SolarRenewable energy development has taken off in the United States over the past decade.  Solar, wind, and other renewable technologies are projected to continue to grow rapidly. But renewables still have a long way to go to replace oil, coal, and natural gas as primary sources of energy.  What will it take to reach that threshold and what obstacles and limits do we need to understand as we transition to a truly sustainable energy economy?

We’ll examine these and other key questions regarding the outlook for renewable energy and what it means for America’s future.


Key Questions:

Cost: What are the important factors driving the total cost of different renewable technologies—e.g. equipment vs. soft costs? How far will costs continue to decline? Will costs be affordable enough to deploy at very large scale?

Density/Scale: Renewables are generally diffuse and distributed energy sources, how does that aid or hinder their prospects to become a primary source of energy?

Energy Quality/Substitutability: Renewable energy is most commonly used to make electricity, how does that affect its substitutability for uses that are currently non-electric—i.e. thermal heating and transportation?

Storage: How important is storage to the future of renewable energy? Are the oft-cited issues about storage overstated?



Bullets below summarize remarks by featured guests; they are not definitive statements by The Energy Xchange. In the spirit of discourse, this information may be revised through continued discussion.

  • Transitioning America’s energy system to run on mostly or entirely renewable wind, water, and solar energy is technically and economically feasible (based on projected costs), according to research led by Mark Jacobson of Stanford University and Mark Delucchi of the University of California, Davis. Their study simulated six years under varying weather conditions with no gaps in energy supply. The primary barriers are social and political–as well as perceptual, most of the public does not understand where their energy comes from or what a transition would look like.
  • Electrification of all sectors—including heating, cooling, industrial processes, and transportation—would be implicit to an all-renewable economy. The efficiency advantages of electric power alone would reduce total U.S. energy use by approximately 30 percent. Modest end-use efficiency improvements would potentially reduce energy use by an additional five to 25 percent.
  • For example, a plan for New York state would include 50 percent wind energy (mostly offshore) and 43 percent solar (mostly from large photovoltaic plants) with remainder from water (hydro and tidal power). The plan would require less than 1 percent of New York’s total land area, mostly for solar PV plants.
  • The projected cost per unit energy would be comparable to present-day fossil fuels—on the order of 13 cents per kilowatt-hour, but total expenses for consumers would be lower because of lower energy use. In many cases, renewables are already the least expensive form of electricity–.e.g. 3.7 cents per kwh for wind in Iowa and South Dakota.
  • An estimated $15 trillion in capital investments—approximately $12 trillion in generation plus $3 trillion in storage—would be required to effect the transition for the United States—for the world, an estimate $100 trillion (for comparison, current global investment in the energy sector is between $1.5 and $2 trillion per year). But investments would offset costs or pay for themselves over time–high capital costs but zero fuel cost.
  • Conversion to renewable energy would also eliminate external costs associated with air pollution and climate change— estimated at approximately $5000 per person—costs which thus far have been de facto subsidies to fossil energy.
  • Solar and wind had been developing slowly but have taken off since about 2008, in part because of high-volume production in China. However, to approach 100 percent renewable energy by 2050, the rate of deployment would need to accelerate by an order of magnitude (factor of ten).
  • The key challenge is that most renewables are diffuse, low-density energy resources which require systems for concentration and storage. However, most storage would not depend on electric storage such as batteries. Most peak loads are associated with heating and cooling which could employ sensible heat storage that basically uses excess energy to heat water or make ice. Seasonal heat storage in soil and use of existing hydropower facilities for pumped water storage would also be important. Most of these storage options are low-cost.
  • The longer we wait to make a transition, the more difficult and costly it is likely to be. It will take both money and ENERGY—nature does offer a financing package for energy, we will need the energy upfront. If we wait too long, energy may be the very resource we find in shortest supply.


Other Key Points

  • Batteries and electric storage using hydrogen would be most important for transportation. Batteries are more efficient, but hydrogen storage may have cost and scale advantages that will expand its role.
  • Vermont has set a statewide goal of 90 percent renewable energy by 2050 for all sectors including transportation, which would require an estimated $30-50 billion in capital investments. Vermont, as a small state with relatively strong political support, is a test case of what is possible
  • Key things that are needed to accelerate deployment of renewables:

Reduce unnecessary delays that drive up costs—“time is money.” Approximately 50 percent of costs for solar, for example, are “soft” costs—installation, permitting, etc. It should not take 6 months to permit something that takes a day to install. For example, Vermont is the only state to implement online registration instead of a permit application process for residential rooftop solar.

Need to get ready for “two ways streets” on the grid to embrace distributed energy.

Demand control—storage is less critical if peak loads can be shaved and shaped.

Fossil fuels should be used for backup not base load when renewables are on line

A major change in thinking—among grid operators and many others. A lot of decisions are still being made based on assumptions about a fossil fuel future.

  • Transportation will be especially challenging because of high POWER demands (not just energy, but energy per unit time) and because of extreme dependence on liquid fossil fuels. Solutions will vary depending on application–freight, passenger, urban, long-haul etc.
  • Electric vehicles have multiple advantages—in terms of energy efficiency, safety, maintenance, air pollution etc. and there is theoretically more than enough available material resources—steel, lithium, rare earth metals etc. But going down the “consumption road” will make the whole endeavor harder—not to mention the embedded costs and energy of maintaining our road system, which may also be economically unsustainable. We need innovation to drive down both the energy and economic costs of moving people and freight.
  • If we want the future to be as comfortable as today, we collectively as a society need to choose a direction, otherwise, we’ll continue to flounder and suffer the negative effects. “Don’t pick winners and losers” has become a red herringwe need to pick some winners.
  • The Solutions Project is bringing together a wide variety of people that might not otherwise collaborate to work through the opportunities and challenges for achieving a 100 percent renewable energy future.



  1. Interesting conversation. One challenge will be the energy (and carbon) cost of building out a parallel energy system, since most of the cost is incurred before any energy is produced, resulting in a “J curve.” This will work better if we replace current consumption with capital consumption, as we would in wartime. Is anyone suggesting this?

  2. I agree that increased use of renewable electric energy in many sectors of our economy will be critical to help achieve the all-renewable economy of the future. See also my recent white paper in which I discuss in more detail how plug-in hybrid electric vehicles can contribute to a sustainable future for transportation: Using the Plug-In Hybrid Electric Vehicle to Transition Society Seamlessly and Profitably From Fossil Fuel to 100% Renewable Energy

  3. The 3.7 cents per kwh for wind power in Iowa and South Dakota, as claimed by Mark Jacobson seems to be including heavy Federal and State subsidies to reach that incredibly low figure. Not including these subsidies in the cost is not a true comparison to fossil fuels, but does seem to be a constantly-repeated obfuscation when discussing wind power.

    1. Thanks for the comment, David. The 3.7 cents/kWh figure cited by Mark Jacobson is for the unsubsidized levelized cost of the wind power in prime locations. That figure was first cited in a study by Lazard (https://www.lazard.com/media/1777/levelized_cost_of_energy_-_version_80.pdf) which put it at the low end of a range. Another study by the Lawrence Berkeley National Laboratory (https://emp.lbl.gov/sites/all/files/lbnl-188167.pdf) suggests this figure is close to the mean for projects in the interior region of the country. Subsidized costs appear to be even lower–2.35 cents/kWh was the national average in 2014; in places like Iowa and South Dakota, it was even lower.

      It is of course very important to distinguish whether or not costs being referenced include subsidies. As you suggest, it is often unclear in many news reports. In this case, subsidies have been factored out of the analysis. Such figures may be hard to believe at first, but given the considerable size and height that modern wind turbines now reach, plus the fact that wind power increases not linearly but cubically with wind speed, the dramatic drop in actual costs should not be too surprising.

  4. > Transportation will be especially challenging because of high POWER demands

    That’s like saying the incandescent bulb can’t be beat. The conventional wisdom about transportation is just as untenable as burning carbon to get around. Eric Schmidt’s investment in automated personal transit operating at 10% the power of cars helps to validate the premise that high capacity elevated vehicles can be 100% solar powered. Unlike cars, podcars above the street don’t have to be built as tanks to protect riders. The Spartan Superway at San Jose State – http://www.superway.us – presented this at Stanford last spring.

  5. My concern for the electric grid is the energy storage issue needed to meet the 0.99.. reliability we are accustomed to. Should we be looking at Concentrating Solar Power with thermal storage and backed by gas when storage is outrun?
    On transportation have you looked at the Artificial Photosynthesis program led by Cal Tech as possibly working and thus creating a drop in fuel so that we don’t need a whole new vehicle technology and infrastructure?

    1. Thanks for the comment, Sol. Storage is of course critical, but it is also often invoked bluntly and dismissively, not as a design parameter to be addressed. What I found most interesting about Mark Jacobson’s remarks was that we need to think “outside the box” about storage. Storage can be achieved in many different ways, not necessarily electric storage like batteries, which is often the most expensive form of storage.

  6. The elephant in the room, which was danced around, but never exposed , is the cost of buying out all the assets currently employed in the mining, transportation, and processing of carbon based fuels. Anyone who thinks this is a “political” problem is kidding themselves. The present investment in pipelines, refineries, strip mining equipment, railroad car inventory, energy conversion units, fueling stations, and storage units, is massive. These are assets with a very long life. The corporations that own them will not give them up unless someone buys them. I wonder who that might be in the switch to renewable energy? I am a fan of Tom Murphy, and he has been an inspiration for me. He is very good at poking holes in most any scheme that involves physics (which is everything I think). I do not fancy myself in his league, but this problem with asset conversion has to be addressed as part and parcel of any energy conversion strategy in my opinion. I would be interested in what others have to say about this.

  7. We have had 2 energy revolutions in the history of humanity: Agricultural and the one due to the coal that linked to the industrial revolution. We need a third energy revolution, because fossil fuels are scarce, and solar energy captured by photosynthesis has a very low efficiency of capture, enough for the life in the planet, but not to sustain complex modern societies.

    The two former revolutions were mental, not technological. Wild cereals were around for centuries before people in Mesopotamia started to use them massively. Coal and vapour machines were around in Europe for centuries before 1780. Around this last date the change to coal as a source of energy was produced by a mental change that allowed for experimentation and new solutions, and this one, by the loss of prestige of dogmatical (Anglican, Calvinist and Roman Catholic) views of the world, as a consequence of wars that didn’t resolve anything. Today we have a dogmatic religion called ”economics”, that dogmatically closes any new path to useful solutions. These will be developed only when the common people becomes so bored and oblivious to ”economics” as the U.K. people were with respect to Christian religion (in its three or more flavours) in the last decades of the 18th century. http://www.not-clima.es

  8. Both revolutions were also technical. Wild cereals are something very different from the tetraploid or hexaploid wheat (a genetic monster) we eat today. Some rare mutations had to be selected, the semi-nomad social structure had to be converted to a stantial one, granaries had to be invented and adopted, etc. The fact that we consider agriculture “natural” should not hide the large effort of our ancestors.

  9. I find it overly-optimistic to believe that we can replace the edifice that has been built upon fossil fuels with ‘renewables’. We appear to have hit a number of limits that will challenge, if not prevent, such a transition for the vast majority of people on the planet.

    There are the environmental limits in terms of both sources of the finite materials necessary to produce and distribute the renewables to a scale capable of meeting energy needs of 7+ billion, and sinks to continue to absorb the pollutants that necessarily are created in this process. There are economic limits, particularly in terms of the capital necessary to support the transition (not to mention the possible collapse of a financialised economic system built upon a fiat currency Ponzi). There are the energy limits themselves in terms of the entire process requiring a significant portion of the fossil fuels that remain to ensure such a transition occurs. And, finally, there are the sociopolitical limits created by particular interest groups holding sway over various aspects of global society (just think about the amount of energy diverted to the military everywhere).

    I find it far more likely that we will experience the overshoot and collapse scenario painted by Meadows et al. in their 1972 text, Limits to Growth, than make a smooth transition to renewables. It might be ‘possible’ but only in an ideal world that hasn’t blown past the various limits to growth that we seem to have already done. http://olduvai.ca/

    1. I agree with Steve Bull, that the transition to renewables will not be made by rational arguments, but only when the “earth” oil fails. The transition to petroleum was made only when there was no more whale oil available. By then, when we have no more petroleum, climate change will most probably have changed our environment and our needs. I have spent some 15 years giving lectures and writing twice weekly in one of the biggest Spanish newspapers with all the rational arguments, to no avail. Man is NOT a rational animal, and acts only out of fear. As climate change is a very slow process we will not see him acting because the fear is not enough for that. Civilization usually rebounds, but the interregnum times are hard.

  10. Obviously the original build-out for all of this will be done using fossil fuels. What happens after those sources of energy are no longer viable? Will this all-renewable system be able to provide the energy needed to actually maintain itself and produce enough extra for anything else? Every time I hear stories like this the proponents give the impression that for the most part we, especially us American, really won’t have to make any major changes to our lifestyle.

    I am with the Tom Murphy’s who are pretty sure that scaling down and cutting back are not, in fact, going to be optional. It is going to happen one way or another. As long as people, especially us Americans, are given the illusion that there is a choice the majority are never going to voluntary choose the scaled down, reduced in any way lifestyle.

  11. Are there any actual examples of at least some small towns that are actually verifiably functioning on all renewables with no more fossil fuel inputs? Maybe if the proponents of this teamed up with the likes of Elon Musk and Amory Lovins and anyone else with deep pockets they could try to make it work other than just models and simulations.

    1. Thanks for that comment, Scott. There are places in the world touted as using all or mostly all renewable energy–typically taking advantage of a particularly abundant local resource–wind in the case of Samso Island in Denmark, biogas for the rural German village of Feldheim, etc. The entire nation of Iceland gets 85 percent of its energy and all of its electricity from geothermal sources.

      Too often though, these and other examples confound the word energy with electricity and leave transportation and liquid fuels out of the equation. It’s understandable–transportation is the toughest nut to crack for renewables–but it seems there is often a collective denial about it. Enough electric cars could conceivably be purchased for a small village, but how scalable is that approach?

      Elon Musk actually experimented with the idea of electric vehicle communities with something called Project Better Place, which was later scrapped. As you suggest, the need for a pilot project that goes the whole way–transportation included, and not just renewable but truly sustainable (not the same thing, by the way)–is still out there.

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