Solar and Wind Alone Can’t Do It
(Why the Green New Deal Needs Fusion to WORK)
- Cost more than fossil fuels
- Take up one fifth of the total US and world land area, destroying large ecosystems
- Consume very large amounts of materials, some of them toxic and rare
- Be highly centralized, and rely on a vulnerable and extremely expensive long-distance grid
From the headlines and the statements of many Green Energy supporters, you would think that we already have the solutions that can replace fossil fuels entirely, that wind and solar can provide cheap, reliable and totally clean energy. The problem is, this is just not true. Solar and wind alone can’t replace fossil fuels. Instead, we need a crash program to research and develop the only real alternative to fossil fuels—fusion energy.
The role of solar and wind power, their expense and environmental impact, is very different if they are considered as possible complete replacements for fossil fuels. Right now, solar and wind power are used to supplement “base-load” sources of electricity—fossil fuel generators, nuclear fission plants and hydropower. In that role, the variability of solar and wind is a nuisance, but not a big problem. For the most part, the electrical grid, powered mainly by sources that can be switched on and off reliably, can efficiency absorb extra power from solar and wind whenever it is available. So in this supplemental role, solar and wind are useful in reducing fossil fuel pollution. But the situation changes entirely if we consider eliminating fossil fuel and nuclear fission energy production and replacing them entirely with solar and wind. Then the variability of the renewable energy sources is a huge problem and greatly increase their cost and impact on the environment, making a total replacement impractical. Let’s see why.
1. Solar and wind will be more expensive than fossil fuel
Solar and wind energy are only available part of the time. A solar energy plant with a peak capacity of 1 MW (it can produce a maximum of 1 MW of electric power) produces about on average 200 kW or 20% of maximum. Half the time the sun is not in the sky and most of the time it’s low in the sky or behind clouds, reducing the power a solar plant can produce. Similarly, a wind farm with a 1 MW peak capacity produces on average 300 kW. (source: IRENA (2018), Renewable Power Generation Costs in 2017, International Renewable Energy Agency, Abu Dhabi.)
Right now, solar energy costs about $1 million per MW of peak capacity and wind costs $1.5 million, comparable to the costs of peak capacity of fossil fuel plants. (same IRENA report) But the fossil fuel plants, as well and nuclear fission and hydroelectric facilities, can operate at peak capacity nearly all the time. If instead we express the price of 1 MW of AVERAGE power production for either solar or wind, it is $5 million for 1 MW of power—far more than fossil.
On top of that if solar and wind are the main source of power, huge batteries have to store energy for periods when the sun is not shining and the wind is not blowing—and calm nights happen quite frequently. It is difficult to predict exactly how many hours or days energy storage would be required to secure continuous energy supply. However, a study by the National Renewable Energy Laboratory (available at https://www.nrel.gov/docs/fy19osti/72401.pdf) shows that a fairly minimum 4-hour storage requirement doubles the cost of solar power.
In addition, it may not be possible even in a continental-sized grid to balance high energy demand for heating (would be all-electric in a system without fossil fuels) with low sunlight during the winter. This could mean that solar and wind systems would have to have still higher peak capacity so that their output in winter would not fall too low.
Even optimistically ignoring this last point, the investment cost for all-solar and wind systems will be around $10/w of average consumption. What does that mean for the whole US?
Right now average energy consumption (all energy, not just electricity) in the US is around 3.3 TW (trillion watts). With modest 1% annual growth in the next 30 years energy consumption will reach 4.4 TW by 2050, the goal year for eliminating fossil fuels. This means that the cost of simply building this system over the next 30 years will be around $44 trillion, or an average expenditure of about $1.5 trillion per year.
Neither solar panels nor wind turbines last forever. They have, at best, 20 year lifetimes. Even ignoring ongoing maintenance costs, the need to replace solar panels and wind turbines as they wear out will add at least $0.5 trillion per year to overall costs, bringing the total to $2 trillion per year.
By comparison, at present the US spends about $1.4 trillion per year for all energy sources—mostly fossil-fuel-based. So, with optimistic assumptions and current prices for solar, wind and energy storage, an all-solar and wind system would increase energy costs by about 50%.
But won’t solar and wind costs continue to drop? We’ll talk about that in section 3.
2. Solar and wind will take up one nearly one fifth of total US and world land area
Both solar energy and wind power (driven by the sun’s energy) are dilute energy resources—they need lots of land for a given amount of power. An NREL survey https://www.nrel.gov/news/press/2013/2269.html shows that solar power plants produce 7 MW of average power per square km of total land use and wind farms only 1.5 MW per km2. To achieve balanced power production, about as much wind power as solar power will be required. To produce the 4.4 TW the US will require by 2050 will mean covering 300,000 km2 with solar panels and 1.5 million km2 with wind farms. The total land area of the US is 10 million km2 so almost one fifth of the total area needs to have either solar panels of wind farms.
To give some comparison the total area of all US cites combined is 100,000 km2, so solar panels alone will cover three times the US urban area. Put another way, this is covering an area ¾ the size of the entire state of California with solar panels. If they were all located in the desert, one third of US deserts would be covered.
Wind farms of course allow agricultural land use within them. But they have a large effect on wildlife, especially birds. The area covered by wind farms would be 50% larger than the area now covered by cropped farmlands.
But energy is a global problem. Providing the world population of 2050, estimated to be about 10 billion people, with the current per capita energy supply of Europe (half that of the US) will take 60 TW of average power. So, about one fifth of the world land area will also be covered by either solar panels or wind farms.
3. Solar and wind consume large amounts of materials, some of them toxic and rare
Both solar and wind generators, being large pieces of equipment, consume large amounts of materials—in both cases about 1,000 tons for each MW of average energy produced. To build an all-renewable grid by 2050 will require additional production of about 200 million tons a year of glass, steel concrete and aluminum. This is a large, although not impossible, amount overall. It would involve a substantial enlargement of some energy-intensive US industries, such as aluminum, which would have to triple in size.
With present technology, key materials in solar panels are toxic and rare. To supply just the needs of a US program, world production of cadmium, a toxic metal, would have to triple to 70,000 tons per year. But replacing fossil fuels is a global effort and a similar program for the world would require one million tons per year of production—a 40-fold increase. (This assumes getting the world population to European standards of energy consumption by 2050—only half what the US uses per capita). Cadmium is found only together with zinc, so world zinc production would have to about triple. Tellurium is needed in almost equal amounts, and this element is rare, about as rare as platinum in the earth’s crust. Present known reserves are only about 20,000 tons, so reserves would have to increase more than 1500-fold to supply the 30 million tons of tellurium needed for a global transition to all solar and wind power. That will be nearly impossible without exploiting the large amounts of tellurium in deep-sea nodules near hydrothermal vents. But deep-sea mining will destroy vast swaths of unique sea-bottom ecosystems. (Source https://www.bbc.com/news/science-environment-39347620.)
The large amounts of materials needed for solar and wind also limits the decrease in costs that can be realistically expected in the future. Already, solar and wind generators (excluding the costs of storage) cost about $10/kg of materials weight. Very few types of machinery cost much less to manufacture. A car costs about $20/kg to produce, while a refrigerator costs about $3/kg. Unlike refrigerators, solar and wind facilities involve considerable labor to install as well, labor that future research is unlikely to reduce given the scale of the facilities. So while it is true that future research could continue to reduce the cost of solar and wind power, it is unlikely that future cost reductions will exceed a factor of two. Just given the physical scale of these technologies, they will never be significantly cheaper than current fossil fuel energy sources.
But can’t solar and wind become much more concentrated as technology improves? The problem is there are basic physical limits that are already close to being reached. Solar power efficiency is at about 18% today and the physical limit is around 30% . So here again, a factor of two improvement is not possible. https://ieeexplore.ieee.org/abstract/document/8674820
4. Solar and wind as primary energy sources would be highly centralized, and rely on a vulnerable and extremely expensive long-distance grid
At present, when they are used a supplemental energy sources, solar and wind seem to be fairly decentralized energy sources. After all, all regions get sunlight and wind. But that would radically change if they were the primary sources. In the US and throughout the world, populations that consume energy are highly concentrated. Extremely large, underpopulated regions with the most sun and wind will be needed to supply the energy for these populations. As a result, electric energy will have to be sent over thousands of miles from sources to consuming regions, creating an expensive grid that is vulnerable to failure.
In the US, energy would have to be transmitted from the western deserts and plains to population centers in the East and on the West Coast. During winter, large amounts of energy would have to be transmitted from sunnier southern areas to colder northern ones.
In Eurasia, huge population concentrations in northern India and eastern China would have to be supplied from wind and solar plants covering large areas of Western China, Mongolia, Kazakhstan and Russia. India in particular would be heavily dependent on northern neighbors for energy. Whether international agreements could actually set up such vast systems is another question.
Transmitting power over thousands of miles of high voltage line involves significant losses. But more significantly, such heavily centralized, yet vast, electrical girds would be highly vulnerable to disruption by natural disasters such as earthquakes, sandstorms, tornadoes and especially geomagnetic storms caused by solar flares. Today’s grids, which are already too vulnerable to blackouts, produce most electricity locally and rely on long distance connections mainly for load-balancing. But a future solar and wind only grid would not only be mainly reliant on distant energy sources, disruption of electricity would mean knocking out all energy.