Wind farm
Wind and solar are inexhaustible. They are ideal energy
resources for powering a modern technological civilization.

Build up Our Clean Energy Supply, Part 1: Electricity


"The answer, my friend, is blowing in the wind."
-Bob Dylan



We can power our civilization on clean, non-polluting energy sources that will never run out. Our biggest task in switching rapidly to a post-carbon global economy will be a massive buildup of clean energy infrastructure.

These energy sources fall into three main categories: solar and wind for electricity, solar power for heating and cooling buildings, and a limited use of biofuels.

On this page, we look at the first category, solar and wind and other sources that supply energy in the form of electricity. These are the most abundant clean energy resources, so electricity will be the basis of the post-carbon energy economy. In addition to building up our supply, we will build a clean energy electric grid to move that electricity efficiently from where it's being produced at the moment to where it's needed, and we'll integrate energy storage into the grid to make sure we always have a reliable supply of energy when we need it.



Photovoltaic Panels (PV)

Photovoltaic panels
Photovoltaic panels turn our rooftops into an electricity-generating
profit center.

Right now, the rooftops of most of our buildings serve no function other than to shelter us from the elements. By covering them with electricity-producing photovoltaic panels, we can turn our rooftops into an energy-harvesting asset. The price of PV panels has been plummeting, dropping 40% in 2011, making them an ever-more affordable way to power our civilization. Photovoltaic panels work well even in climates that are not as consistently sunny as the desert.

These qualities make photovoltaics well suited to local energy production where people live and work (as opposed to solar thermal electricity and wind, where the energy resource is frequently far from the people using the energy). PV panels can be mounted on buildings, used as a roof over parking lots, or used in large-scale solar energy farms, feeding energy into the grid and supplying electricity directly to the buildings they are mounted on.



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Solar Thermal Electricity

Solar thermal electricity, a.k.a. concentrating solar power (CSP)
Solar thermal uses arrays of mirrors to reflect
sunlight onto liquid-filled tubes. The hot liquid
is then used to generate electricity.

Solar thermal electricity has been called “the technology that will save humanity,” due to its tremendous potential, and unique characteristics that allow it to displace coal power. Also known as concentrating solar power (CSP), or solar baseload, this method of harvesting sunlight uses arrays of mirrors that reflect sunlight onto liquid-filled tubes. The concentrated sunlight heats the liquid, which is used to boil water, generating steam pressure which is turned into electricity.

One of the beauties of solar thermal electricity is that it's a form of solar that can produce electricity at night as well as during the day. You can store the hot liquid in insulated tanks, and use it to generate electrical power long after the sun has set. That means it's ideal for providing baseload power, the portion of electricity demand that's needed all the time. And with that liquid stored in tanks, you can turn on electricity production at short notice to feed into the grid whenever needed, a characteristic which in electricity grid-speak means it's “dispatchable”.


An area 300x300 km. (less than one percent of the world's
deserts) covered in solar thermal would be sufficient to
supply the entire world's current electricity needs.

Solar thermal electricity is best suited to extremely sunny climates like deserts. It's estimated that less than one percent of the world's deserts, an area equivalent to a square 300km. by 300km., could supply the entire current electricity demand of the world. We won't need nearly that much area, because we'll have a diverse array of energy sources and because of the efficiency measures that will shrink our need, but it illustrates the potential of the technology.

Another benefit of solar thermal electricity is that the waste heat from the turbines can be used to desalinate sea water, producing fresh water in desert areas located near the ocean.



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Wind Power

Wind power
A global network of land-based wind turbines could supply forty times
the current world-wide demand for electricity, not even counting near-
shore waters, which are some of the best areas for siting turbines.

Wind energy is another heavyweight resource. How much energy could we harvest from wind? One study found that a global network of land-based wind turbines located only in non-forested, ice-free, non-urban areas could supply more than forty times the current worldwide demand for electricity, and five times the current worldwide demand for energy in all its forms.

Those figures were calculated just for wind resources on land, even though some of the best areas for wind electricity are in near-shore waters.

There is vast energy in those invisible rivers of air flowing over our heads. Many areas have reliable strong winds, especially along coasts and on mountains. Modern wind power plants are quiet, and extremely efficient at harvesting energy as electricity. Many people find them quite beautiful, as well.



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Electricity From Biomass, Geothermal, Tides...

A number of other promising energy sources can contribute to the clean electricity supply, although not at the huge potentials of solar and wind.

Wood or other plant materials grown and harvested sustainably can be burned in a power plant for electricity. An advantage of this is that the waste heat generated, which in most power plants gets vented out the smokestack, can be used for heating buildings (Combined Heat and Power, CHP). Denmark uses this method, and is able to heat buildings as much as 21 miles from the power plant, solely from the energy that most power plants waste.

In some areas the Earth's internal heat comes close enough to the surface that it's possible to drill down and use the heat for electricity production. In those areas, geothermal can be a major regional source of electricity. Iceland gets a quarter of its electricity from geothermal.

The ocean is another potential source of carbon-free electrical power. We can potentially harvest electricity from the tides, from waves, and even from the temperature difference between warm surface water and deep, cold water.



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What About Nuclear?

Nuclear power has its advantages: it's extremely energy dense, has a good energy return on energy invested, and it doesn't release greenhouse gases (other than in its construction/decommissioning). Its disadvantages are, well, we all know the disadvantages. Because of nuclear's unique potential to be a low-carbon source of energy, as well as its unique dangers, the appropriate baseline for consideration needs to be "nuclear done right," done safely at every stage of its life cycle. That means:

  • mining wastes are dealt with responsibly, and not allowed to blow in the wind or contaminate groundwater
  • reactors are designed in such a way that the chances of having a catastrophic release of radiation is zero
  • waste is handled in a way that doesn't endanger anyone for as long as it is radioactive
  • the chance of fissionable material getting syphoned off into nuclear or dirty bombs is as close to nonexistent as we can make it

If nuclear can meet these criteria and still be cost-effective, it potentially can be a significant part of the mix of our our post-carbon electric grid. If it can't meet those standards or would be too expensive, then we've got plenty of other options in our toolkit. New technologies like thorium reactors, and third and fourth generation reactors that would consume existing nuclear waste, offer promise for meeting that standard in the future, but these are not ready for prime time yet.



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The Clean Energy Smart Grid

Besides building the infrastructure to harvest clean energy, we'll need to upgrade the existing electric grid to get that energy where it's needed, and use modern information technology to throw in a few tricks to make sure the energy is available when we need it.

One part of the grid overhaul is building and upgrading electric lines to carry electricity from the new sources we'll be developing to the the people using them. (Sources of wind and solar thermal electricity are often located some distance from population centers.) High voltage DC electrical lines are a very efficient way to move electricity long distances, as they lose only three percent of the electricity every 600 miles. (1000 km)

Another function of the upgraded electrical grid will be to manage much more complicated flows of energy than we typically do now. In the old grid, the energy flow is one-way, from the power plant to the consumer. In the clean energy economy, as we put photovoltaic panels on the roofs of many buildings, there will be many more producers of electricity. At some times of day, those buildings will be feeding electricity into the grid, and at other times they'll be pulling electricity from the grid. The clean energy smart grid will function as a kind of energy internet, routing electricity through the network from wherever it's being produced to wherever it's needed at the moment.



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Balancing Electricity Supply and Demand

"But what do you do when the sun's not shining, or the wind's not blowing?" is the often-heard objection to using these clean energy resources. It's true that a common characteristic of solar and wind resources is that they are intermittent. Our needs for electric power vary, too, depending on the time of day and the weather. The times when we need power the most don't always match the times that nature is providing us with abundant power.

Clean energy smart grid
The clean energy smart grid will function as a kind of "energy internet", routing electricity through a
network of supply, demand, and storage, ensuring we always have power when we need it.

A key function of the clean energy smart grid will be to smooth out these mismatches between energy supply and demand, ensuring we always have energy when we need it.

Here's a grab-bag of ways to achieve this. We probably won't need to employ all of these techniques, but they are mentioned simply to illustrate that the tool kit of solutions is large and varied, and that the intermittancy of clean energy supplies is simply not a problem.

  • Diversify the energy portfolio: The wind is always blowing somewhere, and during the daytime the sun is always shining somewhere. By having a variety of power types across diverse geographic locations, all tied into a common grid, there is virtually always power available from many stations.

  • Solar Thermal Electricity heat storage: As described above, the liquid heated during the day can be stored in big insulated tanks of hot liquid, converting it into electricity to feed into the grid at night or whenever needed.

  • Electric vehicle batteries: If we electrify much of our transportation, there will be a vast pool of batteries connected to the grid. Most vehicles are parked 23 out of the 24 hours in a day. The vehicle's owner can agree to let the grid borrow a percentage of the battery's capacity, say up to fifteen percent, at times of peak demand. That energy gets returned once the surge in demand has passed, and the grid must make sure the battery is fully charged at the owner's normal commuting times. Vehicle owners could get compensated thousands of dollars a year for providing a service that is essentially free for them.

  • Local thermal storage of energy
    First-generation distributed thermal storage solutions
    are already commercially available, using grid electricity
    when it's abundant to store heat (top) or cold (bottom).

  • Hot and cold tanks: Much of the energy we use in buildings is for space heating and cooling, and for water heating. By equipping buildings with insulated storage tanks for hot and cold liquid, at times when electricity is abundant and cheap, we can use it to make the hot tank hotter, and/or the cold tank colder (depending on whether heat or cold is most needed at that season). Whenever the building needs to raise or lower its temperature at times when grid electricity is in high demand, it can draw upon the tanks rather than the grid. Also, buildings equipped with solar thermal heating systems can use the same hot tank to store high temperature liquid heated directly from sunlight shining on the building.

  • Compressed air storage: caves and unused mines can be sealed off and used as massive compressed air batteries. It's even possible to use a great big bag, under the ocean or deep lake. When power is abundant, we pump air into the caverns, pressurizing them. When we need that power, let that air out through turbines that convert it to electricity for the grid.

  • Pumped water storage: In areas with suitable geography, we pump water into an elevated reservoir whenever there's an excess of power. When we need it, let that water fall through hydroelectric turbines, getting the energy back as electricity.

  • Match demand time to supply time: With a smart grid, we can set variable pricing for electricity, expensive when it's in high demand, and cheap at times when it's abundant. For household and industrial functions that are not time-sensitive, a simple computerized system can communicate with the smart grid, turning on when power is abundant and cheap.



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Summary

We have the technology to power our civilization on clean energy sources. Massive deployment of new solar and wind, combined with a clean energy grid, and electrifying our transportation system, will give us an excellent quality of life on 100% clean, nonpolluting energy. In order to avoid climate tipping points, it is essential that we create this immediately.



Next: How to run our transportation system on pollution-free energy