Monday 11 July 2011

A Plan to Power 100 Percent of the Planet with Renewables

A feasible plan to power 100 percent of the planet with renewables has been put forward in an article for Scientific American. This plan excludes nuclear and biofuels which the authors also considered to be unsustainable technologies, instead their plan revolves around Wind, Water and Solar energy)

Such a plan is certainly achievable, and could be completed in twenty years, all that is missing is the political will.

Interesting facts from Scientific American:

1. The maximum power consumed worldwide at any given moment is about 12.5 trillion watts (terawatts, or TW)

2. Fifty One Percent of that demand, could be provided by 3.8 million large wind turbines (each rated at five megawatts) worldwide. Although that quantity may sound enormous, it is interesting to note that the world manufactures 73 million cars and light trucks every year.*

3. Another Forty Percent of the power could come from photovoltaics and concentrated solar plants, with about 30 percent of the photovoltaic output from rooftop panels on homes and commercial buildings. About 89,000 photovoltaic and concentrated solar power plants, averaging 300 megawatts apiece, would be needed.**

4. The rest would be made up of 900 hydroelectric stations worldwide, 70 percent of which are already in place.

5. Only about 0.8 percent of the wind base is installed today. The worldwide footprint of the 3.8 million turbines would be less than 50 square kilometers (smaller than Manhattan). When the needed spacing between them is figured, they would occupy about 1 percent of the earth’s land, but the empty space among turbines could be used for agriculture or ranching or as open land or ocean.

6. Enough concrete and steel exist for the millions of wind turbines, and both those commodities are fully recyclable. The most problematic materials may be rare-earth metals such as neodymium used in turbine gearboxes. Although the metals are not in short supply, the low-cost sources are concentrated in China, so countries such as the U.S. could be trading dependence on Middle Eastern oil for dependence on Far Eastern metals. Manufacturers are moving toward gearless turbines, however, so that limitation may become moot.

7. Nonrooftop photovoltaics and concentrated solar plants would occupy about 0.33 percent of the planet’s land.

8. If we stick with fossil fuels, demand by 2030 will rise to 16.9 TW, requiring about 13,000 large new coal plants, which themselves would occupy a lot more land, as would the mining to supply them. Where if we change to renewables demand will either drop or stay steady. This is because these forms of power are intrinsically more efficient and less wasteful with less hidden costs.

9. The average U.S. coal plant is offline 12.5 percent of the year for scheduled and unscheduled maintenance. Compared to Modern wind turbines which have a down time of less than 2 percent on land and less than 5 percent at sea. Photovoltaic systems are also at less than 2 percent. Moreover, when an individual wind, solar or wave device is down, only a small fraction of production is affected; when a coal, nuclear or natural gas plant goes offline, a large chunk of generation is lost.

As Cheap as Coal

Today the cost of wind, geothermal and hydroelectric are all less than seven cents a kilowatt-hour (¢/kWh); wave and solar are higher. But by 2020 and beyond wind, wave and hydro are expected to be 4¢/kWh or less.

For comparison, the average cost in the U.S. in 2007 of conventional power generation and transmission was about 7¢/kWh, and it is projected to be 8¢/kWh in 2020. Power from wind turbines, for example, already costs about the same or less than it does from a new coal or natural gas plant, and in the future wind power is expected to be the least costly of all options.

Solar power is relatively expensive now but should be competitive as early as 2020. A careful analysis by Vasilis Fthenakis of Brookhaven National Laboratory indicates that within 10 years, photovoltaic system costs could drop to about 10¢/kWh, including long-distance transmission and the cost of compressed-air storage of power for use at night. The same analysis estimates that concentrated solar power systems with enough thermal storage to generate electricity 24 hours a day in spring, summer and fall could deliver electricity at 10¢/kWh or less.

When the so-called externality costs (the monetary value of damages to human health, the environment and climate) of fossil-fuel generation are taken into account, these technologies become even more cost-competitive.

Overall construction cost for a Wind Water Solar system might be on the order of $100 trillion worldwide, over 20 years, not including transmission. But this is not money handed out by governments or consumers. It is investment that is paid back through the sale of electricity and energy. And again, relying on traditional sources would raise output from 12.5 to 16.9 TW, requiring thousands more of those plants, costing roughly $10 trillion, not to mention tens of trillions of dollars more in health, environmental and security costs. The WWS plan gives the world a new, clean, efficient energy system rather than an old, dirty, inefficient one.

Scientific American says that taxing fossil fuels or their use to reflect and mitigate their invironmental costs would be good idea.

But even at a minimum eliminating existing subsidies and tax breaks for fossil fuel exploration and extraction would create a more even playing field for renewables.

Scientific American says that misguided alternatives like bio fuels need to be eliminated as well. This would mean removing the large subsidies these alternatives attract.

Scientific American says that, legislators crafting policy must find ways to resist lobbying by the entrenched energy industries. The obstacles are primarily political, not technical.

With sensible policies, nations could set a goal of generating 25 percent of their new energy supply with WWS sources in 10 to 15 years and almost 100 percent of new supply in 20 to 30 years. With extremely aggressive policies, all existing fossil-fuel capacity could theoretically be retired and replaced in the same period.

Society has achieved massive transformations before. During World War II, the U.S. retooled automobile factories to produce 300,000 aircraft, and other countries produced 486,000 more.


pam said...

This sounds wonderful (at least in theory) so, despite the HUGE hurdle of getting world-wide, country-by-country agreement to citing, running and sharing these technologies across the globe, my other main question is an agrument that has been put in the press- Why cant the electricity produced be stored or what happens, as now, when wind turbines are to be turned off when conditions are Too much wind for example?

David said...

The proposed number and size of wind turbines could produce up to 19 TW if they were all running at full capacity. This of course would never happen, it’s typical to assume that wind power runs at an average of about 25% of capacity, which is roughly what is suggested here.

The problem remains what happens when there’s no wind and little sun and very cold weather across a large continental area?

There are other issues. Hydro damns already cause huge environmental problems, can the world really sustain that many more? And is there really enough suitable sites for the turbines with out further environmental destruction?

For any planned switch to renewable energy to work we need to massively cut energy consumption.

In the short term this could be linked to a program of economic stimulation and ‘green jobs’ as buildings are insulated, solar water heaters and photovoltaic panels manufactured, railways expanded, public transport increased and turbines built.

In the longer term it will have to mean an end to growth and a planned shrinkage of the economy. This is impossible within a capitalist frame work.

Grant Morgan’s essay  ‘Beware! The end is nigh!’ : Why global capitalism is tipping towards collapse, and how we can act for a decent future1
has a good section on the energy crisis.

There’s also an ongoing discussion about the idea of a Green New Deal on the Ecosocialism Aotearoa Facebook site, which touches on some of these issues.