Sunday, March 6, 2011

Just how much power do we need anyway?

Just how much power do we need anyway?

We all know we need to get off fossil fuels and replace them with carbon-neutral alternatives. The question is not IF we should choose this path, but how best to get where we need to go. There are those who, fairly enough, worry that those clean renewables aren't up to the job. This is a critical question, because if renewables can't fill the void, then we are left with no option but to build more nuclear reactors, with all the myriad problems that accompany them, most notably price, which is forever rising. So much money is at stake that we need to sort out this question, soon.

It all boils down to power demand. How much power do we need? If the number is such that the most realistically rapid installation rate of new wind, water and solar power supplies won't be enough to satisfy our needs in say, 2030 (by which time we need to have at least made a sizable dent in replacing the existing oil, gas and coal plants), then we have a problem. So what is a reasonable projection of power demand in 2030?

Unfortunately, that depends on whom you ask. Even estimates of current power consumption vary widely For example, over at Yale's e360, David Biello turns to MacArthur fellow Saul Griffith for a scenario that assumes

The U.S. will require roughly 4 terrawatts of power by 2050 (a conservative estimate, given that we already use more than three) You can find similar projections all over the place. But two other analysts, Mark Jacobson and Mark Delucchi, who survey the issue in some detail in a pair of papers discussed here, say current U.S. end use is only 2.5 TW, significantly less than 3 TW, not more. The higher figure is what we produce, the lower is what we use. 

The difference is lost during transmission and distribution, and to wasted heat. (Current end use figures, which are based on the U.S. Energy Information Administration data don't appear in the Jacobson-Delucchi papers, but they are available at Jacobson's website here in an Excel spreadsheet.)

Furthermore, because most electric power options are more efficient than those based on the internal combustion engine, and efficiency is expected to improve across the board in the coming years, they expect U.S. demand to be only 1.78 TW in 2030 if we convert all fossil fuels to wind, water and solar. And make sure we tighten up on the transmission and distribution losses, both of which will be significantly lower if power generation is decentralized and produced closer to where it's used.

Anumakonda Jagadeesh comments:

Interesting article.

Here is a n authoritative forecast on Energy Scene in 2030:

BP Energy Outlook 2030

Emerging Economies to Lead Energy Growth to 2030 and Renewables to Out-Grow oil,Days BP Analysis.

Release date: 19 January 2011

BP's 'base case' - or most likely projection - points to primary energy use growing by nearly 40% over the next twenty years, with 93% of the growth coming from non-OECD (Organisation of Economic Co-operation and Development) countries. Non-OECD countries are seen to rapidly increase their share of overall energy demand from just over half currently to two-thirds. 

Over the same period, energy intensity, a key measure of energy use per unit of economic output, is set to improve globally led by rapid efficiency gains in the same non-OECD economies, under these projections

According to the
 BP Energy Outlook, diversification of energy sources increases and non-fossil fuels (nuclear, hydro and renewables) are together expected to be the biggest source of growth for the first time. Between 2010 to 2030 the contribution to energy growth of renewables (solar, wind, geothermal and biofuels) is seen to increase from 5% to 18%. 

Natural gas is projected to be the fastest growing fossil fuel, and coal and oil are likely to lose market share as all fossil fuels experience lower growth rates. Fossil fuels’ contribution to primary energy growth is projected to fall from 83% to 64%. OECD oil demand peaked in 2005 and in 2030 is projected to be roughly back at its level in 1990. Biofuels will account for 9% of global transport fuels.

Transport growth is seen to slow because of a decline in the OECD. The region’s total demand for oil and other liquids peaked in 2005 and will be back at roughly the level of 1990 by 2030. Toward the end of the period, coal demand in China will no longer be rising and China is projected to become the world’s largest oil consumer.

OPEC’s share of global oil production is set to increase to 46%, a position not seen since 1977. At the same time, oil - and gas - import dependency in the US is likely to fall to levels not seen since the 1990s, because of improved fuel efficiency and the increased share of biofuels. Global consumption growth is also impacted by higher oil prices in recent years and a gradual reduction of subsidies in oil-importing countries. 

The fuel mix changes over time, reflecting long asset lifetimes. Oil, excluding bio-fuels, will grow relatively slowly at 0.6% per year; natural gas is the fastest growing fossil fuel with more than three times the projected growth rate of oil at 2.1% per year. Coal will increase by 1.2% per year and by 2030 it is likely to provide virtually as much energy as oil excluding biofuels. The strong carbon policy drive in OECD countries risks being more than offset by growth in emerging economies.

Wind, solar, bio-fuels and other renewables continue to grow strongly, increasing their share in primary energy from less than 2% now to more than 6% projected by 2030. Biofuels will provide 9% of transport fuels and nuclear and hydropower will grow steadily and gain market share in total energy consumption.

According to the Energy Outlook’s projections, oil continues to suffer a long run decline in market share, while gas steadily gains share. Coal’s recent gains in market share, on the back of rapid industrialisation in China and India in particular, are reversed by 2030, with all three fossil fuels converging on market shares around 27%. The diversifying fuel mix can be seen most clearly in terms of shares of growth. Over the period 1990-2010 fossil fuels contributed 83% of the growth in energy; over the next twenty years fossil fuels are likely to contribute 64% of the growth. Renewables (excluding hydro) and biofuels together account for 18% of the growth in energy to 2030.

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