Tag Archives: wind

Ten Reasons Intermittent Renewables (Wind and Solar PV) are a Problem

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Intermittent renewables–wind and solar photovoltaic panels–have been hailed as an answer to all our energy problems. Certainly, politicians need something to provide hope, especially in countries that are obviously losing their supply of oil, such as the United Kingdom. Unfortunately, the more I look into the situation, the less intermittent renewables have to offer. (Please note that I am not talking about solar hot water heaters. I am talking about intermittent renewables added to the electric grid.)

1. It is doubtful that intermittent renewables actually reduce carbon dioxide emissions.

It is devilishly difficult to figure out whether on not any particular energy source has a favorable impact on carbon dioxide emissions. The obvious first way of looking at emissions is to look at the fuel burned on a day-to-day basis. Intermittent renewables don’t seem to burn fossil fuel on day-to-day basis, while those using fossil fuels do, so wind and solar PV seem to be the winners.

The catch is that there are many direct and indirect ways that fossil fuels come into play in making the devices that create the renewable energy and in their operation on the grid. The researcher must choose “boundaries” for any analysis. In a sense, we need our whole fossil fuel powered system of schools, roads, airports, hospitals, and electricity transmission lines to make any of type of energy product work, whether oil, natural gas, wind, or solar electric–but it is difficult to make boundaries wide enough to cover everything.

The exercise becomes one of trying to guess how much carbon emissions are saved by looking at tops of icebergs, given that the whole rest of the system is needed to support the new additions. The thing that makes the problem more difficult is the fact that intermittent renewables have more energy-related costs that are not easy to measure than fossil fuel powered energy does. For example, there may be land rental costs, salaries of consultants, and (higher) financing costs because of the front-ended nature of the investment. There are also costs for mitigating intermittency and extra long-distance grid connections.

Many intermittent renewables costs seem to be left out of CO2 analyses under the theory that, say, land rental doesn’t really use energy. But the payment for land rental means that the owner can now go and buy more “stuff,” so it acts to raise fossil fuel energy consumption. Continue reading →

Renewables – Good for some things; not so good for others

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Based on the sound of the name renewable, a person might think that using only “renewable” energy is ideal–something we should all strive to use exclusively. But there are lots of energy sources that might be called “renewable,” and lots applications for renewable energy. Clearly not all are equally good. Perhaps we should examine the “Renewables are our savior,” belief a little more closely.

Figure 1. World fuel consumption based on BP's 2012 Statistical Review of World Energy data.

Figure 1. World fuel consumption based on BP’s 2012 Statistical Review of World Energy data.

1. Renewables that we have today won’t replace the quantity of  today’s fossil fuels, in any reasonable timeframe.

Figure 1, above shows the distribution of fuels used since 1965. 

Other renewables, which includes wind, solar, geothermal and other categories of new renewables, in total amounts to 1.6% of world energy supply in 2011, according to BP. The light blue line is not very visible on Figure 1. (The blue line that is visible at the top is “Nuclear.”)

Biofuels, which would include ethanol and other types of biofuels, such as palm oil, amounts to 0.5% of world energy supply. Its orange line is not very visible on the chart either.

Hydroelectric, shown in purple, has been around a long time–since 1880 in the United States. It amounts to 6.4% of world energy supply. Its quantity is not growing very much, because most of the good locations have already been dammed.

In total, the three categories amount to 8.5% of world energy supply. If growth continues at today’s rate, it will be a very long time before renewable energy supply can be expected to amount to more than 10% or 15% of world energy supply. We very clearly cannot operate all the equipment we have today on this quantity of energy. In fact, it is doubtful that we can even cover the basics (food, water, and heat to keep from freezing) for 7 billion people, with this quantity of energy. Continue reading →

Can we invest our way out of an energy shortfall?

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The world has many ideas for solving our energy shortfall, but they all seem to involve investment:

  • Drill for more oil and gas;
  • Develop alternative energy sources;
  • Build more efficient gas-powered cars or electric cars;
  • Fix homes and offices so they are more energy efficient.

I thought I would check through government data to see if we really have a chance of being able to invest enough money to solve our problems.

What I found was more than a little disturbing. United States’ “Net Savings,” as a percentage of Gross National Income has dropped greatly and is now below zero. This is a situation one website described as implying an “unsustainable path”.

Figure 1. US Net Savings as a Percentage of Gross National Income, based on Bureau of Economic Analysis Data (Table 5.1)

Back in the 1950s and 1960s, when the Interstate Expressway System was built and the electric grid that we are still using today was built, Net Savings averaged close to 10% of Gross National Income. It has dropped since then, and is now negative.

Let me explain “Net Savings” by showing a second graph.

Continue reading →

Adjusting Energy Return on Investment (EROI) for Time

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Nate Hagens wrote a post at The Oil Drum called Applying Time to Energy Analysis. Under standard EROI analyses, there is no recognition of time – if you cut down a tree, but couldn’t burn it for energy until 50 years from now, it would count the same in terms of EROI as if you could burn the tree, the day after you cut it down (except perhaps for the embedded energy in the shed where you needed to keep the log for 50 years).

There are a lot of reasons why energy that is not available for a long time might be less valuable. If nothing else, if energy is not available for a long time, it will be necessary to tie up capital in developing this source of energy.* Dennis Meadows of Limits to Growth fame has said that the limiting factor as we approach “Limits to Growth” is capital. If some types of energy production tie up capital disproportionately, this, in itself, is a problem, because it will limit total energy available to society. If these sources of energy are low EROI to begin with, this is a double hit. Continue reading →