Wednesday, March 30, 2011

Twenty Years of Electric Power

While on the subject of electrical energy, I thought I would update my understanding on the total picture—thus beyond nukes and hydro. A very nice data set is available here from the Department of Energy’s hard-working Energy Information Administration. Let’s first look at total electrical generation, in billions of kilowatt hours (kWh) from 1990 through 2009.

At the beginning of this period, we consumed 3 billion kWh. Our use of electricity peaked in 2007 at 4.157 billion. Usage had dropped to 3.95 billion kWh by 2009—indicating that even electrical generation responds to economic turndown by a matching dip in production.

The lower curves show the generation of electricity by selected types of fuels or methods like hydroelectric and wind. Note here that until 2006 the top two were coal and nuclear. After that time natural gas became more important than nuclear. Fourth is hydroelectric. Petroleum was fifth until, in 2008, wind power began to generate more electricity than oil. The categories shown do not exhaust the list— but since petroleum and wind barely show on this chart, a closer view of the others needs another graphic. Herewith the shares of fuels and methods in 2009 as a pie chart:

I am showing the percentage share of the leaders—coal, natural gas, nuclear, hydro, and wind. Together these accounted for just a hair under 97 percent of all electrical generation in 2009. Please note that solar and photovoltaic, while in the pie, is such a tiny sliver so as not to show at all (0.02%).

Finally, here is a chart that shows the growth rates of the various fuels/methods used to get that spark into the wire:

Now this is a most illuminating chart. It shows that wind-power wins, hands down, growing at 18.8 percent—and that’s every year in the 1990-2009 period! The big loser is petroleum. Some of the categories here need additional commentary—also revealing:

• The category “Other Gases” includes, to quote from my source, “blast furnace gas, propane gas, and other manufactured and waste gases derived from fossil fuels.”

• The “Other” category, growing at 6.5 percent a year, includes “non-biogenic municipal solid waste, batteries, chemicals, hydrogen, pitch, purchased steam, sulfur, tire-derived fuels, and miscellaneous technologies.” By non-biogenic I think they mean unlikely to rot, thus paper, cardboard, plastics, wood, etc.

• “Wood and Wood Derived” fuels include “paper pellets, railroad ties, utility poles, wood chips, bark, red liquor, sludge wood, spent sulfite liquor, and black liquor, with other wood waste solids and wood-based liquids.” Various liquids mentioned here are wastes in paper pulping mills.

• “Other Biomass” includes “biogenic municipal solid waste, landfill gas, sludge waste, agricultural byproducts, other biomass solids, other biomass liquids, and other biomass gases (including digester gases and methane).” Biogenic wastes are those that rot, ferment, and throw off gases.

Did you notice the interesting common feature of these categories? They all represent recovery of energy from wastes of some sort. The “Other” category ranks second in overall growth. We can come up with an Environmentally Friendly grouping: Wind, Solar, Wood, Biomass, and Other. In 2009 these accounted for 3.6 percent of total electric power generation. And in 1990? In 1990 they were 0.05 percent of the total—thus a 72-fold increase in the last twenty years. A tiny fraction of total megawattage, but the trend is there—and the growth rates are there as well.

1 comment:

  1. Oh, bravo!. This a lovely look at the otherwise mysterious category of "other renewable sources".