February 6, 2010
A review by Paul Gipe
Energy Self-Reliant States: Second and Expanded Edition by John Farrell and David Morris came out in October, 2009 and it packs a punch. I chewed on it a little at the time but wanted to delve into it more.
I’ve chosen to keep it handy as a reference on what we could do in the US if we every make moving away from fossil-fuels a priority. The 32 page report assembles data from numerous sources, stacking up potential of each technology in each state against in-state consumption.
The report should put to rest the whiners who say we, the US, could never meet our electricity needs with renewables. Those of us specialized in one particular technology have always realized this was rubbish. Wind and solar abound as does geothermal in the Western States.
The report looks at a host of resources: Solar, wind (onshore and offshore), hydro, geothermal, and combined heat and power. The conclusion is one you would expect if you’ve studied the subject at all. We could do it-and many times over.
California
Take California for instance. The Institute for local Self-Reliance (ILSR) estimates that the state could obtain 52% of its electricity from rooftop solar energy alone. Again, not surprising, California is a sunny state after all.
The report based its solar estimates on a Navigant study that assumed only 25% of residential rooftop was suitable for solar and only 60% of commercial rooftops were suitable for solar PV.
ILSR acknowledges this greatly underestimates solar PV’s full potential. Adding potential ground-mounted systems and concentrating solar plants, the potential of solar in California reaches as much as 16 million megawatts.
At an efficiency of 12%, ILSR estimates that PV requires 0.387 MW/acre. Thus, ILSR estimates that less than one percent (0.3%) of the state’s land area would be necessary to meet the states electricity consumption with solar PV-a striking conclusion.
Electric Vehicle Consumption
ILSR’s David Morris has long been an advocate of electric vehicles and this report contains an important discussion on EVs. The report answers that oft-asked question, “Well if we go to EVs won’t we have to double our electricity supply.” I tackled the same question in Wind Energy Basics (2009) and came up with a similar conclusion.
ILSR assumes each passenger vehicle consumes 0.25 kWh/mile travelled (4 miles/kWh). (I used a slightly higher value to be conservative.) Passenger vehicles account for 57% of the 3 trillion vehicle miles travelled. Trucks account for the remainder and need 0.5 kWh/miles (2 miles/kWh) travelled.
ILSR estimates that if 75% of vehicle miles travelled of both classes were converted to electricity it would require an additional 716 TWh/yr or an increase of only 19% in total US electricity consumption. That amount can easily be made up for by savings from other sectors. I’ve found in our own home that Americans can cut their consumption in half.
Wind Energy
Based on Battelles’ “moderate” land exclusion in its 1991 evaluation of US’ wind potential. ILSR raised Battelle’s tower height from 50 m to 80 m, itself a conservative estimate with today’s tall towers.
The report contains several surprises. Sure California could get nearly one-third of its electricity from onshore wind energy. That seems reasonable considering the state’s pioneering role in wind energy. And that the Dakotas-the so-called Saudi Arabia of wind–could get some 14,000 times their current consumption from wind has been known for a long time.
But who would have thought that Michigan and Indian could get more than four-fifths their electricity from onshore wind energy. Currently Indiana gets nearly 90% of its electricity from coal, and Michigan gets more than half of its supply from coal. Imagine rust-belt states like Indiana and Michigan getting the bulk of their electricity from wind energy, and the remainder from rooftop solar PV.
Energy Self-Reliant States: Second and Expanded Edition is another valuable tool for renewable energy advocates in building a case that “yes, even the US can” move to renewables–and the sooner the better.
