By ASHLEY E. ORGAN, Assistant Editor Investing in alternative energy has been high on the priority list in the US. The Obama administration has emphasized the need for the development of substitutes for existing energy sources in response to high oil prices and concern over energy security and climate change. Generating power from the sun, wind, and corn should be simple, but is it really that easy? The Post Carbon Reader is a compilation of essays addressing global issues such as renewable energy and urban agriculture to social justice and community resilience. David Fridley, staff scientist at the Lawrence Berkeley National Laboratory, provides insight into the factors that play a role in the development of renewables in his essay “Nine Challenges of Alternative Energy.” The first three are: 1. Scalability and Timing An alternative energy source must be able to be supplied in the necessary time frame, in the volume needed, and at a reasonable cost, according to Fridley. Although alternatives such as algae-based diesel, cellulosic ethanol, biobutanol, and thin-film solar have proven successful at the small scale, Fridley says that the demonstration scale does not provide an indication of the large-scale production potential. Alternative energy relies on engineering and construction of equipment and manufacturing processes for its production, so output grows in a stepwise function as new capacity comes online. Therefore, it is reliant on timely procurement of the input energy and other required materials, Fridley says. “This difference between ‘production’ of alternative energy and ‘extraction’ of fossil fuels can result in marked constraints on the ability to increase the production of an alternative energy source as it is needed.” 2. Commercialization The question of how far away a proposed alternative energy source stands from being commercialized is related closely to the issue of scalability and timing, according to Fridley. The average time frame between laboratory demonstration of feasibility and full large-scale commercialization is 20 to 25 years. Before a process can be commercially implemented, it must be perfected and optimized with patents developed, demonstration tests performed, pilot plants built and evaluated, environmental impacts assessed, and various studies undertaken. “In other words, technologies that are proved feasible on the benchtop today will likely have little impact until the 2030s,” Fridley says. 3. Substitutability It would be ideal for an alternative energy form to directly integrate into the current energy system and substitute for an existing form without requiring infrastructure changes. According to Fridley, this rarely is the case and the lack of substitutability is pronounced particularly in the case of the electrification of transportation, such as with electric vehicles. “Although it is possible to generate the electricity needed for electrified transportation from wind or solar power, the prerequisites to achieving this are extensive,” he says. “While alternative energy forms may provide the same energy services as another form, they rarely substitute directly, and these additional material costs need to be considered.” For more information on the Post Carbon Reader and the essay by David Fridley, visit