Peak Power

Peak Power Can Come from Energy Island

 by Thomas Manaugh, PhD

 

Energy Island[i] is an ocean-based, power-generating system that can be used to help humanity transition toward using renewable energy sources and away from using fossil fuel energy sources that pollute with climate-changing greenhouse gases. The system taps multiple sources of energy from wind, water, and sun – along with compressed air energy storage (CAES) – to generate and transmit reliable, safe, clean and abundant electricity to the grid. I explore here how Energy Island could serve to help meet a demand for power specifically during periods of peak demand

When AC units get switched on during hot afternoons, high electricity demand is met when the grid draws power from peaker plants.  Peaker power plants typically burn natural gas or diesel fuel, on-demand, to drive turbines that generate electricity. Those plants serve a necessary purpose, but they are expensive and polluting.

Because renewable energy sources are usually understood to be cyclic or intermittent, they are widely believed to be poor candidates as sources of power for peaker power plants. However, when energy storage is added to a power-generating system, renewable energy sources can become reliable, cost-efficient, and clean candidates for powering peaker plants.[ii]

Energy Island as a Peaker Power Plant

Because Energy Island includes robust energy-storage capacity using CAES, it could provide reliable power during periods of high electricity demand. Specifically, multiple renewable energy sources could be used to power pumping of air into compressed-air storage chambers during non-high-demand periods. Later, the compressed air could be released during periods of high demand to power turbines that would generate electricity for the grid.

Below are simple principles of operation that allow Energy Island to serve as both a regular contributor to the grid as well as a peaker power plant:

1)    Multiple sources of energy from wind, water, and sun are used to generate electricity on Energy Island. That electricity serves to power air-compression pumps that charge CAES chambers on Energy Island.  The level of charge is continuously monitored and kept at 98% to 100% during non-peak-demand hours (e.g., 8 PM at night until 2 PM the next day). Only a part of the electricity generated on Energy Island is needed to charge the CAES system.

2)    Electricity that is not needed to charge the CAES system during non-peak-demand periods is transmitted to the grid to contribute to the grid’s baseload power supply.

3)    During peak demand hours (e.g., 2 PM to 8 PM), all electricity generated on Energy Island is transmitted to the grid.  That electricity comes from generating electricity from release of compressed air from CAES as well as electricity generated by the usual multiple sources of renewable energy.

Figure 1 shows a flowchart that describes how Energy Island’s generating capacities are controlled for storing energy and for distribution of power to the grid during peak and non-peak hours of operation.

Figure 1. Operation of Energy Island for directing generated electricity during peak and non-peak hours.

peaker flow chart

 

Discussion

In a recent NASA-supported study scientists concluded that failure to deal with climate change could result in an irreversible collapse of civilization, similar in scope to collapses documented in several advanced civilizations in human history.[iii]  The link between use of fossil fuels and climate change was recently affirmed by the prestigious American Association for the Advancement of Science where it was stated that evidence that the world is warming is as conclusive as that which links smoking and lung cancer.[iv]

“External costs” from burning fossil fuels include all the costs that result from emitting greenhouse gases and other pollutants. Unfortunately, external costs associated with destroying Earth’s livability are not usually given much weight when economic decisions are made about how to provide power to consumers.  Rather, much more weight is given to immediate price comparisons as opposed to long-term costs from climate change. Thus, finding ways for renewable energy to beat out fossil fuels in head-to-head competition on price is a crucial goal for reducing greenhouse gases and ensuring a livable planet now and in the future.

Could Energy Island compete on price with conventional, fossil-fuel peaker power plants? The answer is probably “Yes” because conventional peaker power is very expensive.  Cost per kilowatt hour is generally four or five times higher for peak power than the cost for power that comes from non-peaker plants. An Energy Island that could deliver peak power for 50 cents per kilowatt or less would be quite competitive in many markets. Thus, the high cost of peaker power presents a window of opportunity for Energy Island to compete successfully head-to-head with conventional peaker power plants. How expensive is peaker power? According to one expert, “Something that most people are surprised to hear is that 10 to 20 percent of the overall electricity costs in the U.S. come from the top 100 hours on the electricity system.” [v]

Demand for electricity changes in level with time of day and with seasons. Typically, periods of highest demand are from midafternoon until early evening.  Peaker power plants help provide extra power that is needed during those periods, but those plants remain inactive at other times.  By contrast, Energy Island could serve both as a reliable peaker plant and a contributor to the grid during periods of regular demand. Thus, an “always-on” Energy Island would tend to be more cost-effective than the usual fossil-fuel-using peaker plant. Furthermore, Energy Island would enjoy a long-term advantage bestowed by its ability to tap free energy from the wind, water, and sun.  Costs associated with using fossil fuels, on the other hand, can be expected to become increasingly expensive as fossil fuels inevitably become scarcer and more difficult to find and to extract.
 
 

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i  “Energy Island: Plant of the Future,” retrieved from the Internet at http://powerplant2100.com/energy-island/ on 3/6/2014.

ii  “Dueling Charts of the Day: Peaker Plants vs. Green Power,” retrieved from the Internet at www.greentechmedia.com/articles/read/dueling-charts-of-the-day-peaker-plants-vs.-green-power on 3/6/2014.

iii  “Nasa-funded study: industrial civilisation headed for ‘irreversible collapse’?” retrieved from the Internet at http://www.theguardian.com/environment/earth-insight/2014/mar/14/nasa-civilisation-irreversible-collapse-study-scientists on 3/18/2014.

iv   American Association for the Advancement of Science http://www.climatenewsnetwork.net/2014/03/aaas-climate-risks-irreversible-change/

v  “How Smart Is The Smart Grid? : NPR.” retrieved from the Internet at http://www.npr.org/templates/story/story.php?storyId=128365808 on 3/18/2014.

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