Intermittent energy source: Difference between revisions

Revision as of 20:43, 14 November 2017

Revision as of 20:51, 14 November 2017

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===Complementary power sources and matching demand===

In the past electrical generation was mostly dispatchable and consumer demand led how much and when to dispatch power. The trend in adding intermittent sources such as wind, solar, and run-of-river hydro means the grid is beginning to be led by the intermittent supply from RES harvesting instead.{{Citation needed|reason=RES harvesting|date=November 2017)) The use of intermittent sources relies on electric power grids that are carefully managed, for instance using highly dispatchable generation that is able to shut itself down whenever an intermittent source starts to generate power, and to successfully startup without warning when the intermittents stop generating.<ref>US Department of Energy: [https://www.energy.gov/sites/prod/files/2017/01/f34/Maintaining%20Reliability%20in%20the%20Modern%20Power%20System.pdf Maintaining Reliability in the Modern Power System], December 2016, p. 17</ref> Ideally the capacity of the intermittents would grow to be larger than consumer demand for periods of time, creating excess low price electricity to displace heating fuels or be converted to [[Energy storage|mechanical or chemical storage]] for later use.

The displaced dispatchable generation could be lignite, hard coal, natural gas, biomass, nuclear, geothermal or storage hydro. Rather than starting and starting and stopping intermittentnuclear RESor plantsgeothermal it makesis senseeffective to use them as priorityconstant electricity[[base sourceload]] becausepower, ofany lesspower CO2generated emissionsin andexcess lowof marginaldemand costs.can Biomassdisplace andheating stored hydropower canfuels, be savedconverted forto laterstorage whenor intermittentsold sourcesto areanother not generating powergrid. InBiofuels theand caseconventional of a RES-E surplus ithydro can displacebe heatingsaved fuelsfor (power-to-heat)later orwhen convertedintermittents toare syntheticnot fuelsgenerating forpower. later use.[[Fossil fuel phase-out|Alternatives to burning]] coal and natural gas which produce no [[greenhouse gas]]es may eventually make fossil fuels a [[stranded asset]] that is left in the ground. Highly integrated grids favor flexibility and performance over cost, resulting in more plant capacity and lower [[capacity factor]]s.<ref>Michael G. Richard: [https://www.treehugger.com/renewable-energy/death-capacity-factor-how-wind-solar-ultimately-win-game.html Death by 'capacity factor': Is this how wind and solar ultimately win the game?], 2015-10-06</ref>

* Electricity produced from solar energy couldtends be ato counterbalance to the fluctuating supplies generated from wind. In some locations,Normally it tends to beis windierwindiest at night and during cloudy or stormy weather, soand there is likely to be more sunshine whenon thereclear isdays with less wind.<ref name='AtlanticFragility'>{{cite web|url=http://www.rmi.org/images/other/EnergySecurity/S83-08_FragileDomEnergy.pdf |title=The Fragility of Domestic Energy |accessdate=2008-10-20 |last=Lovins |first=Amory |author2=L. Hunter Lovins |date = November 1983|format=PDF |work=The Atlantic |archiveurl = https://web.archive.org/web/20080625205941/http://www.rmi.org/images/other/EnergySecurity/S83-08_FragileDomEnergy.pdf |archivedate = June 25, 2008}}</ref>

* In some locations, electricity demand may have a high correlation with wind output, particularly in locations where cold temperatures drive electric consumption (as cold air is denser and carries more energy).

* Intermittent solar electricity generation has a direct correlation where hot sunny weather drives high cooling demands. This is an ideal relationship between intermittent energy and demand.