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>> The “dirty electricity” angle is less obvious to me. A power plant typically gets about 60% of energy from a fossil source. A car does about 30%. So even if
by bruce511 4mo ago
>> The “dirty electricity” angle is less obvious to me.
A power plant typically gets about 60% of energy from a fossil source. A car does about 30%. So even if the electricity comes from say coal, it's still more efficient than buying gas in a car engine.
Of course, these days, it's likely that a substantial portion (up to 100% in some cases) is not "fossil electricity" but rather comes from solar, wind, hydro etc. Ie "clean" electricity.
- cptskippy 4mo agoOur energy aggregator is a non-profit Community Choice Aggregator with over 250,000 members that ensures 50% of the energy they purchase comes from renewables and 75% of all energy purchased is carbon free. And for an extra $0.00750 p/kWh you can opt into your consumption coming 100% from renewable sources.
- wqaatwt 4mo agoCoal burns dirtier and and is more Co2 intense than gas though.
- roelschroeven 4mo ago60% efficiency? How do these power plants manage to circumvent the limit set by Carnot efficiency?
- slavik81 4mo agoNatural gas burns at ~2200 K. Ambient temperature is ~300 K. 1 - 300/2200 = 86% as the Carnot limit?
- quickthrowman 4mo agoThey don’t. they capture the waste heat from the gas turbine and use it to make steam to spin another turbine. A gas turbine is ~40% efficient, add in a HRSG to make a combined cycle plant and you can get up to ~60%. You don’t even need a gas turbine to use a HRSG, any exhaust stream with enough heat will work, a boiler plant or similar. https://en.wikipedia.org/wiki/Heat_recovery_steam_generator https://en.wikipedia.org/wiki/Heat_recovery_steam_generator https://en.wikipedia.org/wiki/Combined-cycle_power_plant https://en.wikipedia.org/wiki/Combined-cycle_power_plant