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Quote from: alancalverd on 25/05/2021 23:53:27Quote from: Bored chemist on 25/05/2021 18:33:24And would you like to discuss the piss poor efficiency of the engine? As I said, Sadi Carnot put that one to bed 200 years ago. But those unacquainted with thermodynamics might just refer to Wikipedia :QuoteModern passenger car diesel engines may have an effective efficiency of up to 43%, whilst engines in large diesel trucks, and buses can achieve peak efficiencies around 45%. QuoteThe energy efficiency of a conventional thermal power station is defined as saleable energy produced as a percent of the heating value of the fuel consumed. A simple cycle gas turbine achieves energy conversion efficiencies from 20 to 35%.A bit sad, really, because I'd love to have an electric car, but for the foreseeable future it seems that it's going to burn more fossil fuel than the old diesel I already have, and I care about the planet. But that's the subject of another thread. The UK doesn't use single turbine cycles for gas generators, it uses CCGT, the output from the gas turbines goes through a steam engine, running on the waste heat. They can achieve about 55% efficiency which makes them cheap to run while being less polluting as well. That together with nuclear and the ever growing amount of renewable generation means that the electricity is much more efficiently generated and electric cars make enormous sense in the UK.
Quote from: Bored chemist on 25/05/2021 18:33:24And would you like to discuss the piss poor efficiency of the engine? As I said, Sadi Carnot put that one to bed 200 years ago. But those unacquainted with thermodynamics might just refer to Wikipedia :QuoteModern passenger car diesel engines may have an effective efficiency of up to 43%, whilst engines in large diesel trucks, and buses can achieve peak efficiencies around 45%. QuoteThe energy efficiency of a conventional thermal power station is defined as saleable energy produced as a percent of the heating value of the fuel consumed. A simple cycle gas turbine achieves energy conversion efficiencies from 20 to 35%.A bit sad, really, because I'd love to have an electric car, but for the foreseeable future it seems that it's going to burn more fossil fuel than the old diesel I already have, and I care about the planet. But that's the subject of another thread.
And would you like to discuss the piss poor efficiency of the engine?
Modern passenger car diesel engines may have an effective efficiency of up to 43%, whilst engines in large diesel trucks, and buses can achieve peak efficiencies around 45%.
The energy efficiency of a conventional thermal power station is defined as saleable energy produced as a percent of the heating value of the fuel consumed. A simple cycle gas turbine achieves energy conversion efficiencies from 20 to 35%.
Adding something like a hybrid with smart technology such asmay even push Internal combustion past the 50 maximum percent efficiency of the engine alone.
Quote from: Petrochemicals on 27/05/2021 19:54:27Adding something like a hybrid with smart technology such asmay even push Internal combustion past the 50 maximum percent efficiency of the engine alone.Sadly, the performance of hybrids doesn't match that of conventional ICE vehicles. They are preferred in US cities because there are no emissions at low speeds and short distances, and pretty good as taxis where the regenerative braking and smooth acceleration are handy in heavy traffic, but they will be banned in the UK because for general motoring you are lugging a big battery around the country and in town you are lugging a petrol engine and tank, so your power to weight ratio and thus overall fuel efficiency is compromised compared with a pure electric or ICE vehicle..
As I write, hydro is providing 1.6%, wind 6.4%, biomass 3.3%, solar 1.8% of UK consumption.Gas is running at 49%, coal at 1.5% and nuclear at 15% with around 10% "various imports" and, for as long as it lasts, 6% from pumped storage.So more than half of our present demand is being met by fossil fuels, a significant chunk by outdated nuclear reactors, and frankly damn all from truly renewables. Not good for a warm summer evening with very few electric cars being charged. And well short of the advertised "100% renewable"!Don't be fooled by "installed capacity". Renewables (apart from hydro) rarely deliver 25% of installed capacity.
You can forget hydro. Practically all the useable sites in Scotland are either already developed or too precious to flood, and the rest of the UK is too flat. For solar panels, an average for the UK over a year is about 1 - 2 W/sq ft, so to meet 40 GW you need 20 - 40,000,000 000 square ft of panels, say 1,000,000 acres, about 2% of the total land area. That's only skimming the surface of the problem since you get no solar power at night, so you need at least 500 GWh of battery and 40 GW of inverter capacity to keep the grid running.And of course if we get rid of domestic gas heating and fossil-fuelled cars, we will need about 4 times the current grid capacity. By the time we have moved to all-electric traction and industry we will have about 15% of the country covered in solar cells. That will have quite an ecological impact.
The choice is obvious: reduce the population to a level that can travel around on solar electricity
Both are essential. The scientific problem is that it takes at least 10 years to build a nuclear power station even after the bribes have been paid. The economic problem is that a declining population implies a shrinking economy and falling house prices - the Daily Mail won't like that.
Quote from: alancalverd on 07/09/2021 22:51:54You can forget hydro. Practically all the useable sites in Scotland are either already developed or too precious to flood, and the rest of the UK is too flat. For solar panels, an average for the UK over a year is about 1 - 2 W/sq ft, so to meet 40 GW you need 20 - 40,000,000 000 square ft of panels, say 1,000,000 acres, about 2% of the total land area. That's only skimming the surface of the problem since you get no solar power at night, so you need at least 500 GWh of battery and 40 GW of inverter capacity to keep the grid running.And of course if we get rid of domestic gas heating and fossil-fuelled cars, we will need about 4 times the current grid capacity. By the time we have moved to all-electric traction and industry we will have about 15% of the country covered in solar cells. That will have quite an ecological impact. 2 percent or 4000 sq km is that is for 1/10th of the uk energy usage.