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vvvf inverter for elevator

Author:Elevator Inverter Time:2021-04-09 09:43:52Click:
vvvf inverter for elevator One of Smil’s key arguments is that beliefs in the possibility of a rapid transition are inadequate because they are based on transitioning electricity alone.
Smil appears to be unaware that most scenarios for 100% renewable energy involve transitioning almost all transport and non-electrical heat to renewable electricity.
The main exceptions are long-distance rural road and air transport, which will need renewable fuels.
Smil seems to be under the incorrect impression that we must focus on changing the fossil fuel primary energy inputs – coal, oil and gas – to renewable energy, presumably because the traditional energy flow diagram (see figure) starts with primary energy on the left, then flows through transformation processes (e.g. combustion in a power station) in the middle of the diagram – to provide on the right-hand-side, after substantial energy losses, the end-use energy and hence the energy services we demand: a warm home in winter, hot showers and cold beer.
This puts the cart before the horse.
However, if we start by considering what energy services we really need, we can integrate energy efficiency and conservation with renewable electricity, thus reducing the demand for end-use energy, which will be used mostly as electricity.
Then, when we reduce electricity use by a certain amount, we substitute for approximately three times that amount of energy in primary fossil fuels used for electricity generation.
This is because of the low efficiency of conversion of fossil fuels into electricity, as illustrated. A strategy that moves from right to left is much easier than the opposite.
Smil also asserts that the successful transition of a few countries is irrelevant to a global transition. Presumably he thinks that the rapid ongoing transition of Denmark, with 44% of its electricity in 2017 coming from variable RElec (wind), and Germany with 26%, are special cases.
However, we can also consider the north German states of Schleswig-Holstein and Mecklenburg-Vorpommern (100% net, mostly wind), South Australia (45%, wind + solar PV), Scotland (44% of consumption and over 60% of generation, mostly wind) and several states of the USA (each with 25-30%).
These successful examples are relevant as the pathfinders for other regions, demonstrating how reliability, security, affordability and environmental sustainability can be achieved with high and increasing contributions from variable renewable electricity.
They also continue to drive down the costs of renewable technologies for the rest of the world, which then experiences an easier transition than the pathfinders. Germany’s success in driving the market for solar PV, and so bringing down its costs, brought China into manufacturing PV, resulting in further reductions in costs.