MSE Energy

investment of money into building a plant, payback of investment and interest

independent of fuel consumptions, maintenance, operation etc.

impact on electricity costs

Levelized cost of electricity

compare costs of different technologies, with different life spans, project sizes, returns, risks, ...

economic assessment of lifetime costs per kWh tou build and operate a plant / total energy output of that plant in entire lifetime

=Net present value of total costs = average minimum price for selling energy to reach break-even in lifetime of project

LCOE = (annual capital costs + fuel cost + balance of costs + ROI) / (annual electricity production in kWh)

revenue from selling by-products e.g. heat (Fernwärme) or spent coal for construction

LCOE decreases exponentially with increased capacity (measure for availability), approaches a platform

Energy returned from system and energy required to make system work over lifetime

EROI = Energy returned / energy invested

huge impact for our planet!

Net energy produced

Energy returned = energy invested

assume constant power values for investment and returns

how much power can we generate per m^2

fossil fuels: 500-10000 W/m^2

nuclear 500-7000

solar: 2-50

hydro: 1-7

nuclear processes

energy cannot be created or destroyed; it can only change form.

=> energy is conserved (in a system without losses) / transformed (from one form to another) or transferred (from one system to another)

mass flow or heat transfer or work

if it is independent of the reference system (e.g. the chemical energy of a barrel does not depend on if the barrel is on ground or lifted up)

u = u_ext molecules + u_translation (displacement of molecules) + u_int molecules

u_int molecules = u potential (chemical bonds) + u_rotation + u_vibration + u_atoms (in the atom core)

water can accumulate a lot of internal energy due to its many degrees of freedom compared to a lattice (e.g. different vibrations or rotations) => wate can accumulate a lot of energy at the temperature

statistic thermodynamics are on a microscopic approach (pressure and temperature come from moving molecules)

classic thermodynamics are macroscopic (pressure and temperature come from a fluid)

energy of the system can only change due to heat transfer or work across system boundary, no mass flow possible

of the system itsself, not internal in the system, e.g. a stationary system does not have kinetic or potential energy

write down this assumption every time!

heat transfer: energy interaction caused by temperature difference, exchanged by disordered motion

work: energy transfer without temperature difference, driven by force; exchanged by ordered motions

mechanical definition: energy transfer associated with a force acting through a displacement

energy transfer driven by temperature difference

conduction, convection and radiation

convection is more powerful than conduction because no local change in contact area temperature

radiation: no medium needed, notice T^4 => very efficient heat transfer

no medium needed, very efficient with little temperature difference, if you go to a cold house and start heating, the air gets warm but you still feel cold because the wals are cold and your body emits radiation

emissivity: epsilon, physical constant of material, how much radiation will get off (perfect emitter e=1, complete absorption e=0)

similar:

- both are path functions and inexact differentials, the work depends on the path I choose (not just the state of the system)

- both are boundary phenomena, only recognized when crossing boundaries (no internal force can move a system)

- associated with a process, not a state; systems possess energy but not work or heat

dissimilarities:

- heat needs temperature difference

- external work can only rise a weight or move sth.; heat transfer can also lead to other effects

inexact differentials: depend on path

=> that's why we can make a cycle taht can transform heat into work etc. => thereby we can make a process

inputs into system are +, outputs are -

work = electric or mechanical

mechanical = gravitational, boundary work, acceleration, spring or shaft

heat up a boiler by injecting electrical work (current). the inside will heat up due to ohmic resistance (so work is injected, not heat)

this actually depends on where you put the boundary. is it at the border of the boiler where the cable enters or is it at the touchpoint to the heating coil? (then it would only be heat)

linked to variation of volume of a system, expanison or compression

if you expand, you have negative work in your system because you do work towards the surroundings

wokr needed to compress or extend a spring

rotation of a shaft depending on torque and angular displacement

1 kg

work to lift a certain mass or accelerate it => SUV needs more energy to accelerate than a Smart

in a piston, if the line from state 1 to state 2 is isothermal and the gass is idal, then the delta U =0

path of a process

reversible vs irreversible processes

internal dissipation

can be reversed without change to system or surroundings (both go to initial state)

reversible is theoretical, ideal, you acnnot leave any trace of energy transformations in your environment

infinitesimal change of thermodynamic system in balance, during infinitely long amount of time

e.g. slowly expand a water basin

friction

fast compression and expansion

thermal exchange with finite delta T

mixing

non elastic deformation of solids

joule effect (heat up something with electricity, but you cannot directly turn heat back into electricity in wire)

chemical reactions