Cardset

1. Primary energy are energy sources wich need to be converted to be used (solar radiation, Uranium or crude oil)

1. Secondary Energy is an energy form that has been transformed from primary energy in a conversion process

   (-> Crude Oil to gasoline, solar radiation to electricity)

2. Usefull energy is the energy wich in the end can be used

   (-> light from electricity, heat from gasoline)

• Mechanical Energy (EPot and EKin)

• Electric Energy E = U*I*t

• Chemical Energy -> Enthalpie of the reaction

  
  

1. Energy is conserved (cant be created or destroyed)

2. A closed system can only change its energy content by transferring energy over the system boundary

1. Disorder within a closed system increases or dosent change

2. The conversion of energy in a orderly form (kin. energy) to an energy in a disordered form (heat) is completely possible but not backwards

3. The part of energy, which is convertible into work, decreases during every natural process

• Its impossible to convert heat entirely into work

1. Exergy E:

   • Exergy is the maximum usefull work dischargeable if you bring a system into equlibrium-

     -> The Part wich is converted into work by heat conversion

2. Anergy is the part of energy that cannot be converted into exergy.

• Industrial processes

• Power generation

• Agriculture

• Transportation

• loosley defined as the change in net irradiance in w/sqaure meter

• Fixed costs (independent of the annual utilization)

– Capital charges

– Salaries

– Insurances

– Taxes

– Storage costs...

• Variable costs (dependent of the annual utilization)

– Fuel

– Ammonia

– Lime

– Water treatment

-> Need do react quikly to the load changes from the weather dependend renewables therfore they need:

• energy storages

• fast starting converstional power plant like gas

• Extra high voltage 380kV (Transport and transmission)

• High voltage 220kV (Big companies and public utilitys)

• Medium voltage 110-20kV (normal firms)

• Low voltage 0,4kV (households)

• Efficiency 70 -85 %

• Limiting factors:

  • Number of proper locations

  • Influences on enviroment

Pros:

• No need for fossil fuels

• high storage efficiencies (ca 70%)

Disadvantages:

• Very high demand on the heat storage

• Lead acid battery

• Lithium cell

• Sodium sulfur accumulator

• Flow battery

Joule process

Chapture of Carbondioxid emissions and then stored it or use it.

Residual load = total production – unplannable production (PV, wind, river hydro)

-> Residual load equals the energy amount from storage or power plant

-> reduction in max and min load

• less base (>6500h) and medium load (3000-6500h) needed

  
  

• log wood

• wood chips

• pellets

• rape

• straw bales

• straw pellets

• cereals

With use of ligth energy CO2 can be absorbed and converted into organic biomass

0,25 -1,2%

• Water

• Temperature

• qualitiy of the humus

• low power density leeds to a restricted power output of a power plant-> Power is limited

-> Biomass is particularly applicable for decentralized utilization

• Olive pits

• Ligneous biomass

• Herbaceous biomass (blätter, stroh…)

• sludge (Klärschlamm)

Preatetment can enhance the properties of biomass, there are two ways:

• Physical/ mechanical ( biomass washing or comminution)

• Chemical (washing with organic solvens or dilude with acid)

• Thermophysical ( not availiblel jet

• thermochemical

• biological

-> Thermal treatment of biomass to dry the biomass

Process conditions:

• Absence of oxygen (atm. pressure)

• Temperatures of 200-300°C for 20-60 minutes

• suitable for “dry” biomass (moisture < 50%)

Products:

• Torrefied biomass

• combustible torgas

Biomass cooking in hot, pressurized water at saturation pressure

Process condtions:

• Temperature 170-270°C

• Pressure: up to 35 bar

• from 0,5 to 4 hours

• suitable for “wet” biomass

Products:

• Biochar (pflanzenkohle) with high heating value

• combustible off gas

Process:

1. Mixing biomass with saturated steam 200-220°C

2. Quick depressurization

3. Biomas impacting on walls and particles causes fiber disruption

Main applications:

• Pretreatment process for biomass fermentation

• Pretreatment process for production of “black pellets” (from wood)

• Flue gas losses

  • CO content in flue gas (not fully oxidated)

  • Flue gas temperature

  • mass flow

• Radiations losses

  • surfaface temperatures

• Ash losses

  • Rest coal in ash

  • Ash temperature

• Distribution net losses

  • Temperaturelosses to and from heating net

  • Pressure losses

-> Humidity leads to incomplete combustion which leads to a lower temperature -> increases the fluegas massflow

-> Problem 1: fluegas temperature (t_end) is limited downwards

-> Problem 2: combustion temperature (t_ad) is limited upwards

(depends on lambda and the burner)

Main factor for heat generation:

• Flue gas losses

Main parameters for the firing efficiency:

• Return temperatures

• Air excess and fuel humidity

Other boiler losses:

• Chemical flue gas losses

• Ash

• Surface losses to the environment

Reduction of excess air:

• by staged combustion

• by non-adiabatic combustion

• by flue gas reciculation

Reduction of the flue gas temperature

• by low return temperatures

• by flue gas condensation

Reduction of other losses

• fuel humidity (drying)

• burnou (ash losses)

• the efficiency of heat generation is mainly determind from the combustion temperature and the air excess

• the combustion temperature and the efficiency of biomass furnaces are lower than those of natural gas

• the combustion temperature is limited by the ash melting behavior of biomass

• High energy density

• Low residual moisture, good storage ability

• homogeneity, accurate dosing and efficient handling

-> Clausius Rankine Cycle

0-1 isentrope Verdichtung

1-2 isobare Wärmezufuhr

2-3 isotherme Verdampfung

3-4 Überhitzung

4-5 isentrope Entspannung

5-0 isobare Wärmeabfuhr

electric efficiency of a normal plant is higher compared to a power plant wich producees heat and electricity.

• The CHP coefficient is the ratio between generated electrical power and available heat flow

• The mean CHP coefficient is calculated accordingly, using the electrical work and the available heat.

sigmaflexibilität gibt die Möglichkeit zwischen Wärme und Elektrizität zu variieren.

-> Used to extrakt power from a lower heat level

-> electrical efficiency of 13-16%

pros: - lower heat can be utilized

- plug and play -> easy to install

cons: expensive and mostly poisonos

-> for example in coal fire plants -> still needed and better if not fired with 100% lignite or coal -> can cut costs very efficiently

-> today 30-100% of coal can be substituted

Drying

• outcasting of the water contnent

Pyrolysis

• from 250 - 600°C to crack the big moleculs

Gasification (700^C and more)

• partial oxidation of the residual coke

-> Gas mixture of CO, H2 and CH4 aris

• Tars occur when the tempratures are to low during the gasification process

• Tars leads to coke deposits when its burned

• use it by burning it under very high heats (gas turbines)

-> higher gasification temperatures

-> Elimination of tars by washing it out or catalytic cracking/reforming

-> entrained flow gasifier

from agriculture like:

• slurry (Gülle)

• corn silage

• Sugar beet

from agro-undustry like:

• Beer production

• potato processong

• Sugar production

organic residues of communes and households

• Bio waste containers

-> there are also some small dry fermenter types like a container

CHP with combustion engines:

• Gas-otto engines

• Gas-diesel engines

• Pilot injection engine

Other forms:

• fuel cell

• micro turbine

Motivation:

• Alternative solution to CHP-use in biogas plants

• Bio- methane as transportation fuels

• Biogas as crisis-proof share of the gas supply

Aim:

• Higher methane content

• Securing of combustion related indicators

• for feed in grid gas it needs to hit standarts

• 30-70% radioactive decay

• 30-50% from accretion (Energy from when the earth was formed)

-> temperature gradient from 7,9 K/km

• to be profitable it is needed to extract more heat than the internal radiactive decays can regenerat.

  -> so after about 40 years theres no heat to extract and the borehol is closed

deep geothermal with open systems

the others are closed systems

if it gets very cold in the winter the efficiency of the heat pump decreases strong

-> Available heat is highly dependend on the soil type

Series collectors:

• + Delta T ist higher which leads to a more efficient heat pump

• - Pressure losses

Parallel collectors:

• + Higher Heat and less pressure losses

Trench ground collectors:

• geothermal probes (up to 150m)

  • either drilled or ramed

• Groundwater (4-10m)

Is the utilisation of a artifical heat exchangers

-> All methods use hot stones under ground, utlilised by drilling holes (30-40m) and injecting water

Different Tasks:

• Prevent contamination of other zones

• Prevent from caving-in

• Isolates different zones with different pressures

• Seals off and avoids blowout

• Prevents fluid loss

• Provides a smooth internal bore for installing production equipment.

• Thermal response test:

  • water is injected to the borehole and circulated

with T_i,s = Temperature of the inner wall, T_i = Tempertaur of the room

• Coefficent of performance

-> Tcond - T evap = should be small

• Radiators 45-60°C

• Floor heating (min) 20°C

  Qs = U * A * (T_h - T_umgebung)

• Hot water supply > 60°C

• mechanic compression is replaced by an thermally driven system based on absorption

• efficiency is meassured in GUE:

-> good if theres a lack of green electricity

-> can help in regions where the sail is bad for mechanic heat pums like in bavaria

BUT until today there are driven with natural gas -> CO2

1. Amonia ist Absorber -> Useable Heat

1. Efficient Pump with low power compresses NH3 and H2O

2. Desorbtion of NH3 and H2O with heat (gas firing)

   -> Amonia evaporates

need to be given to be financial sensible:

-> to most important factors are:

• Temperature

• Pressure

1. Saturated liquid is extracted from the underground

2. Flash evaporation throttle (pressure reduction)

3. Steam is “clean”

point 4 on the left side isnt useable for turbine, because of the high droplet share, so by dercreasing the pressure and seperating the steam from the liquid, the steam becomes useable. (point 4 on the right)

• where high pressure ratios are achivable

• high steam moisture needs to be avoided

• -> Same technic as the single flash, besides it has to seperators and to turbine stages to extract more power

ORC preferable if:

• Brine temperature is below 200°C

• Brine is significantly understurated

• low mass flows

Kalina cycle:

• Works with a mixture of water and ammonia as the working fluid Evaporation is characterized by a temperature glide!

BUT:

• Expensive workingfluids

• Amonia is quite hard zu handel

-> isn´t a real thing today

Deep geothermal systems:

• Noise generation by drilling and during operation

• Emission of gases (CH4, NH3, H2S,…)

• Release of minnerals

• Harmfull working fluids

• Seismicity

Near surface geothermal systems:

• Harmfull working fluids

• Horizontal heat exchanges may affect vegetation

• Seismicity

-> dry steam only in very good plasce like Icland

-> in germany you can achieve around 20ct/kwh or 6ct/kwh(thermisch)

-> future for geothermal will be in the heating sector

-> from 22.5 GW to 22 MW -> big power range and a big field of application

• Tidal power plant

• storage

• Pumped storage

• Run on River (ROR)

• availability

• high efficiecy 80-90%

• high lifetime

• energy storage and grid service

• no waste

• grid service

Potential: (storage plants)

Kinetic: (For tideplants)

-> mostly its tryed to harvest both Energys

-> Epot is more important

• losses during inflow of the water

• turbine losses

• gearbox losses

• genertator losses

• Switchyard losses

• Auxiliary supply losses

-> in total the efficiency is around 0,82-0,92

Impuls turbines:

• Peltonturbine

Reaction turbine

• Francisturbine

• Kaplanturbine

• Kaplanbulb

• the energy conversion within the turbine runner is performed at constant (ambient) pressure

• all of the big pressure energy is converted into kinetic energy and is than completly transfered to the turbine

• under constant pressure the kinetic energy is converted into mechanical energy in the buckets of the turbine

-> needs a big hight difference but small amount of wate-> could be found in plants in switzerland

• the pressure energy avaliable at the turbine inlet is only partly converted into kinetic energy due to accerleration in the spiral case, the stay vanes and the guide vanes

• most kinetic and potential energy are converted into mechanical energy

Pelton:

• High hights, low to medium flow

Francis:

• medium to high hights, low to high flow

Kaplan

• low to medium hights, medium to high flow

+:

• power house can be bild on dry area

• sediments can be kept away from the turbines

• power house protected from floods

-:

• significant ecological flow required (-> power loss)

• Flow rate is fixed by the canal, later power upgrades difficult

In Pierhead power plants the piers holding the gates are bigger than normal so that the turbines can be installed within the pier.

+:

• no sediment deposit problem in front of the turbine inlets

• symmetrical inflow to the turbines

• compact design

-:

• poor accessibility of the electromechanical equipment

• piers reduce width for flood discharge

Gates and powerhouse are combined into one Building and submerged in the river.

-> often with kaplan bulb turbines

+:

• optically quite unobstursive

• weight widley distributed onto the soil

• very good flood discharge characteristics

-:

• poor accesibility for maintenacne and repair

• tendency to accumulate sediments

• higher risk of water penetrating the power house

• sometimes the powerhouse is intigrated in the dam itself

-> has pumps so it can work in both directions

Uses the potential energy in the difference in height (head) below high and low tides. (Kaplan bulb turbines)

+:

• high capacity possible

• highly predictable

-:

• high invest costs

• Only few sites meet the requirements (high tidal amplitudes, blocked beach)

-> turbines have to work in both directions

Use the kinetic energy of the moving water with stream turbines. Working principle identical with wind turbines as the same fluid dynamic

+:

• lower ecological impact

• less requirements for sites

-:

• low power output

• poor accessibilility for maintenance

• salt sand and plants

special turbines needed, because of the small speeds <2 m/s

• Head range 150 to 1800 m

• Flow rate about 60m^3/s

• Impulse turbine

• nozzle converts the pressure energy to kinetic energy of a free jet

• wheel consists of spoon shaped buckets

• Vulnerable to erosion, therefore sand load in water should be very low

• normaly 1 or 2 jets but can be up to 6 if high flow rate is needed

• reaction turbine (vertical and horizontal useable)

• typically, the design includes a spiral casing, adjustable guide vanes, fixed turbines blades between a lower and upper turbine ring & a draft tube

• Globally most widely used turbine type

• Turbine is completely filled with water and position is below tailwater level to avoid cavitation

-> Head range 30 to 800m

-> Speed up to 800m^3/s (depends on the model of turbine)

• reaction turbine (vertical and horizontal useable)

• Water is flowing in axial direction through the turbine which is filled with water and below tailwater level

• turbine consists of inlet, adjustable guide vanes as well as turbine blades

-> Head range 2 to 75m

Flow rate up to 800m^3/s

• Erosion/ Abraison

• Caviation

  • static pressure locally drops -> water drops evaporate ->

    pressure raises -> bubbles implode and form a fast jetstream

    -> can lead to big damage

• Dirt and trash

  • regulary cleaned by a automated device

• current and deviation from forecastsed precipitation (niederschlag)

• impact of operators which are active upstream

• ongoing/ panned maintenance work

• urgent ad-hoc requests from stakeholders or trading

-> if controll center loses connection to the power plant -> it shuts it self down automatically

• Normal operation:

• Swelling operations:

• Operation - Minimum water managment

-> if there is not enough water in the river the plant runs on as little water as possible to balance the waterlevel

• Feed in tarif

• Capex

• lifetime of the plant

• technical risks

• market risk

• einviornmental risks

• political risks

Efficiency optimization

• optimized turbine

• optimized generatordesign

• optimized flow design

• better predictions

Flexibility optimization

Ecological performance

• oil free

• model river dynamics

• improve fish friendliness

• effective fish mitigation

Saftey

• drone inspections

• education and training