RES Exam 1 Review (Concepts)

current that changes direction 60 times a second. Can be transmitted over long distances

(AC) Alternating Current

Current that flows in one direction. This type of electricity can be found in a battery

(DC) Direct Current

true

100 kW * s (kilowatt-seconds) is equivalent to 100 kJ true/false

8

1000 kg of water initially at 5 m/s runs through a hydro-generator. If the water leaves the generator at velocity of 3 m/s, and the efficiency of the generator is 100%, how much electricity in kJ (2 significant figures) will we get? Hint: The amount of kinetic energy available for conversion to electricity is the change (KEout - KEin)

294.3

3,000 cubic meters of water is held in a reservoir with average elevation of 10 m. Assume the water density of 1000 kg/m3. How much potential energy (in MJ) do we store in the water? 4 sig figs.

143

A battery "pushes" an electric scooter with 12 kN of force to move it 119 meters every 10 seconds. Assuming 100% energy conversion, how much averaged power is being used (in kW)?

4380 MegaWattHours

A hydro turbine has a maximum power output of 0.5 MW. If it ran at full capacity for one year how much energy would it produce in that year?

4380 MWhrs

A hydro turbine has a maximum power output of 0.5 MegaWatts. If it ran at full capacity for one year how much energy would it produce in that year (in MWhrs)?

d. 4380 MegaWatt Hours

A hydro turbine has a maximum power output of 0.5 MegaWatts. If it ran at full capacity for one year how uch energy would it produce in that year? a. 0.5 MegaWatts b. 2890 MegaWattHours c. 2890 MegaWatts d. 4380 MegaWatt Hours e. 4380 MegaWatts

8760 MWhrs

A hydro turbine has a maximum power output of 1 MW. If it ran at full capacity for one year how much energy would it produce in that year (in MWhrs)?

d. 8760 MegaWatt Hours

A hydro turbine has a maximum power output of 1 MegaWatt. If it ran at full capacity for one year how much energy would it produce in that year? a. 2890 MegaWattHours b. 1 MegaWatt c. 2890 MegaWatts d. 8760 MegaWatt Hours e. 8760 MegaWatts

186

A power plant that generates 894 GWh annually has a capacity factor of 0.55. What is the plant's rated power capacity in MW?

any material that will allow electric current to pass through it easily

Conductor

mechanical to electrical to mechanical

Consider a turbine producing electricity that is then used in an electrical motor to spin a wheel. Select the best answer that describes the conversion of energy mechanical to electrical mechanical to electrical to mechanical thermal to electrical electrical to mechanical

silver, copper, gold, aluminum, all metals

Examples of conductors

glass, plastic, rubber, porcelain, fiberglass

Examples of insulators

About 4 times higher

How does the average per capita power consumption in North America compare to the world average? Note: the per capita energy consumption would be in units like kW/person 4 TIMES HIGHER TWICE AS HIGH 2 TIMES LOWER ABOUT THE SAME

290 Joules

How much energy have you applied to 3 kilogram rock when lifting it 10 meters from the ground to the top of a building? (to the nearest 2 significant figures, assume 100% efficiency and acceleration of gravity = 9.8 m/s2).

2.05

How much power (in kW) is in a circuit that has a load (resistance) of 6.9ohms at a voltage of 119volts?

648

How much power is in a circuit (in W) for a circuit that has 9.0 amps of current and 8.0 ohms of resistance?

1.8 kW

How much power is in a circuit that is 120V and 15 amps (in kW)?

b. 1.8 kW

How much power is in a circuit that is 120V and 15 amps? a. 1.8 kJ b. 1.8 kW c. 8 J d. 8 W

1.8 kW

How much power is in an electrical circuit that is 120V and 15 amps?

59.9

If electricity going into a transformer is at 513 V and 142 A and exits the transformer at 101 V and 432 A, what is the efficiency of the transformer?

Nameplate capacity x 8760 Hour/yr x Conversion Efficiency

If the nameplate capacity (in kW) of a PV panel is known, how would you estimate the actual annual energy output (in kWh) for a given location. Select the best answer: - Nameplate capacity x capacity factor - Nameplate capacity x Hours of daylight/yr - Nameplate capacity x 8760 Hour/yr x Conversion Efficiency - Nameplate capacity x 8760 Hour/yr x Capacity Factor

D- The time period (duration) of power production or use.

If you are given a unit of POWER (such as a kW) what information do you need to calculate ENERGY production or use? A-The peak power use. B-The cost of energy. C-The cost of Power. D-The time period (duration) of power production or use.

b. The time period (duration) of power production or use.

If you are given a unit of POWER (such as a kW) what information do you need to calculate ENERGY production or use? a. The peak power use. b. The time period (duration) of power production or use. c. The cost of Power. d. The cost of energy.

b. multiply the rated capacity the capacity factor and then by the total time ( e.g. hrs) in a year.

If you are given the rated capacity (a power unit lik kW) and the capacity factor (e.g. 50% or 0.5) of an energy production facility, how do you calculate the total annual energy production? a. Multiply the rated capacity by the hours per year and divide by capacity factor. b. multiply the rated capacity the capacity factor and then by the total time ( e.g. hrs) in a year. c. Call Homer Simpson, who works at a nuclear power plant. d. Divide the rated capacity by the capacity factor.

~ 4.5 cents/kWh

If you can sell wind energy to the grid at 6 cents/kWh for 12/hrs per day at the 'on peak' rate and 3 cents/kWh for 12 Hrs per day at the 'off peak' rate. What is the approximate value of the total energy produced from you wind turbine (assuming steady production for the whole day)? Answer in cents/kWh

c. about 4.5 cents/kWh

If you can sell wind energy to the grid at 6 cents/kWh for 12/hrs per day at the 'on peak' rate and 3 cents/kWh for 12 Hrs per day at the 'off peak' rate. what is the approximate value of the total energy produced from you wind turbine (assuming steady production for the whole day) a. more than 6 cents/kWh b. about 6 cents/kWh c. about 4.5 cents/kWh d. less than 3 cents/kwWh e. about 3 cents/kWh

14

If you drop the 3 kg rock you lifted to the top of the building, how fast will it be moving (in m/s) when it hits the ground 10 meters below. Assume that the conversion from Potential to Kinetic Energy is 100% efficient? (answer with at least 2 significant figures)

b. about 500 ExaJoules (EJ)

In the last decade what is approximately the global annual primary energy consumption: a. about 100 ExaJoules (EJ) b. about 500 ExaJoules (EJ) c. about 10 Quads d. about 1000 Quads

any material that will not allow electric current to pass through it

Insulator

d. A mass in motion

Kinetic energy is the energy associated with a. A mass lifted a spcified height above a reference point (in a gravity field) b. Chemical composition c. A temperature difference d. A mass in motion

a. Net Energy Return b. Eutrophication Potential c. Greenhouse Gas Emission

LCA can provide outputs for environmental impacts including: a. Net Energy Return b. Eutrophication Potential c. Greenhouse Gas Emission d. Net Present Value e. Annualized Operational Impact

0.136

Let us consider that a family's annual electricity consumption is 11000 kW-h. Assuming the energy expenditures of the family totaled 1500 per year, calculate the unit price of energy (in $/kWh, with at least 4 significant figures) charged by the utility company.

1.256

Let us consider that a family's annual electricity consumption is 11000 kW-h. What is the power consumption (in kW, with at least three significant figures)?

10 W light bulb on for 1 hour 700 calories of food 90 N of force exerted for 10 m of length

Mark the following situation that describe a quantity of energy (or work). -10 W light bulb on for 1 hour - A turbine that is outputting 10 kJ/s - 700 calories of food - 90 N of force exerted for 10 m of length

Solar Panel (DC) Battery (DC) Wind Turbine (AC) Typical US home (AC)

Match the device to the power type produced or used (AC or DC) Solar Panel Battery Wind Turbine Typical US home

a. The rate of energy production or use

POWER is best described as... a. The rate of energy production or use b. The amount of energy used multiplied by the time over which is it used. (Energy x time) c. The total amount of energy that has been used to perform a task.

GEOTHERMAL

Please mark all of the following that do NOT obtain the originating energy from solar radiation? Geothermal energy Solar Thermal Hydropower Biofuels Wind Energy

- A mass lifted a specified height above a reference point (in a gravity field) - A temperature difference - A compressed spring

Potential energy is the energy associated with Please mark all that apply: - A mass lifted a specified height above a reference point (in a gravity field) - A mass in motion - A temperature difference - A compressed spring

AN ELEVATION CHANGE

Potential energy is the energy associated with: Voltage An elevation change A mass that is in motion A temperature differential

In the afternoon during the hottest months of the year In the late afternoon during cold months of the year In the middle of the night in hot or cold months of the year.

Rank the market value (1 = highest to 3= lowest) of electric energy produced under the following conditions (in the US). In the middle of the night in hot or cold months of the year. In the late afternoon during cold months of the year In the afternoon during the hottest months of the year

the property of a substance to oppose the flow of electricity

Resistance

a. DC has to be converted to AC c. Transformers must be employed to obtain correct voltage?

Select all of the following true statements that are required for electricity to be fed into the US grid. a. DC has to be converted to AC b. AC has to be converted to DC c. Transformers must be employed to obtain correct voltage? d. Transformers must be employed to obtain correct amperage? e. An electricity storage system must be employed

a. Life cycle assessment is the investigation and valuation of the environmental impacts of a product or service b. LCAs are governed by ISO standards

Select the TRUE statements about LCA a. Life cycle assessment is the investigation and valuation of the environmental impacts of a product or service b. LCAs are governed by ISO standards c. There is only one correct way to perform and LCA d. The output of an LCA will tell you definitively if a process is sustainable e. LCAs can only determine environmental impacts for energy systems

a. Investigates cash-flows over the lifetime of a project c. Evaluates physical and economic properties of a technology (e.g. renewable energy) to determine its feasibility e. Defines return on investment (ROI) of a project

Select the following true statements about techno-economic analysis: a. Investigates cash-flows over the lifetime of a project b. Applies to only new technologies c. Evaluates physical and economic properties of a technology (e.g. renewable energy) to determine its feasibility d. Reduces environmental Impacts of a project e. Defines return on investment (ROI) of a project

b. Generate figures and tables to help communicate findings c. Run simulations of alternative technologies or systems d. Simplify calculations and quantify energy and economic inputs and outputs e. Avoids costs of having to build a prototype of the system

Select the following true statements about what an energy model can provide: a. Can demonstrate the effectiveness of a new technology b. Generate figures and tables to help communicate findings c. Run simulations of alternative technologies or systems d. Simplify calculations and quantify energy and economic inputs and outputs e. Avoids costs of having to build a prototype of the system

a. Inputs b. Outputs c. Processes d. System boundary

Select the parts of an LCA model a. Inputs b. Outputs c. Processes d. System boundary e. Co-products

a name given to the use of computer intelligence applied to the transmission and distribution of electricity

Smart Grid

a. Solar

The availability of which of these renewable energy sources is more coincident with electrical demand? a. Solar b. Wind

a. Solar

The availability of which of these renewable energy sources is more coincident with electrical demand? a. Solar b. Wind

8 27048 3246

The following information is to be used for the next 3 questions. A small company is considering installing solar panels to bring their electricity costs. The system consists of solar panels, an inverter, and a battery. The company electricity usage is 15000 kWh/year. The panels are rated at 1.0 kW per module and the area they live in has a capacity factor of 0.30. The system does lose some energy after the modules (from storage at night in batteries, converting from DC to AC, and transformation to the correct voltage). Combined, these are accounted for as energy conversion efficiency of 80.0%. If the goal is to offset current energy consumption using solar PV, how many modules would need to be installed? (give answer as whole modules, can't buy a half module) If the company installed 20 modules how much surplus of electricity would they be able to sell to the grid (in kW-h per year, at least 3 significant figures)? What would be the maximum income the company be able to obtain selling the excess to the grid (in $ every year, at least 5 significant figures), if they install 20 modules? Assume they get $0.12/kWh during the peak hours $0.05/kWh during the non-peak hours. Hint: you may assume the solar panel generate power during peak rate hours - which generally coincide.

c. Amps

The following property describes the flow rate of electrons? a. Resistance b. Voltage c. Amps d. Conductivity

circuit

The following term describes the closed loop that allows electrons to flow

the maximum power that the facility is able to produce under optimal conditions

The rated capacity of a power production facility is. - the maximum power that the facility is able to produce under optimal conditions - the annual average power production - The minimum power output of the facility before it needs to be shut down - the total annual energy production of the facility

c. The maximum power that the facility is able to produce under optimal conditions.

The rated capacity of a power production facility is... a. The total annual energy production of the facility b. The minimum power output of the facility before it needs to be shut down. c. The maximum power that the facility is able to produce under optimal conditions. d. The annual average power production.

the amount of energy that an energy installation will provide under ideal conditions of operation

The rated capacity of an renewable energy system (wind turbine, solar panel, etc) is: - the amount of energy that an energy installation will provide under ideal conditions of operation - the average power generated, divided by the rated peak power - the amount of electricity a generator produces over a specific period of time - the exact amount of electricity the generator provides to the grid as long as it operates

d. 2920 MWhrs

The same 0.5 MW capacity hydro turbine as in the previous question is installed on a river that cannot supply enough water to run it continuously for the entire year. If the turbine is run at full capacity for only 2/3 of the hours in a year how much energy will be produced in that year a. 333 kW b. 8760 MWHrs c. 2920 MW d. 2920 MWhrs e. 8760 MW f. 0.5 MW

2920 MWhrs

The same 0.5 MW capacity hydro turbine as in the previous question is installed on a river that cannot supply enough water to run it continuously for the entire year. If the turbine is run at full capacity for only 2/3 of the hours in a year how much energy will be produced in that year (in MWhrs)?

2890 MWhrs

The same 0.5 MW capacity hydro turbine as in the previous question is installed on a river that has a capacity factor of 0.66 how much energy does it produce in one year?

f. 2920 MWhrs

The same 1 MW hydro turbine as in the previous question is installed on a river that cannot supply enough water to run it continuously for the entire year. If the turbine is run at full capacity for only 1/3 of the year how much energy will be produced in that year a. 333 kW b. 8760 MW c. 8760 MWHrs d. 1 MW e. 2920 MW f. 2920 MWhrs

2920 MWhrs

The same 1 MW hydro turbine as in the previous question is installed on a river that cannot supply enough water to run it continuously for the entire year. If the turbine is run at full capacity for only 1/3 of the year how much energy will be produced in that year (in MWhrs)?

a. Environmental b. Social c. Economic

The triple bottom line considers the following aspects of sustainability a. Environmental b. Social c. Economic d. Global Warming e. Pollution

12 m/s

Use the same rock at the top of the same building as in the previous question. This time you tie a parachute to the rock so that some of the potential energy is not converted to kinetic energy due to friction. If the efficiency of conversion from potential to kinetic energy is now 75%, how fast will the 3 kg rock be moving (in m/s) when it hits the ground 10 meters below?

a. Produce a maximum 10 kW of power under ideal conditions.

A wind turbine with a rated capacity of 10 kW will a. Produce a maximum 10 kW of power under ideal conditions. b. Produce an average of 10 kW of power over a year c. Produce 87600 kWh of energy per year

the rate at which electricity flows through a material

Amperage

a company that provides a public service or product, such as electricity, water, or telephone

Utility

the measurement of the electrical pressure of electricity

Voltage

one watt operating for one hour

Watt hour

the measurement unit of electrical power in a system

Wattage

Coal, natural gas, petroleum, nuclear

What energy sources produce non-renewable electricity

hydro, solar, wind, geothermal, biomass

What energy sources produce renewable electricity

the flow of electrons through a conductor

What is electricity

a. 35% to 45%

What is the conversion efficiency (power coefficient) from power in the wind to power output from the blades for a modern highly engineered horizontal axis high-tip-speed two blade wind turbine? a. 35% to 45% b. 90% to 99% c. 59% or the Betz limit. d. 5% to 15% e. 15% to 30%

d. Pumped Hydro

What is the most widely used and least expensive method of storing large amounts of electrical energy? a. Batteries b. Flywheel storage c. Compressed air d. Pumped Hydro

kg.m2/s2

What is the unit of energy, joule (J) as expressed in terms of base SI units?

b. Mid-afternoon in summer months

When does electric energy have the highest economic value in the US market? a. Mid-afternoon in winter months b. Mid-afternoon in summer months c. Night-time hours in summer months d. Night-time hours in winter months

P=R x I2 P=V2 / R

Which following relationships are true for electrical resistance according to Ohm's Law? P=R x I2 P=V2 / R P=V2 / I R=P / V2

DC-AC inverter

Which of following devices is essential to connect PV panels to the grid? DC-AC Inverter DC-DC converter AC-DC rectifier AC-AC converter

a. Tonnes of Coal b. BTU (British Termal Unit) c. Barrels of Oil d. KiloWattHour e. Joules (kg m2 / s2) i. Quads

Which of the following are measures of ENERGY? a. Tonnes of Coal b. BTU (British Termal Unit) c. Barrels of Oil d. KiloWattHour e. Joules (kg m2 / s2) f. Watt g. BTU/hr h. HorsePower i. Quads j. KiloWatt

d. HorsePower f. Watts (kg m2 / s3) h. BTU/hr

Which of the following are measures of POWER? a. Quads (Quadrillion BTU) b. Tonnes of Coal c. Barrels of Oil d. HorsePower e. Joules (kg m2 / s2) f. Watts (kg m2 / s3) g. kWh (KiloWattHours) h. BTU/hr i. BTU (British Thermal Unit)

3600KJ

Which of the following is equal to 1 kWh (kilowatt-hour) 1 kJ 3600 kJ 1 kJ 3600 J

d. J / s

Which of the following units does NOT represent units of energy (or work)? Select all that apply. N = Newtons, m=meters, s=seconds, J=joules a. (Kg * m2 ) / s2 b. N * m c. kJ d. J / s

b. It allows energy to be used at time other than it is generated. d. I makes energy more valuable because it can be sold at the times during which the demand is greatest.

Which of these are advantages provided by energy storage? (Select all that apply) a. It improves the efficiency of the energy conversion process b. It allows energy to be used at time other than it is generated. c. It increases the total amount of energy generated. d. I makes energy more valuable because it can be sold at the times during which the demand is greatest.

b. Low cost or production and respond slowly to changes in demand

Which of these describe "base-load" electrical generation facilities? a. Electric energy purchased to meet demand b. Low cost or production and respond slowly to changes in demand c. High cost of production and respond quickly to changes in demand d. Electric energy sold because of favorable market conditions

b. Low cost of production and respond slowly to changes in demand

Which of these describe "base-load" electrical generation facilities? a. High cost of production and respond quickly to changes in demand b. Low cost of production and respond slowly to changes in demand c. Electric energy purchased to meet demand d. Electric energy sold because of favorable market conditions

c. Hydro

Which of these renewable energy sources is the most "dispatchable" (i.e. most likely to be available when we need it)? a. Solar b. Wind c. Hydro

b. Hydro

Which of these renewable energy sources is the most "dispatchable" (i.e. most likely to be available when we need it)? a. Wind b. Hydro c. Solar

high cost of production and respond quickly to changes in demand

Which one of these best describes "peak load" electrical generation facilities? - Low cost or production and respond slowly to changes in demand - High cost of production and respond quickly to changes in demand - Electric energy purchased to meet demand - Electric energy sold because of favorable market conditions

b. Liquid Biofuels

Which renewable energy source has the best future potential for fueling transportation needs? a. wind b. Liquid Biofuels c. Geothermal d. solar

a. It would allow them to sell electrical energy during times of the day that are traditionally low demand periods. b. It would transfer transportation energy from foreign energy sources (oil) to domestic sources (coal, natural gas, nuclear and renewable) c. It would allow them to sell more electrical energy d. The batteries in electric vehicles could be used as a way to store electrical energy and improve the management of the transmission and distribution systems.

Why might electric generation and transmission utilities have a favorable view on expanding the fleet of plug-in electric vehicles? (Select all that apply) a. It would allow them to sell electrical energy during times of the day that are traditionally low demand periods. b. It would transfer transportation energy from foreign energy sources (oil) to domestic sources (coal, natural gas, nuclear and renewable) c. It would allow them to sell more electrical energy d. The batteries in electric vehicles could be used as a way to store electrical energy and improve the management of the transmission and distribution systems.

c. Only the continental USA

Wind data for SAM can be customized by downloading a wind resource file from the NREL Wind Toolkit. However these files are limited to a. Most developing countries b. Virtually every location on planet earth c. Only the continental USA d. Only North America

218781

You have a 0.9 MW rated wind turbine that is installed in a location that has a capacity factor of 0.37 based on the wind resources. Assume you can sell wind energy to the grid with the following rates: 8 cents/kWh for 12 hours per day - peak rate 7 cents/kWh for 12 hours per day - off-peak rate What is the predicted income from the turbine over a year (in $)?

8.3

You have installed a solar panel your rural home. Over one year, 606 kWh of energy is generated by the solar panel. 302 kWh of the energy generated by the solar panel is used directly by your household and the rest is sold to your electric utility. Your normal purchase cost of electricity is 9 cents/kWh and you get paid 7.7 cents/kWh for the energy you sell back to the grid. At what electricity rate should you value the energy generated by the panel (in cents/ kWh)? Provide your answer with at least 3 sig figs.

about 8 cents

You have installed a wind turbine at your rural home. About 1/2 of the energy generated by the wind turbine is used directly by your household and 1/2 is sold to your electric utility. Your normal purchase cost of electricity is 10 cents/kWh. You get paid 6 cents/kWh for the energy you sell back to the grid. What is the value (to you) of the energy generated by your wind turbine?

a. About 8 cents per kWh

You have installed a wind turbine at your rural home. About 1/2 of the energy generated by the wind turbine is used directly by your household and 1/2 is sold to your electric utility. Your normal purchase cost of electricity is 10 cents/kWh. You get paid 6 cents/kWh for the energy you sell back to the grid. What is the value (to you) of the energy generated by your wind turbine? a. About 8 cents per kWh b. About 6 cents/kWh c. About 10 cents/kWh d. less than 6 cents/kWh e. more than 10 cents/kWh

~ 8 cents per kWh

You have installed a wind turbine at your rural home. About 1/2 of the energy generated by the wind turbine is used directly by your household and 1/2 is sold to your electric utility. Your normal purchase cost of electricity is 10 cents/kWh. You get paid 6 cents/kWh for the energy you sell back to the grid. What is the value (to you) of the energy generated by your wind turbine? Answer in cents/kWh.

10.5

Your renewable energy system produces 140 kWh per day. 75% of the energy generated by the wind turbine is used directly by your household and 25% is in excess and sold to your electric utility. Your normal purchase cost of electricity is 8 cents/kWh. You get paid 6 cents/kWh for the energy you sell back to the grid. What is the daily value of the 140 kWh of energy generated? 1

c. Energy storage gives intermittent energy sources a higher market value

An inexpensive technology for energy storage would accelerate the development of renewable energy systems because (choose the best answer) a. We would not need to produce as much energy to meet the same demand b. It would increase the need for high cost 'peaking' power generation c. Energy storage gives intermittent energy sources a higher market value

474

Approximately how many Quad is 500.0 EJ (exajoules), the world primary energy consumption? Hint: 1 W = 1 J/s (answer with at least 3 sig figs)

294 294 9.33

The water is maintained in the dam at a height 100.0 m by a river which annually puts 300,000 cubic meters of water through through a turbine at the bottom of the dam (V = 300,000 m3/yr). Assume the density of water is 1,000 kg/m3 and g=9.81 m / s2. As a reminder: PE = mass x gravity x height and mass = density x volume Calculate the annual potential energy contained in the water that is held back by the dam. Assume an average height of the water, h of 100.0 m. How much kinetic energy (KE) is realized if all the water in the previous problem is released through an opening at the bottom of the dam. If the kinetic energy from the years worth of flowing water is transformed into electrical energy using a turbine how much power can be created (in kilowatts, kW). Assume 100% efficient and continuous operation.

5

The world total primary energy consumption is 500 EJ, which is the same as 1.39 x 10? TWh. 8 10 5 11

Piece of equipment that changes the voltage of electricity

Transformer