What is the Carnot limit?

What is the Carnot limit?

An upper limit to the efficiency of a heat engine.

A theoretical economic value of any energy efficiency project.

An upper limit to the amount of electricity that a wind turbine or solar photovoltaic cell could produce.

None of the above.

According to the McKinsey report Unlocking Energy Efficiency in the U.S. Economy, which of the following energy conservation options could reduce carbon emissions while at the same time lowering energy costs enough to pay for the technology?

All of these

Compact fluorescent lighting

More efficient consumer electronics (like computers or television sets)

Combined Heat and Power (CHP)

None of these

The energy intensity of a country's Gross Domestic Product (GDP) is defined as:

The ratio of a country's total annual energy usage to its annual GDP.

The total amount of energy used in a country each year.

The ratio of a country's annual GDP to its annual per-capita energy usage.

The total amount of primary energy commodities produced in a country each year, as a share of that country's overall GDP.

Which of the following countries has a lower energy intensity of GDP and approximately the same GDP per capita as the United States?

Denmark

Canada

South Korea

The United Kingdom

Switzerland

Which of the following sentences describes how communities in Kansas (in the United States) were incentivized to take energy conservation steps?

Communities competed against one another in a contest to reduce energy consumption.

They were forced to by a state mandate.

The state imposed efficiency standards on household appliances sold in that state.

The state offered new grants and tax rebates for energy-efficient products.

The state imposed an energy tax.

Fill in the blank: The upper limit for efficiency in a steam-driven heat engine (like a power plant) is approximately ________?

50%

25%

90%

30%

75%

What is the energy efficiency paradox?

The observation that energy conservation investments can pay for themselves through lower energy costs and help the environment, but few people show interest in making conservation investments.

The observation that energy conservation investments can save money but are horrible for the environment.

The observation that energy conservation investments will increase energy costs but will help to save the environment.

The observation that rich people can make the biggest contributions to lowering overall energy use, but most energy conservation investments are made by poor people.

The observation that combined heat and power (CHP) systems appear to violate theoretical efficiency limits for combustion engines.

Approximately how much of the fuel consumed by the United States each year is wasted because of inefficiencies in energy systems?

55%

25%

90%

10%

45%

Which of the following is NOT considered to have substantial potential to improve energy efficiency in a developed country?

Passenger vehicles that run on biofuels

Combined heat and power (CHP)

Residential lighting (e.g. compact fluorescent or LED bulbs)

Energy-efficient appliances (e.g. refrigerators)

Ground-source heat pumps for residential or commercial buildings.

Most combined heat and power (CHP) systems are fueled by natural gas, but an example in Austria shows how this technology can be feasibly run by what fuel?

Biomass

Solar photovoltaics

Crude oil

Electricity

Waste heat