What is the EROI of hydropower?

Hydroelectric power generation systems have the highest mean EROI value, 84:1 (n of 17 from 12 publications), of electric power generation systems (see Lambert et al., 2012 for references) (Fig. 3).

What is the EROI for solar geothermal and wind power?

That paper finds an EROI of 4 for solar and 16 for wind, without storage, or 1.6 and 3.9, respectively, with storage. That is to say, it finds that for every unit of energy used to build solar panels, society ultimately gets back 4 units of energy.

What is the EROI of nuclear power?

America’s present EROI averages about 40. A mix of 50% renewables, 30% fossil and 20% nuclear gives an average EROI of about 25.

How is EROI calculated?

EROI is calculated by dividing the energy output by the energy input. Measuring total energy output is often easy, especially in the case for an electrical output where some appropriate electricity meter can be used.

What does EROI stand for?

Energy Return on Investment
Energy Return on Investment (EROI) is a ratio for describing a measure of energy produced in relation to the energy used to create it. For instance the ratio would illustrate how much energy is used to locate, extract, deliver, and refine crude oil relative to how much useable energy is created.

What is a good EROI?

EROI = Energy Delivered / Energy Used to Deliver that Energy Instead, it can be put to better use through energy storage (batteries). An EROI sum of at least seven is required to be considered a viable and profitable energy source, while an EROI score of seven represents a break-even point.

What is the EROI of solar panels?

Studies have given figures for the EROI of solar energy as low as 3.9 and as high as 45.45.

Is a low EROI good?

“A very low EROI means most people have to work in the energy-supply industries. One could reduce our EROI to 2.5:1 and survive, but there would be… [fewer] possibilities for other activities.” At the same time, he conceded that “EROIs make a little more sense for a finite fossil fuel resource, like an oil field.

Is a high EROI good?

Generally, we can expect that the highest available EROI energy sources will be used first because these offer the most energy for the least effort. A net energy gain is achieved by expending less energy when attempting to acquire and use a source of energy. EROI analysis is considered part of a life-cycle analysis.

What does a high EROI mean?

When the EROI is large, that means that producing energy from that source is relatively easy and cost-effective. However, when the number is small, obtaining energy from that source is difficult and expensive. For example, when the ratio is 1, there is no return on energy invested.

Why is OTEC not currently used?

Why is OTEC not currently used? It is in an experimental phase and is very expensive.

What is difference between open and closed cycle OTEC?

There are two principle options, an open cycle plant or a closed cycle plant. Hybrids of the two have also been proposed. A closed cycle OTEC plant employs a thermodynamic fluid such as ammonia or a refrigerant like freon. In an open cycle OTEC system the seawater itself is used to provide the thermodynamic fluid.

What is the difference between EROI for coal and hydroelectric power?

So in the case of coal, for example, the EROI for the coal itself would be roughly three times higher than the EROI for electricity from coal (because the typical efficiency of a coal-fired power plant is around 33 percent). Hydroelectric: There are a wide range of EROI values reported for hydroelectric dams, from around 40 to more than 250.

What is EROI (energy return on investment)?

Energy return on investment (EROI) is a means of measuring the quality of various fuels by calculating the ratio between the energy delivered by a particular fuel to society and the energy invested in the capture and delivery of this energy.

What is net energy and EROEI?

Net energy is the close cousin of ERoEI being the surplus energy made available to society from our energy gathering activities. It is defined simply as: If we have ERoEI = 1, then the net energy is zero. We use as much energy to gather energy as energy gathered. The “1” always represents the energy invested.

What is the difference between EROI and Inman’s electricity production values?

For sources of electricity, Inman says he used values that are for electricity produced by a particular source, rather than the EROI for the production of the raw fuel that can be used to make electricity.