The purpose of this study was to analyze the relationship between light intensity, cannabis (Cannabis sativa L.) yields, and profitability. We also look for evidence that spectrum differences across broad-spectrum horticulture lights and general-purpose LEDs affect the relationship between yield and light intensity. Finally, we discuss the financial return of increasing light intensity in order to increase yields. We found that yields increase linearly with light intensity up to at least 1500 mu mol m(-2) s(-1), which is at least twice the intensity that is most commonly used by cannabis growers. That relationship did not appear to be influenced by spectrum quality differences among the lamps included in the study. Finally, for all the intensity ranges that we considered, the value of the gain in yields from increasing light intensity far exceeded the cost of using more electricity.

The purpose of this study was to analyze the relationship between light intensity, cannabis yields, and profitability. We also look for evidence that spectrum differences across broad-spectrum, horticulture lights and general-purpose LEDs impact the relationship between yield and light intensity. Finally, we discuss the financial return of increasing light intensity in order to increase yields. We find that yields increase linearly with light intensity up to at least 1500 μmols/m2·s, which is at least twice the intensity that is most commonly used by cannabis growers. That relationship did not appear to be influenced by spectrum quality differences across the lamps included in the study. Finally, for all the intensity ranges that we considered, the value of the gain in yields from increasing light intensity far exceeded the cost of using more electricity.

One of the goals of the U.S. ethanol mandate is to reduce fossil fuel use in the transportation sector. But some critics of the mandate argue that a more efficient way of reducing fuel consumption would be to focus on improvements in fuel efficiency of motor vehicles. We consider the time span between 2005 and 2015 and ask how much the mandated increases in ethanol use reduced fossil fuel consumption relative to increases in light-duty vehicle fuel efficiency, and how cost-effective each trend was for consumers. We show that, over this time period, changes in vehicle fuel efficiency reduced fossil fuel energy consumption by 0.90%, while increases in ethanol consumption decreased it by 1.21%. Accordingly, fuel savings caused by increases in fuel efficiency saved drivers $40.9B, while the ethanol mandate penalized drivers with $91.5B in additional fuelling costs.

We compare the financial benefits of displacing oil using three alternative-vehicle technologies: natural gas (NGVs), battery-electric (BEVs), and plug-in hybrid electric vehicles (PHEVs). On a cost-per-barrel basis, NGVs would be the least expensive way to displace oil, while PHEVs would be the most expensive. BEVs would displace the most oil. Furthermore, though the BEV case has the highest upfront cost, its payback rate is almost two-times faster than the NGV case. At current energy prices and without considering environmental costs, none of these technologies make financial sense. However, given historical relationships between oil, natural gas and electricity prices, each alternative would make financial sense if oil prices increased to at least $150 per barrel, and BEVs would offer the fastest payback. Finally, though electricity prices are the most volatile, the financial cost of fuel-price uncertainty is lowest for the BEV case. Moreover, the cost of uncertainty is unimportant for all cases, including gasoline-powered vehicles, and should not be an important part of this debate.

Though corn-ethanol is promoted as renewable, models of the production process assume fossil fuel inputs. Moreover, ethanol is promoted as a means of increasing energy security, but there is little discussion of the dependability of its supply. This study investigates the sensibility of promoting corn-ethanol as an automobile fuel, assuming a fully renewable production process. We then use historical data to estimate the supply risk of ethanol relative to imported petroleum. We find that devoting 100% of US corn to ethanol would displace 3.5% of gasoline consumption and the annual supply of the ethanol would be inherently more risky than that of imported oil. Finally, because large temperature increases can simultaneously increase fuel demand and the cost of growing corn, the supply responses of ethanol producers to temperature-induced demand shocks would likely be weaker than those of gasoline producers.

If ethanol were to be produced in a truly sustainable manner, it would take all the corn in the United States to displace about 3.5 percent of our gasoline consumption. Furthermore, ethanol would not necessarily be a more reliable source of fuel. By displacing gasoline with ethanol, we are displacing geo-political risk with yield risk, and historical corn yields have been about twice as volatile as oil imports.

This paper compares the manufacturing and refueling costs of a fuel-cell vehicle (FCV) and a battery electric vehicle (BEV) using an automobile model reflecting the largest segment of light-duty vehicles. We use results from widely-cited government studies to compare the manufacturing and refueling costs of a BEV and a FCV capable of delivering 135hp and driving approximately 300miles. Our results show that a BEV performs far more favorably in terms of cost, energy efficiency, weight, and volume. The differences are particularly dramatic when we assume that energy is derived from renewable resources.