energy production

Global Stilling | Earth Wise

October 20, 2022 By EarthWise Leave a Comment

During the summer of 2021, much of Europe experienced a “wind drought” – wind speeds in many places were about 15% below average. In the UK in particular, winds were unusually calm and wind energy production was dramatically reduced.

Globally, wind speeds have been dropping by about 2.3% per decade since the 1970s. In 2019, however, global average windspeeds actually increased by about 6%. The question is whether a trend of slowing winds – so-called global stilling – is associated with climate change or is just natural variability in action.

Wind results from uneven temperatures in air masses. Much of the world’s wind comes from the difference between the cold air at the poles and the warm air at the tropics. Because the Arctic is warming much faster than the tropics, it is possible that winds will continue to decline around the world.

Another factor people cite is the increase in surface roughness. The number and size of urban buildings continues to increase, which acts as a drag on winds.

Some models predict that wind speeds will decrease over much of the western U.S. and East Coast, but the central U.S. will see an increase. Experts do not all agree about what is happening with global winds. Many believe that the observed changes to date have been within the range of variability. Furthermore, some places have been windier than usual.

All of this really matters for many reasons. Europe is increasingly dependent upon wind power as an alternative to fossil fuels. A 10% drop in wind speed results in a 30% drop in energy generation. Whatever their cause may be, wind droughts cannot be ignored.

**********

Web Links

Global ‘Stilling’: Is Climate Change Slowing Down the Wind?

Photo, posted June 28, 2008, courtesy of Patrick Finnegan via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Liquid Fuels From Carbon Dioxide | Earth Wise

January 5, 2022 By EarthWise Leave a Comment

Most of the world’s energy demands are still being met by burning fossil fuels, thereby releasing carbon dioxide into the atmosphere. The energy system is in the midst of a transition to renewable sources such as solar and wind power, but it will be quite some time before fossil fuels are only a minor part of energy production. To reduce global warming, it will be necessary to prevent the carbon dioxide from fossil fuels from entering the atmosphere by capturing it and either locking it away or making use of it.

Recent research at several Chinese universities has developed a novel electrocatalyst that efficiently converts CO₂ to liquid fuels containing multiple carbon atoms. The main products of the high-efficiency reaction are ethanol, acetone, and n-butanol. Previous electrocatalystic methods have mostly produced simpler hydrocarbons – namely, ones with only a single carbon atom. The fuels the new catalyst produces are much more useful.

The catalyst is made from thin ribbons of a copper/titanium alloy that are etched with hydrofluoric acid to remove the titanium from the surface. The process results in a material with a porous copper surface on an amorphous CuTi alloy. The substance exhibits remarkably high activity, selectivity, and stability for catalyzing the reactions leading to the production of the hydrocarbon fuels.

Converting carbon dioxide into liquid fuels would be advantageous because they have high energy density and are safe to store and transport. Apart from preventing carbon dioxide from entering the atmosphere, the process could also be a way to make use of excess energy produced by solar and wind generation by essentially storing that energy in the form of liquid fuels.

**********

Web Links

Liquid Fuels from Carbon Dioxide

Photo courtesy of Angewandte Chemie via Wiley-VCH.

Earth Wise is a production of WAMC Northeast Public Radio.

Solar Cell Greenhouses | Earth Wise

April 21, 2021 By EarthWise Leave a Comment

A recent study at North Carolina State University has shown that it can be feasible to use see-through solar panels in greenhouses to generate electricity. The idea is to use semi-transparent solar panels on greenhouses that allow some of the light to get in for the plants to grow while making the greenhouses energy neutral or even allowing them to generate more power than they use.

The question is how the semi-transparent solar panels might affect greenhouse crops. To investigate this issue, researchers grew crops of red leaf lettuce from seed to full maturity under a standard set of growing conditions – temperature, water, fertilizer, and CO2 concentration – but varied the light they get.

A control group was exposed to the full spectrum of white light while three experimental groups were exposed to light through different types of filters that absorbed the particular wavelengths of light that would be absorbed by different types of semitransparent solar cells.

The researchers paid close attention to characteristics of the lettuce that are important to growers, grocers, and consumers: general appearance, leaf number, leaf size, and weight. The results were that the lettuce produced using all three kinds of filtered light was essentially identical to that produced in the control group. Further research is underway looking at how harvesting various wavelengths of light affects biological processes for lettuces, tomatoes, and other crops.

Getting growers to use solar-powered greenhouses would be very difficult if doing so would result in a loss of productivity. But given these experimental results, it appears as though the decision will boil down to a simple economic argument about whether the investment in new greenhouse technology would be offset by energy production and its resultant savings.

**********

Web Links

Study Finds Plants Would Grow Well in Solar Cell Greenhouses

Photo, posted April 8, 2008, courtesy of Brian Boucheron via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Shifting Climate Attitudes – Even In Texas | Earth Wise

January 25, 2021 By EarthWise Leave a Comment

Any conversation about climate policy and energy in the United States has to take Texas into consideration. Texas leads the nation in energy production, providing more than one-fifth of U.S. domestically produced energy. Texas also uses more energy than any other state and accounts for almost one-seventh of total U.S. energy consumption. The state’s industrial sector, which includes petroleum refining and chemical manufacturing, accounts for almost half of Texas energy consumption.

As a result, longstanding skepticism among Texans toward the climate movement has represented a real impediment in developing and implementing effective climate policy in this country. But according to new research at the University of Houston, attitudes in Texas have changed and now mirror those in the rest of the United States.

About 80% of Americans believe that climate change is happening, and now about 81% of Texans hold the same view. Two out of three Americans are worried about climate change; more than 60% of Texans agree.

Nationwide, 55% agree that the oil and gas industries have deliberately misled people on climate change; 49% of Texans agree. 64% of Americans say hydraulic fracking has a negative effect on the environment and 61% of Texans agree. People everywhere are willing to pay more for carbon-neutral energy, and a higher premium for gasoline as well.

Mitigation strategies for climate change are not well understood. While 61% nationwide have heard of carbon taxes, less than half are familiar with carbon management, and only a third have heard of carbon pricing.

As the U.S. heads toward reengaging in efforts to address climate change, Texans appear to have caught up with the rest of the nation.

**********

Web Links

Attitudes About Climate Change Are Shifting, Even in Texas

Photo, posted October 1, 2011, courtesy of Steve Rainwater via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Coronavirus And European Energy | Earth Wise

April 23, 2020 By EarthWise Leave a Comment

As people all over the world shelter in place and much ordinary commerce and other activities have ground to a halt, there have been big changes in energy usage. With production halted, offices shut down, schools closed, and public transport operated on reduced timetables, the demand for energy has decreased dramatically.

In Europe, as a result of all this, during the first quarter of this year, renewables’ share of total energy production was greater than 60%. Wind farms provided more than 40% of the renewables’ share of total electricity generation. During February, Denmark, Germany and Ireland saw nearly 50% of their electricity demand met with wind power. Hydroelectric power was the second largest source of renewable energy during the first quarter, with Norway providing the largest share of this. In contrast, generation from nuclear plants was at its lowest first quarter figure for the past five years.

The large shift to renewable generation was in great part due to the overall reduction in demand. This impacts nuclear and fossil-fuel generation much more than renewables because those plants can be throttled back or shut down entirely so as not to needlessly consume costly fuels. Generation that runs on sunlight, wind, or flowing water does not require fuel expenses, so it makes sense to prefer them when demand is reduced.

The reduction in demand has in turn had a major effect on fuel costs as oil reached low prices that haven’t been seen in years.

The decline in demand and fuel prices and the enhanced role of renewables are expected to continue in the current quarter as the timetable for renewed economic activity remains unknown.

**********

Web Links

Renewables achieve clean energy record as COVID-19 hits demand

Photo, posted June 25, 2010, courtesy of Martin Abegglen via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Bigger Is Better For Wind Energy

February 13, 2019 By EarthWise Leave a Comment

Bigger is almost always better for wind power. Bigger wind farms are better than smaller wind farms and bigger wind turbines are better than smaller ones.

The biggest turbines currently available produce nearly 10 MW of power, which is enough to supply over 2,000 homes with electricity. A wind farm with just a few of these turbines could produce enough electricity for a small town. A big wind farm, like the giant 1,550 MW Alta Wind Energy Center in California can generate enough power for a small city.

Vestas Wind Systems, an industry leader based in Denmark, has announced a 10 MW turbine that will be ready for installation in two years. The rotor diameter of the giant machine is 538 feet and the blades sweep out an area of 227,000 square feet, the size of nearly 4 football fields.

Not to be outdone, General Electric is developing a 12 MW offshore wind turbine that will stand 850 feet tall and sweep out an area of more than 400,000 square feet. GE estimates that its 12 MW turbine will achieve nearly twice the capacity factor of its 6 MW turbine.

Companies are building bigger and bigger wind turbines because they are more cost effective. The capacity factor, which is the actual energy production divided by the potential energy production, goes up as the turbines get bigger and more efficient. In terms of dollars spent to produce a given amount of power, larger windfarms are less expensive to build than smaller ones. A wind farm of 200-500 MW capacity is about 40% cheaper per MW capacity than a 25 MW wind farm.

When it comes to wind energy, there is no doubt that bigger is better.

**********

Web Links

Wind Energy — Where Bigger Is Better

Photo, posted February 14, 2012, courtesy of Aaron Warner via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Tidal Turbines Set An Energy Record

October 20, 2017 By EarthWise Leave a Comment

Two turbines in the Pentland Firth in Scotland recently set a world record for monthly energy production from a tidal stream power station. In August, the MeyGen installation off the Caithness coast of Scotland produced 700 MWh of electricity, enough to power 2,000 homes.