PDS AP Environmental Science 8th Period 2011-12

STOP! Before you read the rest of this blog post, sprint down a flight of stairs and run back up again as fast as you can. GO!

Okay, so how do you feel now? A little hot? Congratulations, you just got a little bit of exercise and experienced the same heating concept that is used in Geothermal Energy.

David Blackwell, SMU’s chief geological expert, recently gave a briefing to congress about the future of alternative energy sources in the United States. It was part of a series on the science and technology needed to achieve the United State’s energy goals titled, “The Road to the New Energy Economy.” Blackwell explained that geothermal is going to play a major part in our energy security in the future, and the US is in a prime position to lead the world in conventional and emerging unconventional geothermal techniques. Slowly but surely, the world is beginning to understand the importance of reducing our dependance on fossil fuels, and geothermal energy is going to play a major role in that transition.

Geothermal Energy is a way to produce energy that combines the use of a renewable resource and drilling. Geothermal energy utilizes the heat that comes from the earth’s core. Think about water that is naturally heated such as the water from “Old Faithful.” This spring is heated by convection currents bringing magma from the earth’s mantle to the earth’s crust. Heat and pressure builds up in the spring causing it spew out at temperatures up to 200∘F. Geothermal energy uses the same concept in order to heat homes or turn turbines.

How do you harvest Geothermal Energy?
Remember running up and down those stairs? Water goes through this same journey as it is pumped or circulated underground. As water comes back up, it can be piped into household radiators and has the potential to heat a home. But this heat also has the potential to produce electricity. After the water cools, the cycle repeats, constantly using the earth’s natural heat. So you may have not been as winded when you ran down the stairs, but you may have felt the heat coming back up.

Water moves through this system and can be recycled as well.

How does Geothermal Energy produce electricity?
As water is pumped into the ground, the water is heated and can be pumped, or naturally flows, into a plant where the water is converted into steam. This steam is then used to turn a turbine, used to generate electricity. It’s the same concept as a coal fired power plant but instead of burning coal, you’re heating the water with renewable energy. Some of these power plants drill up to a thousand feet underground just to generate enough energy so some of these plants are not suited for areas.

Video explanation of Geothermal energy:

Geothermal-Energy-Process.aspx

Is Geothermal Energy good for the environment?
Yes! Geothermal energy is a renewable resource so it reduces the amount of fossil fuels we use, which reduces the amount of greenhouse gases we produce. Geothermal energy also produces little to no pollution.
Geothermal energy is also economically beneficial. It not only provides jobs, but it is also 80% more cost effective than using fossil fuels. It reduces our dependence on fossil fuels.

Is Geothermal Energy bad for the environment?
Unfortunately it can be but not as much as non-renewable resources. The water that is pumped underground can be influenced by dangerous chemicals that can seep from the earth’s crust.
Geothermal energy can be more inconvenient rather than environmentally detrimental. Some areas aren’t suited to pump water underground. And although this energy is cost-effective compared to fossil fuels, the cost to design, build, and staff these plants is very expensive.

Which Countries Produce and Use Geothermal Energy?
Many countries in the world have begun producing geothermal energy, the three largest producers being the United States (3,086 MW), the Philippines, and Indonesia. The worldwide capacity of geothermal electricity production is about 10,715 MW, with about 10 countries producing the vast majority of that energy. As a percentage of total electricity use, Iceland is the largest user of geothermal electricity (almost 30% of total electricity is produced geothermally!). 100% of their total electricity is renewable; the other 70% is hydroelectric.

Source:
http://www.conserve-energy-future.com/Advantages_Disadvantages_GeothermalEnergy.php

Tags: energy, geothermal, renewables

In class Tuesday, we discussed the generation of waste in the world and where we put that waste. We learned very quickly that there is no such thing as throwing something completely “away” but that the waste we expend becomes someone elses problem. Let’s start with the basics. EPA data from 2009 estimates that there are 12 billion tons of US solid wastes each year.The percentage of of this waste is dominated by mining and oil extraction (75%) while municipal waste, city or domestic waste, is at 1.5%. Municipal Solid Waste (or MSW) includes all waste from households including recyclables, yard waste, food scraps etc. Since the 1960′s, there has been a steady growth of total amounts of  MSW but in the 90′s, it started to slow and diminish due to the fact that recycling became more available and popular. But not everything can be recycled.

In the US today:

54.3% of our trash is put into Modern Sanitary Landfills

This format is to prevent leachates from getting into groundwater.

33.8% is recovered or recycled

Recycling is sorted and delivered to centers that recover the materials to be used again.

11.9% is incinerated in an attempt to convert waste into energy.

This is a way we can use trash to benefit us but it means that there is a constant demand for trash

Tags: incinerators, landfills, recycling, reduce, reuse, solid waste

The two population growth models we discussed in class were:

• Exponential Growth
• Logistic Growth

Exponential Growth Curve:

When a population is growing without limits at a fixed rate, numbers will climb over time creating a J-Curve. This assumes no limiting factors or resource depletion at the rate of typical exponential growth.

Logistic Growth Curve:

This model is the logistic curve of a population. Overtime births decrease and deaths increase creating an inflection point in the graph where the line will start to level out at K, the carrying capacity. This curve is called an S-Curve. This model assumes that all individuals in a population have the same needs and that the environmental conditions are constant. This is hardly possible in today’s world.

In class we discussed population dynamics between r and K populations. While “r” species have a higher rate of growth and shorter lifespans like bacteria or mice, “K” species have slower growth rates and longer lifespans, like Blue Whales or African elephants. Other animals have traits from both spheres, like a cockaroach because it produces rapidly but has a longer life time. These models could measure either one of the species but it depends on the fixed growth rate and resources. It is more likely for a “r” population to experience exponential growth and have an intrinsic growth rate and approach a carrying capacity easier while a “K” species who has a lower intrinsic growth rate may reach a carrying capacity over a longer period of time.

There are positives negatives with both of these models in that they each have assumptions. The J curve is assuming unlimited resources which is not realistic and the S curve indicates that a population may naturally find its carrying capacity when in reality it may overshoot it (as we saw in the Island Royale simulation.) Since no species exist in isolation, they have producers and predators, predicted populations using models are not always accurate. Models can be used for a basic outline of a populations growth but should not be used as a primary source to predict populations.

Today we reviewed the data Mr. Willard  collected about our ecological foot print. This included the amount of carbon emissions each student produced, how much land was needed to accomodate their lifestyle, and a calculation of how many earths would be necessary if every person were to live that life style. The class average was 5.8 earths which is lower compared to the national average of 6.35. The land we use isn’t just the land we live on, its the land thats used for our food, for our travel, water, coal and many other amenities. How much money your parents make may affect your foot print value and how much we depend on technology in the home. In conclusion the method to calculating the amount of impact comes down to the number of family members, affluence, and the technology used.

Impact= population X affluence X tech

This can be considered per capita or measured by country. Our foot print is important to consider because what we take now may not be there for future generations. The Lorax made that pretty clear. “Unless” we can take lessons from that, and the more resourceful text The Truax, then we may be able to sustain this earth.

Small step, Big foot print

http://iisakeco.glogster.com/what-is-your-ecological-footprint/

Tags: ecofootprint, sustainability

I think the worst environmental problem is over-population.