It seems like the auto industry is heading towards a future of more electric and less gasoline. This is great for the quality of our air and our children’s air. It is also great for reducing the amount of carbon dioxide that we are putting in the atmosphere (assuming they get their electricity from renewable sources). But the coolest part about all of these electric cars taking over our driveways and garages is that they each have a battery built in to them. In a previous blog post I talked about one of the biggest barriers of solar and wind energy is that they fluctuate and we need storage to offset those fluctuations. Soon all of these electric cars will be plugged into the grid and they will communicate with it in order to give and take power as necessary.
Of course a majority of the time, cars will be taking power off the grid so that they can have fully charged batteries for the drive ahead. But it is also likely that when the sun goes down, a small fraction of the electricity stored in millions of cars will be used to pump up the electricity of the gird to supply the night time demand. If we make batteries that can serve multiple purposes such as powering our vehicles and balancing the grid, they become more cost effective and there is more incentive for people to buy them. Just investing in batteries to balance the grid and nothing else is a much tougher sell.
When cars become one with the grid, they will also be able stabilize sudden power failures or sudden spikes in power. Currently if some generating equipment goes offline, it can mean a power outage for customers in the affected area. With car batteries supplementing the grid, these bursts and shortfalls will all be smoothed out. There will be less power failures, and less need to rely on ramping natural gas turbines up and down.
Do your part, go out and buy a plug in electric vehicle today!
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Sun PC: https://3c1703fe8d.site.internapcdn.net/newman/gfx/news/hires/2015/25-researcherss.jpg
I really believe that over the next 20 years the world is going to continue to move in the direction of more renewable energy generation. It seems like the public has a desire for renewable energy while at the same time, the prices of solar are dropping quickly. These economic forces will inevitably lead to new renewable generation coming online.
In the meantime, governments can stimulate the growth of renewables by passing laws requiring states to reach certain renewable goals. Nevada was actually one of the first states to set a renewable energy target. They passed the law in 1997 requiring any energy seller in the state to have at least 25 percent of its energy portfolio be made up of renewables. This was a very aggressive target at the time, and to be fair it is still one of the highest targets in the nation. There is a small problem though. As a state, we were too good at bringing renewable energy online. As of 2013, NV energy was already sourcing 25 percent of its energy from renewable sources. The original 25 percent goal had the intention of ramping up renewable sources slowly until we could achieve the goal by the year 2025.
The unfortunate part of achieving goals is that it usually leads to a more aggressive goal the next time. Well, Nevada met its goal twelve years ahead of schedule, and now it is time to bump up the goal. There is currently a bill in the legislature that would require Nevada to increase its renewable portfolio to 80 percent by the year 2040. Based on talk from people involved with this bill, there is a lot of support for it, and it is likely to pass. Nevada has huge spreads of unused land that can be used for solar generation. It also has the second highest geothermal potential in the country. By passing this bill, we will return to one of the leading states for renewable energy in the nation. Nevada would be second only to Hawaii with their goal of 100 percent renewable by the year 2045.
If you think Nevada should increase its renewable energy portfolio standard please contact your state representative and let them know.
Lead PC: http://www.netwealthstrategies.com/wp-content/uploads/2013/11/target-ft.jpg
NV ENERGY PC: https://www.nvenergy.com/brochures_arch/RenewablesBrochure.pdf
In my blog ‘Identifying Potential Sources of Power Generation’ I discussed the concept of heat sources and heat sinks. Most power plants use the ambient air temperature as their heat sink a.k.a. the cold end of their process. But there are actually two ambient temperatures that can be useful as a heat sink for a power plant. I’m going to try not to get too lost in weeds in this post, so if you want more information about this, you can look up psychrometrics. Anyway, the first one is just the regular air temperature known as the dry bulb temperature. This is the temperature that will come into play for air cooled power plants. The second air temperature that is useful is called the wet bulb temperature. This temperature is based on a combination of the Dry bulb temperature and humidity. The reason that it is important is because this is the temperature that water will evaporate at.
In a water cooled power plant, water is sent through the top of cooling tower (basically a large box with metal mesh inside) and then as it falls some of it evaporates. The cool water that comes out of the cooling tower usually has a temperature a few degrees higher than the wet-bulb temperature but usually several degrees colder than the dry bulb temperature. The cooling water then acts as the plant’s heat sink. One advantage of the water cooled system is that your heat sink will be at a lower temperature and therefore your process will be more efficient. Another advantage is that water is much better at holding and absorbing heat than air is. This also makes your process more efficient. The main downside of a water cooled power plant is that it is often difficult to get water rights to keep them running. A key component of a water cooled plant is that some of the water has to evaporate in the cooling tower. So that water has to be replaced by new water from somewhere.
For an air cooled power plant, the heat sink will be the higher dry bulb temperature. Of course in the opposite of the water cooled scenario, the air cooled plant has lower efficiency. Because air cooled power plants are less efficient it also means the condensers have to be much larger to get the same effect. Air cooled power plants take up much more land area than their water cooled cousins. They also have a lot of moving parts with all of the fans that blow the air. All of those fans require periodic maintenance. The good things about air cooled power plants are that you can put them anywhere even in the middle of a desert, and you don’t have to worry about things freezing.
If you are interested in more renewable energy information follow me on twitter @EvanNWarner
Lead Photo Credit: https://6lli539m39y3hpkelqsm3c2fg-wpengine.netdna-ssl.com/wp-content/uploads/2016/11/shutterstock_liquid_water.jpg
Air Cooled Condenser Photo Credit: http://www.gdareno.com/wp-content/uploads/2015/10/CoolingTower.jpg
In one of my previous blog posts, I discussed a current issue with wind and solar generation. The problem is that the sources come and they go. Obviously the sun goes down at night time, but solar power generation can also be affected by cloud cover. Wind is very sporadic and frequently stops blowing. The grid on the other hand has a never ending demand for electricity. We can’t just tell people to turn off their refrigerators at night time. In order to compensate for this fluctuating supply of power the grid offsets solar and wind generation by ramping up and down coal and natural gas power plants. By ramping up and down these traditional energy sources grid managers are able to stabilize the power supply. This method is used to compensate for a lack of energy supply from solar and wind, but solar also carries another disadvantage.
At sometimes throughout the year, solar energy generators actually supply the grid with too much energy. This is especially the case on clear spring days. It has caused a lot of problems for grid operators in California and other states with large solar supplies. The problem occurs on cool spring days when there is a lot of solar potential and the supply is really high. At the same time, not many people are turning on their air conditioners because of the cool temperature and there is no need for them. This situation creates too much supply and not enough demand. It leads to grid operators having to rapidly curtail equipment to balance the grid. It is a pain for everyone, and it is also bad for large equipment to cycle on and off again. This quirk in the solar market is known as the duck curve because when you plot a graph of the power demand throughout the day it resembles a duck. The times when the demand is lowest happen to be the times when solar is producing at its highest.
Geothermal energy is a great counter balance to this phenomenon because it is base load generation. In other words, geothermal produces a mostly stable supply to the grid 24-7-365. It results in a much smother energy product compared to the over and under supply often faced by solar power. Any grid that wants to have more renewable energy on it will be much better off if its energy mix includes some geothermal power. Hydroelectric is also a good option for base load generation but I understand that most of the feasible places to locate a hydroelectric plant already have one. Geothermal still has a ton of untapped potential in the world.
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Duck Curve Photo Credit: ilsr.org/wp-content/uploads/2014/03/Screenshot-2014-03-25-14.36.08.png
Most of the electricity that we generate today is done so by harnessing differential energy levels. Basically in order to get a turbine to spin, we have to have high pressure at the inlet of the turbine and low pressure at the outlet of the turbine. This should make intuitive sense because if you had equal pressures on both sides of a turbine there would be no flow, and the turbine would not spin. When you have a differential between two energy levels, the high energy state wants to flow to the low energy state and try to equalize. When energy starts to flow we can capture it and use it to turn a turbine. The bigger the differential is between the high energy state, and the low energy state, the more power that can be produced from the system.
The most common energy differential that is used to generate electricity is a temperature differential. When we can find or create a large temperature differential, we can easily convert that to a large pressure differential which can be used to spin a turbine. Some examples of creating a temperature differential are burning coal or natural gas. The energy that is on the hot end of the system is referred to as a heat source. Then there is also the cold side to take into account. Usually the cold side of the temperature differential is the ambient air temperature and it is referred to as a heat sink. So the greater the difference is between the heat source and the heat sink the more efficient the system will be. The heat source is used to boil water and turn it into high pressure steam for the inlet of a turbine while the heat sink is used to condense the steam and create a low pressure area at the outlet of a turbine.
There are also naturally occurring differential energy states. One example of this is a geothermal system. In the case of Geothermal, the heat below the earth’s surface acts as the heat source, and the ambient temperature acts as the heat sink. Another naturally occurring temperature differential is ocean thermal energy conversion. This technology harnesses the difference in temperatures between warm ocean surface temperatures as a heat source, and cold temperatures found deep in the ocean as a heat sink.
Pressure differentials also occur naturally and can be used to turn turbines. The most well-known example of this is wind. High pressure wind wants to flow to areas of low pressure. We can put a wind turbine in its path and capture some of that energy as it flows by.
Another form of differential energy that we capture to generate electricity is water in a high elevation that has a high potential energy. Gravity wants to pull this water down to a low elevation where it would have low potential energy. We capture the difference in potential energy in to form of hydroelectric turbines.
If you can recognize any other areas where there are differential states of energy, try to figure out a way to capture the difference and turn it into electricity.
Lead Photo Credit: http://www.vitamindcouncil.org/wp-content/uploads/2010/07/shutterstock_66782632-e1363289900951.jpg
Cold Hot Photo Credit: http://www.clipartbest.com/cliparts/9i4/6Kp/9i46KpG6T.jpg
Several years ago my boss told me an interesting theory that he had about energy. We were on a long road trip to one of our power plants in the middle of nowhere so he had plenty of time to develop his theory with me. I’ll try to boil down the discussion to what’s relevant to you in this post. Basically he told me that all of the forms of energy that we use to generate power today have their roots in nuclear energy. He is a chemical engineer after all, so he would think this way.
When he first told this to me I didn’t really know how to react. I mean I can think of many forms of energy that are not from nuclear reactions, coal, natural gas, wind etc. But then as we were driving down the long… long highway, we started to go down the list and he systematically showed me that all of them have roots in nuclear reactions.
Let’s start with oil/ natural gas/ and coal. All of these resources are substances that store energy that we can later burn to make electricity. But where do they come from? They come from decomposing plant material that died millions of years ago and the got buried under miles of earth. Where do plants get their energy from? The sun, a giant burning ball of nuclear reactions going off in the sky. What about wind turbines? Well where does wind come from? It comes from air with different pressures that are being heated up by the sun. The different pressures of air then start to move around because they want to equalize. What about solar power? The sun. Even Hydroelectric power has its roots in the sun’s energy. If the sun didn’t heat up water and evaporate it, it would not fall on the top of mountains and then run down them in rivers to power our hydroelectric turbines. What about nuclear power? Just kidding I don’t have to explain that one. Lastly geothermal power comes from heat at the center of the earth given off by nuclear reactions.
All of this stems back to the concept that we cannot create or destroy energy we can only change the form of it. In this case some of the changing forms weren’t actually done by us, but rather by natural processes. I think this is kind of a fun twisted chemical engineery way to look at the world.
If you can think of a form of energy that doesn’t stem from a nuclear reaction please prove me wrong in the comments below.
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Hydroelectric Photo Credit: https://media.licdn.com/mpr/mpr/AAEAAQAAAAAAAAefAAAAJGNhNjFhNzA1LWZmYjctNDBjMi1iNWM1LWE5M2VhZDNmYmU5Nw.jpg
I don’t know if everyone is seeing these glass ball solar collectors all over the internet or if it is just Google recognizing that I want to see stories about renewable energy. But either way I decided to click on the story and see what it was all about. It turns out it is a company called Rawlemon based out of London. They have been working on this product for the last three years. The concept is fairly simple, they use a perfect sphere filled with water to refract sunlight onto a concentrated area. At the point where the sun’s light is most concentrated, they place a photovoltaic cell right in its path. By concentrating the sun’s light, these photovoltaic cells can be up to 70% more efficient than traditional solar panels. It doesn’t hurt that they look pretty impressive too.
It seems like a smart idea to me. I was thinking of something along these lines a few years ago when I was having fun in my backyard burning things with sunlight through a magnifying glass. The Rawlemon innovation is the same concept as concentrating light with a magnifying glass, but the brilliant spherical design allows it to easily track the sun as it moves across the sky. Tracking the sun on a dual access helps increase its efficiency.
In order for this company to gain some publicity and some funding, they have created an Indiegogo campaign where you can buy a little desktop version of their product. Another innovative idea that this company has is to build large scale versions of these solar concentrators and use them as windows in skyscrapers. They would certainly give buildings a modern look, and they could potentially result in net-zero buildings.
One other thought I had about this promising technology is that it probably isn’t very cheap. It seems like in the near future as 3D printing technology improves, people might be able to print large perfect spheres, and then simply fill them with water. The actual solar panels themselves are really small due to the light being concentrated in a small area. If these could be manufactured cheaply, they really have potential to change how we get our power in the future.
If you have any thoughts on how we can use concentrated solar power please let me know in the comments below.
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Magnifying Glass Photo Credit: http://cdn.c.photoshelter.com/img-get/I0000m_8IKJlVsQY/s/860/860/Magnifying-Glass-Sun-Experiment.jpg