Apartment Rentals and Energy Waste

Landlords usually suck. And they probably cause some notable percent of emissions by being lazy (I would guess like 1+%) and not modernizing their apartments (modernizing by 1980s standards).

Drafty rental unit?

Background

A few months ago, I wrote my most-trafficked article about why living in the suburbs is bad for your wallet, and bad for the environment.

A lot of people had some ridiculous responses.

The ultimate point of the article was that living in a city is better for the environment than living in the suburb. Many responses mostly ignored the environmentally friendliness part. These butthurt folk only cared about the size of their house (which, as we showed in the previous article, means they probably suck in terms of energy efficiency). If they did, they would have pointed out the giant gaping hole in my argument: most landlords don't give a care about energy efficiency of your apartment. They aren't paying for utilities, they only care about your rent.

Some Sources of Energy Waste in Houses

In my last article, I pointed out that all houses need some amount of venting. So bigger houses will likely need a lot more energy to heat and cool than smaller houses. The driver of this was how many times per day the house cycled all of its air. It will surprise most people to find that the amount of ventilation that is still considered safe will dump all of your heated / cooled air 15 times per day.

Drafty windows, much? (same disclaimer as below, burrowed image from a commercial website)

In most cases, your landlord doesn't care about how drafty your place is. On other words, the old place I lived in in Somerville probably exchanged all of its heat to the atmosphere about 100 times per day (we could perceptively feel drafts through every window and door). So the place took about 4-8x as much energy to heat as a well-sealed house of the same size.

What incentive does the landlord have to fix this? Absolutely none. He doesn't pay any utilities. He gets rent no matter what. Given that a majority of people won't ask what the air-exchange rate of an apartment is, he won't have to fix it.

What about appliances? Stoves are pretty easy. Electric stoves produce heat by using electricity to heat an element. They are pretty efficient at converting electricity to heat, but newer ones can definitely be more efficient and save you money. Gas stoves, as long as they don't leak, do pretty well despite age.

Remember these fridges? (note: I just burrowed this from a random site since I couldn't find a .gov site with an old fridge)

Fridges, dish washers, clothing washers, and dryers, or really any other appliance (including hot water heaters, etc.) are a very different story.

Just go here and play around with how much you'd save in electricity annually to figure out how much you'd save by buying a new fridge.

And then remember that 1 kwh of electricity requires 1 lbs. of coal. And then let's consider that replacing an early 1990s era fridge with a new energy efficient one in MA will not only save about $200 per year, but will save nearly 1300 kwh. Or 1,300 pounds of coal, if you get all your power from coal (or about 700 lbs. of methane (recall that methane produces a lot less CO2 for the same energy production)). I am going to repeat that again. Replacing a 20 year old fridge will prevent the equivalent of burning 1300 lbs. of coal in environmental change per year.

That's right. Your landlord being lazy and cheap is making us burn 1,300 lbs. of coal per year. And the energy savings from replacing other old appliances is similar.

What about replacing windows, doors, etc., for ones that don't leak? For ones that have a lower amount of heat transfer directly through the window (double paned, triple glazed, etc.)? It's huge. You can even get tax credits to replace old windows, making the payback time less than 5 years. But many landlords don't care about this, because they don't face the costs of heating a home. They would just be paying money for replacement appliances and windows, and they would never see a return on this investment.

I don't think I need to belabor this point. Old appliances and leaky housing are things your landlord doesn't care about, but they are things that matter in terms of energy use.

So how to fix it? That's for policy people to figure out. I'm not one of them. But I would suggest a few things:

1. Require that landlords report yearly costs of heating to 65F in winter, and cooling to 75F in summer, as well as electricity bills, every time they show an apartment to a potential tenant. This way tenants can add this price in to their monthly rent, and it will force landlords to make a correction for the market.

-or-

2. Require landlords to not have appliances that are more than 15 years old, and windows and doors that are not more than 25 years old

Obviously #1 is much better with market mechanisms, paperwork, etc. I would go with that, since there is pretty much no overhead involved.

Anyone else have any ideas to address this? Leave it in the comments!

Also, if you liked this, please subscribe & share. Thanks for reading!

- Jason Munster

*Recall from an earlier article that the energy use of heat from electricity depends entirely on the "energy mix" of the grid. If enough of that electricity comes from renewables (let's conservatively say 3/4), then the amount of CO2 produced from using electric heat will be better than gas heat (even if the last 1/4 is dirty coal, hence using the 3/4 conservative #).

Natural Gas Prices 2

Natural gas flaring (NOAA). Often it is less expensive to burn natural gas than it is to get it to market.

Since I am in the field installing science onto an airplane, this is going to be a short post. In a prior post, I showed graphs with natural gas prices being de-coupled from oil (recreated and updated with the latest numbers here). I decided it was high time to do some maths related to it. All the data is from the EIA, and all the analysis is my own. I had to interpolate average coal prices for the past two years based on its link to specific coal prices.

If you know what correlation is (I think most of you do), skip over the description of correlation and go straight to Maths, since it is very rudimentary, and you could probably make fun of me for writing it. If you want to do better statistics with the data set, let me know and we can have some fun.

One important point! These prices are well-head prices. In other words, it is roughly what the major distributors of gas will pay for the stuff. Your prices as and end-consumer won't change. In other words, they pay less when the price goes down, but they sell you to at the same price. That works out pretty well for them, doesn't it?

Description of Correlation and its Limitations

Correlation: correlation is a measure of how closely two data sets match. In other words, correlation answers the question: when one set of data goes up, does the other go up? It is important to remember that correlation does not imply causation. In the case of natural resources, this idea is very easy to understand. The price of oil and natural gas both rose together in the 90s. This does not mean that the price of oil rose on its own, causing the price of natural gas to rise. Natural gas prices rose for pretty much the same reasons as oil prices rose. In this case, demand for things that burn and produce heat caused an increase in price in both of them.

Long-term prices 1-13

Wellhead hydrocarbon prices over the past 3 decades. The price of natural gas used to follow the price of oil. In 2008 this changed thanks to hydrofracking.

A classic example of the abuse of correlation and causation is ice cream and murders. Both murder rates and ice cream purchases tend to rise in cities at the same time. One could conclude that ice cream causes murderous rampages, or that the best way to relax after murder is to eat ice cream. Both of these are silly to conclude. More likely, there is an outside factor that causes both. It could be hotter weather makes people eat more ice cream, and simultaneously makes them more irritable. Or it could be that hotter weather makes people eat more ice cream, and it also makes more people be outside, where they are more likely to get murdered than in their homes. The point is that correlation can show that two factors are tied together, but often requires more than that to show a direct causal link.

Hokay. Correlation goes from -1 to 1. 0 means no correlation, 1 means perfect positive correlation: one thing rises, the other one rises by a predictable amount. -1 means perfect negative correlation: one thing rises and the other falls by a predictable amount.

The Maths!

NG correlations

The overall correlation between oil and natural gas prices from 1986 to 2012 is .68. This is pretty good for noisy data sets (noisy meaning there are outside factors, like commodity speculation in the markets). The correlation between natural gas and coal over that period is .4. This is pretty low, and partially represents inflationary increases in prices of both of these over time (if I had used real 2005 dollars instead of nominal dollars, all of these correlations might decrease).

More important is breaking out the correlations between early and late. I mentioned in the prior price post that decoupling began to happen in 2007, and then accelerated. The 22 year correlation between gas and oil until end of 2008 was .88, very high, much higher than .68. After this, the gas:oil correlation becomes -.23. The prices have become decoupled. At the same time, the correlation between gas and coal rises to .69. Not great, but definitely more coupled than gas and oil currently are.

One thing is clear about natural gas prices and correlation. Natural gas prices in the US used to be tightly coupled to oil prices. Natural gas prices in the US are no longer coupled to oil prices. They are instead coupled to coal prices, though not as tightly as the prices used to be coupled to oil prices.

Hydrocarbon prices per million BTU after hydrofracking. Pretty easy to see that decoupling, eh?

Hydrocarbon prices per million BTU after hydrofracking. Pretty easy to see that decoupling, eh?

Now we discuss the cause. The cause in this case is definitely hydrofracking in the US. Outside the US, oil and gas prices are still more correlated. Okay, that was a short discussion.

Some caveats: the numbers I used for historic coal prices are mean annual coal spot prices weighted for what was bought. These are correlated to monthly oil and gas prices. These coal prices were not available for the last two years. They are, however, tightly coupled to coal prices in general. I looked at similar priced coal over the two years, and extrapolated the prices for my model based on these. Given the very tight link of mean coal prices to the price of specific types of coal, this is not a faulty method. If someone were to use a more consistent methodology to determine coal prices throughout the entire time period I have sampled, it would produce results that are nearly identical.

Conclusions

Oil prices and natural gas prices were historically tied. With the advent of fracking in the US, natural gas prices decoupled from oil prices, and have coupled with coal prices.

So much for a short post, eh?

Natural Gas Price Drop, and Natural Gas Electricity!

Today’s post is about the shift in US primary energy use from coal to natural gas (AKA methane). Hydrofracking, the hydraulic fracturing of rock to subsequently produce natural gas, is a new favorite pass-time in the US. Natural gas prices used to track oil prices per unit of heat. They now roughly track coal prices per unit heat. As a result, it is now economical to produce electricity from methane rather than coal. As we discussed before, coal produces a whole bunch of dirty pollution, and methane does not. All good, right?

This is very important for both CO2 emissions reduction and for reduction of other pollutants. The math section is chemistry heavy. If you are going to skip a math section, this is the one.

The highest grades of coal have composition C_{240}H_{90}4NS , and lower grade coal is C_{137}H_9O_9NS. All coal is tainted with mercury and other heavy metals. Lower quality coal has more pollutants per unit heat, and this produces more pollution for the same amount of electricity. From the last post, we learned burning coal has quite the array of negative health effects.

The chemical composition of natural gas is CH4. It contains almost no other pollutants. It doesn’t produce particulate matter. When it is burned to produce electricity, we do not have the direct adverse health effects associated with coal. What about the CO2 emissions? These are reduced. Cause of math.

The Math of Chemistry! This is bond enthalpy chemistry. (Feel free to skip ahead if you don’t like the math parts)

Let’s look more closely at the composition of these two things. When any substance burns, it produces heat by converting everything to H2O and CO2. The resulting H2O and CO2 have lower internal energy than the coal or methane that formed them. The difference in energy from the coal to the H2O and CO2 has to be given off as heat.

Before the math: First, what is a mol? It is short for mole. Pretty bad abbreviation, eh? A mol is the number of molecules it takes to make one g times the molecular weight of the molecule. It is 6.022 \cdot 10^{23} molecules. This is confusing. Lets use examples to make it less confusing. Hydrogen has a molecular weight of 1. A single mole of it weighs 1 gram. CH4 has a weight of 16 (12 for the carbon, 4 for each hydrogen). A mole of it weighs 16g. CO2 has a molecular weight of 44, and a mol of it is 44g. Done.

The amount of energy used to hold atoms together to make molecules is the bond energy. Chemical reactions happen, chemical compositions are changed. If the overall energy of bonds are lower after the change, heat has to be released. This creates fire.
Bond energies: C-C bonds (aromatic, the ring-type found in coal) have 519 KJ/mol. C-H is 410. H-O is 460. C=O (double bond) is 799. O=O are 494 KJ/mol.

We simplify coal as aromatic bond chains of 4(-CH-) (this is generous in terms of calculating CO2 produced per unit coal, as all my prior calculations have been) (I stole this clever approach from my advisor, Jim Anderson, to simplify things). CH4 is pretty easy as CH4.

We can write these as:

4(-CH-) \longrightarrow 4CO_2 + 2 H_2O
CH_4 + 2 O_2 \longrightarrow CO_2 + 2H_2O

The molecular weight of our coal is 4*(12+1) or 52. Methane: 12*1+1*4 = 16

Coal: We break four C=C aromatic bonds (only four cause we would be double counting if we did each side of (-CH-), four C-H bonds, and 5 O=O bonds. We form 8 C=O and 4 H-O bonds.
Methane: 4 C-H bonds are broken, as well as 2 O=O bonds (the two O=O bonds are from converting the 4 H bonds into H2O). 2 C=O, and 4 H-O bonds are formed.

Coal:   4 \cdot 519 + 4 \cdot 410 + 5 \cdot 494 - (8 \cdot 799 + 4 \cdot 463) = 2058 \frac{KJ}{mol} = 514 \frac{KJ}{Mol-CO_2}

Methane:   4 \cdot 410 + 2 \cdot 494 - (2 \cdot 799 + 4 \cdot 463) = 810 \frac{KJ}{mol} = 810 \frac{KJ}{Mol-CO_2}

Math done!

The changing landscape of energy production based on cheap NG

Back in the day (pre-2010 or so) natural gas was much more expensive per unit heat than coal was. If you were going to burn something to produce electricity, coal was much cheaper and so produced cheaper electricity. The fact that it was pretty dirty didn’t matter as much. Then hydrofracking happened. Natural gas got cheap. Its price once roughly tracked with but below oil. Now it tracks with coal. This makes it a viable alternative to coal in power production. This fundamentally alters the primary energy landscape in the US. Once more data is available, we will revisit this.

Hydrocarbon Prices 86-12

Historic hydrocarbon prices per million BTU. Natural gas roughly tracked with oil, until hydrofracking made a glut in the market

Hydrocarbon Prices 07-12

Zooming in on the recent few years, the divergence of oil and gas and convergence of coal and gas becomes evident

 

Let’s discuss policy and environmental implications. They are pretty huge.

The math shows that in energy per unit CO2 produced, methane is about 60% more efficient than coal. This means that if we have to burn either methane or coal, and we seek to limit CO2 production, methane is the natural choice. Historically pricing prevented this from happening.

Natural gas is now only slightly more expensive per unit heat than coal. It makes sense to make electricity from natural gas, cause it produces far less pollution per unit heat. Since 2008, the US has reduced the amount of CO2 is produces for the first time in a long time. The reduction of CO2 produced by the US is partially based on this change in natural gas price. We now produce more electricity from methane than we used to. Since methane is more efficient at producing energy per unit CO2 produced, we produce less CO2 as a country.

Many staunch environmentalists argue this is a bad thing. Natural gas is still a hydrocarbon and still produces greenhouse gases. It kills far fewer people directly than coal does. The deaths that came as a result of coal might have pushed us towards a much greener economy. Methane is the lesser of two evils. It produces energy like coal. It produces CO2. It is still a finite resource. It is much better than coal.

Coal: The great of two evils between coal and methane. A picture of anthracite coal to break up the monotony of a text well. From Wikipedia.

Barring legislation to prevent hydrofracking, this trend of cheap NG will continue for a long time in the US. We have massive reserves of natural gas in our shale, and hydrofracking can get it out. This is not limited to the US, but there are only a few countries in the world that will be able to do this.

Before closing, we have one last thing. Many of you looked at the graphs of natural gas prices, saw that they were historically not much higher than coal for many years, and wondered why we didn't have natural gas electricity plants then. There are two answers. The first is that we did. It is why we have so many right now that can instantly go online. The second answer is that the EPA really only started getting strict on coal plants in 2004. The emissions from coal plants add many costs that go beyond the price of coal. Natural gas is pretty clean, so it doesn't face these costs, making it more competitive with coal.

Summary: Hydrofracking in the US has changed the natural gas price to be much lower and has made it a basic energy feedstock rather than a premium one. The US has natural gas power plant capacity, and has started shifting to electricity from natural gas. These power plants produce less harmful emissions as a result. CO2 emissions are reduced for the same amount of electricity. Harmful pollutants that cause heart attacks, asthma, and early death are also reduced. This is pretty huge.

Thanks for reading again, and sorry for the huge length

Jason Munster

* Will pointed out that I had Avogadro's # off by a factor of 10. Fixed

Coal Power Plants

Expect a lot of updates on this post. Thanks to Buck Farmer, who told me that I needed to learn LaTeX to make this prettier.

COAL FIRED POWER PLANTS

A coal fired power plant.

Coal fired power: it provides a lot of our energy, is less expensive than petroleum by far, makes cheap electricity, and causes all sorts of health ailments and pollution. Coal power plants produce particulate matter, sulfur pollution, and other pollution, resulting in deleterious health effects.

Coal fired power plants provide a huge chunk of the world’s energy. It provided almost 50% of US electricity in 2009. Today, the math section is a review of how much energy is in coal, how much coal we need to operate a single power plant, and how much coal we need to operate all the coal fired power plants in the US and China.

The topic of coal fired power plants used to be simple. Thanks to fracking, natural gas prices are now approaching coal prices. This post is written with 2009 information. It is largely relevant today, but this landscape may change in a few years as more power is produced via natural gas in the US. Suffice it to say that natural gas has become considerably cheaper in the US:

Oil be getting expensive, NG be getting cheap!

The price ratio per unit of heat in natural gas prices compared to oil in the US. The ratio used to be around 1. Now you get a lot more heat out of natural gas per dollar, thanks to the abundance from hydrofracking.

We will discuss this more in a future post.

Maths! Warning, this is pretty shocking!

High grade coal has an energy density of about 32MJ/kg (For our math, lets assume the best coal is used everywhere. In reality it is about 24, so my world with coal is 33% nicer than the real world). Compare this to a gallon of gasoline, from my very first post, at 120MJ. A gallon of gas weighs about 3kg, with an energy density of 40MJ/kg, slightly higher than coal, or nearly twice as high an energy density of a majority of coal.

A watt is a joule per second. A megawatt is a megajoule per second. A coal fired power plant can produce 1GW per second, which would be a gigajoule expended per second. But remember from our thermal efficiency post, these powerplants are not all that efficient! Let’s say a coal one averages 35% for thermal efficiency.

 

Coal_eqn1

31.25kg of coal used per second to produce 1GW of heat! But remember from the thermal plants post, thermal plants tend to only be about 35-40% efficient!

Coal_eqn2

A 1000MW coal fired power plant burns nearly 200 lbs of coal PER SECOND to provide power. That is my weight in coal for every second.

Let’s continue blowing your mind. There are 86,400 seconds in a day, yes? (yes).

Coal_eqn3

2.8 megatons of coal per year for a single coal-fired powerplant! Okay, 200 lbs. per second leaves a bigger impression. Here is another way to look at it. How much coal does it take to keep a 100W lightbulb lit for a year?

Coal_eqn4

 

280kg! Per year! This is about 2 lbs. of coal per day to power a 100W lightbulb. “But Jason,” you say, “We don’t get all our electricity from coal!” This is also true. We get almost ½ of our electricity from coal. But say ½ is from coal, the other ½ is from hydro power. If you turn off your light, we get back the ½ from coal, saving a pound of coal from being burnt. What about the ½ from hydro? Welp, that can go and power another light. The ½ of the light that would have been powered by coal. So yeah, even though ½ of our power comes from coal, the opportunity cost of using that light is the equivalent of getting all of it from coal.

Let me repeat that. If you have a 100W incandescent bulb, and you leave it on for a day, you just burnt 2 lbs. of coal. Good job. If turning off your lights to save on electricity is not enough to get you to shut em off, just picture that much coal burning to keep that light on. Your laptop computer uses about 2-3 pounds if it runs the entire day. Your TV, if left on, will burn more like 10 lbs. of coal a  day.

One last part. China provided 500GW of coal power provided in 2012. The US provided 200GW in 2009 (note: thanks to shale gas and fracking and using the gas to produce electricity, the amount provided by coal has dropped!). 200GW of coal power in the US means 600 megatons of coal per year in the US using our numbers, and 1500 megatons of coal in China. And remember, my numbers are rosier than the real world.

Turn off your lights.

The qualitative stuff!

Emissions from coal-fired power plants, and health trade-offs

Smog. Not fun to breath.

Burning coal emits sulfur (which can be mitigated through special filters, but often is not), CO2, NO and NO2, mercury (also can be mitigated, usually is in the US), other metals, and fine particles (called PM2.5 and PM10 for Particulate Matter of radius 2.5 microns and less, and radius 10 microns or less, respectively). Sulfur causes irritation and lung problems, smog, and acid rain. CO2 and NOx contribute to global warming, NOx also to smog. Mercury emissions are the reason we can no longer eat fish every day. PM2.5 causes cancer, asthma, and severe lung problems. Coal power plant emissions can lead to ozone at ground level, which causes smog and serious respiration issues.

Later we will discuss black carbon vs. sulfur here, since they have opposite effects on regional warming vs. cooling. Today we discuss the health effects of a coal fired power plant.

In the US, where coal-fired power is relatively clean, it causes tens of thousands of deaths per year. It causes hundreds of thousands of heart attacks, asthma attacks, ER visits, and hospital admissions per year. A compilation of EPA and heavily peer-reviewed articles estimates 13,200 deaths and 20,000 heart attacks were caused by coal-fired power plants in 2010. In 2004, before the EPA starting getting aggressive, these numbers looked like 24,000 deaths per year in the US.  The rate of asthma is drastically increased in the area of coal fired power plants. The US even then had relatively stringent requirements on power plants. When you factor in the population and lax controls of countries like China and India, I have heard estimates of premature deaths caused globally by coal fired power to be in the millions, and even larger numbers for asthma.These adverse effects are much more likely to be caused by the wealthy regions that use more electricity per capita than the poor regions that host the power plants and the adverse effects. In other words, the electricity used by large mansions in wealthy neighborhoods often comes from powerplants placed near poor neighborhoods.

The coal used by the US and China directly contribute to global warming on a huge scale. In a future post that describes the composition of the atmosphere and how greenhouse gases work, we’ll get directly into those numbers.

Satellite image of pollution in China. From: http://earthobservatory.nasa.gov/IOTD/view.php?id=76935

Beijing's got a bit of a particulates in the air in the winter. I was in an airplane in Beijing on this day. They announced "The fog is too thick to take off." Except it was below freezing and the air was dessicated, making fog unlikely.
A more clear day near Beijing

 

Let’s be pragmatic for a second.What’s worse than deaths and heart attacks caused by coal-fired power? Not having electricity to power your hospitals and other vital services. If you are a poor or developing country that can’t afford fancy nuclear or renewable electricity, and you don’t have access to hydro power, putting up a coal plant to power cities enough for basic services is a no-brainer.  Wealthier countries have a choice: suffer the pollution, or spend more money and avoid it by building more expensive yet cleaner electricity sources. The US as a whole can easily afford to do this. Pakistan and India? Not so much.

Take-aways: Turn your lights off, they require a lot of coal. Avoid breathing or raising children near coal-fired reactors.

-Jason Munster

Base load electricity vs Peak Load

Base load Electricity vs. Peak Electricity

I was writing a post about how a coal fired power plant works, and then realized that I needed to describe more about our electrical power grid and how each power component fits into it. Also, speaking of power grids, there is an excellent game called Power Grid that anyone who knows me should come over and play.

Base load electricity!

Electricity_demand_profile_NE

Pictured above is the electricity demand for an October day in New England. Notice that throughout the middle of the night, the electricity demand is roughly 10GW. Throughout the day it ramps past 15GW. Base load electricity in this case is 10GW. It is the minimum amount of electricity needed at any point. All power plants that provide base load electricity will run 24 hours a day. Base load power plants need to be very reliable so they don’t shut down unexpectedly.

Base load electricity requirements do change throughout the year. During the sweltering summer in southern states, air conditioners are constantly on, drawing more electricity in the summer. In some countries, there is not enough base load electricity to provide electricity in the worst months. In Pakistan, for instance, there will not be viable electricity more than 4 hours per day for several months. We will return to base load electricity soon.

Peak electricity is whatever is above base load. In the above figure, it is the all the extra stuff from 10GW to 15GW. Peaking power presents special challenges, because it can be unpredictable. If the temperature is several degrees warmer in a summer afternoon, the peak electricity requirements can be greater than predicted. Power plants that are capable of ramping up power quickly will compensate for peak electricity demand. “Ramp Rate” is the MW per minute a turbine can spin up at. This ramp rate is important, and we will get back to that almost immediately.

A brief interlude on cost! Base load electricity tends to be pretty cheap. A base load plant will not get paid as much for electricity. Peaking plants are designed to turn on only when electricity is more in demand. This means they get to charge more! A peaking power plant will figuratively not get out of bed in the morning for less than 50% above base load electricity rates.

Okay so here is where things get somewhat more complicated. Some power plants can never be taken offline in short order (think nuclear). Thermal power plants tend to take longer to create enough heat and steam to spin up their turbines, including both coal and nuclear, and some types of natural gas. Anything that takes a long time to spin up is meant for base load power.

A nuclear power plant with the nuclear plant (small rectangle buildings and one cylindrical building) and a cooling tower (big steaming parabolic-shaped tower). Nuclear power plants never shut down, except to change fuel rods.

A nuclear power plant with the nuclear plant (small rectangle buildings and one cylindrical building) and a cooling tower (big steaming parabolic-shaped tower). Nuclear power plants never shut down, except to change fuel rods.

Other types spin up very quickly. For some, like natural gas plants that are designed to deal only with the peak electricity use, a typical turbine can ramp at a massive 20MW per minute (most plants have several turbines, and can ramp at multiples of 20MW!). Why don’t we use these for base load, since they seem so flexible? These fast-ramping systems are not designed to be always-on. They accrue damage if they do not have downtime.

Let’s talk about renewables. A power plant has to produce either base load or peaking electricity on demand to be useful. We have the magic of hydro electricity. It combines a very high ramp rate, and also capable of maintaining base load electricity.  Wind and solar at first seem terrible. They only work when the wind is blowing or when the sun is shining. So they cannot provide either base load or peaking electricity, right? Fortunately, this is not correct. Due to complexities we will discuss in later posts, wind and solar can be installed and paired with each other and with other tech to produce somewhat reliable base load electricity or peak electricity.

One example? When does electricity demand peak in the summer?

If you said when it gets hot and air conditioners work harder and draw more electricity, you are onto something. And it gets hot when the sun shines. Put some solar panels on your roof, and you see your solar panel electricity production rise coinciding with your need for more electricity for house cooling.

Every power plant type has important considerations for peak load vs. base load. As we look at each in turn, it will become apparent how important this distinction is.

One last thing before closing. How do power plants figure out when to turn on? In New England, we have a group called ISO New England. It projects electricity demand based upon yearly trends (people consume a ton of electricity over holidays, and at different time periods!) and upon weather forecasts. Each day, every power plant puts in a bid for how many cents per kilowatt hour they need to turn on. In other words, it’s the figurative “price per kwh to get out of bed.” If demand is projected to rise to such a point that the bid for a plant is met, that plant will turn on once the price hits that. This is confusing. Let’s use an example.

We have three power plants in our imaginary tiny country. Since I keep bringing up this country, I am going to call is JasonLand (for now). JasonLand currently has a coal fired plant, a nuclear plant, and a natural gas plant designed for peaking. The nuclear plant cannot shut down. It will literally bid -$0.50/kwh to  ensure that no matter how low the price is, it will produce electricity. Our coal-fired power plant is baseload, but will shut down on days when it is not needed. It will bid $0.07/kwh. As soon as the price rises above this, it will start up (this is simplified, starting a coal power plant takes a long time). Our peaking gas plant will bid in at $0.11/kwh. Once people get home and need more power, or when it is a really hot day, our peaking gas plant will spin up its turbines rapidly.

So how do these bids work? How much does each plant get paid? As demand rises, price rises, and the power plant earns more for every kwh. Our nuclear power plant will make a small amount in the middle of the night, and make more during the daytime. I’ll leave you to ponder why a power plant would choose to not run until a certain payment threshold is hit.

Because I can’t help myself, let’s close with a tiny bit of math. A realistic price for energy in New England is about $0.15/kwh. To make it easy, let’s convert to $150,000/gwh*. A nuclear plant is about 1gw. It will produce 24 gwh of electricity in a day. That is $3,600,000 in revenue per day. Every week it earns nearly $25 million. I hope at this point any regular reader is beginning to get a sense of how staggering numbers associated with energy use are.

Thanks for reading again!

Jason Munster

*Correction: original post was a factor of 10 short.