Are LNG export terminals good or bad?

Tags

CO2, export terminals, fossil fuels, GHGs, LNG, methane, natural gas, oregon

The US has widely adopted hydraulic fracturing (fracking) which has domestically led to cheap natural gas. Since natural gas is 2.5 to 3 times more expensive worldwide, many expect that exporting natural gas could benefit both the US and other countries. However transporting natural gas is more difficult than oil. Companies need either pipelines or liquid natural gas (LNG) facilities/tankers to economically transport it.

credit: ihrdc.com

LNG facilities compress and cool natural gas to its liquid state (124 kPa, -162 degrees C). This allows for ocean tankers to hold 600 times as much natural gas for a given volume. While it might seem energy intensive to make natural gas that cold, keep it cold, and transport it thousands of kilometers, most GHG emissions (90%) still come from extraction and combustion.

There have been several proposed export terminals throughout the US, but two in Oregon. One in Coos Bay and another in Warrenton. While there are many other pros and cons, I want to highlight a few important ones.

Greenhouse gases

A recent study has found that natural gas exports could reduce GHG emissions. The authors assume that LNG could be used to replace coal in Asia or Russian natural gas in Europe. In both cases, there is a net reduction in total GHG emissions. This essentially supports the “bridge fuel” argument. It says that natural gas can serve as a fuel as we transition from coal to low-carbon technologies for electricity production.

However, natural gas can be used in other ways such as plastic production or home heating. These activities have less clear benefits. Also, US exports could lead to increased domestic fracking and even increased domestic coal consumption as natural gas prices increase. In addition, another study has shown that natural gas as a “bridge fuel” could increase electricity consumption, increase methane emissions, and/or delay investment in truly low-carbon technologies.

Social impacts

Domestically, a few jobs would be created. Some US companies would prefer to keep cheap natural gas prices to themselves, but LNG exports would certainly boost world economic output. Exports could provide Asian markets with cleaner-than-coal cheap electricity. It is important to acknowledge that the US and Europe grew wealthy by exploiting fossil fuels and that we don’t have the right to demand that poorer countries abandon fossil fuels immediately.

Other environmental impacts

As new pipeline must be laid to get natural gas to the export facility, significant impacts could occur. Construction and maintenance of the pipeline would necessitate a clear swath through forests (public and private) and construction that may temporarily disrupt waterways.

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We should immediately work to reduce fossil fuel consumption; we can afford the extra costs and we are responsible for most of the current climate change. Ultimately we need an effective carbon tax. This is necessary to address climate change and could displace other taxes. It would still allow for exports when it makes sense for all parties. We’ve recognized that fossil fuels are a problem and ways to mitigate their use. We now need the political will to implement these solutions.

Today, there is a rally in Salem, OR to protest the proposed LNG export terminals. Please consider joining us, contacting your representatives, and please just discuss these issues with your friends.

Further reading

• Portland propane terminal pros and cons (environmental emphasis)
• US LNG export pros and cons (economic emphasis)

 

 

What is a capacity factor?

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capacity, capacity factor, coal, electricity, hydro, natural gas, nuclear, power plant, solar, transition, wind

Capacity is the maximum power that a plant is designed to output. A 1000 MW plant can output 1000 megawatts of power (or 1000 megajoules per second), but sometimes it outputs less than that. For instance, it might operate at a lower power or not at all while undergoing maintenance. A capacity factor is defined as the actual output of a electricity generating device over it’s maximum possible generation during the same time period.

For example, a power plant that is rated at 1000 MW capacity and generates 7500 GWh over a full year:

• actual generation = 7500 GWh/year
• possible generation = 1000 MW * 8760 hrs/yr * (1 GW / 1000 MW) = 8760 GWh/yr
• capacity factor = 7500 GWh/yr / 8760 GWh/yr = 0.856

The plant operated 85.6% of time at full power. This could mean that all year it operated at 85.6% or that for 312 days it was at full power and the other 53 days it was shut off producing no power. More likely it was somewhere in between.

The EIA has plotted monthly capacity factor data for the US over several years:

The monthly breakdown gives a better idea of the mix of sources as the year progresses. Nuclear power plants are refueled only once every 18 or 24 months. They try to time these outages for fall and spring because demand is lower in those months (less air conditioning and heating is used). The capacity factor of wind on the other hand reliably tends to be lowest in the late summer. Natural gas combustion turbines are usually used as peak power which means they only turn on when no other source on the grid can increase output (the hottest summer days).

Since the capacity factor changes throughout the year, the way to compare between sources is to use the annual average.

A coal plant operates on average 65% of the time. A geothermal plant 70% of the time. The capacity factor shows how well the plant is used, but it doesn’t tell us which fuels Americans use more:

Or combined into one plot with

We need to rapidly transition our system away from using so much fossil fuels for our electricity. If wind has only a 30% capacity factor, it will need to radically expand its capacity in order to replace significant portions of other fuels. Transitioning from fossil fuels in other sectors like heating and transportation will be even more difficult.

Can I really provide my entire lifetime’s worth of energy with a golf ball?

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coal, energy consumption, golf ball, lifetime, natural gas, nuclear, USA

A recent article in The Independent, suggested that:

A golf-ball-sized lump of uranium would supply the lifetime’s energy needs of a typical person, equivalent to 56 tanker trucks of natural gas, 800 elephant-sized bags of coal or a renewable battery as tall as 16 “super” skyscraper buildings placed one on top of the other.

I tend to disapprove of these types of statistics because they don’t compare apples to apples. So, I decided to make some simple estimates for average American use (note that this is close to double an average European’s use).

This is a little tricky because as I discussed in The basics of energy, each energy type is different. However, the EIA has been converting back and forth regularly for many years. The idea is to work backwards from electrical energy to get the amount of heat energy. For a typical coal or nuclear plant this is roughly 1 part electric = 3 parts heat (based on thermal efficiency).

First, let’s look at historical usage rates from the EIA and use a few guesses to estimate future usage. I include two linear trend lines. One suggests growth over time, while the other suggests a slight decrease over time.

If we assume the average life expectancy is 80 years and that the person is 40 years old in 2015, our typical energy user lives from 1975 to 2055. After plugging these values into the trend line equations, we can calculate total emissions by just using the formula for a trapezoid (A = b * (h1+h2) / 2).

That means our estimate for cumulative use by an average American is between 26,700 and 29,600 million Btus. Checking the MIT_conversion sheet, the heat content of several fuels are:

• coal is 21.5 million Btu / ton
• natural gas is 50 million Btu / ton
• uranium is 379,000 million Btu / ton mined

High estimates are therefore (and low):

• coal: 1,377 tons (1241)
• natural gas: 592 tons (534)
• uranium: 0.078 tons mined (0.070)

Now of course, each material has a different density, but this comparison seems more useful. And if these numbers seem too big to picture easily, it’s easy to pick a smaller time-frame. For instance, fuel use over an average week during the lifetime:

• coal: 728 pounds
• natural gas: 313 pounds
• uranium: 0.04 pounds mined

The article suggests that a golf ball sized uranium slug could provide power for a lifetime, but with different assumptions we arrive at 78 kg or the average weight of an American. Since uranium is very dense, that volume is just slightly larger than a gallon of milk. Still pretty impressive compared to other fuels.

But you might be worried about nuclear for other reasons. In the coming weeks I’ll be comparing electricity generation from coal and nuclear. Post in the comments if there are specific issues you want me to talk about.