Growth of renewable energy is extremely exciting (and very much needed), but the rate at which it is coming online is slow. It will be decades before renewables can carry the majority of the electricity load. In the meantime, we need to keep global temperature rises in check with the tools at our disposal.
This involves decarbonizing our fossil fuel energy infrastructure until clean technologies such as solar and wind can be relied on to power our society. Current estimates say that we need to bring annual CO2 emissions to under 16 gigatons in order for global temperatures to rise by less than 2 degrees Celsius.
To properly understand the scale of this task, consider that in 2014 we emitted roughly 36 gigatons of CO2. In order to do achieve a sufficient reduction in CO2, we need an “all of the above approach” that includes:
- Energy Efficiency
- Energy Conservation
- Switching from Coal to Natural Gas
- Nuclear Energy
- Carbon Capture and Storage
Energy Efficiency. To date, energy efficiency has had a far larger impact on reducing emissions than renewables – and it’s not even close. The efficiency gains come from a wide variety of improvements including:
- Fuel efficient cars
- Better insulation on houses
- High efficiency lights
- Better power plants
- High efficiency home appliances
Prior to 1974 the energy usage in the US was highly correlated to the economy (eg. an increase in economic output resulted in an increase in energy usage). Since the energy crisis of 1974, the US economy has experienced tremendous growth, but energy consumption has stayed relatively flat due to the efficiency gains.
Energy Conservation. The basic premise of energy conservation is to use less energy wherever possible, and various policies have been used to achieve this. Some of them include:
- Zoning reforms to increase urban density so that people can walk or bike to where they need to go.
- Telecommuting (working from home) options for employees.
- Automation systems that turn off lighting in buildings during hours when there are no occupants.
Interestingly, a lot of older buildings were built without light switches as energy was so inexpensive back in the day. Many of these building had to get retrofitted with light switches later on.
Switching from Coal to Natural Gas. Natural gas is a much cleaner burning fuel than coal. To generate the same amount of energy, natural gas only produces 56% of the CO2 that coal does. Furthermore, natural gas only emits 20% the NOx and .03% of the SO2 when compared with coal.
Due to switching from coal to natural gas, we have seen a 20% reduction in CO2 emissions from coal since 2006. Overall, we are trending in the right direction in this area. In 1993, only 13 percent of electricity generation was coming from natural gas, and 53% was coming from coal. In 2014, 39% of electricity is coming from natural gas and 39 percent is coming from coal.
We see natural gas as the primary “bridge fuel” to sustain our society until enough renewable energy is available.
Nuclear energy. This energy source uses radioactive materials to generate heat and boil water into steam. The steam is then used to drive turbines to generate electricity.
Analysis of nuclear energy shows that its level of CO2 emissions is comparable to renewable energy sources. However, there are concerns related to the proliferation of nuclear materials as well as the potential for power plant meltdown that makes this energy source unattractive. Even with these concerns, we feel that nuclear power should be a part of our energy portfolio for the future.
Renewables. Renewable energy includes a wide variety of technologies such as wind, solar, geothermal, tidal, and hydro. In 2013, roughly 14% of US electrical generation came from renewable sources.
According to current estimates, renewable energy will only account for 18% of US electrical generation by 2040. We are on the right trajectory, but renewables alone will not be able to sufficiently decarbonize our energy infrastructure in time to prevent catastrophic climate change, which is typically seen as a 2 degree Celsius rise in global temperatures.
Carbon Capture and Storage (CCS). This technology involves capturing carbon from the atmosphere or point sources (such as power plants), and storing the carbon underground. Some people see CCS as THE method to solve our energy issues, but we believe this method cannot sufficiently decarbonize our energy structure on its own. The reasoning is as follows:
- For CCS to sufficiently decarbonize our energy structure, it should function around the “billion tons of carbon reduction per year” level. There is nothing magical about the billion tons of carbon number. It is simply around the order of magnitude we need in order to make a noticeable difference in CO2 emissions.
- A billion tons of carbon converts to 31 billion barrels of supercritical CO2. This would be a massive amount of liquid to move. This is almost equivalent to the annual production of oil around the world.
- If we want to run CCS at this level, the amount of infrastructure required to inject the liquid carbon into the ground would be enormous. Another potential issue is that there is uncertainty around whether there is enough pore space to inject the CO2 without causing earthquakes.
Many experts do not considered CCS to be a large player in reducing carbon emissions on its own.
As can be seen, there is much work to be done in order to decarbonize our energy infrastructure. One key thing we want to point out is that there are no technical obstacles for us to overcome in order to implement all of the carbon reduction methods mentioned above. There are certainly economic and political factors to overcome, but the technology we have today is more than good enough for us to reach our carbon reduction goals.