Can the right space program save Earth? - Part 2
This is part 2 of a writeup for my dry run for a talk I’m giving on David Goldsmith’s Age of Infinity Google Meet at 11:30 AM PST on January 14th. The title of the talk is the same as the title for this report. Last week I covered the current overpopulation crisis and how it is made even worse by Global Warming. In this report I will show how products mined on the moon can greatly reduce carbon dioxide emissions, thereby giving humanity the time, it needs to bring the birth rates down. This note has parts in common with my November 16, 2020 note.
To review what we learned last week, we, the population of Earth, are facing several interconnected problems in the near future. These problems are overpopulation combined with poverty and starvation caused by Global Warming. First overpopulation. A projection of Earth’s past and future population is shown in figure 1 below.
Figure 1 – UN Projections of World Population
Note, that the total population in 2100 is greatly driven by female fertility assumption which in turn is driven by the poverty levels and education levels found in third world countries today. It has been demonstrated numerous times that when the population of third world countries are better educated and poverty is reduced, the birth rate almost always falls. Providing better education and better jobs requires more energy and more infrastructure per person and this is why the major portion of fossil fuels used today are being burned in third world countries. They are trying to work the education and starvation problem as best they can with the resources available. The developed countries could greatly help solve this problem by providing low-cost renewable energy technologies that can compete economically with fossil-fuel energy sources in the third world. This is a far better solution than raising taxes on fossil fuels.
Figure 2 – Global Primary Energy Consumption by Energy Source (2010 – 2050)
Obviously, the Green Revolution was not a factor in generating the data for this figure given the large growth in fossil fuels especially coal. This figure is based on the economic decisions made by utilities to determine the choice of what type of powerplant to build next. These decisions are based on the technologies available, the capital costs for the plant and infrastructure, and the cost and availability of the fuel source required. It is a relatively simple economic trade, not factoring in carbon emissions. At the current time and in the near future, most third world countries can afford only the cheapest options, like coal. More developed countries can afford to replace their coal plants with cleaner and more efficient dual-cycle natural gas plants. Nuclear powerplants should be under consideration, but they need a complete makeover to compete in these markets after numerous operating disasters. The Generation IV nuclear technologies required are in the wings but need solid support from government agencies to transition to ready and available for use. Right now, only China and India are pursuing Generation IV nuclear powerplants. Unfortunately, the U.S. Nuclear Regulatory Commission (NRC) has totally fumbled any effort for the U.S. to compete in this area, so we’re going to be experiencing brownouts at night or burning natural gas for a very long time in the United States.
As figure 2 shows renewable energies should be the biggest energy source by 2050, but they will still only be 28% of the total mix. This means that new technologies must be developed, soon, to replace the fossil fuels predicted to be consumed between now and 2050 or we are going to revisit the Cretaceous Age climatic wise. Figure 3 below shows where the CO2 is being currently being generated and which are the hardest emissions to eliminate.
Figure 3 The Hardest CO2 Emissions to Eliminate
The biggest emitter is base load and variable-load electricity generation, and real progress has been made there by embracing renewable energy sources (Photovoltaic and Windmills) and replacing variable-load coalfired plants with cleaner and more efficient natural gas turbines. Final elimination of carbon emissions will require nuclear powerplants or large banks of batteries with inverters. Unfortunately, batteries provide only very limited backup and are a prescription for blackouts if nature does not cooperate. Nuclear is a far better solution long term. The next biggest carbon emitter is short and medium range transportation (cars & trucks). Definite progress is made here also with electric cars and trucks starting to make real inroads in current and future sales predictions. There are still unresolved issues with having enough charging stations and the fact that the majority of our electricity is still generated using fossil fuels.
The hardest carbon emissions to eliminate shown in figure 3 are long-haul trucking and shipping, plus aviation; because they can’t be hooked up to the electric grid, and batteries have insufficient energy per kilogram to compete with fossil fuels (I continue to maintain that fossil fuels can only be replaced with cheaper renewable solutions, and not be legislated out of existence while they remain cheaper). Note that electrical energy solutions to remove carbon emissions from cement and iron production were covered in Nov 15 Rocketdoc Notes.
So how is the final elimination of fossil fuels from long-haul trucking and shipping, plus aviation, driven by mining the moon? First of all, let me state that my crystal ball is pretty cloudy with respect to ocean shipping and long-range aviation. Near-term (next 30 years) I see I switch from diesel and jet-A to liquified natural gas and gradually liquid hydrogen to reduce and then eliminate carbon emissions. Power would be generated by turbines not significantly different from current powerplants on these systems. Eventually, it would make sense to power long-range aircraft and ocean shipping with a compact fusion reactor using D-He3 fuels. D-He3 reduces neutron emission by about 80% relative to first generation fuels like D-T, making for a much lighter, more efficient powerplant. Fusion-powered airplanes and shipping would retain the turbines and have hydrogen available for backup and emergency power.
As it turns out, replacing fossil fuels used for converting the world from fossil fuels to renewables plus nuclear requires some metals that are scarce and/or expensive to remove from the Earth’s crust. These metals are commonly referred to as Platinum Group Metals (PGMs) and Rare Earth Elements (REEs). Another energy commodity that is almost nonexistent on Earth but relatively easy to obtain on the moon is He3, the best near-term fusion fuel. We are rapidly approaching the point where if SpaceX’s Starship system is successful, humanity can occupy Low Earth Orbit (LEO) and start providing PGMs and REEs from the moon for prices competitive with the mining the diminishing ores on Earth. Remember, the key to elimination of fossil fuels is to have a cheaper, more efficient renewable solution. Check out Chapter 8 in my book for details on the economics of lunar mining. Figure 4 below shows the regions of the moon which are especially rich in Iron (left) and Thorium metals (right) which is a telltale for Potassium+ Rare Earth Elements+ Phosphorus known as KREEP. This data indicates there are abundant resources in the lunar regolith to provide the critical metals needed to support the technologies crucial to replacing fossil fuels.
Figure 4 – Abundance of Critical Metals on the Lunar Surface
The picture is clearer for long-haul trucking and short-range aircraft like helicopters. They could go with turbine engines burning hydrogen, but it more efficient and cheaper to go with hydrogen in fuel cells. A fuel cell is almost twice as efficient as a small turbine engine, halving the fuel consumption. This application will probably drive the market for lunar mining. Platinum Group Metals are used primarily in sensors and catalysts. The biggest upcoming use is going to be as the catalyst in fuel cell electrodes. A 95-kW fuel cell will require about 50 grams of platinum and if you project converting all 15 million US long-haul trucks to hydrogen fuel cells it is going to require 1500 mT of platinum. Current worldwide production of Platinum is 130 mT/yr. The lunar regolith on the near side contains unknown millions of tons of nickel-iron asteroid material which has been raining down for the last 4.5 billion years, and this nickel-iron has an average of 100 to 150 parts per million of PGMs dissolved in it. Most of this nickel-iron is lying in the upper three meters of the regolith and is easily and cheaply separated from the rest of the regolith using magnetic separation. The nickel-iron is gasified using hot carbon monoxide using the Mond process discovered in 1890. The nickel and iron components are collected and stored separately as dust when the carbon monoxide is recycled. The residue from this process forms a dust enriched in Pt (about 0.5 wt.%) along with many other siderophile elements (like gold). After collection, this enriched residue dust would be sent back to Earth for further processing. A single lunar miner machine described in Chapter 8 of my book could harvest enough nickel-iron to yield an average about 360 kg of PGMs per year. At that rate it would only take a few hundred regolith miners to supply enough PGMs to solve the long-haul trucking and short-range airplane problem back on Earth. A single mining base on the moon would be supplied by dozens of regolith miners and there would be dozens of bases.
Each regolith mining machine also harvests 30 kg of He3 per year which is enough to generate about 2000 GW-hrs of electricity in a moderately efficient fusion reactor back on Earth. With hundreds of regolith miners operating, they could easily support the variable power required to back up an Earth-wide wind and solar power system. The areas measure high in He3 are shown in figure 5 below.
Figure 5 Abundance of He3 on the Lunar Surface
This tells me that Global Warming will probably be a huge inconvenience and a money sink, but unless we let it get out of control, it will not be a threat to civilization. The world needs to respond to this threat in a timely and well-thought-out manner to mitigate the problem. Yeah, good luck with that. My motto is “Remember the Cretaceous” for that is where we are headed with >1000 ppm CO2 if we do nothing.
It is New Year’s Eve and that’s enough for this week. I’ll address part 3 dealing with the Rare Earth Elements next week. Let’s be done with 2020 and get 2021 off to a good start.
Thanks for reading.