I was on the phone yesterday talking Ellis Martin into attending the Graphite Express Conference that GraphiteBlog is a sponsor of today in Vancouver. He did his usual song and dance about how much better his weather was in LA, but finally agreed once he was sure that I was aware of the favour he was extending.
And for those that have missed the news, I have been quarantined to my home due to a viral thing that seems to be propagating everywhere. So what else would I cling too tenaciously on Day 9 to read this afternoon, but a scientific article on graphite foam as insulation for geothermal energy applications?
Years ago I had (still own it) GeothermalBlog.com so this article Graphite Foam could help suck terawatts from seawater caught my eye as I had no idea that graphite could be used this way. Yes we know that geothermal power is a stable source of renewable energy because it is available at a constant rate, but the idea that graphite foam could be used as an efficient heat conductor when harvesting energy for offshore power stations -- makes me wonder what the real market demand here is?
Let me provide some context: when there is a temperature difference between water at the surface and water thousands of feet below it is in theory possible to harvest that energy. The greater the temperature difference the greater the amount of energy that can be extracted. Bearing this in mind, consider the possibilities of harvesting geothermal energy from ocean water in tropical areas. These waters can reach temperatures of 70-80 °F degrees at the surface and drop to 40 °F within a few thousand feet in depth along the water column. Believe it or not, this difference of 30-40 °F difference in temperature “is enough to boil ammonia, use it to drive a turbine to produce power, and then condense the ammonia again to start all over.”
Yes, the beauty of a geothermal energy system is that no fuel is necessary and no waste is generated. The Oak Ridge National Laboratory Oak (ORNL) estimates that offshore power stations in tropical settings can potentially generate 3-5 terawatts of power. While this seems exciting, you should check out Reykjavik, Iceland where 95% of their energy comes from geothermal power.
This is where the graphite foam comes in. Graphite foam has lots of surface area and is a very efficient heat conductor which is essential to any heat exchange system. The ORNL further estimates that using graphite foam could “either half the cost or double the efficiency of any heat-based power source which covers not just these seawater plants, but traditional power plants (coal, nuclear, etc) as well.” A demonstration site of this seawater energy plant is planned to commence operation this spring in Hawaii.