Letter of the Week

Jun 22 2021

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Letter of the Week

Each week, we receive tens – even hundreds – of letters from you, our loyal Bridge readers. We can’t always reply to them, but we have a LOT of appreciation for your sometimes practical, sometimes crazy, and always radical ideas. Letter of the Week is our way of celebrating your brilliance and your drive to make the world a better place. If you want to send us a letter, drop us a line at [email protected]

May 20, 2021

Aspiring scientist, seven year old Riley Marie from Virginia sent us the detailed letter below, complete with a flying floating garden model to boot! Check out her carbon removal solution and send us your crazy ideas at [email protected]

April 27, 2021

We love to see your letters and hear your radical ideas. This week, we have two early entries for the $100M XPRIZE Carbon Removal, courtesy of future scientists Andrew and Lauren, who are five years old and also happen to be twins. Check out their robot and drone designs below, and as ever, send your ideas at [email protected]

April 23, 2021

Carbon Capture: 

As an environmentalist, I look to nature to solve the complications we now face as a whole earth. 

I admire your EV efforts. Although I can envision solar panels incorporated into the cars’design – personal solar car parts sold with every vehicle air possible solar windshield shades to care a more off-grid vehicle since our future faces the impossibility of neutralizing the isotope. 

Carbon capture: an idea that keeps haunting me. I propose a dog compost / collection site at every dog park in the U.S. When an enzyme is added to the dog waste the compost becomes fertilizer for trees. I believe if you do the numbers you will be impressed. 


April 17, 2021


I was in the oil and gas industry for 20 years and have recently changed my business plan. 

I’ve launched a line of business to grow Kelp in the deepwater Gulf of Mexico to capture carbon and reduce methane attached to abandoned offshore platforms. Phase I is to grow the Kelp and Phase II is to sell the end product focused on ruminates to convert methane to hydrogen. Kelp captures 20x the amount of carbon per acre of a forest and reduces methane. And methane traps ~30x the heat of CO2. You get a double benefit environmentally. 

Initially, we will focus on selling the dried Kelp to cattle ranchers. With just 2 ounces of Kelp additive it reduces methane emissions >90% (per Harvard University, US Davis, CSIRO studies).  

Cattle also gain weight faster (up to 20%) because instead of producing methane they produce hydrogen which is less energy intensive. The rancher will save $100k per 1,000 head of cattle on feed alone. More food with less resources.

In addition they will be able to market their beef as Methane Free which I have never seen before and will attract more end-users at a higher price. They will also be eligible for 45Q tax credits.   

I believe this initiative could be consistent with your goals of continuously improving the environment.

I would love to discuss this further with you and learn about any resources you can provide. 

Thank you


April 4, 2021

Thanks for the mental coffee

Thanks, guys,

For the weekly reminders. This is important if you want us to keep thinking. Your stimulation got me going. I hope you will get to the last paragraph below. (Skip the rest if you must.)

The discussion about food is very important. It reminds me of what I think is near the top of man's greatest inventions: agriculture. (Oh, yes, at some time, every science began as an invention.) Man reached the maximum carrying capacity on the earth in about 10,000 BC, with around one million people. He was eating animals to extinction. The animals and plants of the earth were being depleted. Then, someone got the wonderful idea that if we couldn't just forage and kill enough food, then we could grow it for ourselves. (Remind you of today's letter?) The pre-civilization hunter-gatherer period ended, at least over much of the land.

Today, a large portion of the land surface is devoted to farming and animal husbandry.  (And with this came the notion of land ownership.) But, wait, what about the oceans of the earth? They are still stuck at the hunter-gatherer stage, and it's generally recognized that 90% of the natural productivity of the world's oceans has been destroyed.

Thanks to agriculture, we are now keeping about 8 billion people alive, and we see that again we have met or exceeded the earth's carrying capacity.  We can ease our footprint on the land by extending our creativity to the open oceans--we can bring them back to full productivity and beyond--ocean husbandry.  (Most natural CO2 takeup is in the oceans--let's boost it by increasing ocean primary production--more food, better air.)


April 2, 2021

Dear XPRIZE,  

I have really been enjoying your weekly binary polls of late and it got me thinking. l was pondering about if people apply the same morals to artificial protein substitutes as they do to the animal equivalents? I would love it if you could ask your prestigious audience that very question? 

Thank you. Ellie 

March 28, 2021


This is no crazy idea. It is a carbon sequestration response to the crisis of Climate Change.  Everyone talks about planting trees as the way to absorb the carbon dioxide already in the air. This is a noble effort to use photosynthesis but sadly much too inefficient and slow and also not capable of providing sustenance and building economies to benefit society across a broad spectrum, from corporations to individuals in community. 

The answer is “micro-trees” if you will, which are algae. Algae has the highest photosynthetic efficiency (PE) of any known plant. It grows in both fresh water and brackish/saline water, of its own volition. 

My years-long study of water-related uses and issues and understanding the biology convinces me that the intentional practice of algaculture is possible TODAY within our existing water/energy-related infrastructure. The capital Return on Investment is immense and easily within a 5-year window.  

I am looking for an opportunity to share “the rest of the story” with interested parties willing to join me and others in pursuit of large-scale algae farming with possible direct links to existing energy generation facilities. 

Thank you.


*Letters have been edited for clarity and names have been shortened. The views expressed within these letters are the opinions of our fantastic fans and followers and do not necessarily reflect the official position or policy of XPRIZE.