Have your lunch and heat it too
Solar-powered lunch box keeps your food warm and your conscience clear.
This Solar-Powered Lunch Box makes it possible, managing to bring hot food to the outdoors without polluting the greenery in the effort. Teo Song Wei developed the concept as a green way to keep warm foods warm until you're ready to eat them.
As the idea is still a concept, you might have to stick to sandwiches for the time being. If it ever becomes a reality, you'll find me with my heated eats by the pond in the park.