Travelling to Bath, England, Dick and Jem meet up with an eco-minded sandwich shop owner eager to create an environmentally-friendly delivery vehicle. Riding around town on a tandem bike, Dick and Jem experience first-hand the challenges of creating a green vehicle able to cope with the hills and cobblestones of Bath. To build a lightweight ‘green machine’, Dick and Jem will need to make something small and agile – able to accelerate uphill and manoeuvre through traffic. The solution: an air-propelled motorbike. To test the idea, Jem catapults himself and his bike off an air-powered ‘cannon’ using a single piston engine. But, for the bike to actually work, the duo must squeeze 5,000 litres of air – an amount that would take the space of an elephant at normal pressure – into a tank that will fit on the bike. This much compressed air could cause an explosion if involved in a collision so Dick and Jem must develop proper safety measures. The biggest test will be getting the air-propelled motorbike to pass government inspection.

Down on the farm in rural England, Dick and Jem must tame a fuel-guzzling monster by turning cow manure into natural gas. Farmer Andy’s grain dryer uses 90 litres of gas an hour to dry 10 tonnes of grain. Drinking over 450 kilograms of fuel for one crop, this gas guzzler burns as much fossil fuel in one ten hour day as a family car might in an entire year. Cashing in on the farm’s hefty amount of cow dung, Dick and Jem hatch a plan to harvest the methane found naturally in cow manure. But storing a vast amount of this explosive gas is dangerous and Dick and Jem must work out a solution to keep their latest eco-friendly experiment from blowing up – literally. The pair cuts down an old 2-ton oil tank and submerge it in a custom-built massive water bath to minimize the explosion risk. But, when the methane tank isn’t producing enough energy to heat the dryer, Dick and Jem must think creatively to come up with a quick fix.

In Water War, Dick and Jem must make England’s most remote youth hostel completely energy self-sufficient. With the only reliable energy source miles away, the pair must use only the natural resources found in the valley to help power this hostel. But where will Dick and Jem find enough energy to generate enough electricity to keep the hostel up and running? Setting out with two very different game plans, Dick looks to generate energy from a local stream while Jem searches for enough wind power to create a high-powered wind turbine. Jem must create wind turbine blades that are each just over one metre long, and perfectly aerodynamic and identical. With Jem’s wind turbine almost complete, Dick must haul 27 reels of heavy-duty fire hose up the mountain to trap power from a waterfall that is nearly one kilometre away from the hostel. By week’s end, they have built a fully functioning and de-mountable Wind Turbine – and a compact Cross Flow Water Turbine. But, will either eco-friendly solution generate enough electricity to keep the Black Sail hostel open?

In an area known as the ‘frying pan of Spain’, Dick and Jem head to Andalucía in their eco-friendly workshop to help one farmer pump enough water from his well to sustain his cattle. Dick and Jem devise radically different solutions to farmer Jesus’ water problem – Dick harnesses wind power using a traditional windmill pump while Jem pushes his inventive boundaries to the limit with a Stirling engine. But, ambitious Jem may have bitten off more than he can chew, by also volunteering to build a massive solar cooker to make enough paella for an entire crowd at the annual Andalucían festival. While Dick sails along creating his windmill, Jem struggles to pull together a Stirling engine, which uses temperature differences inside a cylinder to move a piston, which can then be used to power machinery – in Jem’s case working a pump to draw water from the well. Will Jem’s ingenuity pay off or will the tried and true windmill pump win out? And, more importantly, can either of these two engineers cook well enough to please the audience with their traditional Spanish paella?

Invited by former Olympic sailor Alberto Sonino, Dick and Jem travel to Venice, Italy, to help save one of the world’s most beautiful cities from the damaging effect of boat pollution. With 40,000 boats commuting around Venice, exhaust from Europe’s largest car-free zone mixes with water and creates an acid that is eroding away the historic buildings’ precious facades. With a stunning U.S. $30,000 boat provided by Alberto, Dick and Jem get to work on creating an electric-powered motor. To power the engine using a clean power resource, Dick and Jem outfit the water taxi with solar panels that re-charge the motor’s batteries. To test the design, Alberto creates a marathon course that will take at least two hours, encountering open water, bridges, tight canals, traffic and a meeting with the head of Venice’s waterways. Satisfied with the result, Dick and Jem next challenge themselves to build an electric speed boat, using a specialized go-kart motor. Will this boat sink or swim?

Dick Strawbridge and Jem Stansfield bring their eco-engineering talents to County Clare, on the west coast of Ireland in an attempt to harness the power of the ocean waves. It has been calculated that the sea around Ireland could contain enough wave energy to supply over eighteen times the country's entire electrical demand; however, the destructive nature of waves make them a difficult energy source to tap. Taking on the Atlantic Ocean, Dick and Jem want to generate green electricity for Irish surfers Keith and Rosy who tour the coast looking for the best waves in their travel trailer, the 'surf shack'. With a few days and some simple resources, Dick and Jem work with the surfers on a test project that will put the waves to work. Using practical experiments and demonstrations, the Planet Mechanics devise a huge wave energy converter with some surplus sewer pipe and steel and bolt it to a concrete pier. Can the wave converter survive the ravages of the sea? And can it generate electricity required to power the 'surf shack'?

Dick Strawbridge and Jem Stansfield, travel to Liverpool, England, to try to find a solution to Britain’s affordable housing crisis. They have been invited by Professor Kronenburg, Head of Architecture at Liverpool University to help turn cheap and plentiful shipping containers into the economical and sustainable homes of the future. There are enough shipping containers in existence to circle the Earth more than twice if laid end-to-end. In just six days, with a budget of U.S $20,000, Dick, Jem and six architecture students try to transform three 6-metre metal shipping containers into a habitable home. The heat and hot water come from a wood burning stove and thermal store, power for the ultra-efficient LED lights comes from solar panels and the electricity for a house computer comes from an old gym exercise bike! The Planet Mechanic’s can-do approach and eco-expertise combined with Professor Kronenburg’s design input illustrates that a solution to a major social problem is within our grasp.

In this episode, they modified a pick-up truck to run on gases emitted by burning wood.