On paper, California has the perfect ingredients for the next big investment craze – green energy. With a never-ending supply of sunshine, some of the world's cleverest brains and most sophisticated venture capital community, the Silicon Valley culture which brought the world the technological revolution is unsurprisingly leading the field in planet-saving innovations.
Yet this week, Britain's top inventors arrived, determined to do the impossible – and sell California everything from solar panels to power supplies for their gadgets.
The plucky British inventors, with ideas ranging from a new type of low-power hand-dryer to a shipping container that use bugs to "eat" waste food and turn it into energy, are part of a government initiative to try to bring the best of Britain's inventions to the world.
The 16 Clean and Cool Mission companies have spent the week networking with some of Silicon Valley's top venture capital firms and technology giants in an attempt to woo investors and find customers.
Christophe Williams, the founder and managing director of Naked Energy, has perhaps the toughest job – selling solar panels developed on an industrial estate in Guilford to California.
His firm has a unique design which combines traditional solar panels with a water-heating element – all housed in a tube which can be placed on the roof of an average home.
"The support network from the UK has made our lives so much easier and facilitated so many introductions during the week," he claimed, and his company has so far secured meetings with venture capital firms and potential customers.
"We've really had the red carpet rolled out wherever we have been, which maximises our chances of success," he added.
Organised by UK Trade and Investment, the Technology Strategy Board and British entrepreneur Oli Barrett, the group is one of three missions organised each year, and brings firms to the heart of Silicon Valley, where 40 per cent of the world's funding deals for "cleantech" firms are signed.
The Technology Strategy Board hopes the mission could lead to major investments in Britain, and help the UK become a world leader in the sector, bringing both investment and jobs.
"Our mission is to make UK business more successful through innovation, and part of that is making it into a business," said Richard Miller, the head of sustainability from the Technology Strategy Board.
The 16 firms selected to join the mission from hundreds of applicants, have endured a gruelling week of networking events and pitches to Silicon Valley's biggest names.
"We're always keen to help businesses develop, and it's a focused week for these firms – we get them to talk to loads and loads of people," Mr Miller admitted. "We find people actually develop their idea, and some even change their business model over the course of the week.
"We first came two years ago, and one firm was set up by two firms on the bus to the airport – the conversation between the firms is incredibly valuable," he said.
The companies attending say that they have been overwhelmed by the response, with many having had dozens of offers from investors and potential orders.
They have been shepherded through a series of meeting with venture capitalists and customers, with many admitting they were astonished by the reception they got.
"Silicon Valley is a supermarket for start-up firms, and it's great to have a navigator through that," said Simon Davis of Moixa, one of the16 firms.
"We're hoping to find investors and partners for trials, and it has already proved very successful with a lot of interest," he said.
UK technology that could turn the world green
SEaB Energy, Southampton
What it does: Convert unwanted food into energy. Bacteria consume the waste, and emit a cocktail of digestive gases. The MuckBuster then filters the gas to obtain methane, which is run through a combined heat and power unit to provide electricity and heat for buildings or hot water. The whole system fits into a 40-foot shipping container for easy delivery, installation and distribution, and costs around 95,000.
"We're talking to large supermarket chains, who can put waste food in and use it to chill food," said chief executive Sandra Sassow. "We can also do remote village power generation, disaster recovery and even work with restaurants – although we did find in the food sector they hated the name MuckBuster, so we had to rename it the MB400."
Moixa Energy, London
What it does: From the firm that invented the USB rechargable battery, Primrose Hill-based firm Moixa plans to replace the power adapters for everything from LED lighting to laptops with a simple USB cable instead. The founder Simon Daniel has already built a home server that uses solar panels to store energy for the system, meaning that you can recharge your gadgets, power your lighting and recharge your phone – all by using green energy and without having to use bulky, inefficient power supply.
"We want to transform the world by enabling everything to be powered by universal USB sockets – we are ahead of what's happening in the US, and hope we can stay there," said Mr Daniel.
Smart solar panels
Naked Energy, Guildford
What it does: A combination electricity-generating photovoltaic cell and hot-water-generating solar thermal panel in one. The panels, which are long tubes, combine two of the most popular forms of green energy in one. Expected to be on the market later this year, the inventors have been working with Imperial College to perfect the design, and hope to see them in offices, factories and homes.
"It's a hybrid product where we produce hot water and electricity incredibly efficiently – by combining them, we can make the solar panels work more efficiently, and create 46 per cent more electricity than our competitors," said Christophe Williams, the founder and managing director. "We're generating more energy per square metre than any other panel – which makes a difference in places like London."
Zeta LED, Bicester
What it does: The Lifebulb consumes 10 watts of power and puts out as much light as a standard, 60-watt, incandescent lightbulb. However, unlike other LED lights, it uses a neat design to include air vents in the design, making it cheaper to manufacture and giving it a unique look. Because the design does not require either a heatsink or a glass covering, the Lifebulb is expected to be far cheaper than competitor's products when it goes on sale later this year. The design is also the same shape as a "normal" lightbulb, meaning that it can be used everywhere.
"The first bulbs are being made by hand and we will sell them for £19.99 next month, but once we get a licensing deal with a manufacturer we reckon the price will fall to £15 and then at scale you could get the price below £10 a bulb," said Anthony McClellan, commercial director at Zeta Controls.
Greening the desert
Seawater Greenhouse, London
What it does: The surprise hit of the week, Seawater Greenhouse inventor Charlie Paton says he can make the desert bloom with seawater, corrugated cardboard and wind. The company has created a porous wall with a cardboard core that essentially functions like a humidifier for greenhouses. The wall is inserted into the structure of a greenhouse and serves as one of the walls. When wind blows, pores in the wall's surface channel water molecules carried by the wind into ducts in the cardboard. The droplets condense into a mist and then mist serves to both water the plants in the greenhouse and also lower the ambient temperature, which helps in plant growth.