Around 26,000 people have passed through the Abu Dhabi National Exhibition Centre during the past week, attracted by the presence of some of the largest and most innovative green (and not so green) companies on the planet exhibiting at the annual World Future Energy Summit.

Here are five key lessons for delegates at the summit, plus one warning.

The UAE is very serious about renewable energy

Many countries in the region have rather half-heartedly supported the idea of shifting away from the fossil fuels that have provided their major income stream for decades – just look at Saudi Arabia demanding compensation in case the UN's Green Climate Fund impinges on its profits.

But the UAE, which is already developing one of the world's premier eco-cities in the form of the high profile Masdar City, is clearly attempting to move beyond the lip-service to environmental issues paid by some of its neighbours.

"The UAE wants to reinforce its strong position as an energy exporter by leading in renewable energy," Dr Sultan Ahmed Al Jaber, chief executive of Masdar, Abu Dhabi's green energy firm, told the summit. "We want to guarantee out position worldwide by providing clean solutions."

The plan is clear: "We are not an oil and gas exporter, but an energy exporter, and that's what we want to stay".

Countries finally seem to be waking up to the green opportunity

Namely that going green is big business – this may seem obvious to supporters of the green economy, but it is easy to forget that in many people's minds "green" is an additional expense.

That representatives from major economies such as China, Germany and Japan have been joined by smaller nations such as Sweden, Belgium and Serbia shows just how seriously countries are taking green growth. And the presence of considerable star power in the form of Chinese Premier Wen Jiabao, South Korean PM Kim Hwang-sik and several Emirati leaders, reflects the increasing importance renewable energy has in emerging economies.

Add UN Chief Ban Ki-moon and Christiana Figueres to the frankly mind-boggling stands hosted by Masdar, Siemens, GE, Mitsubishi, and Vestas and you have a real life demonstration of the market potential analysts have been forecasting.

Perhaps equally telling is the lack of any major UK government presence to back up the sterling efforts of UKTI. Lord Howell of Guildford is in attendance, you'll be pleased to know. No, us neither.

We might just be doomed

IEA chief economist Fatih Birol has been leading the charge on this one, warning that the world will soon be locked into a trajectory towards a six degrees temperature rise, three times what scientists estimate will be needed to prevent the worst effects of climate change.

We've already used 85 per cent of our emissions for a two degrees rise, Birol warned, so unless we cease building factories, power plants and roads, we really are going to need an energy revolution to stop potentially catastrophic temperature increases.

Away from the keynote speakers, side-panels are equally gloomy. Developers warn of tough times ahead, whether because of the financial crisis, cuts to renewable energy payments, or the continuation of enormous subsidies for fossil fuels.

However, the bright spot has been the huge capacity for innovation and the genuine belief that the climate challenge can be met with technology that is already available today.

Britain is leading the way on innovation

You name it, someone here has stuck solar on it. We've had Bertrand Piccard from SolarImpulse, the solar powered plane, the PlanetSolar boat has docked, and a number of cars on display either have banks of solar panels or are powered by solar-derived electricity.

So hats off to UK design company Pauley, which has raised the bar with the Solar Cucumber, a floating desalinisation device that uses solar power and reverse osmosis to separate salt from water. Designed to bring fresh water to coastal communities, the Cucumber self-cleans, provides water at source, and anchoring a load together would create an artificial reef for marine life to thrive.

Meanwhile, Apple Green homes are showing off a house that is so effectively insulated and powered by onsite energy sources that its running costs could be less than £400 a year. Social housing providers in Portland Orgeon, Brazil and New Zealand have all expressed interest, while a £100,000 version could solve the private housing crisis by allowing buyers to use the feed-in payments generated by solar panels on the roof as a deposit. Alex Salmond is very impressed, we hear.

Speaking of which...

Scotland has already left the union

If the stands at WFES are anything to go by, anyway. The Great Britain stand is almost matched in size by a notably separate Scotland stand, which Alex Salmond manned for a period. On Tuesday Salmond cemented a partnership with Masdar, which the rest of the UK is not involved in. Some work for Lord Howell to do there.