Global warning

Sitting on BA219 to Denver bound for the Eighth World Renewal Energy Congress I tried to get my head around the concept of the ‘carbon economy’. Could it really be appropriate to leave the planet’s future to a quasi-economic trading system? And what is a kilogram of carbon worth? £264 is the ‘cost to society’ according to the government but what is the market value? How many lumps of coal would I need to buy a Budweiser and what reaction would I get from the barman if I tried? As these thoughts continued to spin round my head in the first plenary session of the Congress disaster struck. The very first speaker started talking about the ‘hydrogen economy’. Have I missed something? How much is hydrogen worth then, and what would I use to pay for my Budweiser – water?

Putting these worries to the back of my mind I set about looking for the key learning themes that would emerge over the week. The title of the Congress, which took place between 29 August and 3 September, was Linking the world with renewable energy and this was a truly international gathering with 1000 delegates representing over 90 countries. The various technical streams included all the renewables, as you would expect, with much enthusiasm for photovoltaics (we celebrated 50 years since the design of the first solar cell), wind, wave, hydrogen cells and biomass. The low energy architecture sessions to which I contributed provided opportunities for the practising engineer to learn from experiences gained in various climates and cultures, and there were sessions on policy, poverty and gender.

Being an energy rich western man I am ashamed to say that I had never really considered the relationship between energy and gender. Wendy Annecke, an expert on gender issues from South Africa soon put me right on that one. As she travels the world talking to women in developing countries she repeatedly hears two messages, she informed us. The first is that ‘women are on the up’ – great, I’m with you on that one – and the second is that ‘men are useless’….Mmm thanks. For many women in the developing world the consequences of energy poverty are a heavy burden, quite literally. It is they that collect and carry the wood for fuel, and then sit in a smoke filled environment as they prepare the family meal on an open stove.

Spending a week in the delightful modern city of Denver may sound like fun, and indeed it was, but I missed the family. I was reminded of this by Alex Zahnd of Kathmandu University in Nepal. Speaking passionately about the benefits that solar powered technology is bringing to remote mountain villages he mentioned that children are not named there until they reach the age of five, because half will have died by that age. For these people an artificial light is like magic and top of their wish list is a hygienic latrine and clean drinking water. The irony is that it is in these communities that renewable energy is making the biggest difference. As an American asked ruefully on seeing the solar panel linked to an led light cluster that the Nepalese mountain dwellers are enjoying: “When will this technology be coming here?”

Renewable energy comes in two categories: large scale and building-integrated. We heard much about the commitments of various countries to increasing the proportion of grid power to come from renewable sources. Our own Energy Minister, Stephen Timms, put in an appearance and reiterated the message from the Energy White Paper: 10% renewable generation by 2010, and what amounts to a further 10% increase per decade to 2050. In the US there is no federal commitment but the government is encouraging individual states to set targets, arguing that a ‘one size fits all’ policy is not appropriate in such a large and diverse country. But the barriers are still huge. A leading figure in the US supply industry was invited to speak to us after the gala dinner. He stated that it is easier for his company to get a licence to build a nuclear plant than for a hydro-electric plant. This is a joke, though unfortunately not the type that we had hoped to hear from our after dinner speaker.

Of more direct interest to CIBSE members will be the progress of building integrated technologies. Here the story is more patchy. Solar thermal is becoming a mature technology while photovoltaics are well understood if still relatively inefficient and costly (particularly for a sun barren British climate). Capital costs have been falling and will continue to do so. With conventional fuel costs increasing there was optimism that the crossover into commercial viability on a large scale may not be too far away. Wind power technologies are well advanced but due to the variability of the supply do not lend themselves so well to localised applications. Hydrogen fuel cells on the other hand are being seen as a possible building integrated application even on a domestic scale, possibly using the family hydrogen fuel car as a power source for the home. The technological challenges that the generation, storage and usage of hydrogen represent remain significant. The hydrogen economy is evidently a long term aim.

As a delegate from India reminded us, the most environmentally friendly unit of energy is the one that we don’t use. For the time being energy efficiency remains the most powerful weapon that engineers can bring to bear in their day-to-day work. This was brought home to me in a very direct way. Bumping into the director of engineering for the conference hotel (a Londoner!) gave me the opportunity to blag myself a tour of the back of house facilities and the story was an all too familiar one. Oversizing means that they often have to superimpose a load onto the centrifugal chillers just to keep them operating in a stable manner. The fan coil units to the 615 guest rooms are meant to operate as a two pipe changeover system but the controls in the rooms don’t work properly so the electric back-up heaters have been employed for heating for the last three years. The domestic water and central air handling plant heating loads are served from the city’s steam district heating system but guess what, they are literally throwing the condensate energy down the drain. No wonder the manholes are hot.

So let’s look for opportunities to employ building integrated renewables, but the lesson has to be that energy efficiency still comes first. This means designing energy efficient building envelopes with simple low intensity services that actually work and looking hard at the operation of existing buildings to optimise their performance. There are a lot of easy wins out there.

Andrew Pettifer is a director with consulting engineers Gifford.