subota, 23. listopada 2010.
SOLAR SERDAR going ZERO on CARBON
The generally accepted view among scientists is that cuts in greenhouse-gas emissions of more than 60% are needed if we are to stabilise atmospheric concentrations of the gases that cause global warming. Let's start with that assumption and go further later. The average British household puts six tonnes of carbon dioxide emissions each year into the thin atmosphere of our planet, and 10 tonnes if we include our travel. Ten tonnes of heat-trapping gas. Enough to fill two Olympic-size swimming pools. Enough, combined with everyone else's emissions around the world, to slowly cook the planet, tip the climate into frenzied chaos, wipe out economic growth, devastate ecosystems in the oceans and onland, create hundreds of millions of refugees, and place at risk a liveable future for our children. On this, George Monbiot and I agree, no doubt.
If we want to avoid wrecking our planet, we have to cut from 10 tonnes to four or less. Each and every household needs to do this. If energy-intensive households can do it, industrial, commercial, and public buildings can certainly follow. If we Brits can lead the way (eco-Churchill, where art thou?), then surely the rest of the world can follow. (At least, in principle).
Saving the first two of the four tonnes is like falling off a log. What's more, you make a little money by saving them. By enacting basic energy-saving measures, the Energy Saving Trust has shown that our average household can save two tonnes of carbon dioxide and set aside around £250 towards the holiday rail fares. There are lots of options. In un-insulated homes, 30% of the heat lost escapes through the walls. And stated another way, if you don't have cavity wall insulation, you end up paying up to 25% more on your bills.
Pouring insulating foam between the double layers that make up most external walls built since 1930 takes a contractor around 3 hours, and thereafter saves you between £100-120 per year. Solid external walls can also be insulated by applying decorative weatherproofing and internal walls by applying insulation boards or infilled wooden battens.
Another 30% of heat-loss is through the roof. Adding a 27 cm layer of insulation in your loft is the simplest and cheapest of all the efficiency measures, and can save you £140-£170 a year on fuel bills. A further 20% or so can escape from poorly insulated window frames and single-glazed windows. Double glazing can cut heating bills by £60-70 per year.
The same principle applies, on a smaller scale, to all the other ways heat can escape. Doors, windows and floorboards can all be simply draught-proofed with sealant. All these savings are calculated at last year's fuel prices. This year, with soaring gas prices, the savings will be higher. Next year and into the future: place your bets on how much higher still.
With the first two tonnes of carbon dioxide comprehensively banked, and a lot of inflation-proofing built into our household, let us move to tonne number three. Here we might have to shell out a little investment in the future on a longer payback. Most appliances these days are fitted with an EU energy label that shows where the appliance fits on a scale from A (most efficient) to G (most energy guzzling). Many also have an "energy saving recommended" label certified by the Energy Saving Trust (EST). Washing machines that are EST certified use over 30% less energy than typical old ones. Certified dishwashers will use around 40% less. Certified fridges and freezers use over 60% less. Certified lightbulbs use even less still. The bottom line is this. Every light and appliance in the building must be A-graded.
I know how easy it is to do this in a home. A few years ago, I moved into a terraced house in Richmond. The previous occupant had consumed electricity at more than the national average per household of around 3,500 kiloWatt hours (kWh) per year. I changed every light and appliance in the house. As result, almost overnight, I cut my consumption by more than two thirds, to just over 1,000 kWh per year.
I didn't cheat. I lived there full time, I allowed my daughter to use her energy-vampire of a hairdryer every day (okay, grudgingly), my Chardonnay was just as chilled as anyone else's in Richmond, and I drank more than my average share of it. The high-efficiency appliances I bought weren't that noticeably different in price from the inefficient ones I avoided. (Okay, maybe I'm on shaky ground here. So forget the holiday railfare contribution and invest it in Grade A appliances). My electricity-consumed cost me just a third of what I would have paid had I been a "normal" consumer. With every 1,000 kWh offsetting around half a tonne of carbon dioxide, I saved over a tonne - as I say - more or less overnight. Goodness me, we have cut three tonnes out of four already. And we haven't even started talking about energy SUPPLY yet.
A family of technologies, the renewable micro-generators, can generate green electricity and heating right where you need it at home, or at the workplace. You can generate electricity with solar photovoltaic (PV) panels or rooftiles, small wind turbines, or small combined heat-and-power (CHP) units whether driven by biomass or natural gas. (I'm not a zealot. A little gas is okay). You can also generate hot water and heating with solar thermal, biomass boilers, ground-sourced heat pumps, or micro-CHP powered by gas or biomass.
I have personal experience of this family of technologies, especially solar photovoltaics. I run a company making £15million a year selling them. (So I have a vested interest. So the nuclear and fossil lobbies don't?). I lived in the UK's first PV rooftile home, the Richmond terraced house mentioned above. I easily generated the electricity I needed with a small 1.6 kilowatt PV rooftile array, and in fact exported a net 14% to the national grid. I generated more than 1,100 kWh per year. I saved around half that fourth tonne of carbon dioxide, in other words. Had I installed a small amount of any other renewable micro-generator - a single solar thermal water heater, for example - I could have saved well over a tonne.
So there you have it. Four out of six tonnes of carbon dioxide easily saved. If every household in the UK and abroad did the same in percentage terms, atmospheric greenhouse-gas concentrations could be stabilised, if the majority of scientists are right. (All this assumes, of course, that you don't spoil it all by having a Ryanair frequent flier card, or fail to offset your emissions if you have to fly somewhere).
The other thing George Monbiot rejects is the notion that we can go the whole hog, and run the entire energy economy on renewables-and-efficiency at some point in the future. I am sure we can. Those fifth and sixth tonnes can go, and most of the four tonnes used in transport to boot. Note that nowhere in the thoughts above have I mentioned the "big" renewables: wind, biomass, wave, tidal, hydro and so on.More info at email@example.com
Together with some colleagues on the UK Government's Renewables Advisory Board (in case you wonder, they don't listen to us), I spent a bit of time recently wondering what we could do if we really tried. We concluded that the renewables family (big and micro), if hooked up effectively in strategic harness with efficient-energy technologies, could provide all the UK's energy at some point in the future, and/or - renewable family by renewable family - large slices of that demand. Wind power onshore and offshore could provide around 14% of expected national energy demand, or 47TWh per year, if just 17 GW could be installed by 2020. Marine technologies, on conservative assumptions, might add another 2 GW. Projected UK bioenergy resources for 2050 could reasonably be expected to provide 10-20 TWh pa, depending on electricity price. This could increase to 50 TWh pa with effective use of currently more expensive crops. Alternatively the same biomass resources could contribute significantly to the heat or transport demand sectors.
I have not talked yet about timing, or improved technologies that exist but are not yet in the market. We have some time to go low on carbon, we do not have to do it overnight. I agree with George that 60% cuts by 2050, the UK government target, is way too late. But neither do we have to achieve deep cuts overnight.
Let us not forget that, and imagine instead what we could do if we mobilised as though for war. Let's also not forget the wave of innovation that is underway on low carbon technologies. I see this first hand in my day job. Efficiencies will improve dramatically, and prices will fall steeply, while as the costs of gas and the other fossil fuels go right on rising. George's snipes at solar photovoltaics are rooted in the wrong century, in this respect. (I'll explore that further in my solarcentury blog). Technology is responsible for many of the world's ills, but it can also help enormously in addressing global problems.
We could run the world on renewables and efficiency. All we need is real microcosms like the ones my company provide (vested interest that we are), willingness to think outside the box, and effective political leadership. The solidarity of environmentalists like George would, of course, help.
Jeremy Leggett for
Croatian Renewable Energy Center