- More on tidal power - Better biofuels - UK fuel duty rise to fight climate change - The truth becomes more inconvenient
More on tidal power
Following last week’s mention of the Severn barrage, the project now has the blessing of the Sustainable Development Commission, the influential body chaired by Jonathan Porritt. The blessing, however, is conditional. First, the SDC only supports the scheme if other wetland habitats are developed to provide feeding grounds for birds displaced by the barrage, which seems entirely sensible. Second, the Commission says that the scheme should be held in public ownership, to assure long-term sustainability (whatever that means).
They also argue that lower interest rates would be available for a publicly-owned scheme and that this would reduce the cost of electricity generated. This may simply betray the left-leaning values of some senior environmentalists, who seem to think that private industry cannot be trusted to work to high standards of environmental protection. In practice, there are good and bad examples from both sectors: it is the underlying regulatory framework and its enforcement which is the key issue.
However, other environmental groups such as WWF and the RSPB do not agree with the SDC. In their view, the scheme is misjudged and could instead be replaced by an alternative tidal lagoon project. The SDC, in turn, say that such an approach is unproven. That does not mean they should be dismissed. The concept is to build two concentric dams enclosing a two-part artificial lagoon in an area of high tidal flow. Water would flow in and out of the lagoon via the outer dam, and a controlled flow can also be maintained in and out of the inner lagoon. Mounting turbines in the dam walls, as for conventional hydro-power, could provide a fairly steady rate of electricity generation.
This is in contrast to the proposed barrage scheme, which would only generate power at certain parts of the tidal cycle, albeit that the output would still be far more reliable than from wind farms. The environmental impact of the tidal lagoon proposal would be much less, since the tides in the estuary would remain relatively unchanged. Of course, despite the apparent attractions, there would still be problems, not least of which would be rapid silting up of the lagoon, requiring constant dredging. However, similar problems would beset the Severn barrage.
A further option exists which does not seem to have hit the headlines. This is the Alderney Tidal Power project, a scheme which would see power generated from turbines on the seabed, with a likely rather small environmental impact. Despite this, the potential generation capacity is large, as the Channel Islands are in an area of high tidal flow. Power can also easily be transmitted by cable to neighbouring France, and thereby to the UK or anywhere else with international inter-connections. The first arrays are to be put on the seabed off Alderney next year, well before any work will have started on the Severn estuary scheme.
The message is that there are other options for the partial replacement of fossil fuels by alternative sources of energy. Our future energy security is likely to be based on a mix of old, new and evolving technologies, which will inevitably change with time.
In a similar vein, we should note that the story of biofuels still has a long way to develop. Despite its many drawbacks, grain-derived ethanol production has increased enormously in the last year or two. Bio-diesel has shown the same trend. Although the impact of oil palm estates has given rise to some concern, this still represents a useful alternative fuel with high energy density and significant carbon reduction. Nevertheless, continued growth is limited by the availability of vegetable oil supplies without having too great an impact on the human food market.
The most promising route towards biofuels taking a significant part of the market is to use waste biomass – straw, for example – or wood as the feedstock. There are a number of companies actively working in this area, but breaking down cellulosic materials quickly and cheaply is a challenge. Given the ability to modify micro-organisms and enzymes, this looks to be a soluble problem, although the economic competitiveness is not guaranteed.
But arguably as important as the feedstock is the product. The Economist recently published an interesting review of the possibilities (Ethanol, schmethanol; 29th September). The best that is becoming commercial so far is bio-butanol, and alcohols of increasing chain length offer significant improvements in energy density. But a number of groups (including Craig Venter’s Synthetic Genomics, seemingly always at the cutting edge of new technologies) are moving way beyond that. Their aim is to tailor bacteria to produce anything from synthetic crude oil to specific molecules such as isoprenoids.
Such developments hold the promise of genuinely being competitive with petrol and diesel. But, of course, by the time they are ready for the market, who knows what else might be available. The hydrogen economy might be upon us (powered by the tides, nuclear fission or perhaps even wind). All-electric cars may be the answer. Virtual reality may have reached the stage of development where we simply don’t feel the need to travel as much. It would be a brave person who bet on the likely scenario by mid-century.
UKfuel duty rise to fight climate change
British motorists, already paying more for petrol (and much more for diesel) than almost anywhere else in the world, are now being charged an extra two pence or so per litre for their fuel. The government’s stated intention is to encourage greater use of (also very expensive) public transport. All the indications are that this simply does not work. People use the form of transport which suits them best (often the car) and just grumble about the cost. Pretending that higher taxes really alter behaviour, rather than just fill government coffers, is hypocritical.
To make matters worse, the latest announcement tries to sweeten the pill by claiming that the tax increase will reduce carbon dioxide emissions and help the fight against climate change. In so doing, they doubtless hope to make the tax rise more acceptable to an environmentally-aware electorate. Unfortunately, for the vast majority, this will just increase already high levels of cynicism.
The truth becomes more inconvenient
Although the final judgement in the case challenging the use of “An Inconvenient Truth” as a factual teaching aid in English schools has not yet been delivered, the High Court has this week given some strong leads on what this will be. Mr Justice Burton has said that the film does promote “partisan political views”. Despite this, it may still be shown to schoolchildren as long as teachers follow guidelines to ensure that what is actually opinion is not presented as fact.
The full judgement – which will surely be highly embarrassing for the government – will be delivered next week.