From Andreas Firewolf
Helen Knight’s article suggesting methane as a solution to the energy crisis read like an advertisement from the gas industry (12 June, p 44).
The article mentions nothing about the amount of energy that it takes to free the methane from the rock where it is held. The cost of extracting and burning coal is about 0.64 kilograms of CO2 per kilowatt-hour of energy we get from it. The cost of burning natural gas is about 0.45 kilograms. So if extracting methane requires more than 30 per cent of the energy it yields, using coal would be cheaper and better for the environment.
As to our present energy sources, coal-fired electricity-generating plants don’t have to be “dirty”. Imagine small coal plants, operated by a family of farmers, surrounded by algae tanks and greenhouses that use the waste heat and CO2: this would greatly reduce the CO2 footprint of the generating plant.
It is also wrong to dismiss renewables like solar and wind energy as “unpredictable”. Any excess output can be used to convert water to hydrogen, which can then be stored, and used to generate electricity in a fuel cell when extra power is needed. Solar cells get cheaper by the minute: last year the cost fell below the $1-per-watt mark. We are at the beginning of a solar revolution.
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From Jerome Ravetz, Institute for Science, Innovation and Society, University of Oxford
It is reassuring to read that industry is trying to reduce the environmental footprint of shale-well drilling and hydraulic fracturing, or hydrofracking.
As Kara Cusolito wrote recently in The Nation (21 June), former vice-president Dick Cheney’s “Halliburton loophole” now means that there is no federal supervision of hydrofracking beyond a voluntary agreement with the companies. Inspection is left to individual states, and can be sketchy. The town of Dimock, Pennsylvania, has already suffered from widespread and diverse forms of contamination.
Since hydrofracking depends on passing large quantities of water and chemicals through the rock, it would seem prudent to assume that the industry needs stronger regulation than it has hitherto had.
Oxford, UK
Finsterwolde, The Netherlands
