Wednesday, May 21, 2003

Stupid Visions

Maree Howard's column on Scoop this morning (Electricity 'Solution' Devoid Of Imagination) lambasts the government for showing a "lack of imagination, vision and lateral thinking", and presents an alternative solution to the power crisis: we should pump water over the Southern Alps from the West Coast to fill the dams, powering the pumps with "the very electricity generated from that water". Furthermore, we should "recycle the water back to the lakes after it has been used to generate electricity at Benmore, or any other hydro station, instead of letting it run to waste."

Readers who didn't sleep through fourth-form science will notice that this violates the law of Conservation of Energy. Pumping the water back up to the dam will take exactly as much energy as we would get out of it. More, in fact, since neither pumps nor dam are 100% efficient. Likewise, pumping water from the West Coast is a losing proposition if it comes from lower than the dam (and if we take the inefficiencies of our pumps and dam into account, probably from substantially higher as well). TANSTAAFL, and all that.

Howard's second suggestion - that we look at upgrading the capacity of the Cook Strait Cable - is also a loser, but for different reasons. Yes, transmission to the north is limited by the cable. But imagine what would happen if it wasn't (or if we had a bigger one): electricity-hungry Auckland would simply be able to drain the South Island hydro lakes that much faster, and we'd be even worse off in a dry year than we are now. The problem is not a throughput bottleneck, it's that there isn't enough generation capacity in the North Island - and the only way to fix it is to build more power stations.