So, how's our race between consumption and production coming along? Adding both shallow and deep offshore wind to the production stack, the green stack has a lead. Something I'd like you to notice about this race, though, is this contrast: how easy it is to toss a bigger log on the consumption fire, and how difficult it is to grow the production stack. As I write this paragraph, I'm feeling a little cold, so I step over to my thermostat and turn it up. It's so simple for me to consume an extra 30 kWh per day. But squeezing an extra 30 kWh per day per person from renewables requires an industrialization of the environment so large it is hard to imagine.
To create 48 kWh per day of offshore wind per person in the UK would require 60 million tons of concrete and steel - one ton per person. Annual world steel production is about 1200 million tons, which is 0.2 tons per person in the world. During the second world war, American shipyards built 2751 Liberty ships, each containing 7000 tons of steel - that's a total of 19 million tons of steel, or 0.1 tons per American. So the building of 60 million tons of wind turbines is not off the scale of achievability; but don't kid yourself into thinking that it's easy. Making this many windmills is as big a feat as building the Liberty ships.
For comparison, to make 48 kWh per day of nuclear power per person in the UK would require 8 million tons of steel and 0.14 million tons of concrete. We can also compare the 60 million tons of offshore wind hardware that we're trying to imagine with the existing fossil-fuel hardware already sitting in and around the North Sea (figure 10.4). In 1997, 200 installations and 7000 km of pipelines in the UK waters of the North Sea contained 8 million tons of steel and concrete. The newly built Langeled gas pipeline from Norway to Britain, which will convey gas with a power of 25 GW (10kWh/d/p), used another 1 million tons of steel and 1 million tons of concrete (figure 10.5).
The UK government announced on 10th December 2007 that it would permit the creation of 33 GW of offshore wind capacity (which would deliver on average 10 GW to the UK, or 4.4 kWh per day per person), a plan branded "pie in the sky" by some in the wind industry. Let's run with a round figure of 4 kWh per day per person. This is one quarter of my
Deep offshore wind: 32 kWh/d
Shallow offshore wind: 16 kWh/d
Biomass: food, biofuel, wood, waste incin'n, landfill gas: 24 kWh/d
Solar heating: 13 kWh/d
Solar heating: 13 kWh/d
shallow 16 kWh per day per person. To obtain this average power requires roughly 10000 "3MW" wind turbines like those in figure 10.1. (They have a capacity of "3 MW" but on average they deliver 1MW. I pop quotes round "3 MW" to indicate that this is a capacity, a peak power.)
What would this "33 GW"' of power cost to erect? Well, the "90 MW" Kentish Flats farm cost £105 million, so "33 GW" would cost about £33 billion. One way to clarify this £33 billion cost of offshore wind delivering 4kWh/d per person is to share it among the UK population; that comes out to £550 per person. This is a much better deal, incidentally, than microturbines. A roof-mounted microturbine currently costs about £1500 and, even at a very optimistic windspeed of 6m/s, delivers only 1.6kWh/d. In reality, in a typical urban location in England, such microturbines deliver 0.2 kWh per day.
Another bottleneck constraining the planting of wind turbines is the special ships required. To erect 10000 wind turbines ("33 GW") over a period of 10 years would require roughly 50 jack-up barges. These cost £60 million each, so an extra capital investment of £3 billion would be required. Not a show-stopper compared with the £33bn price tag already quoted, but the need for jack-up barges is certainly a detail that requires some forward planning.
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Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable. The usage of renewable energy sources is very important when considering the sustainability of the existing energy usage of the world. While there is currently an abundance of non-renewable energy sources, such as nuclear fuels, these energy sources are depleting. In addition to being a non-renewable supply, the non-renewable energy sources release emissions into the air, which has an adverse effect on the environment.