The average cost of a roof mounted wind turbine is around Â£2,000 which will also need to be maintained (The Energy Savings Trust estimate that this could cost Â£100 to Â£200 per year). Find our list of roof mounted turbine manufacturers here.
You can substitute vegetable oil, cup for cup, for shortening. Using oil versus shortening will change the texture of baked goods. The shortening, being a solid fat, will add more air to the batter when beaten in, giving the end product more of a cakey structure rather than the more dense structure oil will give. Ultimate Baking Secrets Revealed.
Start with a cake, muffin or cookie recipe. (Stick with butter or shortening for pie crusts). Try substituting one-fourth or half the butter with oil. And don't substitute the same amount: try two thirds to three fourths as much oil. In other words, to replace 4 tablespoons of butter, experiment with a scant 3 tablespoons of oil.