Renew Extra Weekly

There is a lot of energy in the seas, as we remember each Winter when storms do major damage. We are learning how to harvest some of it. Wave and tidal power are often grouped together, although they are based on very different energy sources. Waves are created by the motion of winds over the seas, so waves are really stored wind energy, whereas tides are due to the gravitational pull of the moon and the lesser pull of the more remote sun on the sea.  Wave and tidal power have both been seen as promising sources of renewable energy , but so far progress has been limited, especially in the case of wave energy. It has proved hard to extract power form the sometimes very chaotic interface between air and water.  There have been some spectacular prototype wave system failures during storms and the technology is still struggling to get to scale around the world.   However, there is still much enthusiasm and hope for the future, as well as some success, especially with sm...

Carbon dioxide removal systems, taking carbon dioxide gas out of the atmosphere, are touted as techno-fixes for global warming, but in practice they can sometimes put more green house gases into the air net than they take out, a recent study claims.  Carbon capture and storage (CCS) is perhaps the most familiar of the carbon removal options. With CCS, the CO2 produced by coal- or gas-fired power stations is collected and then stored, although, so far, most of the few systems that have been built simply use it for enhanced oil recovery (EOR)- squeezing more oil out of near empty oil wells. In that case, when the oil is burnt, you get more CO2 back again. Some Direct Air Capture (DAC) systems have been built with a storage option, but the proportion of CO2 in the atmosphere is much lower than that in power station exhausts, and DAC use a lot of energy to extract CO2 from it: so we are no further forward if this is fossil energy, and not much further forward if this is renewable energ...

Heat pumps run like refrigerators in reverse. Instead of pumping heat out of sealed box, they pump heat from outside a building into it. And crucially they use electricity to do this very efficiently, much more so that just by using the electricity direct for heating.   The UK government is keen for all home owners to move over to using heat pumps. However, only 0.8% of UK homes have a heat pump at present. Last year just 30,000 heat pumps were installed in Britain. In contrast, according to Andrew Warren from the British Energy Efficiency Federation, around 1.6 million new condensing gas boilers were put in. We are going the wrong way. According to the Committee on Climate Change, 19 million heat pumps will need to be installed by 2050 to reach net zero emissions, and hybrid heat pumps (with gas boiler back up) will need to be widely used by 2035. But the UK Energy Research Centre recently suggested that, on its current trajectory, it will take the UK 700 years to transition ...

The fallout from last Decembers Energy White Paper included a claim from the contrarian Global Warming Policy Foundation (GWPF) that system costs for a high renewables zero carbon future had been down played. It said they would in fact be higher than the social cost of carbon. That in turn relied on close reading of an appendix to the White Paper on modelling UK electricity supply , which itself also has some very odd things to say: it seems to see nuclear (and carbon capture) as low cost: ‘low-cost solutions at low carbon intensities can only be achieved with a combination of new nuclear and gas CCUS’. However, it says that the use of hydrogen makes it more flexible, and it admits that ‘it is technically possible for higher levels of hydrogen-fired generation to also replace nuclear and gas CCUS’, although it adds that ‘this is dependent on the quantity and cost of hydrogen available for generating electricity’. Quite a range of views then, turning mainly on costs- these still being ...

Wind and solar technologies use renewable, naturally replenished, resources to make energy. However, as has increasingly become recognized , the materials needed to build these systems, and their associated energy stores, are not renewable and have to be extracted from the ground, with, often, major environmental damage occurring. And some may become increasingly scarce.    Certainly the shift to renewable energy requires a mix of metals, such as copper, cobalt, nickel, rare earths, lithium and silver, some of which have only previously been mined in small amounts. Under an expanding renewables scenario, demand for these metals could rise dramatically, and require new sources of primary and recycled metals.  A recent Earthworks review noted that, on the basis of a global scenario with renewables supplying two-thirds of electricity by 2050, as well as batteries for electric passenger cars, commercial vehicles, buses and stationary storage, ‘demand from renewable energy ...